mirror of https://github.com/docker/docs.git
1987 lines
48 KiB
Markdown
1987 lines
48 KiB
Markdown
---
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description: Compose file reference
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keywords: fig, composition, compose version 2, docker
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title: Compose file version 2 reference
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toc_max: 4
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toc_min: 1
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---
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{% include compose-eol.md %}
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## Reference and guidelines
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These topics describe version 2 of the Compose file format.
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## Compose and Docker compatibility matrix
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There are several versions of the Compose file format – 1, 2, 2.x, and 3.x. The
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table below is a quick look. For full details on what each version includes and
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how to upgrade, see **[About versions and upgrading](compose-versioning.md)**.
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{% include content/compose-matrix.md %}
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## Service configuration reference
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The Compose file is a [YAML](https://yaml.org) file defining
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[services](#service-configuration-reference),
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[networks](#network-configuration-reference) and
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[volumes](#volume-configuration-reference).
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The default path for a Compose file is `./docker-compose.yml`.
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> **Tip**: You can use either a `.yml` or `.yaml` extension for this file.
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> They both work.
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A service definition contains configuration that is applied to each
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container started for that service, much like passing command-line parameters to
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`docker run`. Likewise, network and volume definitions are analogous to
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`docker network create` and `docker volume create`.
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As with `docker run`, options specified in the Dockerfile, such as `CMD`,
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`EXPOSE`, `VOLUME`, `ENV`, are respected by default - you don't need to
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specify them again in `docker-compose.yml`.
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You can use environment variables in configuration values with a Bash-like
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`${VARIABLE}` syntax - see [variable substitution](#variable-substitution) for
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full details.
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This section contains a list of all configuration options supported by a service
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definition in version 2.
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### blkio_config
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A set of configuration options to set block IO limits for this service.
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version: "{{ site.compose_file_v2 }}"
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services:
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foo:
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image: busybox
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blkio_config:
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weight: 300
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weight_device:
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- path: /dev/sda
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weight: 400
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device_read_bps:
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- path: /dev/sdb
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rate: '12mb'
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device_read_iops:
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- path: /dev/sdb
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rate: 120
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device_write_bps:
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- path: /dev/sdb
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rate: '1024k'
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device_write_iops:
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- path: /dev/sdb
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rate: 30
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#### device_read_bps, device_write_bps
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Set a limit in bytes per second for read / write operations on a given device.
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Each item in the list must have two keys:
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* `path`, defining the symbolic path to the affected device
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* `rate`, either as an integer value representing the number of bytes or as
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a string expressing a [byte value](#specifying-byte-values).
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#### device_read_iops, device_write_iops
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Set a limit in operations per second for read / write operations on a given
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device. Each item in the list must have two keys:
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* `path`, defining the symbolic path to the affected device
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* `rate`, as an integer value representing the permitted number of operations
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per second.
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#### weight
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Modify the proportion of bandwidth allocated to this service relative to other
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services. Takes an integer value between 10 and 1000, with 500 being the
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default.
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#### weight_device
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Fine-tune bandwidth allocation by device. Each item in the list must have
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two keys:
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* `path`, defining the symbolic path to the affected device
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* `weight`, an integer value between 10 and 1000
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### build
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Configuration options that are applied at build time.
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`build` can be specified either as a string containing a path to the build
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context:
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```yaml
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version: "{{ site.compose_file_v2 }}"
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services:
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webapp:
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build: ./dir
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```
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Or, as an object with the path specified under [context](#context) and
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optionally [Dockerfile](#dockerfile) and [args](#args):
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```yaml
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version: "{{ site.compose_file_v2 }}"
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services:
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webapp:
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build:
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context: ./dir
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dockerfile: Dockerfile-alternate
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args:
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buildno: 1
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```
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If you specify `image` as well as `build`, then Compose names the built image
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with the `webapp` and optional `tag` specified in `image`:
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```yaml
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build: ./dir
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image: webapp:tag
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```
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This results in an image named `webapp` and tagged `tag`, built from `./dir`.
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#### context
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> Added in [version 2.0](compose-versioning.md#version-2) file format.
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Either a path to a directory containing a Dockerfile, or a url to a git repository.
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When the value supplied is a relative path, it is interpreted as relative to the
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location of the Compose file. This directory is also the build context that is
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sent to the Docker daemon.
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Compose builds and tags it with a generated name, and uses that image
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thereafter.
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```yaml
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build:
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context: ./dir
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```
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#### dockerfile
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Alternate Dockerfile.
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Compose uses an alternate file to build with. A build path must also be
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specified.
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```yaml
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build:
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context: .
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dockerfile: Dockerfile-alternate
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```
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#### args
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> Added in [version 2.0](compose-versioning.md#version-2) file format.
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Add build arguments, which are environment variables accessible only during the
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build process.
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First, specify the arguments in your Dockerfile:
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```dockerfile
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# syntax=docker/dockerfile:1
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ARG buildno
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ARG gitcommithash
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RUN echo "Build number: $buildno"
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RUN echo "Based on commit: $gitcommithash"
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```
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Then specify the arguments under the `build` key. You can pass a mapping
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or a list:
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```yaml
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build:
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context: .
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args:
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buildno: 1
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gitcommithash: cdc3b19
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```
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```yaml
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build:
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context: .
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args:
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- buildno=1
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- gitcommithash=cdc3b19
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```
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> Scope of build-args
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>
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> In your Dockerfile, if you specify `ARG` before the `FROM` instruction,
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> `ARG` is not available in the build instructions under `FROM`.
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> If you need an argument to be available in both places, also specify it under
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> the `FROM` instruction. Refer to the [understand how ARGS and FROM interact](../../engine/reference/builder.md#understand-how-arg-and-from-interact)
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> section in the documentation for usage details.
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You can omit the value when specifying a build argument, in which case its value
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at build time is the value in the environment where Compose is running.
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```yaml
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args:
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- buildno
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- gitcommithash
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```
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> Tip when using boolean values
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>
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> YAML boolean values (`"true"`, `"false"`, `"yes"`, `"no"`, `"on"`,
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> `"off"`) must be enclosed in quotes, so that the parser interprets them as
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> strings.
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#### cache_from
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> Added in [version 2.2](compose-versioning.md#version-22) file format
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A list of images that the engine uses for cache resolution.
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```yaml
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build:
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context: .
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cache_from:
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- alpine:latest
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- corp/web_app:3.14
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```
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#### extra_hosts
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Add hostname mappings at build-time. Use the same values as the docker client `--add-host` parameter.
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```yaml
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extra_hosts:
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- "somehost:162.242.195.82"
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- "otherhost:50.31.209.229"
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```
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An entry with the ip address and hostname is created in `/etc/hosts` inside containers for this build, e.g:
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```console
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162.242.195.82 somehost
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50.31.209.229 otherhost
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```
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#### isolation
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> Added in [version 2.1](compose-versioning.md#version-21) file format.
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Specify a build’s container isolation technology. On Linux, the only supported value
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is `default`. On Windows, acceptable values are `default`, `process` and
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`hyperv`. Refer to the
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[Docker Engine docs](../../engine/reference/commandline/run.md#isolation)
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for details.
