Engine API v1.19

Estimated reading time: 42 minutes

1. Brief introduction

  • The daemon listens on unix:///var/run/docker.sock but you can Bind Docker to another host/port or a Unix socket.
  • The API tends to be REST. However, for some complex commands, like attach or pull, the HTTP connection is hijacked to transport stdout, stdin and stderr.
  • When the client API version is newer than the daemon’s, these calls return an HTTP 400 Bad Request error message.

2. Endpoints

2.1 Containers

List containers

GET /containers/json

List containers

Example request:

GET /v1.19/containers/json?all=1&before=8dfafdbc3a40&size=1 HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

[
     {
             "Id": "8dfafdbc3a40",
             "Names":["/boring_feynman"],
             "Image": "ubuntu:latest",
             "Command": "echo 1",
             "Created": 1367854155,
             "Status": "Exit 0",
             "Ports": [{"PrivatePort": 2222, "PublicPort": 3333, "Type": "tcp"}],
             "Labels": {
                     "com.example.vendor": "Acme",
                     "com.example.license": "GPL",
                     "com.example.version": "1.0"
             },
             "SizeRw": 12288,
             "SizeRootFs": 0
     },
     {
             "Id": "9cd87474be90",
             "Names":["/coolName"],
             "Image": "ubuntu:latest",
             "Command": "echo 222222",
             "Created": 1367854155,
             "Status": "Exit 0",
             "Ports": [],
             "Labels": {},
             "SizeRw": 12288,
             "SizeRootFs": 0
     },
     {
             "Id": "3176a2479c92",
             "Names":["/sleepy_dog"],
             "Image": "ubuntu:latest",
             "Command": "echo 3333333333333333",
             "Created": 1367854154,
             "Status": "Exit 0",
             "Ports":[],
             "Labels": {},
             "SizeRw":12288,
             "SizeRootFs":0
     },
     {
             "Id": "4cb07b47f9fb",
             "Names":["/running_cat"],
             "Image": "ubuntu:latest",
             "Command": "echo 444444444444444444444444444444444",
             "Created": 1367854152,
             "Status": "Exit 0",
             "Ports": [],
             "Labels": {},
             "SizeRw": 12288,
             "SizeRootFs": 0
     }
]

Query parameters:

  • all – 1/True/true or 0/False/false, Show all containers. Only running containers are shown by default (i.e., this defaults to false)
  • limit – Show limit last created containers, include non-running ones.
  • since – Show only containers created since Id, include non-running ones.
  • before – Show only containers created before Id, include non-running ones.
  • size – 1/True/true or 0/False/false, Show the containers sizes
  • filters - a JSON encoded value of the filters (a map[string][]string) to process on the containers list. Available filters:
  • exited=<int>; – containers with exit code of <int> ;
  • status=(restarting running paused exited)
  • label=key or label="key=value" of a container label

Status codes:

  • 200 – no error
  • 400 – bad parameter
  • 500 – server error

Create a container

POST /containers/create

Create a container

Example request:

POST /v1.19/containers/create HTTP/1.1
Content-Type: application/json

{
       "Hostname": "",
       "Domainname": "",
       "User": "",
       "AttachStdin": false,
       "AttachStdout": true,
       "AttachStderr": true,
       "Tty": false,
       "OpenStdin": false,
       "StdinOnce": false,
       "Env": [
               "FOO=bar",
               "BAZ=quux"
       ],
       "Cmd": [
               "date"
       ],
       "Entrypoint": null,
       "Image": "ubuntu",
       "Labels": {
               "com.example.vendor": "Acme",
               "com.example.license": "GPL",
               "com.example.version": "1.0"
       },
       "Volumes": {
         "/volumes/data": {}
       },
       "WorkingDir": "",
       "NetworkDisabled": false,
       "MacAddress": "12:34:56:78:9a:bc",
       "ExposedPorts": {
               "22/tcp": {}
       },
       "HostConfig": {
         "Binds": ["/tmp:/tmp"],
         "Links": ["redis3:redis"],
         "LxcConf": {"lxc.utsname":"docker"},
         "Memory": 0,
         "MemorySwap": 0,
         "CpuShares": 512,
         "CpuPeriod": 100000,
         "CpuQuota": 50000,
         "CpusetCpus": "0,1",
         "CpusetMems": "0,1",
         "BlkioWeight": 300,
         "OomKillDisable": false,
         "PidMode": "",
         "PortBindings": { "22/tcp": [{ "HostPort": "11022" }] },
         "PublishAllPorts": false,
         "Privileged": false,
         "ReadonlyRootfs": false,
         "Dns": ["8.8.8.8"],
         "DnsSearch": [""],
         "ExtraHosts": null,
         "VolumesFrom": ["parent", "other:ro"],
         "CapAdd": ["NET_ADMIN"],
         "CapDrop": ["MKNOD"],
         "RestartPolicy": { "Name": "", "MaximumRetryCount": 0 },
         "NetworkMode": "bridge",
         "Devices": [],
         "Ulimits": [{}],
         "LogConfig": { "Type": "json-file", "Config": {} },
         "SecurityOpt": [],
         "CgroupParent": ""
      }
  }

Example response:

  HTTP/1.1 201 Created
  Content-Type: application/json

  {
       "Id":"e90e34656806",
       "Warnings":[]
  }

JSON parameters:

  • Hostname - A string value containing the hostname to use for the container.
  • Domainname - A string value containing the domain name to use for the container.
  • User - A string value specifying the user inside the container.
  • AttachStdin - Boolean value, attaches to stdin.
  • AttachStdout - Boolean value, attaches to stdout.
  • AttachStderr - Boolean value, attaches to stderr.
  • Tty - Boolean value, Attach standard streams to a tty, including stdin if it is not closed.
  • OpenStdin - Boolean value, opens stdin,
  • StdinOnce - Boolean value, close stdin after the 1 attached client disconnects.
  • Env - A list of environment variables in the form of ["VAR=value", ...]
  • Labels - Adds a map of labels to a container. To specify a map: {"key":"value", ... }
  • Cmd - Command to run specified as a string or an array of strings.
  • Entrypoint - Set the entry point for the container as a string or an array of strings.
  • Image - A string specifying the image name to use for the container.
  • Volumes - An object mapping mount point paths (strings) inside the container to empty objects.
  • WorkingDir - A string specifying the working directory for commands to run in.
  • NetworkDisabled - Boolean value, when true disables networking for the container
  • ExposedPorts - An object mapping ports to an empty object in the form of: "ExposedPorts": { "<port>/<tcp|udp>: {}" }
  • HostConfig
    • Binds – A list of bind mounts for this container. Each item is a string in one of these forms:
      • host-src:container-dest to bind-mount a host path into the container. Both host-src, and container-dest must be an absolute path.
      • host-src:container-dest:ro to make the bind mount read-only inside the container. Both host-src, and container-dest must be an absolute path.
    • Links - A list of links for the container. Each link entry should be in the form of container_name:alias.
    • LxcConf - LXC specific configurations. These configurations only work when using the lxc execution driver.
    • Memory - Memory limit in bytes.
    • MemorySwap - Total memory limit (memory + swap); set -1 to enable unlimited swap. You must use this with memory and make the swap value larger than memory.
    • CpuShares - An integer value containing the container’s CPU Shares (ie. the relative weight vs other containers).
    • CpuPeriod - The length of a CPU period in microseconds.
    • CpuQuota - Microseconds of CPU time that the container can get in a CPU period.
    • CpusetCpus - String value containing the cgroups CpusetCpus to use.
    • CpusetMems - Memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only effective on NUMA systems.
    • BlkioWeight - Block IO weight (relative weight) accepts a weight value between 10 and 1000.
    • OomKillDisable - Boolean value, whether to disable OOM Killer for the container or not.
    • PidMode - Set the PID (Process) Namespace mode for the container; "container:<name|id>": joins another container’s PID namespace "host": use the host’s PID namespace inside the container
    • PortBindings - A map of exposed container ports and the host port they should map to. A JSON object in the form { <port>/<protocol>: [{ "HostPort": "<port>" }] } Take note that port is specified as a string and not an integer value.
    • PublishAllPorts - Allocates a random host port for all of a container’s exposed ports. Specified as a boolean value.
    • Privileged - Gives the container full access to the host. Specified as a boolean value.
    • ReadonlyRootfs - Mount the container’s root filesystem as read only. Specified as a boolean value.
    • Dns - A list of DNS servers for the container to use.
    • DnsSearch - A list of DNS search domains
    • ExtraHosts - A list of hostnames/IP mappings to add to the container’s /etc/hosts file. Specified in the form ["hostname:IP"].
    • VolumesFrom - A list of volumes to inherit from another container. Specified in the form <container name>[:<ro|rw>]
    • CapAdd - A list of kernel capabilities to add to the container.
    • Capdrop - A list of kernel capabilities to drop from the container.
    • RestartPolicy – The behavior to apply when the container exits. The value is an object with a Name property of either "always" to always restart or "on-failure" to restart only when the container exit code is non-zero. If on-failure is used, MaximumRetryCount controls the number of times to retry before giving up. The default is not to restart. (optional) An ever increasing delay (double the previous delay, starting at 100mS) is added before each restart to prevent flooding the server.
    • NetworkMode - Sets the networking mode for the container. Supported values are: bridge, host, none, and container:<name|id>
    • Devices - A list of devices to add to the container specified as a JSON object in the form { "PathOnHost": "/dev/deviceName", "PathInContainer": "/dev/deviceName", "CgroupPermissions": "mrw"}
    • Ulimits - A list of ulimits to set in the container, specified as { "Name": <name>, "Soft": <soft limit>, "Hard": <hard limit> }, for example: Ulimits: { "Name": "nofile", "Soft": 1024, "Hard": 2048 }
    • SecurityOpt: A list of string values to customize labels for MLS systems, such as SELinux.
    • LogConfig - Log configuration for the container, specified as a JSON object in the form { "Type": "<driver_name>", "Config": {"key1": "val1"}}. Available types: json-file, syslog, journald, none. syslog available options are: address.
    • CgroupParent - Path to cgroups under which the container’s cgroup is created. If the path is not absolute, the path is considered to be relative to the cgroups path of the init process. Cgroups are created if they do not already exist.

Query parameters:

  • name – Assign the specified name to the container. Must match /?[a-zA-Z0-9_-]+.

Status codes:

  • 201 – no error
  • 400 – bad parameter
  • 404 – no such container
  • 406 – impossible to attach (container not running)
  • 409 – conflict
  • 500 – server error

Inspect a container

GET /containers/(id or name)/json

Return low-level information on the container id

Example request:

  GET /v1.19/containers/4fa6e0f0c678/json HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{
	"AppArmorProfile": "",
	"Args": [
		"-c",
		"exit 9"
	],
	"Config": {
		"AttachStderr": true,
		"AttachStdin": false,
		"AttachStdout": true,
		"Cmd": [
			"/bin/sh",
			"-c",
			"exit 9"
		],
		"Domainname": "",
		"Entrypoint": null,
		"Env": [
			"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
		],
		"ExposedPorts": null,
		"Hostname": "ba033ac44011",
		"Image": "ubuntu",
		"Labels": {
			"com.example.vendor": "Acme",
			"com.example.license": "GPL",
			"com.example.version": "1.0"
		},
		"MacAddress": "",
		"NetworkDisabled": false,
		"OnBuild": null,
		"OpenStdin": false,
		"PortSpecs": null,
		"StdinOnce": false,
		"Tty": false,
		"User": "",
		"Volumes": null,
		"WorkingDir": ""
	},
	"Created": "2015-01-06T15:47:31.485331387Z",
	"Driver": "devicemapper",
	"ExecDriver": "native-0.2",
	"ExecIDs": null,
	"HostConfig": {
		"Binds": null,
		"BlkioWeight": 0,
		"CapAdd": null,
		"CapDrop": null,
		"ContainerIDFile": "",
		"CpusetCpus": "",
		"CpusetMems": "",
		"CpuShares": 0,
		"CpuPeriod": 100000,
		"Devices": [],
		"Dns": null,
		"DnsSearch": null,
		"ExtraHosts": null,
		"IpcMode": "",
		"Links": null,
		"LxcConf": [],
		"Memory": 0,
		"MemorySwap": 0,
		"OomKillDisable": false,
		"NetworkMode": "bridge",
		"PidMode": "",
		"PortBindings": {},
		"Privileged": false,
		"ReadonlyRootfs": false,
		"PublishAllPorts": false,
		"RestartPolicy": {
			"MaximumRetryCount": 2,
			"Name": "on-failure"
		},
		"LogConfig": {
			"Config": null,
			"Type": "json-file"
		},
		"SecurityOpt": null,
		"VolumesFrom": null,
		"Ulimits": [{}]
	},
	"HostnamePath": "/var/lib/docker/containers/ba033ac4401106a3b513bc9d639eee123ad78ca3616b921167cd74b20e25ed39/hostname",
	"HostsPath": "/var/lib/docker/containers/ba033ac4401106a3b513bc9d639eee123ad78ca3616b921167cd74b20e25ed39/hosts",
	"LogPath": "/var/lib/docker/containers/1eb5fabf5a03807136561b3c00adcd2992b535d624d5e18b6cdc6a6844d9767b/1eb5fabf5a03807136561b3c00adcd2992b535d624d5e18b6cdc6a6844d9767b-json.log",
	"Id": "ba033ac4401106a3b513bc9d639eee123ad78ca3616b921167cd74b20e25ed39",
	"Image": "04c5d3b7b0656168630d3ba35d8889bd0e9caafcaeb3004d2bfbc47e7c5d35d2",
	"MountLabel": "",
	"Name": "/boring_euclid",
	"NetworkSettings": {
		"Bridge": "",
		"Gateway": "",
		"IPAddress": "",
		"IPPrefixLen": 0,
		"MacAddress": "",
		"PortMapping": null,
		"Ports": null
	},
	"Path": "/bin/sh",
	"ProcessLabel": "",
	"ResolvConfPath": "/var/lib/docker/containers/ba033ac4401106a3b513bc9d639eee123ad78ca3616b921167cd74b20e25ed39/resolv.conf",
	"RestartCount": 1,
	"State": {
		"Error": "",
		"ExitCode": 9,
		"FinishedAt": "2015-01-06T15:47:32.080254511Z",
		"OOMKilled": false,
		"Paused": false,
		"Pid": 0,
		"Restarting": false,
		"Running": true,
		"StartedAt": "2015-01-06T15:47:32.072697474Z"
	},
	"Volumes": {},
	"VolumesRW": {}
}

