244 lines
8.8 KiB
Markdown
244 lines
8.8 KiB
Markdown
<!--[metadata]>
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+++
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title = "Configuring and running Docker"
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description = "Configuring and running the Docker daemon on various distributions"
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keywords = ["docker, daemon, configuration, running, process managers"]
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[menu.main]
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parent = "smn_administrate"
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weight = 3
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+++
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<![end-metadata]-->
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# Configuring and running Docker on various distributions
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After successfully installing Docker, the `docker` daemon runs with its default
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configuration.
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In a production environment, system administrators typically configure the
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`docker` daemon to start and stop according to an organization's requirements. In most
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cases, the system administrator configures a process manager such as `SysVinit`, `Upstart`,
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or `systemd` to manage the `docker` daemon's start and stop.
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### Running the docker daemon directly
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The `docker` daemon can be run directly using the `docker daemon` command. By default it listens on
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the Unix socket `unix:///var/run/docker.sock`
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$ docker daemon
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INFO[0000] +job init_networkdriver()
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INFO[0000] +job serveapi(unix:///var/run/docker.sock)
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INFO[0000] Listening for HTTP on unix (/var/run/docker.sock)
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...
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...
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### Configuring the docker daemon directly
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If you're running the `docker` daemon directly by running `docker daemon` instead
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of using a process manager, you can append the configuration options to the `docker` run
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command directly. Other options can be passed to the `docker` daemon to configure it.
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Some of the daemon's options are:
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| Flag | Description |
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|-----------------------|-----------------------------------------------------------|
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| `-D`, `--debug=false` | Enable or disable debug mode. By default, this is false. |
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| `-H`,`--host=[]` | Daemon socket(s) to connect to. |
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| `--tls=false` | Enable or disable TLS. By default, this is false. |
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Here is a an example of running the `docker` daemon with configuration options:
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$ docker daemon -D --tls=true --tlscert=/var/docker/server.pem --tlskey=/var/docker/serverkey.pem -H tcp://192.168.59.3:2376
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These options :
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- Enable `-D` (debug) mode
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- Set `tls` to true with the server certificate and key specified using `--tlscert` and `--tlskey` respectively
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- Listen for connections on `tcp://192.168.59.3:2376`
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The command line reference has the [complete list of daemon flags](../reference/commandline/daemon.md)
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with explanations.
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## Ubuntu
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As of `14.04`, Ubuntu uses Upstart as a process manager. By default, Upstart jobs
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are located in `/etc/init` and the `docker` Upstart job can be found at `/etc/init/docker.conf`.
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After successfully [installing Docker for Ubuntu](../installation/ubuntulinux.md),
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you can check the running status using Upstart in this way:
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$ sudo status docker
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docker start/running, process 989
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### Running Docker
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You can start/stop/restart the `docker` daemon using
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$ sudo start docker
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$ sudo stop docker
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$ sudo restart docker
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### Configuring Docker
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You configure the `docker` daemon in the `/etc/default/docker` file on your
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system. You do this by specifying values in a `DOCKER_OPTS` variable.
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To configure Docker options:
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1. Log into your host as a user with `sudo` or `root` privileges.
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2. If you don't have one, create the `/etc/default/docker` file on your host. Depending on how
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you installed Docker, you may already have this file.
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3. Open the file with your favorite editor.
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```
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$ sudo vi /etc/default/docker
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```
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4. Add a `DOCKER_OPTS` variable with the following options. These options are appended to the
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`docker` daemon's run command.
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```
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DOCKER_OPTS="-D --tls=true --tlscert=/var/docker/server.pem --tlskey=/var/docker/serverkey.pem -H tcp://192.168.59.3:2376"
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```
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These options :
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- Enable `-D` (debug) mode
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- Set `tls` to true with the server certificate and key specified using `--tlscert` and `--tlskey` respectively
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- Listen for connections on `tcp://192.168.59.3:2376`
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The command line reference has the [complete list of daemon flags](../reference/commandline/daemon.md)
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with explanations.
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5. Save and close the file.
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6. Restart the `docker` daemon.
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```
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$ sudo restart docker
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```
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7. Verify that the `docker` daemon is running as specified with the `ps` command.
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```
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$ ps aux | grep docker | grep -v grep
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```
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### Logs
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By default logs for Upstart jobs are located in `/var/log/upstart` and the logs for `docker` daemon
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can be located at `/var/log/upstart/docker.log`
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$ tail -f /var/log/upstart/docker.log
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INFO[0000] Loading containers: done.