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If unspecified, Compose will use the `isolation` value found in the service's definition
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to determine the value to use for builds.
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#### labels
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> Added in [version 2.1](compose-versioning.md#version-21) file format
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Add metadata to the resulting image using [Docker labels](../../config/labels-custom-metadata.md).
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You can use either an array or a dictionary.
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It's recommended that you use reverse-DNS notation to prevent your labels from
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conflicting with those used by other software.
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```yaml
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build:
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context: .
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labels:
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com.example.description: "Accounting webapp"
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com.example.department: "Finance"
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com.example.label-with-empty-value: ""
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```
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```yaml
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build:
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context: .
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labels:
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- "com.example.description=Accounting webapp"
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- "com.example.department=Finance"
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- "com.example.label-with-empty-value"
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```
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#### network
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> Added in [version 2.2](compose-versioning.md#version-22) file format
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Set the network containers connect to for the `RUN` instructions during
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build.
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```yaml
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build:
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context: .
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network: host
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```
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```yaml
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build:
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context: .
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network: custom_network_1
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```
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Use `none` to disable networking during build:
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```yaml
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build:
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context: .
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network: none
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```
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#### shm_size
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> Added in [version 2.3](compose-versioning.md#version-23) file format
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Set the size of the `/dev/shm` partition for this build's containers. Specify
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as an integer value representing the number of bytes or as a string expressing
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a [byte value](#specifying-byte-values).
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```yaml
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build:
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context: .
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shm_size: '2gb'
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```
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```yaml
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build:
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context: .
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shm_size: 10000000
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```
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#### target
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> Added in [version 2.3](compose-versioning.md#version-23) file format
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Build the specified stage as defined inside the `Dockerfile`. See the
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[multi-stage build docs](../../build/building/multi-stage.md) for
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details.
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```yaml
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build:
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context: .
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target: prod
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```
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### cap_add, cap_drop
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Add or drop container capabilities.
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See `man 7 capabilities` for a full list.
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```yaml
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cap_add:
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- ALL
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cap_drop:
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- NET_ADMIN
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- SYS_ADMIN
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```
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### cgroup_parent
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Specify an optional parent cgroup for the container.
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```yaml
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cgroup_parent: m-executor-abcd
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```
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### command
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Override the default command.
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```yaml
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command: bundle exec thin -p 3000
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```
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The command can also be a list, in a manner similar to
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[dockerfile](../../engine/reference/builder.md#cmd):
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```yaml
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command: ["bundle", "exec", "thin", "-p", "3000"]
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```
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### container_name
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Specify a custom container name, rather than a generated default name.
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```yaml
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container_name: my-web-container
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```
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Because Docker container names must be unique, you cannot scale a service beyond
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1 container if you have specified a custom name. Attempting to do so results in
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an error.
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### cpu_rt_runtime, cpu_rt_period
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> Added in [version 2.2](compose-versioning.md#version-22) file format
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Configure CPU allocation parameters using the Docker daemon realtime scheduler.
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```yaml
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cpu_rt_runtime: '400ms'
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cpu_rt_period: '1400us'
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```
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Integer values will use microseconds as units:
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```yaml
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cpu_rt_runtime: 95000
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cpu_rt_period: 11000
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```
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### device_cgroup_rules
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> Added in [version 2.3](compose-versioning.md#version-23) file format.
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Add rules to the cgroup allowed devices list.
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```yaml
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device_cgroup_rules:
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- 'c 1:3 mr'
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- 'a 7:* rmw'
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```
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### devices
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List of device mappings. Uses the same format as the `--device` docker
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client create option.
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```yaml
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devices:
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- "/dev/ttyUSB0:/dev/ttyUSB0"
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```
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### depends_on
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> Added in [version 2.0](compose-versioning.md#version-2) file format.
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Express dependency between services. Service dependencies cause the following
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behaviors:
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- `docker-compose up` starts services in dependency order. In the following
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example, `db` and `redis` are started before `web`.
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- `docker-compose up SERVICE` automatically includes `SERVICE`'s
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dependencies. In the example below, `docker-compose up web` also
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creates and starts `db` and `redis`.
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- `docker-compose stop` stops services in dependency order. In the following
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example, `web` is stopped before `db` and `redis`.
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Simple example:
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```yaml
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version: "{{ site.compose_file_v2 }}"
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services:
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web:
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build: .
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depends_on:
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- db
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- redis
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redis:
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image: redis
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db:
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image: postgres
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```
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> **Note**
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>
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> `depends_on` does not wait for `db` and `redis` to be "ready" before
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> starting `web` - only until they have been started. If you need to wait
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> for a service to be ready, see [Controlling startup order](../startup-order.md)
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> for more on this problem and strategies for solving it.
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> Added in [version 2.1](compose-versioning.md#version-21) file format.
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A healthcheck indicates that you want a dependency to wait
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for another container to be "healthy" (as indicated by a successful state from
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the healthcheck) before starting.
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Example:
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```yaml
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version: "{{ site.compose_file_v2 }}"
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services:
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web:
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build: .
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depends_on:
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db:
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condition: service_healthy
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redis:
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condition: service_started
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redis:
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image: redis
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db:
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image: postgres
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healthcheck:
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test: "exit 0"
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```
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In the above example, Compose waits for the `redis` service to be started
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(legacy behavior) and the `db` service to be healthy before starting `web`.
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See the [healthcheck section](#healthcheck) for complementary
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information.
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### dns
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Custom DNS servers. Can be a single value or a list.
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```yaml
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dns: 8.8.8.8
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```
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```yaml
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dns:
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- 8.8.8.8
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- 9.9.9.9
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```
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### dns_opt
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List of custom DNS options to be added to the container's `resolv.conf` file.
|
||
|
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```yaml
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dns_opt:
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- use-vc
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- no-tld-query
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```
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### dns_search
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||
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Custom DNS search domains. Can be a single value or a list.
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||
|
||
```yaml
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dns_search: example.com
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```
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||
|
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```yaml
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dns_search:
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- dc1.example.com
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- dc2.example.com
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```
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### entrypoint
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||
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Override the default entrypoint.
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||
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```yaml
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entrypoint: /code/entrypoint.sh
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```
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||
|
||
The entrypoint can also be a list, in a manner similar to
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[dockerfile](../../engine/reference/builder.md#entrypoint):
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||
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||
```yaml
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entrypoint: ["php", "-d", "memory_limit=-1", "vendor/bin/phpunit"]
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```
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||
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||
> **Note**
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||
>
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||
> Setting `entrypoint` both overrides any default entrypoint set on the service's
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||
> image with the `ENTRYPOINT` Dockerfile instruction, *and* clears out any default
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||
> command on the image - meaning that if there's a `CMD` instruction in the
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||
> Dockerfile, it is ignored.