Status codes:

  • 200 – no error
  • 404 – no such container
  • 500 – server error

List processes running inside a container

GET /containers/(id or name)/top

List processes running inside the container id. On Unix systems this is done by running the ps command. This endpoint is not supported on Windows.

Example request:

GET /v1.19/containers/4fa6e0f0c678/top HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{
   "Titles" : [
     "UID", "PID", "PPID", "C", "STIME", "TTY", "TIME", "CMD"
   ],
   "Processes" : [
     [
       "root", "13642", "882", "0", "17:03", "pts/0", "00:00:00", "/bin/bash"
     ],
     [
       "root", "13735", "13642", "0", "17:06", "pts/0", "00:00:00", "sleep 10"
     ]
   ]
}

Example request:

GET /v1.19/containers/4fa6e0f0c678/top?ps_args=aux HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{
  "Titles" : [
    "USER","PID","%CPU","%MEM","VSZ","RSS","TTY","STAT","START","TIME","COMMAND"
  ]
  "Processes" : [
    [
      "root","13642","0.0","0.1","18172","3184","pts/0","Ss","17:03","0:00","/bin/bash"
    ],
    [
      "root","13895","0.0","0.0","4348","692","pts/0","S+","17:15","0:00","sleep 10"
    ]
  ],
}

Query parameters:

  • ps_args – ps arguments to use (e.g., aux), defaults to -ef

Status codes:

  • 200 – no error
  • 404 – no such container
  • 500 – server error

Get container logs

GET /containers/(id or name)/logs

Get stdout and stderr logs from the container id

Note: This endpoint works only for containers with the json-file or journald logging drivers.

Example request:

 GET /v1.19/containers/4fa6e0f0c678/logs?stderr=1&stdout=1&timestamps=1&follow=1&tail=10&since=1428990821 HTTP/1.1

Example response:

 HTTP/1.1 101 UPGRADED
 Content-Type: application/vnd.docker.raw-stream
 Connection: Upgrade
 Upgrade: tcp

 
 {{ STREAM }}

Query parameters:

  • follow – 1/True/true or 0/False/false, return stream. Default false.
  • stdout – 1/True/true or 0/False/false, show stdout log. Default false.
  • stderr – 1/True/true or 0/False/false, show stderr log. Default false.
  • since – UNIX timestamp (integer) to filter logs. Specifying a timestamp will only output log-entries since that timestamp. Default: 0 (unfiltered)
  • timestamps – 1/True/true or 0/False/false, print timestamps for every log line. Default false.
  • tail – Output specified number of lines at the end of logs: all or <number>. Default all.

Status codes:

  • 101 – no error, hints proxy about hijacking
  • 200 – no error, no upgrade header found
  • 404 – no such container
  • 500 – server error

Inspect changes on a container’s filesystem

GET /containers/(id or name)/changes

Inspect changes on container id’s filesystem

Example request:

GET /v1.19/containers/4fa6e0f0c678/changes HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

[
     {
             "Path": "/dev",
             "Kind": 0
     },
     {
             "Path": "/dev/kmsg",
             "Kind": 1
     },
     {
             "Path": "/test",
             "Kind": 1
     }
]

Values for Kind:

  • 0: Modify
  • 1: Add
  • 2: Delete

Status codes:

  • 200 – no error
  • 404 – no such container
  • 500 – server error

Export a container

GET /containers/(id or name)/export

Export the contents of container id

Example request:

GET /v1.19/containers/4fa6e0f0c678/export HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/octet-stream


{{ TAR STREAM }}

Status codes:

  • 200 – no error
  • 404 – no such container
  • 500 – server error

Get container stats based on resource usage

GET /containers/(id or name)/stats

This endpoint returns a live stream of a container’s resource usage statistics.

Example request:

GET /v1.19/containers/redis1/stats HTTP/1.1

Example response:

  HTTP/1.1 200 OK
  Content-Type: application/json

  {
     "read" : "2015-01-08T22:57:31.547920715Z",
     "network" : {
        "rx_dropped" : 0,
        "rx_bytes" : 648,
        "rx_errors" : 0,
        "tx_packets" : 8,
        "tx_dropped" : 0,
        "rx_packets" : 8,
        "tx_errors" : 0,
        "tx_bytes" : 648
     },
     "memory_stats" : {
        "stats" : {
           "total_pgmajfault" : 0,
           "cache" : 0,
           "mapped_file" : 0,
           "total_inactive_file" : 0,
           "pgpgout" : 414,
           "rss" : 6537216,
           "total_mapped_file" : 0,
           "writeback" : 0,
           "unevictable" : 0,
           "pgpgin" : 477,
           "total_unevictable" : 0,
           "pgmajfault" : 0,
           "total_rss" : 6537216,
           "total_rss_huge" : 6291456,
           "total_writeback" : 0,
           "total_inactive_anon" : 0,
           "rss_huge" : 6291456,
           "hierarchical_memory_limit" : 67108864,
           "total_pgfault" : 964,
           "total_active_file" : 0,
           "active_anon" : 6537216,
           "total_active_anon" : 6537216,
           "total_pgpgout" : 414,
           "total_cache" : 0,
           "inactive_anon" : 0,
           "active_file" : 0,
           "pgfault" : 964,
           "inactive_file" : 0,
           "total_pgpgin" : 477
        },
        "max_usage" : 6651904,
        "usage" : 6537216,
        "failcnt" : 0,
        "limit" : 67108864
     },
     "blkio_stats" : {},
     "cpu_stats" : {
        "cpu_usage" : {
           "percpu_usage" : [
              8646879,
              24472255,
              36438778,
              30657443
           ],
           "usage_in_usermode" : 50000000,
           "total_usage" : 100215355,
           "usage_in_kernelmode" : 30000000
        },
        "system_cpu_usage" : 739306590000000,
        "throttling_data" : {"periods":0,"throttled_periods":0,"throttled_time":0}
     },
     "precpu_stats" : {
        "cpu_usage" : {
           "percpu_usage" : [
              8646879,
              24350896,
              36438778,
              30657443
           ],
           "usage_in_usermode" : 50000000,
           "total_usage" : 100093996,
           "usage_in_kernelmode" : 30000000
        },
        "system_cpu_usage" : 9492140000000,
        "throttling_data" : {"periods":0,"throttled_periods":0,"throttled_time":0}
     }
  }

