mirror of https://github.com/docker/cli.git
727 lines
34 KiB
Markdown
727 lines
34 KiB
Markdown
---
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title: "run"
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description: "The run command description and usage"
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keywords: "run, command, container"
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---
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<!-- This file is maintained within the docker/docker Github
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repository at https://github.com/docker/docker/. Make all
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pull requests against that repo. If you see this file in
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periodically be overwritten by the definitive file. Pull
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requests which include edits to this file in other repositories
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will be rejected.
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-->
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# run
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```markdown
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Usage: docker run [OPTIONS] IMAGE [COMMAND] [ARG...]
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Run a command in a new container
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Options:
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--add-host value Add a custom host-to-IP mapping (host:ip) (default [])
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-a, --attach value Attach to STDIN, STDOUT or STDERR (default [])
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--blkio-weight value Block IO (relative weight), between 10 and 1000
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--blkio-weight-device value Block IO weight (relative device weight) (default [])
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--cap-add value Add Linux capabilities (default [])
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--cap-drop value Drop Linux capabilities (default [])
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--cgroup-parent string Optional parent cgroup for the container
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--cidfile string Write the container ID to the file
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--cpu-count int The number of CPUs available for execution by the container.
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Windows daemon only. On Windows Server containers, this is
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approximated as a percentage of total CPU usage.
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--cpu-percent int Limit percentage of CPU available for execution
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by the container. Windows daemon only.
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The processor resource controls are mutually
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exclusive, the order of precedence is CPUCount
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first, then CPUShares, and CPUPercent last.
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--cpu-period int Limit CPU CFS (Completely Fair Scheduler) period
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--cpu-quota int Limit CPU CFS (Completely Fair Scheduler) quota
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-c, --cpu-shares int CPU shares (relative weight)
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--cpus NanoCPUs Number of CPUs (default 0.000)
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--cpu-rt-period int Limit the CPU real-time period in microseconds
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--cpu-rt-runtime int Limit the CPU real-time runtime in microseconds
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--cpuset-cpus string CPUs in which to allow execution (0-3, 0,1)
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--cpuset-mems string MEMs in which to allow execution (0-3, 0,1)
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-d, --detach Run container in background and print container ID
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--detach-keys string Override the key sequence for detaching a container
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--device value Add a host device to the container (default [])
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--device-read-bps value Limit read rate (bytes per second) from a device (default [])
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--device-read-iops value Limit read rate (IO per second) from a device (default [])
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--device-write-bps value Limit write rate (bytes per second) to a device (default [])
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--device-write-iops value Limit write rate (IO per second) to a device (default [])
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--disable-content-trust Skip image verification (default true)
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--dns value Set custom DNS servers (default [])
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--dns-option value Set DNS options (default [])
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--dns-search value Set custom DNS search domains (default [])
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--entrypoint string Overwrite the default ENTRYPOINT of the image
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-e, --env value Set environment variables (default [])
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--env-file value Read in a file of environment variables (default [])
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--expose value Expose a port or a range of ports (default [])
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--group-add value Add additional groups to join (default [])
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--health-cmd string Command to run to check health
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--health-interval duration Time between running the check (ns|us|ms|s|m|h) (default 0s)
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--health-retries int Consecutive failures needed to report unhealthy
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--health-timeout duration Maximum time to allow one check to run (ns|us|ms|s|m|h) (default 0s)
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--help Print usage
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-h, --hostname string Container host name
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-i, --interactive Keep STDIN open even if not attached
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--io-maxbandwidth string Maximum IO bandwidth limit for the system drive (Windows only)
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(Windows only). The format is `<number><unit>`.
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Unit is optional and can be `b` (bytes per second),
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`k` (kilobytes per second), `m` (megabytes per second),
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or `g` (gigabytes per second). If you omit the unit,
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the system uses bytes per second.
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--io-maxbandwidth and --io-maxiops are mutually exclusive options.