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||
|
||
### env_file
|
||
|
||
Add environment variables from a file. Can be a single value or a list.
|
||
|
||
If you have specified a Compose file with `docker-compose -f FILE`, paths in
|
||
`env_file` are relative to the directory that file is in.
|
||
|
||
Environment variables declared in the [environment](#environment) section
|
||
_override_ these values – this holds true even if those values are
|
||
empty or undefined.
|
||
|
||
```yaml
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||
env_file: .env
|
||
```
|
||
|
||
```yaml
|
||
env_file:
|
||
- ./common.env
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||
- ./apps/web.env
|
||
- /opt/runtime_opts.env
|
||
```
|
||
|
||
Compose expects each line in an env file to be in `VAR=VAL` format. Lines
|
||
beginning with `#` are treated as comments and are ignored. Blank lines are
|
||
also ignored.
|
||
|
||
```console
|
||
# Set Rails/Rack environment
|
||
RACK_ENV=development
|
||
```
|
||
|
||
> **Note**
|
||
>
|
||
> If your service specifies a [build](#build) option, variables defined in
|
||
> environment files are _not_ automatically visible during the build. Use
|
||
> the [args](#args) sub-option of `build` to define build-time environment
|
||
> variables.
|
||
|
||
The value of `VAL` is used as is and not modified at all. For example if the
|
||
value is surrounded by quotes (as is often the case of shell variables), the
|
||
quotes are included in the value passed to Compose.
|
||
|
||
Keep in mind that _the order of files in the list is significant in determining
|
||
the value assigned to a variable that shows up more than once_. The files in the
|
||
list are processed from the top down. For the same variable specified in file
|
||
`a.env` and assigned a different value in file `b.env`, if `b.env` is
|
||
listed below (after), then the value from `b.env` stands. For example, given the
|
||
following declaration in `docker-compose.yml`:
|
||
|
||
```yaml
|
||
services:
|
||
some-service:
|
||
env_file:
|
||
- a.env
|
||
- b.env
|
||
```
|
||
|
||
And the following files:
|
||
|
||
```console
|
||
# a.env
|
||
VAR=1
|
||
```
|
||
|
||
and
|
||
|
||
```console
|
||
# b.env
|
||
VAR=hello
|
||
```
|
||
|
||
`$VAR` is `hello`.
|
||
|
||
### environment
|
||
|
||
Add environment variables. You can use either an array or a dictionary. Any
|
||
boolean values (true, false, yes, no) need to be enclosed in quotes to ensure
|
||
they are not converted to True or False by the YML parser.
|
||
|
||
Environment variables with only a key are resolved to their values on the
|
||
machine Compose is running on, which can be helpful for secret or host-specific values.
|
||
|
||
```yaml
|
||
environment:
|
||
RACK_ENV: development
|
||
SHOW: 'true'
|
||
SESSION_SECRET:
|
||
```
|
||
|
||
```yaml
|
||
environment:
|
||
- RACK_ENV=development
|
||
- SHOW=true
|
||
- SESSION_SECRET
|
||
```
|
||
|
||
> **Note**
|
||
>
|
||
> If your service specifies a [build](#build) option, variables defined in
|
||
> `environment` are _not_ automatically visible during the build. Use the
|
||
> [args](#args) sub-option of `build` to define build-time environment
|
||
> variables.
|
||
|
||
### expose
|
||
|
||
Expose ports without publishing them to the host machine - they'll only be
|
||
accessible to linked services. Only the internal port can be specified.
|
||
|
||
```yaml
|
||
expose:
|
||
- "3000"
|
||
- "8000"
|
||
```
|
||
|
||
### extends
|
||
|
||
Extend another service, in the current file or another, optionally overriding
|
||
configuration.
|
||
|
||
You can use `extends` on any service together with other configuration keys.
|
||
The `extends` value must be a dictionary defined with a required `service`
|
||
and an optional `file` key.
|
||
|
||
```yaml
|
||
extends:
|
||
file: common.yml
|
||
service: webapp
|
||
```
|
||
|
||
The `service` is the name of the service being extended, for example
|
||
`web` or `database`. The `file` is the location of a Compose configuration
|
||
file defining that service.
|
||
|
||
If you omit the `file` Compose looks for the service configuration in the
|
||
current file. The `file` value can be an absolute or relative path. If you
|
||
specify a relative path, Compose treats it as relative to the location of the
|
||
current file.
|
||
|
||
You can extend a service that itself extends another. You can extend
|
||
indefinitely. Compose does not support circular references and `docker-compose`
|
||
returns an error if it encounters one.
|
||
|
||
For more on `extends`, see the
|
||
[the extends documentation](../extends.md#extending-services).
|
||
|
||
### external_links
|
||
|
||
Link to containers started outside this `docker-compose.yml` or even outside of
|
||
Compose, especially for containers that provide shared or common services.
|
||
`external_links` follow semantics similar to the legacy option `links` when
|
||
specifying both the container name and the link alias (`CONTAINER:ALIAS`).
|
||
|
||
```yaml
|
||
external_links:
|
||
- redis_1
|
||
- project_db_1:mysql
|
||
- project_db_1:postgresql
|
||
```
|
||
|
||
> **Note**
|
||
>
|
||
> If you're using the [version 2 or above file format](compose-versioning.md#version-2),
|
||
> the externally-created containers must be connected to at least one of the same
|
||
> networks as the service that is linking to them. [Links](compose-file-v2.md#links)
|
||
> are a legacy option. We recommend using [networks](#networks) instead.
|
||
|
||
### extra_hosts
|
||
|
||
Add hostname mappings. Use the same values as the docker client `--add-host` parameter.
|
||
|
||
```yaml
|
||
extra_hosts:
|
||
- "somehost:162.242.195.82"
|
||
- "otherhost:50.31.209.229"
|
||
```
|
||
|
||
An entry with the ip address and hostname is created in `/etc/hosts` inside containers for this service, e.g:
|
||
|
||
```console
|
||
162.242.195.82 somehost
|
||
50.31.209.229 otherhost
|
||
```
|
||
|
||
### group_add
|
||
|
||
Specify additional groups (by name or number) which the user inside the
|
||
container should be a member of. Groups must exist in both the container and the
|
||
host system to be added. An example of where this is useful is when multiple
|
||
containers (running as different users) need to all read or write the same
|
||
file on the host system. That file can be owned by a group shared by all the
|
||
containers, and specified in `group_add`. See the
|
||
[Docker documentation](../../engine/reference/run.md#additional-groups) for more
|
||
details.
|
||
|
||
A full example:
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
services:
|
||
myservice:
|
||
image: alpine
|
||
group_add:
|
||
- mail
|
||
```
|
||
|
||
Running `id` inside the created container shows that the user belongs to
|
||
the `mail` group, which would not have been the case if `group_add` were not
|
||
used.
|
||
|
||
### healthcheck
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Configure a check that's run to determine whether or not containers for this
|
||
service are "healthy". See the docs for the
|
||
[HEALTHCHECK Dockerfile instruction](../../engine/reference/builder.md#healthcheck)
|
||
for details on how healthchecks work.
|
||
|
||
```yaml
|
||
healthcheck:
|
||
test: ["CMD", "curl", "-f", "http://localhost"]
|
||
interval: 1m30s
|
||
timeout: 10s
|
||
retries: 3
|
||
start_period: 40s
|
||
```
|
||
|
||
`interval`, `timeout` and `start_period` are specified as
|
||
[durations](#specifying-durations).
|
||
|
||
> Added in [version 2.3](compose-versioning.md#version-23) file format.