The precpu_stats is the cpu statistic of last read, which is used for calculating the cpu usage percent. It is not the exact copy of the cpu_stats field.

Query parameters:

  • stream – 1/True/true or 0/False/false, pull stats once then disconnect. Default true.

Status codes:

  • 200 – no error
  • 404 – no such container
  • 500 – server error

Resize a container TTY

POST /containers/(id or name)/resize?h=<height>&w=<width>

Resize the TTY for container with id. You must restart the container for the resize to take effect.

Example request:

  POST /v1.19/containers/4fa6e0f0c678/resize?h=40&w=80 HTTP/1.1

Example response:

  HTTP/1.1 200 OK
  Content-Length: 0
  Content-Type: text/plain; charset=utf-8

Query parameters:

  • h – height of tty session
  • w – width

Status codes:

  • 200 – no error
  • 404 – No such container
  • 500 – Cannot resize container

Start a container

POST /containers/(id or name)/start

Start the container id

Note: For backwards compatibility, this endpoint accepts a HostConfig as JSON-encoded request body. See create a container for details.

Example request:

POST /v1.19/containers/e90e34656806/start HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Status codes:

  • 204 – no error
  • 304 – container already started
  • 404 – no such container
  • 500 – server error

Stop a container

POST /containers/(id or name)/stop

Stop the container id

Example request:

POST /v1.19/containers/e90e34656806/stop?t=5 HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Query parameters:

  • t – number of seconds to wait before killing the container

Status codes:

  • 204 – no error
  • 304 – container already stopped
  • 404 – no such container
  • 500 – server error

Restart a container

POST /containers/(id or name)/restart

Restart the container id

Example request:

POST /v1.19/containers/e90e34656806/restart?t=5 HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Query parameters:

  • t – number of seconds to wait before killing the container

Status codes:

  • 204 – no error
  • 404 – no such container
  • 500 – server error

Kill a container

POST /containers/(id or name)/kill

Kill the container id

Example request:

POST /v1.19/containers/e90e34656806/kill HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Query parameters:

  • signal - Signal to send to the container: integer or string like SIGINT. When not set, SIGKILL is assumed and the call waits for the container to exit.

Status codes:

  • 204 – no error
  • 404 – no such container
  • 500 – server error

Rename a container

POST /containers/(id or name)/rename

Rename the container id to a new_name

Example request:

POST /v1.19/containers/e90e34656806/rename?name=new_name HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Query parameters:

  • name – new name for the container

Status codes:

  • 204 – no error
  • 404 – no such container
  • 409 - conflict name already assigned
  • 500 – server error

Pause a container

POST /containers/(id or name)/pause

Pause the container id

Example request:

POST /v1.19/containers/e90e34656806/pause HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Status codes:

  • 204 – no error
  • 404 – no such container
  • 500 – server error

Unpause a container

POST /containers/(id or name)/unpause

Unpause the container id

Example request:

POST /v1.19/containers/e90e34656806/unpause HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Status codes:

  • 204 – no error
  • 404 – no such container
  • 500 – server error

Attach to a container

POST /containers/(id or name)/attach

Attach to the container id

Example request:

POST /v1.19/containers/16253994b7c4/attach?logs=1&stream=0&stdout=1 HTTP/1.1

Example response:

HTTP/1.1 101 UPGRADED
Content-Type: application/vnd.docker.raw-stream
Connection: Upgrade
Upgrade: tcp


{{ STREAM }}

Query parameters:

  • logs – 1/True/true or 0/False/false, return logs. Default false.
  • stream – 1/True/true or 0/False/false, return stream. Default false.
  • stdin – 1/True/true or 0/False/false, if stream=true, attach to stdin. Default false.
  • stdout – 1/True/true or 0/False/false, if logs=true, return stdout log, if stream=true, attach to stdout. Default false.
  • stderr – 1/True/true or 0/False/false, if logs=true, return stderr log, if stream=true, attach to stderr. Default false.

Status codes:

  • 101 – no error, hints proxy about hijacking
  • 200 – no error, no upgrade header found
  • 400 – bad parameter
  • 404 – no such container
  • 500 – server error

Stream details:

When using the TTY setting is enabled in POST /containers/create , the stream is the raw data from the process PTY and client’s stdin. When the TTY is disabled, then the stream is multiplexed to separate stdout and stderr.

The format is a Header and a Payload (frame).

HEADER

The header contains the information which the stream writes (stdout or stderr). It also contains the size of the associated frame encoded in the last four bytes (uint32).

It is encoded on the first eight bytes like this:

header := [8]byte{STREAM_TYPE, 0, 0, 0, SIZE1, SIZE2, SIZE3, SIZE4}

STREAM_TYPE can be:

  • 0: stdin (is written on stdout)
  • 1: stdout
  • 2: stderr

SIZE1, SIZE2, SIZE3, SIZE4 are the four bytes of the uint32 size encoded as big endian.

PAYLOAD

The payload is the raw stream.

IMPLEMENTATION

The simplest way to implement the Attach protocol is the following:

1.  Read eight bytes.
2.  Choose `stdout` or `stderr` depending on the first byte.
3.  Extract the frame size from the last four bytes.
4.  Read the extracted size and output it on the correct output.
5.  Goto 1.

Attach to a container (websocket)

GET /containers/(id or name)/attach/ws

Attach to the container id via websocket

Implements websocket protocol handshake according to RFC 6455

Example request

GET /v1.19/containers/e90e34656806/attach/ws?logs=0&stream=1&stdin=1&stdout=1&stderr=1 HTTP/1.1

Example response

{{ STREAM }}

Query parameters:

  • logs – 1/True/true or 0/False/false, return logs. Default false.
  • stream – 1/True/true or 0/False/false, return stream. Default false.
  • stdin – 1/True/true or 0/False/false, if stream=true, attach to stdin. Default false.
  • stdout – 1/True/true or 0/False/false, if logs=true, return stdout log, if stream=true, attach to stdout. Default false.
  • stderr – 1/True/true or 0/False/false, if logs=true, return stderr log, if stream=true, attach to stderr. Default false.