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--io-maxiops uint Maximum IOps limit for the system drive (Windows only)
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--ip string Container IPv4 address (e.g. 172.30.100.104)
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--ip6 string Container IPv6 address (e.g. 2001:db8::33)
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--ipc string IPC namespace to use
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--isolation string Container isolation technology
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--kernel-memory string Kernel memory limit
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-l, --label value Set meta data on a container (default [])
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--label-file value Read in a line delimited file of labels (default [])
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--link value Add link to another container (default [])
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--link-local-ip value Container IPv4/IPv6 link-local addresses (default [])
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--log-driver string Logging driver for the container
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--log-opt value Log driver options (default [])
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--mac-address string Container MAC address (e.g. 92:d0:c6:0a:29:33)
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-m, --memory string Memory limit
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--memory-reservation string Memory soft limit
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--memory-swap string Swap limit equal to memory plus swap: '-1' to enable unlimited swap
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--memory-swappiness int Tune container memory swappiness (0 to 100) (default -1)
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--mount value Attach a filesystem mount to the container (default [])
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--name string Assign a name to the container
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--network-alias value Add network-scoped alias for the container (default [])
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--network string Connect a container to a network
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'bridge': create a network stack on the default Docker bridge
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'none': no networking
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'container:<name|id>': reuse another container's network stack
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'host': use the Docker host network stack
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'<network-name>|<network-id>': connect to a user-defined network
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--no-healthcheck Disable any container-specified HEALTHCHECK
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--oom-kill-disable Disable OOM Killer
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--oom-score-adj int Tune host's OOM preferences (-1000 to 1000)
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--pid string PID namespace to use
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--pids-limit int Tune container pids limit (set -1 for unlimited)
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--privileged Give extended privileges to this container
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-p, --publish value Publish a container's port(s) to the host (default [])
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-P, --publish-all Publish all exposed ports to random ports
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--read-only Mount the container's root filesystem as read only
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--restart string Restart policy to apply when a container exits (default "no")
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Possible values are : no, on-failure[:max-retry], always, unless-stopped
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--rm Automatically remove the container when it exits
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--runtime string Runtime to use for this container
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--security-opt value Security Options (default [])
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--shm-size string Size of /dev/shm, default value is 64MB.
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The format is `<number><unit>`. `number` must be greater than `0`.
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Unit is optional and can be `b` (bytes), `k` (kilobytes), `m` (megabytes),
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or `g` (gigabytes). If you omit the unit, the system uses bytes.
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--sig-proxy Proxy received signals to the process (default true)
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--stop-signal string Signal to stop a container, SIGTERM by default (default "SIGTERM")
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--stop-timeout=10 Timeout (in seconds) to stop a container
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--storage-opt value Storage driver options for the container (default [])
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--sysctl value Sysctl options (default map[])
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--tmpfs value Mount a tmpfs directory (default [])
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-t, --tty Allocate a pseudo-TTY
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--ulimit value Ulimit options (default [])
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-u, --user string Username or UID (format: <name|uid>[:<group|gid>])
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--userns string User namespace to use
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'host': Use the Docker host user namespace
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'': Use the Docker daemon user namespace specified by `--userns-remap` option.
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--uts string UTS namespace to use
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-v, --volume value Bind mount a volume (default []). The format
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is `[host-src:]container-dest[:<options>]`.
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The comma-delimited `options` are [rw|ro],
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[z|Z], [[r]shared|[r]slave|[r]private], and
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[nocopy]. The 'host-src' is an absolute path
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or a name value.
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--volume-driver string Optional volume driver for the container
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--volumes-from value Mount volumes from the specified container(s) (default [])
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-w, --workdir string Working directory inside the container
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```
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The `docker run` command first `creates` a writeable container layer over the
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specified image, and then `starts` it using the specified command. That is,
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`docker run` is equivalent to the API `/containers/create` then
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`/containers/(id)/start`. A stopped container can be restarted with all its
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previous changes intact using `docker start`. See `docker ps -a` to view a list
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of all containers.
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The `docker run` command can be used in combination with `docker commit` to
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[*change the command that a container runs*](commit.md). There is additional detailed information about `docker run` in the [Docker run reference](../run.md).