|
||
>
|
||
> The `start_period` option was added in file format 2.3.
|
||
|
||
`test` must be either a string or a list. If it's a list, the first item must be
|
||
either `NONE`, `CMD` or `CMD-SHELL`. If it's a string, it's equivalent to
|
||
specifying `CMD-SHELL` followed by that string.
|
||
|
||
```yaml
|
||
# Hit the local web app
|
||
test: ["CMD", "curl", "-f", "http://localhost"]
|
||
```
|
||
|
||
As above, but wrapped in `/bin/sh`. Both forms below are equivalent.
|
||
|
||
```yaml
|
||
test: ["CMD-SHELL", "curl -f http://localhost || exit 1"]
|
||
```
|
||
|
||
```yaml
|
||
test: curl -f https://localhost || exit 1
|
||
```
|
||
|
||
To disable any default healthcheck set by the image, you can use `disable: true`.
|
||
This is equivalent to specifying `test: ["NONE"]`.
|
||
|
||
```yaml
|
||
healthcheck:
|
||
disable: true
|
||
```
|
||
|
||
### image
|
||
|
||
Specify the image to start the container from. Can either be a repository/tag or
|
||
a partial image ID.
|
||
|
||
```yaml
|
||
image: redis
|
||
```
|
||
```yaml
|
||
image: ubuntu:18.04
|
||
```
|
||
```yaml
|
||
image: tutum/influxdb
|
||
```
|
||
```yaml
|
||
image: example-registry.com:4000/postgresql
|
||
```
|
||
```yaml
|
||
image: a4bc65fd
|
||
```
|
||
|
||
If the image does not exist, Compose attempts to pull it, unless you have also
|
||
specified [build](#build), in which case it builds it using the specified
|
||
options and tags it with the specified tag.
|
||
|
||
### init
|
||
|
||
> Added in [version 2.2](compose-versioning.md#version-22) file format.
|
||
|
||
Run an init inside the container that forwards signals and reaps processes.
|
||
Set this option to `true` to enable this feature for the service.
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
services:
|
||
web:
|
||
image: alpine:latest
|
||
init: true
|
||
```
|
||
|
||
> The default init binary that is used is [Tini](https://github.com/krallin/tini),
|
||
> and is installed in `/usr/libexec/docker-init` on the daemon host. You can
|
||
> configure the daemon to use a custom init binary through the
|
||
> [`init-path` configuration option](../../engine/reference/commandline/dockerd.md#daemon-configuration-file).
|
||
|
||
### isolation
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Specify a container’s isolation technology. On Linux, the only supported value
|
||
is `default`. On Windows, acceptable values are `default`, `process` and
|
||
`hyperv`. Refer to the
|
||
[Docker Engine docs](../../engine/reference/commandline/run.md#isolation)
|
||
for details.
|
||
|
||
### labels
|
||
|
||
Add metadata to containers using [Docker labels](../../config/labels-custom-metadata.md). You can use either an array or a dictionary.
|
||
|
||
It's recommended that you use reverse-DNS notation to prevent your labels from conflicting with those used by other software.
|
||
|
||
```yaml
|
||
labels:
|
||
com.example.description: "Accounting webapp"
|
||
com.example.department: "Finance"
|
||
com.example.label-with-empty-value: ""
|
||
```
|
||
|
||
```yaml
|
||
labels:
|
||
- "com.example.description=Accounting webapp"
|
||
- "com.example.department=Finance"
|
||
- "com.example.label-with-empty-value"
|
||
```
|
||
|
||
### links
|
||
|
||
Link to containers in another service. Either specify both the service name and
|
||
a link alias (`"SERVICE:ALIAS"`), or just the service name.
|
||
|
||
> Links are a legacy option. We recommend using
|
||
> [networks](#networks) instead.
|
||
|
||
```yaml
|
||
web:
|
||
links:
|
||
- "db"
|
||
- "db:database"
|
||
- "redis"
|
||
```
|
||
|
||
Containers for the linked service are reachable at a hostname identical to
|
||
the alias, or the service name if no alias was specified.
|
||
|
||
Links are not required to enable services to communicate - by default,
|
||
any service can reach any other service at that service’s name. (See also, the
|
||
[Links topic in Networking in Compose](../networking.md#link-containers).)
|
||
|
||
Links also express dependency between services in the same way as
|
||
[depends_on](#depends_on), so they determine the order of service startup.
|
||
|
||
> **Note**
|
||
>
|
||
> If you define both links and [networks](#networks), services with
|
||
> links between them must share at least one network in common to
|
||
> communicate. We recommend using networks instead.
|
||
|
||
### logging
|
||
|
||
Logging configuration for the service.
|
||
|
||
```yaml
|
||
logging:
|
||
driver: syslog
|
||
options:
|
||
syslog-address: "tcp://192.168.0.42:123"
|
||
```
|
||
|
||
The `driver` name specifies a logging driver for the service's
|
||
containers, as with the ``--log-driver`` option for docker run
|
||
([documented here](../../config/containers/logging/configure.md)).
|
||
|
||
The default value is json-file.
|
||
|
||
```yaml
|
||
driver: "json-file"
|
||
```
|
||
```yaml
|
||
driver: "syslog"
|
||
```
|
||
```yaml
|
||
driver: "none"
|
||
```
|
||
|
||
> **Note**
|
||
>
|
||
> Only the `json-file` and `journald` drivers make the logs available directly
|
||
> from `docker-compose up` and `docker-compose logs`. Using any other driver
|
||
> does not print any logs.
|
||
|
||
Specify logging options for the logging driver with the ``options`` key, as with the ``--log-opt`` option for `docker run`.
|
||
|
||
Logging options are key-value pairs. An example of `syslog` options:
|
||
|
||
```yaml
|
||
driver: "syslog"
|
||
options:
|
||
syslog-address: "tcp://192.168.0.42:123"
|
||
```
|
||
|
||
### network_mode
|
||
|
||
> Changed in [version 2](compose-versioning.md#version-2) file format.
|
||
|
||
Network mode. Use the same values as the docker client `--network` parameter, plus
|
||
the special form `service:[service name]`.
|
||
|
||
```yaml
|
||
network_mode: "bridge"
|
||
```
|
||
```yaml
|
||
network_mode: "host"
|
||
```
|
||
```yaml
|
||
network_mode: "none"
|
||
```
|
||
```yaml
|
||
network_mode: "service:[service name]"
|
||
```
|
||
```yaml
|
||
network_mode: "container:[container name/id]"
|
||
```
|
||
|
||
### networks
|
||
|
||
> Changed in [version 2](compose-versioning.md#version-2) file format.
|
||
|
||
Networks to join, referencing entries under the
|
||
[top-level `networks` key](#network-configuration-reference).
|
||
|
||
```yaml
|
||
services:
|
||
some-service:
|
||
networks:
|
||
- some-network
|
||
- other-network
|
||
```
|
||
|
||
#### aliases
|
||
|
||
Aliases (alternative hostnames) for this service on the network. Other containers on the same network can use either the service name or this alias to connect to one of the service's containers.
|
||
|
||
Since `aliases` is network-scoped, the same service can have different aliases on different networks.
|
||
|
||
> **Note**
|
||
>
|
||
> A network-wide alias can be shared by multiple containers, and even by multiple
|
||
> services. If it is, then exactly which container the name resolves to is not
|
||
> guaranteed.
|
||
|
||
The general format is shown here.
|
||
|
||
```yaml
|
||
services:
|
||
some-service:
|
||
networks:
|
||
some-network:
|
||
aliases:
|
||
- alias1
|
||
- alias3
|
||
other-network:
|
||
aliases:
|
||
- alias2
|
||
```
|
||
|
||
In the example below, three services are provided (`web`, `worker`, and `db`),
|
||
along with two networks (`new` and `legacy`). The `db` service is reachable at
|
||
the hostname `db` or `database` on the `new` network, and at `db` or `mysql` on
|
||
the `legacy` network.