Status codes:

  • 200 – no error
  • 400 – bad parameter
  • 404 – no such container
  • 500 – server error

Wait a container

POST /containers/(id or name)/wait

Block until container id stops, then returns the exit code

Example request:

POST /v1.19/containers/16253994b7c4/wait HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{"StatusCode": 0}

Status codes:

  • 200 – no error
  • 404 – no such container
  • 500 – server error

Remove a container

DELETE /containers/(id or name)

Remove the container id from the filesystem

Example request:

DELETE /v1.19/containers/16253994b7c4?v=1 HTTP/1.1

Example response:

HTTP/1.1 204 No Content

Query parameters:

  • v – 1/True/true or 0/False/false, Remove the volumes associated to the container. Default false.
  • force - 1/True/true or 0/False/false, Kill then remove the container. Default false.
  • link - 1/True/true or 0/False/false, Remove the specified link associated to the container. Default false.

Status codes:

  • 204 – no error
  • 400 – bad parameter
  • 404 – no such container
  • 409 – conflict
  • 500 – server error

Copy files or folders from a container

POST /containers/(id or name)/copy

Copy files or folders of container id

Example request:

POST /v1.19/containers/4fa6e0f0c678/copy HTTP/1.1
Content-Type: application/json

{
     "Resource": "test.txt"
}

Example response:

HTTP/1.1 200 OK
Content-Type: application/x-tar


{{ TAR STREAM }}

Status codes:

  • 200 – no error
  • 404 – no such container
  • 500 – server error

2.2 Images

List Images

GET /images/json

Example request:

GET /v1.19/images/json?all=0 HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

[
  {
     "RepoTags": [
       "ubuntu:12.04",
       "ubuntu:precise",
       "ubuntu:latest"
     ],
     "Id": "8dbd9e392a964056420e5d58ca5cc376ef18e2de93b5cc90e868a1bbc8318c1c",
     "Created": 1365714795,
     "Size": 131506275,
     "VirtualSize": 131506275,
     "Labels": {}
  },
  {
     "RepoTags": [
       "ubuntu:12.10",
       "ubuntu:quantal"
     ],
     "ParentId": "27cf784147099545",
     "Id": "b750fe79269d2ec9a3c593ef05b4332b1d1a02a62b4accb2c21d589ff2f5f2dc",
     "Created": 1364102658,
     "Size": 24653,
     "VirtualSize": 180116135,
     "Labels": {
        "com.example.version": "v1"
     }
  }
]

Example request, with digest information:

GET /v1.19/images/json?digests=1 HTTP/1.1

Example response, with digest information:

HTTP/1.1 200 OK
Content-Type: application/json

[
  {
    "Created": 1420064636,
    "Id": "4986bf8c15363d1c5d15512d5266f8777bfba4974ac56e3270e7760f6f0a8125",
    "ParentId": "ea13149945cb6b1e746bf28032f02e9b5a793523481a0a18645fc77ad53c4ea2",
    "RepoDigests": [
      "localhost:5000/test/busybox@sha256:cbbf2f9a99b47fc460d422812b6a5adff7dfee951d8fa2e4a98caa0382cfbdbf"
    ],
    "RepoTags": [
      "localhost:5000/test/busybox:latest",
      "playdate:latest"
    ],
    "Size": 0,
    "VirtualSize": 2429728,
    "Labels": {}
  }
]

The response shows a single image Id associated with two repositories (RepoTags): localhost:5000/test/busybox: and playdate. A caller can use either of the RepoTags values localhost:5000/test/busybox:latest or playdate:latest to reference the image.

You can also use RepoDigests values to reference an image. In this response, the array has only one reference and that is to the localhost:5000/test/busybox repository; the playdate repository has no digest. You can reference this digest using the value: localhost:5000/test/busybox@sha256:cbbf2f9a99b47fc460d...

See the docker run and docker build commands for examples of digest and tag references on the command line.

Query parameters:

  • all – 1/True/true or 0/False/false, default false
  • filters – a JSON encoded value of the filters (a map[string][]string) to process on the images list. Available filters:
  • dangling=true
  • label=key or label="key=value" of an image label
  • filter - only return images with the specified name

Build image from a Dockerfile

POST /build

Build an image from a Dockerfile

Example request:

POST /v1.19/build HTTP/1.1
Content-Type: application/x-tar


{{ TAR STREAM }}

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{"stream": "Step 1/5..."}
{"stream": "..."}
{"error": "Error...", "errorDetail": {"code": 123, "message": "Error..."}}

The input stream must be a tar archive compressed with one of the following algorithms: identity (no compression), gzip, bzip2, xz.

The archive must include a build instructions file, typically called Dockerfile at the archive’s root. The dockerfile parameter may be used to specify a different build instructions file. To do this, its value must be the path to the alternate build instructions file to use.

The archive may include any number of other files, which are accessible in the build context (See the ADD build command).

The Docker daemon performs a preliminary validation of the Dockerfile before starting the build, and returns an error if the syntax is incorrect. After that, each instruction is run one-by-one until the ID of the new image is output.

The build is canceled if the client drops the connection by quitting or being killed.

Query parameters:

  • dockerfile - Path within the build context to the Dockerfile. This is ignored if remote is specified and points to an individual filename.
  • t – A name and optional tag to apply to the image in the name:tag format. If you omit the tag the default latest value is assumed.
  • remote – A Git repository URI or HTTP/HTTPS URI build source. If the URI specifies a filename, the file’s contents are placed into a file called Dockerfile.
  • q – Suppress verbose build output.
  • nocache – Do not use the cache when building the image.
  • pull - Attempt to pull the image even if an older image exists locally.
  • rm - Remove intermediate containers after a successful build (default behavior).
  • forcerm - Always remove intermediate containers (includes rm).
  • memory - Set memory limit for build.
  • memswap - Total memory (memory + swap), -1 to enable unlimited swap.
  • cpushares - CPU shares (relative weight).
  • cpusetcpus - CPUs in which to allow execution (e.g., 0-3, 0,1).
  • cpuperiod - The length of a CPU period in microseconds.
  • cpuquota - Microseconds of CPU time that the container can get in a CPU period.

Request Headers:

  • Content-type – Set to "application/x-tar".
  • X-Registry-Config – base64-encoded ConfigFile object

Status codes:

  • 200 – no error
  • 500 – server error

Create an image

POST /images/create

Create an image either by pulling it from the registry or by importing it

Example request:

POST /v1.19/images/create?fromImage=busybox&tag=latest HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{"status": "Pulling..."}
{"status": "Pulling", "progress": "1 B/ 100 B", "progressDetail": {"current": 1, "total": 100}}
{"error": "Invalid..."}
...