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For information on connecting a container to a network, see the ["*Docker network overview*"](https://docs.docker.com/engine/userguide/networking/).
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## Examples
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### Assign name and allocate pseudo-TTY (--name, -it)
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$ docker run --name test -it debian
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root@d6c0fe130dba:/# exit 13
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$ echo $?
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13
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$ docker ps -a | grep test
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d6c0fe130dba debian:7 "/bin/bash" 26 seconds ago Exited (13) 17 seconds ago test
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This example runs a container named `test` using the `debian:latest`
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image. The `-it` instructs Docker to allocate a pseudo-TTY connected to
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the container's stdin; creating an interactive `bash` shell in the container.
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In the example, the `bash` shell is quit by entering
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`exit 13`. This exit code is passed on to the caller of
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`docker run`, and is recorded in the `test` container's metadata.
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### Capture container ID (--cidfile)
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$ docker run --cidfile /tmp/docker_test.cid ubuntu echo "test"
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This will create a container and print `test` to the console. The `cidfile`
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flag makes Docker attempt to create a new file and write the container ID to it.
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If the file exists already, Docker will return an error. Docker will close this
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file when `docker run` exits.
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### Full container capabilities (--privileged)
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$ docker run -t -i --rm ubuntu bash
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root@bc338942ef20:/# mount -t tmpfs none /mnt
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mount: permission denied
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This will *not* work, because by default, most potentially dangerous kernel
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capabilities are dropped; including `cap_sys_admin` (which is required to mount
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filesystems). However, the `--privileged` flag will allow it to run:
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$ docker run -t -i --privileged ubuntu bash
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root@50e3f57e16e6:/# mount -t tmpfs none /mnt
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root@50e3f57e16e6:/# df -h
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Filesystem Size Used Avail Use% Mounted on
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none 1.9G 0 1.9G 0% /mnt
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The `--privileged` flag gives *all* capabilities to the container, and it also
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lifts all the limitations enforced by the `device` cgroup controller. In other
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words, the container can then do almost everything that the host can do. This
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flag exists to allow special use-cases, like running Docker within Docker.
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### Set working directory (-w)
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$ docker run -w /path/to/dir/ -i -t ubuntu pwd
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The `-w` lets the command being executed inside directory given, here
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`/path/to/dir/`. If the path does not exist it is created inside the container.
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### Set storage driver options per container
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$ docker run -it --storage-opt size=120G fedora /bin/bash
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This (size) will allow to set the container rootfs size to 120G at creation time.
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This option is only available for the `devicemapper`, `btrfs`, `overlay2`,
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`windowsfilter` and `zfs` graph drivers.
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For the `devicemapper`, `btrfs`, `windowsfilter` and `zfs` graph drivers,
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user cannot pass a size less than the Default BaseFS Size.
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For the `overlay2` storage driver, the size option is only available if the
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backing fs is `xfs` and mounted with the `pquota` mount option.
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Under these conditions, user can pass any size less then the backing fs size.
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### Mount tmpfs (--tmpfs)
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$ docker run -d --tmpfs /run:rw,noexec,nosuid,size=65536k my_image
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The `--tmpfs` flag mounts an empty tmpfs into the container with the `rw`,
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`noexec`, `nosuid`, `size=65536k` options.
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### Mount volume (-v, --read-only)
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$ docker run -v `pwd`:`pwd` -w `pwd` -i -t ubuntu pwd
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The `-v` flag mounts the current working directory into the container. The `-w`
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lets the command being executed inside the current working directory, by
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changing into the directory to the value returned by `pwd`. So this
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combination executes the command using the container, but inside the
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current working directory.
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$ docker run -v /doesnt/exist:/foo -w /foo -i -t ubuntu bash
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When the host directory of a bind-mounted volume doesn't exist, Docker
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will automatically create this directory on the host for you. In the
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example above, Docker will create the `/doesnt/exist`
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folder before starting your container.