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
|
||
services:
|
||
web:
|
||
image: "nginx:alpine"
|
||
networks:
|
||
- new
|
||
|
||
worker:
|
||
image: "my-worker-image:latest"
|
||
networks:
|
||
- legacy
|
||
|
||
db:
|
||
image: mysql
|
||
networks:
|
||
new:
|
||
aliases:
|
||
- database
|
||
legacy:
|
||
aliases:
|
||
- mysql
|
||
|
||
networks:
|
||
new:
|
||
legacy:
|
||
```
|
||
|
||
#### ipv4_address, ipv6_address
|
||
|
||
Specify a static IP address for containers for this service when joining the network.
|
||
|
||
The corresponding network configuration in the
|
||
[top-level networks section](#network-configuration-reference) must have an
|
||
`ipam` block with subnet and gateway configurations covering each static address.
|
||
|
||
> If IPv6 addressing is desired, the [`enable_ipv6`](#enable_ipv6) option must be set.
|
||
|
||
An example:
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
|
||
services:
|
||
app:
|
||
image: busybox
|
||
command: ifconfig
|
||
networks:
|
||
app_net:
|
||
ipv4_address: 172.16.238.10
|
||
ipv6_address: 2001:3984:3989::10
|
||
|
||
networks:
|
||
app_net:
|
||
driver: bridge
|
||
enable_ipv6: true
|
||
ipam:
|
||
driver: default
|
||
config:
|
||
- subnet: 172.16.238.0/24
|
||
gateway: 172.16.238.1
|
||
- subnet: 2001:3984:3989::/64
|
||
gateway: 2001:3984:3989::1
|
||
```
|
||
|
||
#### link_local_ips
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Specify a list of link-local IPs. Link-local IPs are special IPs which belong
|
||
to a well known subnet and are purely managed by the operator, usually
|
||
dependent on the architecture where they are deployed. Therefore they are not
|
||
managed by docker (IPAM driver).
|
||
|
||
Example usage:
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
services:
|
||
app:
|
||
image: busybox
|
||
command: top
|
||
networks:
|
||
app_net:
|
||
link_local_ips:
|
||
- 57.123.22.11
|
||
- 57.123.22.13
|
||
networks:
|
||
app_net:
|
||
driver: bridge
|
||
```
|
||
|
||
#### priority
|
||
|
||
Specify a priority to indicate in which order Compose should connect the
|
||
service's containers to its networks. If unspecified, the default value is `0`.
|
||
|
||
In the following example, the `app` service connects to `app_net_1` first
|
||
as it has the highest priority. It then connects to `app_net_3`, then
|
||
`app_net_2`, which uses the default priority value of `0`.
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
services:
|
||
app:
|
||
image: busybox
|
||
command: top
|
||
networks:
|
||
app_net_1:
|
||
priority: 1000
|
||
app_net_2:
|
||
|
||
app_net_3:
|
||
priority: 100
|
||
networks:
|
||
app_net_1:
|
||
app_net_2:
|
||
app_net_3:
|
||
```
|
||
|
||
> **Note**
|
||
>
|
||
> If multiple networks have the same priority, the connection order is undefined.
|
||
|
||
### pid
|
||
|
||
```yaml
|
||
pid: "host"
|
||
```
|
||
```yaml
|
||
pid: "container:custom_container_1"
|
||
```
|
||
```yaml
|
||
pid: "service:foobar"
|
||
```
|
||
|
||
If set to one of the following forms: `container:<container_name>`,
|
||
`service:<service_name>`, the service shares the PID address space of the
|
||
designated container or service.
|
||
|
||
If set to "host", the service's PID mode is the host PID mode. This turns
|
||
on sharing between container and the host operating system the PID address
|
||
space. Containers launched with this flag can access and manipulate
|
||
other containers in the bare-metal machine's namespace and vice versa.
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
>
|
||
> The `service:` and `container:` forms require [version 2.1](compose-versioning.md#version-21) or above
|
||
|
||
### pids_limit
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Tunes a container's PIDs limit. Set to `-1` for unlimited PIDs.
|
||
|
||
```yaml
|
||
pids_limit: 10
|
||
```
|
||
|
||
### platform
|
||
|
||
> Added in [version 2.4](compose-versioning.md#version-24) file format.
|
||
|
||
Target platform containers for this service will run on, using the
|
||
`os[/arch[/variant]]` syntax, e.g.
|
||
|
||
```yaml
|
||
platform: osx
|
||
```
|
||
```yaml
|
||
platform: windows/amd64
|
||
```
|
||
```yaml
|
||
platform: linux/arm64/v8
|
||
```
|
||
|
||
This parameter determines which version of the image will be pulled and/or
|
||
on which platform the service's build will be performed.
|
||
|
||
### ports
|
||
|
||
Expose ports. Either specify both ports (`HOST:CONTAINER`), or just the container
|
||
port (an ephemeral host port is chosen).
|
||
|
||
> **Note**
|
||
>
|
||
> When mapping ports in the `HOST:CONTAINER` format, you may experience
|
||
> erroneous results when using a container port lower than 60, because YAML
|
||
> parses numbers in the format `xx:yy` as a base-60 value. For this reason,
|
||
> we recommend always explicitly specifying your port mappings as strings.
|
||
|
||
```yaml
|
||
ports:
|
||
- "3000"
|
||
- "3000-3005"
|
||
- "8000:8000"
|
||
- "9090-9091:8080-8081"
|
||
- "49100:22"
|
||
- "127.0.0.1:8001:8001"
|
||
- "127.0.0.1:5000-5010:5000-5010"
|
||
- "6060:6060/udp"
|
||
- "12400-12500:1240"
|
||
```
|
||
|
||
### runtime
|
||
|
||
> Added in [version 2.3](compose-versioning.md#version-23) file format.
|
||
|
||
Specify which runtime to use for the service's containers. Default runtime
|
||
and available runtimes are listed in the output of `docker info`.
|
||
|
||
```yaml
|
||
web:
|
||
image: busybox:latest
|
||
command: true
|
||
runtime: runc
|
||
```
|
||
|
||
### scale
|
||
|
||
> Added in [version 2.2](compose-versioning.md#version-22) file format.
