moby--moby/docs/man/docker.1.md

% DOCKER(1) Docker User Manuals % William Henry % APRIL 2014

NAME

docker - Docker image and container command line interface

SYNOPSIS

docker [OPTIONS] COMMAND [arg...]

DESCRIPTION

docker has two distinct functions. It is used for starting the Docker daemon and to run the CLI (i.e., to command the daemon to manage images, containers etc.) So docker is both a server, as a daemon, and a client to the daemon, through the CLI.

To run the Docker daemon you do not specify any of the commands listed below but must specify the -d option. The other options listed below are for the daemon only.

The Docker CLI has over 30 commands. The commands are listed below and each has its own man page which explain usage and arguments.

To see the man page for a command run man docker .

OPTIONS

-D=true|false Enable debug mode. Default is false.

-H, --host=[unix:///var/run/docker.sock]: tcp://[host:port] to bind or unix://[/path/to/socket] to use. The socket(s) to bind to in daemon mode specified using one or more tcp://host:port, unix:///path/to/socket, fd://* or fd://socketfd.

--api-enable-cors=true|false Enable CORS headers in the remote API. Default is false.

-b="" Attach containers to a pre-existing network bridge; use 'none' to disable container networking

--bip="" Use the provided CIDR notation address for the dynamically created bridge (docker0); Mutually exclusive of -b

-d=true|false Enable daemon mode. Default is false.

--dns="" Force Docker to use specific DNS servers

-g="" Path to use as the root of the Docker runtime. Default is /var/lib/docker.

--fixed-cidr="" IPv4 subnet for fixed IPs (ex: 10.20.0.0/16); this subnet must be nested in the bridge subnet (which is defined by -b or --bip)

--icc=true|false Allow unrestricted inter-container and Docker daemon host communication. If disabled, containers can still be linked together using --link option (see docker-run(1)). Default is true.

--ip="" Default IP address to use when binding container ports. Default is 0.0.0.0.

--ip-masq=true|false Enable IP masquerading for bridge's IP range. Default is true.

--iptables=true|false Disable Docker's addition of iptables rules. Default is true.

-l, --log-level="debug|info|error|fatal"" Set the logging level. Default is info.

--label="[]" Set key=value labels to the daemon (displayed in docker info)

--mtu=VALUE Set the containers network mtu. Default is 1500.

-p="" Path to use for daemon PID file. Default is /var/run/docker.pid

--registry-mirror=:// Prepend a registry mirror to be used for image pulls. May be specified multiple times.

-s="" Force the Docker runtime to use a specific storage driver.

--storage-opt=[] Set storage driver options. See STORAGE DRIVER OPTIONS.

-v=true|false Print version information and quit. Default is false.

--selinux-enabled=true|false Enable selinux support. Default is false. SELinux does not presently support the BTRFS storage driver.

COMMANDS

docker-attach(1) Attach to a running container

docker-build(1) Build an image from a Dockerfile

docker-commit(1) Create a new image from a container's changes

docker-cp(1) Copy files/folders from a container's filesystem to the host at path

docker-create(1) Create a new container

docker-diff(1) Inspect changes on a container's filesystem

docker-events(1) Get real time events from the server

docker-exec(1) Run a command in a running container

docker-export(1) Stream the contents of a container as a tar archive

docker-history(1) Show the history of an image

docker-images(1) List images

docker-import(1) Create a new filesystem image from the contents of a tarball

docker-info(1) Display system-wide information

docker-inspect(1) Return low-level information on a container

docker-kill(1) Kill a running container (which includes the wrapper process and everything inside it)

docker-load(1) Load an image from a tar archive

docker-login(1) Register or Login to a Docker registry server

docker-logout(1) Log the user out of a Docker registry server

docker-logs(1) Fetch the logs of a container

docker-pause(1) Pause all processes within a container

docker-port(1) Lookup the public-facing port which is NAT-ed to PRIVATE_PORT

docker-ps(1) List containers

docker-pull(1) Pull an image or a repository from a Docker registry server

docker-push(1) Push an image or a repository to a Docker registry server

docker-restart(1) Restart a running container

docker-rm(1) Remove one or more containers

docker-rmi(1) Remove one or more images

docker-run(1) Run a command in a new container

docker-save(1) Save an image to a tar archive

docker-search(1) Search for an image in the Docker index

docker-start(1) Start a stopped container

docker-stop(1) Stop a running container

docker-tag(1) Tag an image into a repository

docker-top(1) Lookup the running processes of a container

docker-unpause(1) Unpause all processes within a container

docker-version(1) Show the Docker version information

docker-wait(1) Block until a container stops, then print its exit code

STORAGE DRIVER OPTIONS

Options to storage backend can be specified with --storage-opt flags. The only backend which currently takes options is devicemapper. Therefore use these flags with **-s=**devicemapper.

Here is the list of devicemapper options:

dm.basesize

Specifies the size to use when creating the base device, which limits the size of images and containers. The default value is 10G. Note, thin devices are inherently "sparse", so a 10G device which is mostly empty doesn't use 10 GB of space on the pool. However, the filesystem will use more space for the empty case the larger the device is. Warning: This value affects the system-wide "base" empty filesystem that may already be initialized and inherited by pulled images.

dm.loopdatasize

Specifies the size to use when creating the loopback file for the "data" device which is used for the thin pool. The default size is 100G. Note that the file is sparse, so it will not initially take up this much space.

dm.loopmetadatasize

Specifies the size to use when creating the loopback file for the "metadadata" device which is used for the thin pool. The default size is 2G. Note that the file is sparse, so it will not initially take up this much space.

dm.fs

Specifies the filesystem type to use for the base device. The supported options are "ext4" and "xfs". The default is "ext4"

dm.mkfsarg

Specifies extra mkfs arguments to be used when creating the base device.

dm.mountopt

Specifies extra mount options used when mounting the thin devices.

dm.datadev

Specifies a custom blockdevice to use for data for the thin pool.

If using a block device for device mapper storage, ideally both datadev and metadatadev should be specified to completely avoid using the loopback device.

dm.metadatadev

Specifies a custom blockdevice to use for metadata for the thin pool.

For best performance the metadata should be on a different spindle than the data, or even better on an SSD.

If setting up a new metadata pool it is required to be valid. This can be achieved by zeroing the first 4k to indicate empty metadata, like this:

dd if=/dev/zero of=/dev/metadata_dev bs=4096 count=1

dm.blocksize

Specifies a custom blocksize to use for the thin pool. The default blocksize is 64K.

dm.blkdiscard

Enables or disables the use of blkdiscard when removing devicemapper devices. This is enabled by default (only) if using loopback devices and is required to res-parsify the loopback file on image/container removal.

Disabling this on loopback can lead to much faster container removal times, but will prevent the space used in /var/lib/docker directory from being returned to the system for other use when containers are removed.

EXAMPLES

Launching docker daemon with devicemapper backend with particular block devices for data and metadata:

docker -d -s=devicemapper \
  --storage-opt dm.datadev=/dev/vdb \
  --storage-opt dm.metadatadev=/dev/vdc \
  --storage-opt dm.basesize=20G

Client

For specific client examples please see the man page for the specific Docker command. For example:

man docker run

HISTORY

April 2014, Originally compiled by William Henry (whenry at redhat dot com) based on docker.com source material and internal work.