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$ docker run --read-only -v /icanwrite busybox touch /icanwrite/here
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Volumes can be used in combination with `--read-only` to control where
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a container writes files. The `--read-only` flag mounts the container's root
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filesystem as read only prohibiting writes to locations other than the
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specified volumes for the container.
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$ docker run -t -i -v /var/run/docker.sock:/var/run/docker.sock -v /path/to/static-docker-binary:/usr/bin/docker busybox sh
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By bind-mounting the docker unix socket and statically linked docker
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binary (refer to [get the linux binary](
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https://docs.docker.com/engine/installation/binaries/#/get-the-linux-binary)),
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you give the container the full access to create and manipulate the host's
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Docker daemon.
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For in-depth information about volumes, refer to [manage data in containers](https://docs.docker.com/engine/tutorials/dockervolumes/)
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### Add bin-mounts or volumes using the --mount flag
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The `--mount` flag allows you to mount volumes, host-directories and `tmpfs`
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mounts in a container.
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The `--mount` flag supports most options that are supported by the `-v` or the
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`--volume` flag, but uses a different syntax. For in-depth information on the
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`--mount` flag, and a comparison between `--volume` and `--mount`, refer to
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the [service create command reference](service_create.md#add-bind-mounts-or-volumes).
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Examples:
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$ docker run --read-only --mount type=volume,target=/icanwrite busybox touch /icanwrite/here
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$ docker run -t -i --mount type=bind,src=/data,dst=/data busybox sh
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### Publish or expose port (-p, --expose)
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$ docker run -p 127.0.0.1:80:8080 ubuntu bash
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This binds port `8080` of the container to port `80` on `127.0.0.1` of the host
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machine. The [Docker User
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Guide](https://docs.docker.com/engine/userguide/networking/default_network/dockerlinks/)
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explains in detail how to manipulate ports in Docker.
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$ docker run --expose 80 ubuntu bash
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This exposes port `80` of the container without publishing the port to the host
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system's interfaces.
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### Set environment variables (-e, --env, --env-file)
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$ docker run -e MYVAR1 --env MYVAR2=foo --env-file ./env.list ubuntu bash
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This sets simple (non-array) environmental variables in the container. For
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illustration all three
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flags are shown here. Where `-e`, `--env` take an environment variable and
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value, or if no `=` is provided, then that variable's current value, set via
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`export`, is passed through (i.e. `$MYVAR1` from the host is set to `$MYVAR1`
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in the container). When no `=` is provided and that variable is not defined
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in the client's environment then that variable will be removed from the
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container's list of environment variables. All three flags, `-e`, `--env` and
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`--env-file` can be repeated.
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Regardless of the order of these three flags, the `--env-file` are processed
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first, and then `-e`, `--env` flags. This way, the `-e` or `--env` will
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override variables as needed.
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$ cat ./env.list
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TEST_FOO=BAR
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$ docker run --env TEST_FOO="This is a test" --env-file ./env.list busybox env | grep TEST_FOO
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TEST_FOO=This is a test
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The `--env-file` flag takes a filename as an argument and expects each line
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to be in the `VAR=VAL` format, mimicking the argument passed to `--env`. Comment
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lines need only be prefixed with `#`
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An example of a file passed with `--env-file`
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$ cat ./env.list
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TEST_FOO=BAR
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# this is a comment
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TEST_APP_DEST_HOST=10.10.0.127
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TEST_APP_DEST_PORT=8888
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_TEST_BAR=FOO
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TEST_APP_42=magic
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helloWorld=true
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123qwe=bar
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org.spring.config=something
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# pass through this variable from the caller
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TEST_PASSTHROUGH
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$ TEST_PASSTHROUGH=howdy docker run --env-file ./env.list busybox env
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PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
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HOSTNAME=5198e0745561
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TEST_FOO=BAR
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TEST_APP_DEST_HOST=10.10.0.127
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TEST_APP_DEST_PORT=8888
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_TEST_BAR=FOO
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TEST_APP_42=magic
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helloWorld=true
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TEST_PASSTHROUGH=howdy
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HOME=/root
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123qwe=bar
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org.spring.config=something
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$ docker run --env-file ./env.list busybox env
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PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
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HOSTNAME=5198e0745561
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TEST_FOO=BAR
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TEST_APP_DEST_HOST=10.10.0.127
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TEST_APP_DEST_PORT=8888
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_TEST_BAR=FOO
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TEST_APP_42=magic
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helloWorld=true
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TEST_PASSTHROUGH=
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HOME=/root
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123qwe=bar
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org.spring.config=something
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### Set metadata on container (-l, --label, --label-file)
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A label is a `key=value` pair that applies metadata to a container. To label a container with two labels:
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$ docker run -l my-label --label com.example.foo=bar ubuntu bash
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The `my-label` key doesn't specify a value so the label defaults to an empty
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string(`""`). To add multiple labels, repeat the label flag (`-l` or `--label`).