|
||
|
||
Specify the default number of containers to deploy for this service. Whenever
|
||
you run `docker-compose up`, Compose creates or removes containers to match
|
||
the specified number. This value can be overridden using the
|
||
[`--scale`](../../engine/reference/commandline/compose_up.md)
|
||
|
||
```yaml
|
||
web:
|
||
image: busybox:latest
|
||
command: echo 'scaled'
|
||
scale: 3
|
||
```
|
||
|
||
### security_opt
|
||
|
||
Override the default labeling scheme for each container.
|
||
|
||
```yaml
|
||
security_opt:
|
||
- label:user:USER
|
||
- label:role:ROLE
|
||
```
|
||
|
||
### stop_grace_period
|
||
|
||
Specify how long to wait when attempting to stop a container if it doesn't
|
||
handle SIGTERM (or whatever stop signal has been specified with
|
||
[`stop_signal`](#stop_signal)), before sending SIGKILL. Specified
|
||
as a [duration](#specifying-durations).
|
||
|
||
```yaml
|
||
stop_grace_period: 1s
|
||
```
|
||
|
||
```yaml
|
||
stop_grace_period: 1m30s
|
||
```
|
||
|
||
By default, `stop` waits 10 seconds for the container to exit before sending
|
||
SIGKILL.
|
||
|
||
### stop_signal
|
||
|
||
Sets an alternative signal to stop the container. By default `stop` uses
|
||
SIGTERM. Setting an alternative signal using `stop_signal` causes
|
||
`stop` to send that signal instead.
|
||
|
||
```yaml
|
||
stop_signal: SIGUSR1
|
||
```
|
||
|
||
### storage_opt
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Set storage driver options for this service.
|
||
|
||
```yaml
|
||
storage_opt:
|
||
size: '1G'
|
||
```
|
||
|
||
### sysctls
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Kernel parameters to set in the container. You can use either an array or a
|
||
dictionary.
|
||
|
||
```yaml
|
||
sysctls:
|
||
net.core.somaxconn: 1024
|
||
net.ipv4.tcp_syncookies: 0
|
||
```
|
||
|
||
```yaml
|
||
sysctls:
|
||
- net.core.somaxconn=1024
|
||
- net.ipv4.tcp_syncookies=0
|
||
```
|
||
|
||
### tmpfs
|
||
|
||
Mount a temporary file system inside the container. Can be a single value or a list.
|
||
|
||
```yaml
|
||
tmpfs: /run
|
||
```
|
||
|
||
```yaml
|
||
tmpfs:
|
||
- /run
|
||
- /tmp
|
||
```
|
||
|
||
### ulimits
|
||
|
||
Override the default ulimits for a container. You can either specify a single
|
||
limit as an integer or soft/hard limits as a mapping.
|
||
|
||
```yaml
|
||
ulimits:
|
||
nproc: 65535
|
||
nofile:
|
||
soft: 20000
|
||
hard: 40000
|
||
```
|
||
|
||
### userns_mode
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
```yaml
|
||
userns_mode: "host"
|
||
```
|
||
|
||
Disables the user namespace for this service, if Docker daemon is configured with user namespaces.
|
||
See [dockerd](../../engine/security/userns-remap.md#disable-namespace-remapping-for-a-container) for
|
||
more information.
|
||
|
||
### volumes
|
||
|
||
Mount host paths or named volumes. Named volumes need to be specified with the
|
||
[top-level `volumes` key](#volume-configuration-reference).
|
||
|
||
#### Short syntax
|
||
|
||
The short syntax uses the generic `[SOURCE:]TARGET[:MODE]` format, where
|
||
`SOURCE` can be either a host path or volume name. `TARGET` is the container
|
||
path where the volume is mounted. Standard modes are `ro` for read-only
|
||
and `rw` for read-write (default).
|
||
|
||
You can mount a relative path on the host, which expands relative to
|
||
the directory of the Compose configuration file being used. Relative paths
|
||
should always begin with `.` or `..`.
|
||
|
||
```yaml
|
||
volumes:
|
||
# Just specify a path and let the Engine create a volume
|
||
- /var/lib/mysql
|
||
|
||
# Specify an absolute path mapping
|
||
- /opt/data:/var/lib/mysql
|
||
|
||
# Path on the host, relative to the Compose file
|
||
- ./cache:/tmp/cache
|
||
|
||
# User-relative path
|
||
- ~/configs:/etc/configs/:ro
|
||
|
||
# Named volume
|
||
- datavolume:/var/lib/mysql
|
||
```
|
||
|
||
#### Long syntax
|
||
|
||
> Added in [version 2.3](compose-versioning.md#version-23) file format.
|
||
|
||
The long form syntax allows the configuration of additional fields that can't be
|
||
expressed in the short form.
|
||
|
||
- `type`: the mount type `volume`, `bind`, `tmpfs` or `npipe`
|
||
- `source`: the source of the mount, a path on the host for a bind mount, or the
|
||
name of a volume defined in the
|
||
[top-level `volumes` key](#volume-configuration-reference). Not applicable for a tmpfs mount.
|
||
- `target`: the path in the container where the volume is mounted
|
||
- `read_only`: flag to set the volume as read-only
|
||
- `bind`: configure additional bind options
|
||
- `propagation`: the propagation mode used for the bind
|
||
- `volume`: configure additional volume options
|
||
- `nocopy`: flag to disable copying of data from a container when a volume is
|
||
created
|
||
- `tmpfs`: configure additional tmpfs options
|
||
- `size`: the size for the tmpfs mount in bytes
|
||
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
services:
|
||
web:
|
||
image: nginx:alpine
|
||
ports:
|
||
- "80:80"
|
||
volumes:
|
||
- type: volume
|
||
source: mydata
|
||
target: /data
|
||
volume:
|
||
nocopy: true
|
||
- type: bind
|
||
source: ./static
|
||
target: /opt/app/static
|
||
|
||
networks:
|
||
webnet:
|
||
|
||
volumes:
|
||
mydata:
|
||
```
|
||
|
||
> **Note**
|
||
>
|
||
> When creating bind mounts, using the long syntax requires the
|
||
> referenced folder to be created beforehand. Using the short syntax
|
||
> creates the folder on the fly if it doesn't exist.
|
||
> See the [bind mounts documentation](../../storage/bind-mounts.md#differences-between--v-and---mount-behavior)
|
||
> for more information.
|
||
|
||
### volume\_driver
|
||
|
||
Specify a default volume driver to be used for all declared volumes on this
|
||
service.
|
||
|
||
```yaml
|
||
volume_driver: mydriver
|
||
```
|
||
|
||
> **Note**
|
||
>
|
||
> In [version 2 files](compose-versioning.md#version-2), this
|
||
> option only applies to anonymous volumes (those specified in the image,
|
||
> or specified under `volumes` without an explicit named volume or host path).
|
||
> To configure the driver for a named volume, use the `driver` key under the
|
||
> entry in the [top-level `volumes` option](#volume-configuration-reference).
|
||
|
||
|
||
See [Docker Volumes](../../storage/volumes.md) and
|
||
[Volume Plugins](/engine/extend/plugins_volume/) for more information.
|
||
|
||
### volumes_from
|
||
|
||
Mount all of the volumes from another service or container, optionally
|
||
specifying read-only access (``ro``) or read-write (``rw``). If no access level
|
||
is specified, then read-write is used.