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INFO[0000] docker daemon: 1.6.0 4749651; execdriver: native-0.2; graphdriver: aufs
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INFO[0000] +job acceptconnections()
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INFO[0000] -job acceptconnections() = OK (0)
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INFO[0000] Daemon has completed initialization
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## CentOS / Red Hat Enterprise Linux / Fedora
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As of `7.x`, CentOS and RHEL use `systemd` as the process manager. As of `21`, Fedora uses
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`systemd` as its process manager.
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After successfully installing Docker for [CentOS](../installation/centos.md)/[Red Hat Enterprise Linux](../installation/rhel.md)/[Fedora](../installation/fedora.md), you can check the running status in this way:
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$ sudo systemctl status docker
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### Running Docker
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You can start/stop/restart the `docker` daemon using
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$ sudo systemctl start docker
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$ sudo systemctl stop docker
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$ sudo systemctl restart docker
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If you want Docker to start at boot, you should also:
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$ sudo systemctl enable docker
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### Configuring Docker
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You configure the `docker` daemon in the `/etc/sysconfig/docker` file on your
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host. You do this by specifying values in a variable. For CentOS 7.x and RHEL 7.x, the name
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of the variable is `OPTIONS` and for CentOS 6.x and RHEL 6.x, the name of the variable is
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`other_args`. For this section, we will use CentOS 7.x as an example to configure the `docker`
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daemon.
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By default, systemd services are located either in `/etc/systemd/service`, `/lib/systemd/system`
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or `/usr/lib/systemd/system`. The `docker.service` file can be found in either of these three
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directories depending on your host.
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To configure Docker options:
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1. Log into your host as a user with `sudo` or `root` privileges.
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2. If you don't have one, create the `/etc/sysconfig/docker` file on your host. Depending on how
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you installed Docker, you may already have this file.
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3. Open the file with your favorite editor.
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```
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$ sudo vi /etc/sysconfig/docker
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```
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4. Add a `OPTIONS` variable with the following options. These options are appended to the
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command that starts the `docker` daemon.
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```
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OPTIONS="-D --tls=true --tlscert=/var/docker/server.pem --tlskey=/var/docker/serverkey.pem -H tcp://192.168.59.3:2376"
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```
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These options :
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- Enable `-D` (debug) mode
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- Set `tls` to true with the server certificate and key specified using `--tlscert` and `--tlskey` respectively
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- Listen for connections on `tcp://192.168.59.3:2376`
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The command line reference has the [complete list of daemon flags](../reference/commandline/daemon.md)
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with explanations.
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5. Save and close the file.
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6. Restart the `docker` daemon.
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```
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$ sudo systemctl restart docker
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```
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7. Verify that the `docker` daemon is running as specified with the `ps` command.
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```
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$ ps aux | grep docker | grep -v grep
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```
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### Logs
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systemd has its own logging system called the journal. The logs for the `docker` daemon can
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be viewed using `journalctl -u docker`
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$ sudo journalctl -u docker
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May 06 00:22:05 localhost.localdomain systemd[1]: Starting Docker Application Container Engine...
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May 06 00:22:05 localhost.localdomain docker[2495]: time="2015-05-06T00:22:05Z" level="info" msg="+job serveapi(unix:///var/run/docker.sock)"
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May 06 00:22:05 localhost.localdomain docker[2495]: time="2015-05-06T00:22:05Z" level="info" msg="Listening for HTTP on unix (/var/run/docker.sock)"
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May 06 00:22:06 localhost.localdomain docker[2495]: time="2015-05-06T00:22:06Z" level="info" msg="+job init_networkdriver()"
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May 06 00:22:06 localhost.localdomain docker[2495]: time="2015-05-06T00:22:06Z" level="info" msg="-job init_networkdriver() = OK (0)"
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May 06 00:22:06 localhost.localdomain docker[2495]: time="2015-05-06T00:22:06Z" level="info" msg="Loading containers: start."
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May 06 00:22:06 localhost.localdomain docker[2495]: time="2015-05-06T00:22:06Z" level="info" msg="Loading containers: done."
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May 06 00:22:06 localhost.localdomain docker[2495]: time="2015-05-06T00:22:06Z" level="info" msg="docker daemon: 1.5.0-dev fc0329b/1.5.0; execdriver: native-0.2; graphdriver: devicemapper"
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May 06 00:22:06 localhost.localdomain docker[2495]: time="2015-05-06T00:22:06Z" level="info" msg="+job acceptconnections()"
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May 06 00:22:06 localhost.localdomain docker[2495]: time="2015-05-06T00:22:06Z" level="info" msg="-job acceptconnections() = OK (0)"
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_Note: Using and configuring journal is an advanced topic and is beyond the scope of this article._
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