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The `key=value` must be unique to avoid overwriting the label value. If you
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specify labels with identical keys but different values, each subsequent value
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overwrites the previous. Docker uses the last `key=value` you supply.
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Use the `--label-file` flag to load multiple labels from a file. Delimit each
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label in the file with an EOL mark. The example below loads labels from a
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labels file in the current directory:
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$ docker run --label-file ./labels ubuntu bash
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The label-file format is similar to the format for loading environment
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variables. (Unlike environment variables, labels are not visible to processes
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running inside a container.) The following example illustrates a label-file
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format:
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com.example.label1="a label"
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# this is a comment
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com.example.label2=another\ label
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com.example.label3
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You can load multiple label-files by supplying multiple `--label-file` flags.
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For additional information on working with labels, see [*Labels - custom
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metadata in Docker*](https://docs.docker.com/engine/userguide/labels-custom-metadata/) in the Docker User
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Guide.
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### Connect a container to a network (--network)
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When you start a container use the `--network` flag to connect it to a network.
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This adds the `busybox` container to the `my-net` network.
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```bash
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$ docker run -itd --network=my-net busybox
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```
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You can also choose the IP addresses for the container with `--ip` and `--ip6`
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flags when you start the container on a user-defined network.
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```bash
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$ docker run -itd --network=my-net --ip=10.10.9.75 busybox
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```
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If you want to add a running container to a network use the `docker network connect` subcommand.
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You can connect multiple containers to the same network. Once connected, the
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containers can communicate easily need only another container's IP address
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or name. For `overlay` networks or custom plugins that support multi-host
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connectivity, containers connected to the same multi-host network but launched
|
|
from different Engines can also communicate in this way.
|
|
|
|
**Note**: Service discovery is unavailable on the default bridge network.
|
|
Containers can communicate via their IP addresses by default. To communicate
|
|
by name, they must be linked.
|
|
|
|
You can disconnect a container from a network using the `docker network
|
|
disconnect` command.
|
|
|
|
### Mount volumes from container (--volumes-from)
|
|
|
|
$ docker run --volumes-from 777f7dc92da7 --volumes-from ba8c0c54f0f2:ro -i -t ubuntu pwd
|
|
|
|
The `--volumes-from` flag mounts all the defined volumes from the referenced
|
|
containers. Containers can be specified by repetitions of the `--volumes-from`
|
|
argument. The container ID may be optionally suffixed with `:ro` or `:rw` to
|
|
mount the volumes in read-only or read-write mode, respectively. By default,
|
|
the volumes are mounted in the same mode (read write or read only) as
|
|
the reference container.
|
|
|
|
Labeling systems like SELinux require that proper labels are placed on volume
|
|
content mounted into a container. Without a label, the security system might
|
|
prevent the processes running inside the container from using the content. By
|
|
default, Docker does not change the labels set by the OS.
|
|
|
|
To change the label in the container context, you can add either of two suffixes
|
|
`:z` or `:Z` to the volume mount. These suffixes tell Docker to relabel file
|
|
objects on the shared volumes. The `z` option tells Docker that two containers
|
|
share the volume content. As a result, Docker labels the content with a shared
|
|
content label. Shared volume labels allow all containers to read/write content.
