command: docker create short: Create a new container long: |- The `docker create` command creates a writeable container layer over the specified image and prepares it for running the specified command. The container ID is then printed to `STDOUT`. This is similar to `docker run -d` except the container is never started. You can then use the `docker start ` command to start the container at any point. This is useful when you want to set up a container configuration ahead of time so that it is ready to start when you need it. The initial status of the new container is `created`. Please see the [run command](run.md) section and the [Docker run reference](../run.md) for more details. usage: docker create [OPTIONS] IMAGE [COMMAND] [ARG...] pname: docker plink: docker.yaml options: - option: add-host description: Add a custom host-to-IP mapping (host:ip) - option: attach shorthand: a description: Attach to STDIN, STDOUT or STDERR - option: blkio-weight default_value: "0" description: | Block IO (relative weight), between 10 and 1000, or 0 to disable (default 0) - option: blkio-weight-device default_value: '[]' description: Block IO weight (relative device weight) - option: cap-add description: Add Linux capabilities - option: cap-drop description: Drop Linux capabilities - option: cgroup-parent description: Optional parent cgroup for the container - option: cidfile description: Write the container ID to the file - option: cpu-count default_value: "0" description: CPU count (Windows only) - option: cpu-percent default_value: "0" description: CPU percent (Windows only) - option: cpu-period default_value: "0" description: Limit CPU CFS (Completely Fair Scheduler) period - option: cpu-quota default_value: "0" description: Limit CPU CFS (Completely Fair Scheduler) quota - option: cpu-rt-period default_value: "0" description: Limit CPU real-time period in microseconds - option: cpu-rt-runtime default_value: "0" description: Limit CPU real-time runtime in microseconds - option: cpu-shares shorthand: c default_value: "0" description: CPU shares (relative weight) - option: cpus description: Number of CPUs - option: cpuset-cpus description: CPUs in which to allow execution (0-3, 0,1) - option: cpuset-mems description: MEMs in which to allow execution (0-3, 0,1) - option: device description: Add a host device to the container - option: device-cgroup-rule description: Add a rule to the cgroup allowed devices list - option: device-read-bps default_value: '[]' description: Limit read rate (bytes per second) from a device - option: device-read-iops default_value: '[]' description: Limit read rate (IO per second) from a device - option: device-write-bps default_value: '[]' description: Limit write rate (bytes per second) to a device - option: device-write-iops default_value: '[]' description: Limit write rate (IO per second) to a device - option: disable-content-trust default_value: "true" description: Skip image verification - option: dns description: Set custom DNS servers - option: dns-opt description: Set DNS options - option: dns-option description: Set DNS options - option: dns-search description: Set custom DNS search domains - option: entrypoint description: Overwrite the default ENTRYPOINT of the image - option: env shorthand: e description: Set environment variables - option: env-file description: Read in a file of environment variables - option: expose description: Expose a port or a range of ports - option: group-add description: Add additional groups to join - option: health-cmd description: Command to run to check health - option: health-interval default_value: 0s description: Time between running the check (ms|s|m|h) (default 0s) - option: health-retries default_value: "0" description: Consecutive failures needed to report unhealthy - option: health-start-period default_value: 0s description: | Start period for the container to initialize before starting health-retries countdown (ms|s|m|h) (default 0s) - option: health-timeout default_value: 0s description: | Maximum time to allow one check to run (ms|s|m|h) (default 0s) - option: help default_value: "false" description: Print usage - option: hostname shorthand: h description: Container host name - option: init default_value: "false" description: | Run an init inside the container that forwards signals and reaps processes - option: interactive shorthand: i default_value: "false" description: Keep STDIN open even if not attached - option: io-maxbandwidth default_value: "0" description: | Maximum IO bandwidth limit for the system drive (Windows only) - option: io-maxiops default_value: "0" description: Maximum IOps limit for the system drive (Windows only) - option: ip description: IPv4 address (e.g., 172.30.100.104) - option: ip6 description: IPv6 address (e.g., 2001:db8::33) - option: ipc description: IPC namespace to use - option: isolation description: Container isolation technology - option: kernel-memory default_value: "0" description: Kernel memory limit - option: label shorthand: l description: Set meta data on a container - option: label-file description: Read in a line delimited file of labels - option: link description: Add link to another container - option: link-local-ip description: Container IPv4/IPv6 link-local addresses - option: log-driver description: Logging driver for the container - option: log-opt description: Log driver options - option: mac-address description: Container MAC address (e.g., 92:d0:c6:0a:29:33) - option: memory shorthand: m default_value: "0" description: Memory limit - option: memory-reservation default_value: "0" description: Memory soft limit - option: memory-swap default_value: "0" description: | Swap limit equal to memory plus swap: '-1' to enable unlimited swap - option: memory-swappiness default_value: "-1" description: Tune container memory swappiness (0 to 100) - option: mount description: Attach a filesystem mount to the container - option: name description: Assign a name to the container - option: net default_value: default description: Connect a container to a network - option: net-alias description: Add network-scoped alias for the container - option: network default_value: default description: Connect a container to a network - option: network-alias description: Add network-scoped alias for the container - option: no-healthcheck default_value: "false" description: Disable any container-specified HEALTHCHECK - option: oom-kill-disable default_value: "false" description: Disable OOM Killer - option: oom-score-adj default_value: "0" description: Tune host's OOM preferences (-1000 to 1000) - option: pid description: PID namespace to use - option: pids-limit default_value: "0" description: Tune container pids limit (set -1 for unlimited) - option: privileged default_value: "false" description: Give extended privileges to this container - option: publish shorthand: p description: Publish a container's port(s) to the host - option: publish-all shorthand: P default_value: "false" description: Publish all exposed ports to random ports - option: read-only default_value: "false" description: Mount the container's root filesystem as read only - option: restart default_value: "no" description: Restart policy to apply when a container exits - option: rm default_value: "false" description: Automatically remove the container when it exits - option: runtime description: Runtime to use for this container - option: security-opt description: Security Options - option: shm-size default_value: "0" description: Size of /dev/shm - option: stop-signal default_value: SIGTERM description: Signal to stop a container - option: stop-timeout default_value: "0" description: Timeout (in seconds) to stop a container - option: storage-opt description: Storage driver options for the container - option: sysctl default_value: map[] description: Sysctl options - option: tmpfs description: Mount a tmpfs directory - option: tty shorthand: t default_value: "false" description: Allocate a pseudo-TTY - option: ulimit default_value: '[]' description: Ulimit options - option: user shorthand: u description: 'Username or UID (format: [:])' - option: userns description: User namespace to use - option: uts description: UTS namespace to use - option: volume shorthand: v description: Bind mount a volume - option: volume-driver description: Optional volume driver for the container - option: volumes-from description: Mount volumes from the specified container(s) - option: workdir shorthand: w description: Working directory inside the container examples: |- ### Create and start a container ```bash $ docker create -t -i fedora bash 6d8af538ec541dd581ebc2a24153a28329acb5268abe5ef868c1f1a261221752 $ docker start -a -i 6d8af538ec5 bash-4.2# ``` ### Initialize volumes As of v1.4.0 container volumes are initialized during the `docker create` phase (i.e., `docker run` too). For example, this allows you to `create` the `data` volume container, and then use it from another container: ```bash $ docker create -v /data --name data ubuntu 240633dfbb98128fa77473d3d9018f6123b99c454b3251427ae190a7d951ad57 $ docker run --rm --volumes-from data ubuntu ls -la /data total 8 drwxr-xr-x 2 root root 4096 Dec 5 04:10 . drwxr-xr-x 48 root root 4096 Dec 5 04:11 .. ``` Similarly, `create` a host directory bind mounted volume container, which can then be used from the subsequent container: ```bash $ docker create -v /home/docker:/docker --name docker ubuntu 9aa88c08f319cd1e4515c3c46b0de7cc9aa75e878357b1e96f91e2c773029f03 $ docker run --rm --volumes-from docker ubuntu ls -la /docker total 20 drwxr-sr-x 5 1000 staff 180 Dec 5 04:00 . drwxr-xr-x 48 root root 4096 Dec 5 04:13 .. -rw-rw-r-- 1 1000 staff 3833 Dec 5 04:01 .ash_history -rw-r--r-- 1 1000 staff 446 Nov 28 11:51 .ashrc -rw-r--r-- 1 1000 staff 25 Dec 5 04:00 .gitconfig drwxr-sr-x 3 1000 staff 60 Dec 1 03:28 .local -rw-r--r-- 1 1000 staff 920 Nov 28 11:51 .profile drwx--S--- 2 1000 staff 460 Dec 5 00:51 .ssh drwxr-xr-x 32 1000 staff 1140 Dec 5 04:01 docker ``` Set storage driver options per container. ```bash $ docker create -it --storage-opt size=120G fedora /bin/bash ``` This (size) will allow to set the container rootfs size to 120G at creation time. This option is only available for the `devicemapper`, `btrfs`, `overlay2`, `windowsfilter` and `zfs` graph drivers. For the `devicemapper`, `btrfs`, `windowsfilter` and `zfs` graph drivers, user cannot pass a size less than the Default BaseFS Size. For the `overlay2` storage driver, the size option is only available if the backing fs is `xfs` and mounted with the `pquota` mount option. Under these conditions, user can pass any size less then the backing fs size. ### Specify isolation technology for container (--isolation) This option is useful in situations where you are running Docker containers on Windows. The `--isolation=` option sets a container's isolation technology. On Linux, the only supported is the `default` option which uses Linux namespaces. On Microsoft Windows, you can specify these values: | Value | Description | |-----------|---------------------------------------------------------------------------------------------------------------------------------------------------------------| | `default` | Use the value specified by the Docker daemon's `--exec-opt` . If the `daemon` does not specify an isolation technology, Microsoft Windows uses `process` as its default value if the daemon is running on Windows server, or `hyperv` if running on Windows client. | | `process` | Namespace isolation only. | | `hyperv` | Hyper-V hypervisor partition-based isolation. | Specifying the `--isolation` flag without a value is the same as setting `--isolation="default"`. ### Dealing with dynamically created devices (--device-cgroup-rule) Devices available to a container are assigned at creation time. The assigned devices will both be added to the cgroup.allow file and created into the container once it is run. This poses a problem when a new device needs to be added to running container. One of the solution is to add a more permissive rule to a container allowing it access to a wider range of devices. For example, supposing our container needs access to a character device with major `42` and any number of minor number (added as new devices appear), the following rule would be added: ``` docker create --device-cgroup-rule='c 42:* rmw' -name my-container my-image ``` Then, a user could ask `udev` to execute a script that would `docker exec my-container mknod newDevX c 42 ` the required device when it is added. NOTE: initially present devices still need to be explicitely added to the create/run command