mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
158 lines
5.3 KiB
Markdown
158 lines
5.3 KiB
Markdown
<!--[metadata]>
|
|
+++
|
|
title = "Control and configure Docker with systemd"
|
|
description = "Controlling and configuring Docker using systemd"
|
|
keywords = ["docker, daemon, systemd, configuration"]
|
|
[menu.main]
|
|
parent = "smn_administrate"
|
|
weight = 7
|
|
+++
|
|
<![end-metadata]-->
|
|
|
|
# Control and configure 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.
|
|
|
|
## Starting the Docker daemon
|
|
|
|
Once Docker is installed, you will need to start the Docker daemon.
|
|
|
|
$ sudo systemctl start docker
|
|
# or on older distributions, you may need to use
|
|
$ sudo service docker start
|
|
|
|
If you want Docker to start at boot, you should also:
|
|
|
|
$ sudo systemctl enable docker
|
|
# or on older distributions, you may need to use
|
|
$ sudo chkconfig docker on
|
|
|
|
## 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 a systemd drop-in file. These are local files in
|
|
the `/etc/systemd/system/docker.service.d` directory. This could also be
|
|
`/etc/systemd/system/docker.service`, which also works for overriding the
|
|
defaults from `/lib/systemd/system/docker.service`.
|
|
|
|
However, if you had previously used a package which had an `EnvironmentFile`
|
|
(often pointing to `/etc/sysconfig/docker`) then for backwards compatibility,
|
|
you drop a file in the `/etc/systemd/system/docker.service.d`
|
|
directory including the following:
|
|
|
|
[Service]
|
|
EnvironmentFile=-/etc/sysconfig/docker
|
|
EnvironmentFile=-/etc/sysconfig/docker-storage
|
|
EnvironmentFile=-/etc/sysconfig/docker-network
|
|
ExecStart=
|
|
ExecStart=/usr/bin/docker daemon -H fd:// $OPTIONS \
|
|
$DOCKER_STORAGE_OPTIONS \
|
|
$DOCKER_NETWORK_OPTIONS \
|
|
$BLOCK_REGISTRY \
|
|
$INSECURE_REGISTRY
|
|
|
|
To check if the `docker.service` uses an `EnvironmentFile`:
|
|
|
|
$ sudo systemctl show docker | grep EnvironmentFile
|
|
EnvironmentFile=-/etc/sysconfig/docker (ignore_errors=yes)
|
|
|
|
Alternatively, find out where the service file is located:
|
|
|
|
$ sudo systemctl status docker | grep Loaded
|
|
Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled)
|
|
$ sudo grep EnvironmentFile /usr/lib/systemd/system/docker.service
|
|
EnvironmentFile=-/etc/sysconfig/docker
|
|
|
|
You can customize the Docker daemon options using override files as explained in the
|
|
[HTTP Proxy example](#http-proxy) below. The files located in `/usr/lib/systemd/system`
|
|
or `/lib/systemd/system` contain the default options and should not be edited.
|
|
|
|
### 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.
|
|
|
|
In this example, we'll assume that your `docker.service` file looks something like:
|
|
|
|
[Unit]
|
|
Description=Docker Application Container Engine
|
|
Documentation=https://docs.docker.com
|
|
After=network.target docker.socket
|
|
Requires=docker.socket
|
|
|
|
[Service]
|
|
Type=notify
|
|
ExecStart=/usr/bin/docker daemon -H fd://
|
|
LimitNOFILE=1048576
|
|
LimitNPROC=1048576
|
|
|
|
[Install]
|
|
Also=docker.socket
|
|
|
|
This will allow us to add extra flags via a drop-in file (mentioned above) by
|
|
placing a file containing the following in the `/etc/systemd/system/docker.service.d`
|
|
directory:
|
|
|
|
[Service]
|
|
ExecStart=
|
|
ExecStart=/usr/bin/docker daemon -H fd:// --graph="/mnt/docker-data" --storage-driver=overlay
|
|
|
|
You can also set other environment variables in this file, for example, the
|
|
`HTTP_PROXY` environment variables described below.
|
|
|
|
To modify the ExecStart configuration, specify an empty configuration followed
|
|
by a new configuration as follows:
|
|
|
|
[Service]
|
|
ExecStart=
|
|
ExecStart=/usr/bin/docker daemon -H fd:// --bip=172.17.42.1/16
|
|
|
|
If you fail to specify an empty configuration, Docker reports an error such as:
|
|
|
|
docker.service has more than one ExecStart= setting, which is only allowed for Type=oneshot services. Refusing.
|
|
|
|
### HTTP proxy
|
|
|
|
This example overrides the default `docker.service` file.
|
|
|
|
If you are behind a HTTP proxy server, for example in corporate settings,
|
|
you will need to add this configuration in the Docker systemd service file.
|
|
|
|
First, create a systemd drop-in directory for the docker service:
|
|
|
|
mkdir /etc/systemd/system/docker.service.d
|
|
|
|
Now create a file called `/etc/systemd/system/docker.service.d/http-proxy.conf`
|
|
that adds the `HTTP_PROXY` environment variable:
|
|
|
|
[Service]
|
|
Environment="HTTP_PROXY=http://proxy.example.com:80/"
|
|
|
|
If you have internal Docker registries that you need to contact without
|
|
proxying you can specify them via the `NO_PROXY` environment variable:
|
|
|
|
Environment="HTTP_PROXY=http://proxy.example.com:80/" "NO_PROXY=localhost,127.0.0.1,docker-registry.somecorporation.com"
|
|
|
|
Flush changes:
|
|
|
|
$ sudo systemctl daemon-reload
|
|
|
|
Verify that the configuration has been loaded:
|
|
|
|
$ sudo systemctl show docker --property Environment
|
|
Environment=HTTP_PROXY=http://proxy.example.com:80/
|
|
|
|
Restart Docker:
|
|
|
|
$ sudo systemctl restart docker
|
|
|
|
## Manually creating the systemd unit files
|
|
|
|
When installing the binary without a package, you may want
|
|
to integrate Docker with systemd. For this, simply install the two unit files
|
|
(service and socket) from [the github
|
|
repository](https://github.com/docker/docker/tree/master/contrib/init/systemd)
|
|
to `/etc/systemd/system`.
|