|
|
The `Z` option tells Docker to label the content with a private unshared label.
|
|
Only the current container can use a private volume.
|
|
|
|
### Attach to STDIN/STDOUT/STDERR (-a)
|
|
|
|
The `-a` flag tells `docker run` to bind to the container's `STDIN`, `STDOUT`
|
|
or `STDERR`. This makes it possible to manipulate the output and input as
|
|
needed.
|
|
|
|
$ echo "test" | docker run -i -a stdin ubuntu cat -
|
|
|
|
This pipes data into a container and prints the container's ID by attaching
|
|
only to the container's `STDIN`.
|
|
|
|
$ docker run -a stderr ubuntu echo test
|
|
|
|
This isn't going to print anything unless there's an error because we've
|
|
only attached to the `STDERR` of the container. The container's logs
|
|
still store what's been written to `STDERR` and `STDOUT`.
|
|
|
|
$ cat somefile | docker run -i -a stdin mybuilder dobuild
|
|
|
|
This is how piping a file into a container could be done for a build.
|
|
The container's ID will be printed after the build is done and the build
|
|
logs could be retrieved using `docker logs`. This is
|
|
useful if you need to pipe a file or something else into a container and
|
|
retrieve the container's ID once the container has finished running.
|
|
|
|
### Add host device to container (--device)
|
|
|
|
$ docker run --device=/dev/sdc:/dev/xvdc --device=/dev/sdd --device=/dev/zero:/dev/nulo -i -t ubuntu ls -l /dev/{xvdc,sdd,nulo}
|
|
brw-rw---- 1 root disk 8, 2 Feb 9 16:05 /dev/xvdc
|
|
brw-rw---- 1 root disk 8, 3 Feb 9 16:05 /dev/sdd
|
|
crw-rw-rw- 1 root root 1, 5 Feb 9 16:05 /dev/nulo
|
|
|
|
It is often necessary to directly expose devices to a container. The `--device`
|
|
option enables that. For example, a specific block storage device or loop
|
|
device or audio device can be added to an otherwise unprivileged container
|
|
(without the `--privileged` flag) and have the application directly access it.
|
|
|
|
By default, the container will be able to `read`, `write` and `mknod` these devices.
|
|
This can be overridden using a third `:rwm` set of options to each `--device`
|
|
flag:
|
|
|
|
|
|
$ docker run --device=/dev/sda:/dev/xvdc --rm -it ubuntu fdisk /dev/xvdc
|
|
|
|
Command (m for help): q
|
|
$ docker run --device=/dev/sda:/dev/xvdc:r --rm -it ubuntu fdisk /dev/xvdc
|
|
You will not be able to write the partition table.
|
|
|
|
Command (m for help): q
|
|
|
|
$ docker run --device=/dev/sda:/dev/xvdc:rw --rm -it ubuntu fdisk /dev/xvdc
|
|
|
|
Command (m for help): q
|
|
|
|
$ docker run --device=/dev/sda:/dev/xvdc:m --rm -it ubuntu fdisk /dev/xvdc
|
|
fdisk: unable to open /dev/xvdc: Operation not permitted
|
|
|
|
> **Note:**
|
|
> `--device` cannot be safely used with ephemeral devices. Block devices
|
|
> that may be removed should not be added to untrusted containers with
|
|
> `--device`.
|
|
|
|
### Restart policies (--restart)
|
|
|
|
Use Docker's `--restart` to specify a container's *restart policy*. A restart
|
|
policy controls whether the Docker daemon restarts a container after exit.
|
|
Docker supports the following restart policies:
|
|
|
|
<table>
|
|
<thead>
|
|
<tr>
|
|
<th>Policy</th>
|
|
<th>Result</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody>
|
|
<tr>
|
|
<td><strong>no</strong></td>
|
|
<td>
|
|
Do not automatically restart the container when it exits. This is the
|
|
default.
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td>
|
|
<span style="white-space: nowrap">
|
|
<strong>on-failure</strong>[:max-retries]
|
|
</span>
|
|
</td>
|
|
<td>
|
|
Restart only if the container exits with a non-zero exit status.
|
|
Optionally, limit the number of restart retries the Docker
|
|
daemon attempts.