When using this endpoint to pull an image from the registry, the X-Registry-Auth header can be used to include a base64-encoded AuthConfig object.

Query parameters:

  • fromImage – Name of the image to pull.
  • fromSrc – Source to import. The value may be a URL from which the image can be retrieved or - to read the image from the request body.
  • repo – Repository name.
  • tag – Tag. If empty when pulling an image, this causes all tags for the given image to be pulled.

Request Headers:

  • X-Registry-Auth – base64-encoded AuthConfig object

Status codes:

  • 200 – no error
  • 404 - repository does not exist or no read access
  • 500 – server error

Inspect an image

GET /images/(name)/json

Return low-level information on the image name

Example request:

GET /v1.19/images/ubuntu/json HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{
   "Created": "2013-03-23T22:24:18.818426-07:00",
   "Container": "3d67245a8d72ecf13f33dffac9f79dcdf70f75acb84d308770391510e0c23ad0",
   "ContainerConfig": {
      "Hostname": "",
      "User": "",
      "AttachStdin": false,
      "AttachStdout": false,
      "AttachStderr": false,
      "Tty": true,
      "OpenStdin": true,
      "StdinOnce": false,
      "Env": null,
      "Cmd": ["/bin/bash"],
      "Dns": null,
      "Image": "ubuntu",
      "Labels": {
         "com.example.vendor": "Acme",
         "com.example.license": "GPL",
         "com.example.version": "1.0"
      },
      "Volumes": null,
      "VolumesFrom": "",
      "WorkingDir": ""
   },
   "Id": "b750fe79269d2ec9a3c593ef05b4332b1d1a02a62b4accb2c21d589ff2f5f2dc",
   "Parent": "27cf784147099545",
   "Size": 6824592
}

Status codes:

  • 200 – no error
  • 404 – no such image
  • 500 – server error

Get the history of an image

GET /images/(name)/history

Return the history of the image name

Example request:

GET /v1.19/images/ubuntu/history HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

[
    {
        "Id": "3db9c44f45209632d6050b35958829c3a2aa256d81b9a7be45b362ff85c54710",
        "Created": 1398108230,
        "CreatedBy": "/bin/sh -c #(nop) ADD file:eb15dbd63394e063b805a3c32ca7bf0266ef64676d5a6fab4801f2e81e2a5148 in /",
        "Tags": [
            "ubuntu:lucid",
            "ubuntu:10.04"
        ],
        "Size": 182964289,
        "Comment": ""
    },
    {
        "Id": "6cfa4d1f33fb861d4d114f43b25abd0ac737509268065cdfd69d544a59c85ab8",
        "Created": 1398108222,
        "CreatedBy": "/bin/sh -c #(nop) MAINTAINER Tianon Gravi <admwiggin@gmail.com> - mkimage-debootstrap.sh -i iproute,iputils-ping,ubuntu-minimal -t lucid.tar.xz lucid http://archive.ubuntu.com/ubuntu/",
        "Tags": null,
        "Size": 0,
        "Comment": ""
    },
    {
        "Id": "511136ea3c5a64f264b78b5433614aec563103b4d4702f3ba7d4d2698e22c158",
        "Created": 1371157430,
        "CreatedBy": "",
        "Tags": [
            "scratch12:latest",
            "scratch:latest"
        ],
        "Size": 0,
        "Comment": "Imported from -"
    }
]

Status codes:

  • 200 – no error
  • 404 – no such image
  • 500 – server error

Push an image on the registry

POST /images/(name)/push

Push the image name on the registry

Example request:

POST /v1.19/images/test/push HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{"status": "Pushing..."}
{"status": "Pushing", "progress": "1/? (n/a)", "progressDetail": {"current": 1}}}
{"error": "Invalid..."}
...

If you wish to push an image on to a private registry, that image must already have a tag into a repository which references that registry hostname and port. This repository name should then be used in the URL. This duplicates the command line’s flow.

Example request:

POST /v1.19/images/registry.acme.com:5000/test/push HTTP/1.1

Query parameters:

  • tag – The tag to associate with the image on the registry. This is optional.

Request Headers:

  • X-Registry-Auth – base64-encoded AuthConfig object.

Status codes:

  • 200 – no error
  • 404 – no such image
  • 500 – server error

Tag an image into a repository

POST /images/(name)/tag

Tag the image name into a repository

Example request:

POST /v1.19/images/test/tag?repo=myrepo&force=0&tag=v42 HTTP/1.1

Example response:

HTTP/1.1 201 Created

Query parameters:

  • repo – The repository to tag in
  • force – 1/True/true or 0/False/false, default false
  • tag - The new tag name

Status codes:

  • 201 – no error
  • 400 – bad parameter
  • 404 – no such image
  • 409 – conflict
  • 500 – server error

Remove an image

DELETE /images/(name)

Remove the image name from the filesystem

Example request:

DELETE /v1.19/images/test HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-type: application/json

[
 {"Untagged": "3e2f21a89f"},
 {"Deleted": "3e2f21a89f"},
 {"Deleted": "53b4f83ac9"}
]

Query parameters:

  • force – 1/True/true or 0/False/false, default false
  • noprune – 1/True/true or 0/False/false, default false

Status codes:

  • 200 – no error
  • 404 – no such image
  • 409 – conflict
  • 500 – server error

Search images

GET /images/search

Search for an image on Docker Hub. This API returns both is_trusted and is_automated images. Currently, they are considered identical. In the future, the is_trusted property will be deprecated and replaced by the is_automated property.

Note: The response keys have changed from API v1.6 to reflect the JSON sent by the registry server to the docker daemon’s request.