|
||
|
||
```yaml
|
||
volumes_from:
|
||
- service_name
|
||
- service_name:ro
|
||
- container:container_name
|
||
- container:container_name:rw
|
||
```
|
||
|
||
> Changed in [version 2](compose-versioning.md#version-2) file format.
|
||
|
||
### restart
|
||
|
||
`no` is the default restart policy, and it doesn't restart a container under any circumstance. When `always` is specified, the container always restarts. The `on-failure` policy restarts a container if the exit code indicates an on-failure error.
|
||
|
||
```yaml
|
||
restart: "no"
|
||
```
|
||
```yaml
|
||
restart: "always"
|
||
```
|
||
```yaml
|
||
restart: "on-failure"
|
||
```
|
||
```yaml
|
||
restart: "unless-stopped"
|
||
```
|
||
|
||
{: id="cpu-and-other-resources"}
|
||
|
||
### cpu_count, cpu_percent, cpu\_shares, cpu\_period, cpu\_quota, cpus, cpuset, domainname, hostname, ipc, mac\_address, mem\_limit, memswap\_limit, mem\_swappiness, mem\_reservation, oom_kill_disable, oom_score_adj, privileged, read\_only, shm\_size, stdin\_open, tty, user, working\_dir
|
||
|
||
Each of these is a single value, analogous to its
|
||
[docker run](../../engine/reference/run.md#runtime-constraints-on-resources) counterpart.
|
||
|
||
> Added in [version 2.2](compose-versioning.md#version-22) file format.
|
||
>
|
||
> The `cpu_count`, `cpu_percent`, and `cpus` options were added in [version 2.2](compose-versioning.md#version-22).
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
>
|
||
> The `oom_kill_disable` and `cpu_period` options were added in [version 2.1](compose-versioning.md#version-21).
|
||
|
||
```yaml
|
||
cpu_count: 2
|
||
cpu_percent: 50
|
||
cpus: 0.5
|
||
cpu_shares: 73
|
||
cpu_quota: 50000
|
||
cpu_period: 20ms
|
||
cpuset: 0,1
|
||
|
||
user: postgresql
|
||
working_dir: /code
|
||
|
||
domainname: foo.com
|
||
hostname: foo
|
||
ipc: host
|
||
mac_address: 02:42:ac:11:65:43
|
||
|
||
mem_limit: 1000000000
|
||
memswap_limit: 2000000000
|
||
mem_reservation: 512m
|
||
privileged: true
|
||
|
||
oom_score_adj: 500
|
||
oom_kill_disable: true
|
||
|
||
read_only: true
|
||
shm_size: 64M
|
||
stdin_open: true
|
||
tty: true
|
||
```
|
||
|
||
<a name="orig-resources"></a>
|
||
|
||
## Specifying durations
|
||
|
||
Some configuration options, such as the `interval` and `timeout` sub-options for
|
||
[`healthcheck`](#healthcheck), accept a duration as a string in a
|
||
format that looks like this:
|
||
|
||
2.5s
|
||
10s
|
||
1m30s
|
||
2h32m
|
||
5h34m56s
|
||
|
||
The supported units are `us`, `ms`, `s`, `m` and `h`.
|
||
|
||
## Specifying byte values
|
||
|
||
Some configuration options, such as the `device_read_bps` sub-option for
|
||
[`blkio_config`](#blkio_config), accept a byte value as a string in a format
|
||
that looks like this:
|
||
|
||
2b
|
||
1024kb
|
||
2048k
|
||
300m
|
||
1gb
|
||
|
||
The supported units are `b`, `k`, `m` and `g`, and their alternative notation `kb`,
|
||
`mb` and `gb`. Decimal values are not supported at this time.
|
||
|
||
## Volume configuration reference
|
||
|
||
While it is possible to declare [volumes](#volumes) on the fly as part of the
|
||
service declaration, this section allows you to create named volumes that can be
|
||
reused across multiple services (without relying on `volumes_from`), and are
|
||
easily retrieved and inspected using the docker command line or API.
|
||
See the [docker volume](../../engine/reference/commandline/volume_create.md)
|
||
subcommand documentation for more information.
|
||
|
||
See [use volumes](../../storage/volumes.md) and [volume plugins](/engine/extend/plugins_volume/)
|
||
for general information on volumes.
|
||
|
||
Here's an example of a two-service setup where a database's data directory is
|
||
shared with another service as a volume so that it can be periodically backed
|
||
up:
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
|
||
services:
|
||
db:
|
||
image: db
|
||
volumes:
|
||
- data-volume:/var/lib/db
|
||
backup:
|
||
image: backup-service
|
||
volumes:
|
||
- data-volume:/var/lib/backup/data
|
||
|
||
volumes:
|
||
data-volume:
|
||
```
|
||
|
||
An entry under the top-level `volumes` key can be empty, in which case it
|
||
uses the default driver configured by the Engine (in most cases, this is the
|
||
`local` driver). Optionally, you can configure it with the following keys:
|
||
|
||
### driver
|
||
|
||
Specify which volume driver should be used for this volume. Defaults to whatever
|
||
driver the Docker Engine has been configured to use, which in most cases is
|
||
`local`. If the driver is not available, the Engine returns an error when
|
||
`docker-compose up` tries to create the volume.
|
||
|
||
```yaml
|
||
driver: foobar
|
||
```
|
||
|
||
### driver_opts
|
||
|
||
Specify a list of options as key-value pairs to pass to the driver for this
|
||
volume. Those options are driver-dependent - consult the driver's
|
||
documentation for more information. Optional.
|
||
|
||
```yaml
|
||
volumes:
|
||
example:
|
||
driver_opts:
|
||
type: "nfs"
|
||
o: "addr=10.40.0.199,nolock,soft,rw"
|
||
device: ":/docker/example"
|
||
```
|
||
|
||
### external
|
||
|
||
If set to `true`, specifies that this volume has been created outside of
|
||
Compose. `docker-compose up` does not attempt to create it, and raises
|
||
an error if it doesn't exist.
|
||
|
||
For version 2.0 of the format, `external` cannot be used in
|
||
conjunction with other volume configuration keys (`driver`, `driver_opts`,
|
||
`labels`). This limitation no longer exists for
|
||
[version 2.1](compose-versioning.md#version-21) and above.
|
||
|
||
In the example below, instead of attempting to create a volume called
|
||
`[projectname]_data`, Compose looks for an existing volume simply
|
||
called `data` and mount it into the `db` service's containers.