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td><strong>always</strong></td>
|
|
<td>
|
|
Always restart the container regardless of the exit status.
|
|
When you specify always, the Docker daemon will try to restart
|
|
the container indefinitely. The container will also always start
|
|
on daemon startup, regardless of the current state of the container.
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td><strong>unless-stopped</strong></td>
|
|
<td>
|
|
Always restart the container regardless of the exit status, but
|
|
do not start it on daemon startup if the container has been put
|
|
to a stopped state before.
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
|
|
$ docker run --restart=always redis
|
|
|
|
This will run the `redis` container with a restart policy of **always**
|
|
so that if the container exits, Docker will restart it.
|
|
|
|
More detailed information on restart policies can be found in the
|
|
[Restart Policies (--restart)](../run.md#restart-policies-restart)
|
|
section of the Docker run reference page.
|
|
|
|
### Add entries to container hosts file (--add-host)
|
|
|
|
You can add other hosts into a container's `/etc/hosts` file by using one or
|
|
more `--add-host` flags. This example adds a static address for a host named
|
|
`docker`:
|
|
|
|
$ docker run --add-host=docker:10.180.0.1 --rm -it debian
|
|
root@f38c87f2a42d:/# ping docker
|
|
PING docker (10.180.0.1): 48 data bytes
|
|
56 bytes from 10.180.0.1: icmp_seq=0 ttl=254 time=7.600 ms
|
|
56 bytes from 10.180.0.1: icmp_seq=1 ttl=254 time=30.705 ms
|
|
^C--- docker ping statistics ---
|
|
2 packets transmitted, 2 packets received, 0% packet loss
|
|
round-trip min/avg/max/stddev = 7.600/19.152/30.705/11.553 ms
|
|
|
|
Sometimes you need to connect to the Docker host from within your
|
|
container. To enable this, pass the Docker host's IP address to
|
|
the container using the `--add-host` flag. To find the host's address,
|
|
use the `ip addr show` command.
|
|
|
|
The flags you pass to `ip addr show` depend on whether you are
|
|
using IPv4 or IPv6 networking in your containers. Use the following
|
|
flags for IPv4 address retrieval for a network device named `eth0`:
|
|
|
|
$ HOSTIP=`ip -4 addr show scope global dev eth0 | grep inet | awk '{print \$2}' | cut -d / -f 1`
|
|
$ docker run --add-host=docker:${HOSTIP} --rm -it debian
|
|
|
|
For IPv6 use the `-6` flag instead of the `-4` flag. For other network
|
|
devices, replace `eth0` with the correct device name (for example `docker0`
|
|
for the bridge device).
|
|
|
|
### Set ulimits in container (--ulimit)
|
|
|
|
Since setting `ulimit` settings in a container requires extra privileges not
|
|
available in the default container, you can set these using the `--ulimit` flag.
|
|
`--ulimit` is specified with a soft and hard limit as such:
|
|
`<type>=<soft limit>[:<hard limit>]`, for example:
|
|
|
|
$ docker run --ulimit nofile=1024:1024 --rm debian sh -c "ulimit -n"
|
|
1024
|
|
|
|
> **Note:**
|
|
> If you do not provide a `hard limit`, the `soft limit` will be used
|
|
> for both values. If no `ulimits` are set, they will be inherited from
|
|
> the default `ulimits` set on the daemon. `as` option is disabled now.
|
|
> In other words, the following script is not supported:
|
|
> `$ docker run -it --ulimit as=1024 fedora /bin/bash`
|
|
|
|
The values are sent to the appropriate `syscall` as they are set.
|
|
Docker doesn't perform any byte conversion. Take this into account when setting the values.