Example request:

GET /v1.19/images/search?term=sshd HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

[
        {
            "star_count": 12,
            "is_official": false,
            "name": "wma55/u1210sshd",
            "is_trusted": false,
            "is_automated": false,
            "description": ""
        },
        {
            "star_count": 10,
            "is_official": false,
            "name": "jdswinbank/sshd",
            "is_trusted": false,
            "is_automated": false,
            "description": ""
        },
        {
            "star_count": 18,
            "is_official": false,
            "name": "vgauthier/sshd",
            "is_trusted": false,
            "is_automated": false,
            "description": ""
        }
...
]

Query parameters:

  • term – term to search

Status codes:

  • 200 – no error
  • 500 – server error

2.3 Misc

Check auth configuration

POST /auth

Get the default username and email

Example request:

POST /v1.19/auth HTTP/1.1
Content-Type: application/json

{
     "username": "hannibal",
     "password": "xxxx",
     "email": "hannibal@a-team.com",
     "serveraddress": "https://index.docker.io/v1/"
}

Example response:

HTTP/1.1 200 OK

Status codes:

  • 200 – no error
  • 204 – no error
  • 500 – server error

Display system-wide information

GET /info

Display system-wide information

Example request:

GET /v1.19/info HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{
    "Containers": 11,
    "CpuCfsPeriod": true,
    "CpuCfsQuota": true,
    "Debug": false,
    "DockerRootDir": "/var/lib/docker",
    "Driver": "btrfs",
    "DriverStatus": [[""]],
    "ExecutionDriver": "native-0.1",
    "ExperimentalBuild": false,
    "HttpProxy": "http://test:test@localhost:8080",
    "HttpsProxy": "https://test:test@localhost:8080",
    "ID": "7TRN:IPZB:QYBB:VPBQ:UMPP:KARE:6ZNR:XE6T:7EWV:PKF4:ZOJD:TPYS",
    "IPv4Forwarding": true,
    "Images": 16,
    "IndexServerAddress": "https://index.docker.io/v1/",
    "InitPath": "/usr/bin/docker",
    "InitSha1": "",
    "KernelVersion": "3.12.0-1-amd64",
    "Labels": [
        "storage=ssd"
    ],
    "MemTotal": 2099236864,
    "MemoryLimit": true,
    "NCPU": 1,
    "NEventsListener": 0,
    "NFd": 11,
    "NGoroutines": 21,
    "Name": "prod-server-42",
    "NoProxy": "9.81.1.160",
    "OomKillDisable": true,
    "OperatingSystem": "Boot2Docker",
    "RegistryConfig": {
        "IndexConfigs": {
            "docker.io": {
                "Mirrors": null,
                "Name": "docker.io",
                "Official": true,
                "Secure": true
            }
        },
        "InsecureRegistryCIDRs": [
            "127.0.0.0/8"
        ]
    },
    "SwapLimit": false,
    "SystemTime": "2015-03-10T11:11:23.730591467-07:00"
}

Status codes:

  • 200 – no error
  • 500 – server error

Show the docker version information

GET /version

Show the docker version information

Example request:

GET /v1.19/version HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{
     "Version": "1.5.0",
     "Os": "linux",
     "KernelVersion": "3.18.5-tinycore64",
     "GoVersion": "go1.4.1",
     "GitCommit": "a8a31ef",
     "Arch": "amd64",
     "ApiVersion": "1.19"
}

Status codes:

  • 200 – no error
  • 500 – server error

Ping the docker server

GET /_ping

Ping the docker server

Example request:

GET /v1.19/_ping HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: text/plain

OK

Status codes:

  • 200 - no error
  • 500 - server error

Create a new image from a container’s changes

POST /commit

Create a new image from a container’s changes

Example request:

POST /v1.19/commit?container=44c004db4b17&comment=message&repo=myrepo HTTP/1.1
Content-Type: application/json

{
     "Hostname": "",
     "Domainname": "",
     "User": "",
     "AttachStdin": false,
     "AttachStdout": true,
     "AttachStderr": true,
     "PortSpecs": null,
     "Tty": false,
     "OpenStdin": false,
     "StdinOnce": false,
     "Env": null,
     "Cmd": [
             "date"
     ],
     "Volumes": {
             "/tmp": {}
     },
     "Labels": {
             "key1": "value1",
             "key2": "value2"
      },
     "WorkingDir": "",
     "NetworkDisabled": false,
     "ExposedPorts": {
             "22/tcp": {}
     }
}

Example response:

HTTP/1.1 201 Created
Content-Type: application/json

{"Id": "596069db4bf5"}

JSON parameters:

  • config - the container’s configuration

Query parameters:

  • container – source container
  • repo – repository
  • tag – tag
  • comment – commit message
  • author – author (e.g., “John Hannibal Smith <hannibal@a-team.com>”)

Status codes:

  • 201 – no error
  • 404 – no such container
  • 500 – server error

Monitor Docker’s events

GET /events

Get container events from docker, in real time via streaming.

Docker containers report the following events:

attach, commit, copy, create, destroy, die, exec_create, exec_start, export, kill, oom, pause, rename, resize, restart, start, stop, top, unpause

Docker images report the following events:

untag, delete

Example request:

GET /v1.19/events?since=1374067924

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{"status": "create", "id": "dfdf82bd3881","from": "ubuntu:latest", "time":1374067924}
{"status": "start", "id": "dfdf82bd3881","from": "ubuntu:latest", "time":1374067924}
{"status": "stop", "id": "dfdf82bd3881","from": "ubuntu:latest", "time":1374067966}
{"status": "destroy", "id": "dfdf82bd3881","from": "ubuntu:latest", "time":1374067970}

Query parameters:

  • since – Timestamp. Show all events created since timestamp and then stream
  • until – Timestamp. Show events created until given timestamp and stop streaming
  • filters – A json encoded value of the filters (a map[string][]string) to process on the event list. Available filters:
  • container=<string>; – container to filter
  • event=<string>; – event to filter
  • image=<string>; – image to filter

Status codes:

  • 200 – no error
  • 500 – server error

Get a tarball containing all images in a repository

GET /images/(name)/get

Get a tarball containing all images and metadata for the repository specified by name.

If name is a specific name and tag (e.g. ubuntu:latest), then only that image (and its parents) are returned. If name is an image ID, similarly only that image (and its parents) are returned, but with the exclusion of the ‘repositories’ file in the tarball, as there were no image names referenced.

See the image tarball format for more details.

Example request

GET /v1.19/images/ubuntu/get

Example response:

HTTP/1.1 200 OK
Content-Type: application/x-tar

Binary data stream

Status codes:

  • 200 – no error
  • 500 – server error

Get a tarball containing all images

GET /images/get

Get a tarball containing all images and metadata for one or more repositories.

For each value of the names parameter: if it is a specific name and tag (e.g. ubuntu:latest), then only that image (and its parents) are returned; if it is an image ID, similarly only that image (and its parents) are returned and there would be no names referenced in the ‘repositories’ file for this image ID.

See the image tarball format for more details.

Example request

GET /v1.19/images/get?names=myname%2Fmyapp%3Alatest&names=busybox

Example response:

HTTP/1.1 200 OK
Content-Type: application/x-tar

Binary data stream

Status codes:

  • 200 – no error
  • 500 – server error

Load a tarball with a set of images and tags into docker

POST /images/load

Load a set of images and tags into a Docker repository. See the image tarball format for more details.

