docs/config/daemon/systemd.md

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---
description: Controlling and configuring Docker using systemd
keywords: docker, daemon, systemd, configuration
redirect_from:
- /engine/articles/systemd/
- /articles/systemd/
- /engine/admin/systemd/
title: Control Docker with systemd
---
Many Linux distributions use systemd to start the Docker daemon. This document
shows a few examples of how to customize Docker's settings.
## Start the Docker daemon
### Start manually
Once Docker is installed, you need to start the Docker daemon.
Most Linux distributions use `systemctl` to start services. If you
do not have `systemctl`, use the `service` command.
- **`systemctl`**:
```bash
$ sudo systemctl start docker
```
- **`service`**:
```bash
$ sudo service docker start
```
### Start automatically at system boot
If you want Docker to start at boot, see
[Configure Docker to start on boot](/install/linux/linux-postinstall.md/#configure-docker-to-start-on-boot).
## Custom Docker daemon options
There are a number of ways to configure the daemon flags and environment variables
for your Docker daemon. The recommended way is to use the platform-independent
`daemon.json` file, which is located in `/etc/docker/` on Linux by default. See
[Daemon configuration file](/engine/reference/commandline/dockerd.md/#daemon-configuration-file).
You can configure nearly all daemon configuration options using `daemon.json`. The following
example configures two options. One thing you cannot configure using `daemon.json` mechanism is
a [HTTP proxy](#http-proxy).
### Runtime directory and storage driver
You may want to control the disk space used for Docker images, containers,
and volumes by moving it to a separate partition.
To accomplish this, set the following flags in the `daemon.json` file:
```none
{
"data-root": "/mnt/docker-data",
"storage-driver": "overlay"
}
```
### HTTP/HTTPS proxy
The Docker daemon uses the `HTTP_PROXY`, `HTTPS_PROXY`, and `NO_PROXY` environmental variables in
its start-up environment to configure HTTP or HTTPS proxy behavior. You cannot configure
these environment variables using the `daemon.json` file.
This example overrides the default `docker.service` file.
If you are behind an HTTP or HTTPS proxy server, for example in corporate settings,
you need to add this configuration in the Docker systemd service file.
1. Create a systemd drop-in directory for the docker service:
```bash
$ sudo mkdir -p /etc/systemd/system/docker.service.d
```
2. Create a file called `/etc/systemd/system/docker.service.d/http-proxy.conf`
that adds the `HTTP_PROXY` environment variable:
```conf
[Service]
Environment="HTTP_PROXY=http://proxy.example.com:80/"
```
Or, if you are behind an HTTPS proxy server, create a file called
`/etc/systemd/system/docker.service.d/https-proxy.conf`
that adds the `HTTPS_PROXY` environment variable:
```conf
[Service]
Environment="HTTPS_PROXY=https://proxy.example.com:443/"
```
3. If you have internal Docker registries that you need to contact without
proxying you can specify them via the `NO_PROXY` environment variable:
```conf
[Service]
Environment="HTTP_PROXY=http://proxy.example.com:80/" "NO_PROXY=localhost,127.0.0.1,docker-registry.somecorporation.com"
```
Or, if you are behind an HTTPS proxy server:
```conf
[Service]
Environment="HTTPS_PROXY=https://proxy.example.com:443/" "NO_PROXY=localhost,127.0.0.1,docker-registry.somecorporation.com"
```
4. Flush changes:
```bash
$ sudo systemctl daemon-reload
```
5. Restart Docker:
```bash
$ sudo systemctl restart docker
```
6. Verify that the configuration has been loaded:
```bash
$ systemctl show --property=Environment docker
Environment=HTTP_PROXY=http://proxy.example.com:80/
```
Or, if you are behind an HTTPS proxy server:
```bash
$ systemctl show --property=Environment docker
Environment=HTTPS_PROXY=https://proxy.example.com:443/
```
## Configure where the Docker daemon listens for connections
See
[Configure where the Docker daemon listens for connections](/install/linux/linux-postinstall.md#control-where-the-docker-daemon-listens-for-connections).
## Manually create the systemd unit files
When installing the binary without a package, you may want
to integrate Docker with systemd. For this, install the two unit files
(`service` and `socket`) from [the github
repository](https://github.com/moby/moby/tree/master/contrib/init/systemd)
to `/etc/systemd/system`.