|
|
|
|
#### For `nproc` usage
|
|
|
|
Be careful setting `nproc` with the `ulimit` flag as `nproc` is designed by Linux to set the
|
|
maximum number of processes available to a user, not to a container. For example, start four
|
|
containers with `daemon` user:
|
|
|
|
docker run -d -u daemon --ulimit nproc=3 busybox top
|
|
docker run -d -u daemon --ulimit nproc=3 busybox top
|
|
docker run -d -u daemon --ulimit nproc=3 busybox top
|
|
docker run -d -u daemon --ulimit nproc=3 busybox top
|
|
|
|
The 4th container fails and reports "[8] System error: resource temporarily unavailable" error.
|
|
This fails because the caller set `nproc=3` resulting in the first three containers using up
|
|
the three processes quota set for the `daemon` user.
|
|
|
|
### Stop container with signal (--stop-signal)
|
|
|
|
The `--stop-signal` flag sets the system call signal that will be sent to the container to exit.
|
|
This signal can be a valid unsigned number that matches a position in the kernel's syscall table, for instance 9,
|
|
or a signal name in the format SIGNAME, for instance SIGKILL.
|
|
|
|
### Optional security options (--security-opt)
|
|
|
|
On Windows, this flag can be used to specify the `credentialspec` option.
|
|
The `credentialspec` must be in the format `file://spec.txt` or `registry://keyname`.
|
|
|
|
### Stop container with timeout (--stop-timeout)
|
|
|
|
The `--stop-timeout` flag sets the the timeout (in seconds) that a pre-defined (see `--stop-signal`) system call
|
|
signal that will be sent to the container to exit. After timeout elapses the container will be killed with SIGKILL.
|
|
|
|
### Specify isolation technology for container (--isolation)
|
|
|
|
This option is useful in situations where you are running Docker containers on
|
|
Microsoft Windows. The `--isolation <value>` option sets a container's isolation
|
|
technology. On Linux, the only supported is the `default` option which uses
|
|
Linux namespaces. These two commands are equivalent on Linux:
|
|
|
|
```
|
|
$ docker run -d busybox top
|
|
$ docker run -d --isolation default busybox top
|
|
```
|
|
|
|
On Microsoft Windows, can take any of 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. |
|
|
| `process` | Namespace isolation only. |
|
|
| `hyperv` | Hyper-V hypervisor partition-based isolation. |
|
|
|
|
On Windows, the default isolation for client is `hyperv`, and for server is
|
|
`process`. Therefore when running on Windows server without a `daemon` option
|
|
set, these two commands are equivalent:
|
|
```
|
|
$ docker run -d --isolation default busybox top
|
|
$ docker run -d --isolation process busybox top
|
|
```
|
|
|
|
If you have set the `--exec-opt isolation=hyperv` option on the Docker `daemon`,
|
|
if running on Windows server, any of these commands also result in `hyperv` isolation:
|
|
|
|
```
|
|
$ docker run -d --isolation default busybox top
|
|
$ docker run -d --isolation hyperv busybox top
|
|
```
|
|
|
|
### Configure namespaced kernel parameters (sysctls) at runtime
|
|
|
|
The `--sysctl` sets namespaced kernel parameters (sysctls) in the
|
|
container. For example, to turn on IP forwarding in the containers
|
|
network namespace, run this command:
|
|
|
|
$ docker run --sysctl net.ipv4.ip_forward=1 someimage
|
|
|
|
|
|
> **Note**: Not all sysctls are namespaced. Docker does not support changing sysctls
|
|
> inside of a container that also modify the host system. As the kernel
|
|
> evolves we expect to see more sysctls become namespaced.
|
|
|
|
#### Currently supported sysctls
|
|
|
|
`IPC Namespace`:
|
|
|
|
kernel.msgmax, kernel.msgmnb, kernel.msgmni, kernel.sem, kernel.shmall, kernel.shmmax, kernel.shmmni, kernel.shm_rmid_forced
|
|
Sysctls beginning with fs.mqueue.*
|
|
|
|
If you use the `--ipc=host` option these sysctls will not be allowed.
|
|
|
|
`Network Namespace`:
|
|
Sysctls beginning with net.*
|
|
|
|
If you use the `--network=host` option using these sysctls will not be allowed.
|