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
|
||
services:
|
||
db:
|
||
image: postgres
|
||
volumes:
|
||
- data:/var/lib/postgresql/data
|
||
|
||
volumes:
|
||
data:
|
||
external: true
|
||
```
|
||
|
||
You can also specify the name of the volume separately from the name used to
|
||
refer to it within the Compose file:
|
||
|
||
```yaml
|
||
volumes:
|
||
data:
|
||
external:
|
||
name: actual-name-of-volume
|
||
```
|
||
|
||
> Deprecated in [version 2.1](compose-versioning.md#version-21) file format.
|
||
>
|
||
> external.name was deprecated in version 2.1 file format use `name` instead.
|
||
{: .important }
|
||
|
||
### labels
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Add metadata to containers using
|
||
[Docker labels](../../config/labels-custom-metadata.md). You can use either
|
||
an array or a dictionary.
|
||
|
||
It's recommended that you use reverse-DNS notation to prevent your labels from
|
||
conflicting with those used by other software.
|
||
|
||
```yaml
|
||
labels:
|
||
com.example.description: "Database volume"
|
||
com.example.department: "IT/Ops"
|
||
com.example.label-with-empty-value: ""
|
||
```
|
||
|
||
```yaml
|
||
labels:
|
||
- "com.example.description=Database volume"
|
||
- "com.example.department=IT/Ops"
|
||
- "com.example.label-with-empty-value"
|
||
```
|
||
|
||
### name
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Set a custom name for this volume. The name field can be used to reference
|
||
volumes that contain special characters. The name is used as is
|
||
and will **not** be scoped with the stack name.
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
volumes:
|
||
data:
|
||
name: my-app-data
|
||
```
|
||
|
||
It can also be used in conjunction with the `external` property:
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
volumes:
|
||
data:
|
||
external: true
|
||
name: my-app-data
|
||
```
|
||
|
||
## Network configuration reference
|
||
|
||
The top-level `networks` key lets you specify networks to be created. For a full
|
||
explanation of Compose's use of Docker networking features, see the
|
||
[Networking guide](../networking.md).
|
||
|
||
### driver
|
||
|
||
Specify which driver should be used for this network.
|
||
|
||
The default driver depends on how the Docker Engine you're using is configured,
|
||
but in most instances it is `bridge` on a single host and `overlay` on a
|
||
Swarm.
|
||
|
||
The Docker Engine returns an error if the driver is not available.
|
||
|
||
```yaml
|
||
driver: overlay
|
||
```
|
||
|
||
> Changed in [version 2.1](compose-versioning.md#version-21) file format.
|
||
>
|
||
> Starting with Compose file format 2.1, overlay networks are always created as
|
||
> `attachable`, and this is not configurable. This means that standalone
|
||
> containers can connect to overlay networks.
|
||
|
||
### driver_opts
|
||
|
||
Specify a list of options as key-value pairs to pass to the driver for this
|
||
network. Those options are driver-dependent - consult the driver's
|
||
documentation for more information. Optional.
|
||
|
||
```yaml
|
||
driver_opts:
|
||
foo: "bar"
|
||
baz: 1
|
||
```
|
||
|
||
### enable_ipv6
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Enable IPv6 networking on this network.
|
||
|
||
### ipam
|
||
|
||
Specify custom IPAM config. This is an object with several properties, each of
|
||
which is optional:
|
||
|
||
- `driver`: Custom IPAM driver, instead of the default.
|
||
- `config`: A list with zero or more config blocks, each containing any of
|
||
the following keys:
|
||
- `subnet`: Subnet in CIDR format that represents a network segment
|
||
- `ip_range`: Range of IPs from which to allocate container IPs
|
||
- `gateway`: IPv4 or IPv6 gateway for the master subnet
|
||
- `aux_addresses`: Auxiliary IPv4 or IPv6 addresses used by Network driver,
|
||
as a mapping from hostname to IP
|
||
- `options`: Driver-specific options as a key-value mapping.
|
||
|
||
A full example:
|
||
|
||
```yaml
|
||
ipam:
|
||
driver: default
|
||
config:
|
||
- subnet: 172.28.0.0/16
|
||
ip_range: 172.28.5.0/24
|
||
gateway: 172.28.5.254
|
||
aux_addresses:
|
||
host1: 172.28.1.5
|
||
host2: 172.28.1.6
|
||
host3: 172.28.1.7
|
||
options:
|
||
foo: bar
|
||
baz: "0"
|
||
```
|
||
|
||
### internal
|
||
|
||
By default, Docker also connects a bridge network to it to provide external
|
||
connectivity. If you want to create an externally isolated overlay network,
|
||
you can set this option to `true`.
|
||
|
||
### labels
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Add metadata to containers using
|
||
[Docker labels](../../config/labels-custom-metadata.md). You can use either
|
||
an array or a dictionary.
|
||
|
||
It's recommended that you use reverse-DNS notation to prevent your labels from
|
||
conflicting with those used by other software.
|
||
|
||
```yaml
|
||
labels:
|
||
com.example.description: "Financial transaction network"
|
||
com.example.department: "Finance"
|
||
com.example.label-with-empty-value: ""
|
||
```
|
||
|
||
```yaml
|
||
labels:
|
||
- "com.example.description=Financial transaction network"
|
||
- "com.example.department=Finance"
|
||
- "com.example.label-with-empty-value"
|
||
```
|
||
|
||
### external
|
||
|
||
If set to `true`, specifies that this network has been created outside of
|
||
Compose. `docker-compose up` does not attempt to create it, and raises
|
||
an error if it doesn't exist.
|
||
|
||
For version 2.0 of the format, `external` cannot be used in conjunction with
|
||
other network configuration keys (`driver`, `driver_opts`, `ipam`, `internal`).
|
||
This limitation no longer exists for
|
||
[version 2.1](compose-versioning.md#version-21) and above.
|
||
|
||
In the example below, `proxy` is the gateway to the outside world. Instead of
|
||
attempting to create a network called `[projectname]_outside`, Compose
|
||
looks for an existing network simply called `outside` and connect the `proxy`
|
||
service's containers to it.
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
|
||
services:
|
||
proxy:
|
||
build: ./proxy
|
||
networks:
|
||
- outside
|
||
- default
|
||
app:
|
||
build: ./app
|
||
networks:
|
||
- default
|
||
|
||
networks:
|
||
outside:
|
||
external: true
|
||
```
|
||
|
||
You can also specify the name of the network separately from the name used to
|
||
refer to it within the Compose file:
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
networks:
|
||
outside:
|
||
external:
|
||
name: actual-name-of-network
|
||
```
|
||
|
||
Not supported for version 2 `docker-compose` files. Use
|
||
[network_mode](#network_mode) instead.
|
||
|
||
### name
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
Set a custom name for this network. The name field can be used to reference
|
||
networks which contain special characters. The name is used as is
|
||
and will **not** be scoped with the stack name.
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
networks:
|
||
network1:
|
||
name: my-app-net
|
||
```
|
||
|
||
It can also be used in conjunction with the `external` property:
|
||
|
||
```yaml
|
||
version: "{{ site.compose_file_v2 }}"
|
||
networks:
|
||
network1:
|
||
external: true
|
||
name: my-app-net
|
||
```
|
||
|
||
## Variable substitution
|
||
|
||
{% include content/compose-var-sub.md %}
|
||
|
||
## Extension fields
|
||
|
||
> Added in [version 2.1](compose-versioning.md#version-21) file format.
|
||
|
||
{% include content/compose-extfields-sub.md %}
|
||
|
||
## Compose documentation
|
||
|
||
- [User guide](../index.md)
|
||
- [Installing Compose](../install/index.md)
|
||
- [Compose file versions and upgrading](compose-versioning.md)
|
||
- [Sample apps with Compose](../samples-for-compose.md)
|
||
- [Command line reference](../reference/index.md)
|