Example request

POST /v1.19/images/load
Content-Type: application/x-tar

Tarball in body

Example response:

HTTP/1.1 200 OK

Status codes:

  • 200 – no error
  • 500 – server error

Image tarball format

An image tarball contains one directory per image layer (named using its long ID), each containing these files:

  • VERSION: currently 1.0 - the file format version
  • json: detailed layer information, similar to docker inspect layer_id
  • layer.tar: A tarfile containing the filesystem changes in this layer

The layer.tar file contains aufs style .wh..wh.aufs files and directories for storing attribute changes and deletions.

If the tarball defines a repository, the tarball should also include a repositories file at the root that contains a list of repository and tag names mapped to layer IDs.

{"hello-world":
    {"latest": "565a9d68a73f6706862bfe8409a7f659776d4d60a8d096eb4a3cbce6999cc2a1"}
}

Exec Create

POST /containers/(id or name)/exec

Sets up an exec instance in a running container id

Example request:

POST /v1.19/containers/e90e34656806/exec HTTP/1.1
Content-Type: application/json

{
  "AttachStdin": true,
  "AttachStdout": true,
  "AttachStderr": true,
  "Cmd": ["sh"],
  "Tty": true,
  "User": "123:456"
}

Example response:

HTTP/1.1 201 Created
Content-Type: application/json

{
     "Id": "f90e34656806",
     "Warnings":[]
}

JSON parameters:

  • AttachStdin - Boolean value, attaches to stdin of the exec command.
  • AttachStdout - Boolean value, attaches to stdout of the exec command.
  • AttachStderr - Boolean value, attaches to stderr of the exec command.
  • Tty - Boolean value to allocate a pseudo-TTY.
  • Cmd - Command to run specified as a string or an array of strings.
  • User - A string value specifying the user, and optionally, group to run the exec process inside the container. Format is one of: "user", "user:group", "uid", or "uid:gid".

Status codes:

  • 201 – no error
  • 404 – no such container

Exec Start

POST /exec/(id)/start

Starts a previously set up exec instance id. If detach is true, this API returns after starting the exec command. Otherwise, this API sets up an interactive session with the exec command.

Example request:

POST /v1.19/exec/e90e34656806/start HTTP/1.1
Content-Type: application/json

{
 "Detach": false,
 "Tty": false
}

Example response:

HTTP/1.1 200 OK
Content-Type: application/vnd.docker.raw-stream


{{ STREAM }}

JSON parameters:

  • Detach - Detach from the exec command.
  • Tty - Boolean value to allocate a pseudo-TTY.

Status codes:

  • 200 – no error
  • 404 – no such exec instance

Stream details:

Similar to the stream behavior of POST /containers/(id or name)/attach API

Exec Resize

POST /exec/(id)/resize

Resizes the tty session used by the exec command id. The unit is number of characters. This API is valid only if tty was specified as part of creating and starting the exec command.

Example request:

POST /v1.19/exec/e90e34656806/resize?h=40&w=80 HTTP/1.1
Content-Type: text/plain

Example response:

HTTP/1.1 201 Created
Content-Type: text/plain

Query parameters:

  • h – height of tty session
  • w – width

Status codes:

  • 201 – no error
  • 404 – no such exec instance

Exec Inspect

GET /exec/(id)/json

Return low-level information about the exec command id.

Example request:

GET /v1.19/exec/11fb006128e8ceb3942e7c58d77750f24210e35f879dd204ac975c184b820b39/json HTTP/1.1

Example response:

HTTP/1.1 200 OK
Content-Type: plain/text

{
  "ID" : "11fb006128e8ceb3942e7c58d77750f24210e35f879dd204ac975c184b820b39",
  "Running" : false,
  "ExitCode" : 2,
  "ProcessConfig" : {
    "privileged" : false,
    "user" : "",
    "tty" : false,
    "entrypoint" : "sh",
    "arguments" : [
      "-c",
      "exit 2"
    ]
  },
  "OpenStdin" : false,
  "OpenStderr" : false,
  "OpenStdout" : false,
  "Container" : {
    "State" : {
      "Running" : true,
      "Paused" : false,
      "Restarting" : false,
      "OOMKilled" : false,
      "Pid" : 3650,
      "ExitCode" : 0,
      "Error" : "",
      "StartedAt" : "2014-11-17T22:26:03.717657531Z",
      "FinishedAt" : "0001-01-01T00:00:00Z"
    },
    "ID" : "8f177a186b977fb451136e0fdf182abff5599a08b3c7f6ef0d36a55aaf89634c",
    "Created" : "2014-11-17T22:26:03.626304998Z",
    "Path" : "date",
    "Args" : [],
    "Config" : {
      "Hostname" : "8f177a186b97",
      "Domainname" : "",
      "User" : "",
      "AttachStdin" : false,
      "AttachStdout" : false,
      "AttachStderr" : false,
      "PortSpecs": null,
      "ExposedPorts" : null,
      "Tty" : false,
      "OpenStdin" : false,
      "StdinOnce" : false,
      "Env" : [ "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" ],
      "Cmd" : [
        "date"
      ],
      "Image" : "ubuntu",
      "Volumes" : null,
      "WorkingDir" : "",
      "Entrypoint" : null,
      "NetworkDisabled" : false,
      "MacAddress" : "",
      "OnBuild" : null,
      "SecurityOpt" : null
    },
    "Image" : "5506de2b643be1e6febbf3b8a240760c6843244c41e12aa2f60ccbb7153d17f5",
    "NetworkSettings" : {
      "IPAddress" : "172.17.0.2",
      "IPPrefixLen" : 16,
      "MacAddress" : "02:42:ac:11:00:02",
      "Gateway" : "172.17.42.1",
      "Bridge" : "docker0",
      "PortMapping" : null,
      "Ports" : {}
    },
    "ResolvConfPath" : "/var/lib/docker/containers/8f177a186b977fb451136e0fdf182abff5599a08b3c7f6ef0d36a55aaf89634c/resolv.conf",
    "HostnamePath" : "/var/lib/docker/containers/8f177a186b977fb451136e0fdf182abff5599a08b3c7f6ef0d36a55aaf89634c/hostname",
    "HostsPath" : "/var/lib/docker/containers/8f177a186b977fb451136e0fdf182abff5599a08b3c7f6ef0d36a55aaf89634c/hosts",
    "LogPath": "/var/lib/docker/containers/1eb5fabf5a03807136561b3c00adcd2992b535d624d5e18b6cdc6a6844d9767b/1eb5fabf5a03807136561b3c00adcd2992b535d624d5e18b6cdc6a6844d9767b-json.log",
    "Name" : "/test",
    "Driver" : "aufs",
    "ExecDriver" : "native-0.2",
    "MountLabel" : "",
    "ProcessLabel" : "",
    "AppArmorProfile" : "",
    "RestartCount" : 0,
    "Volumes" : {},
    "VolumesRW" : {}
  }
}

Status codes:

  • 200 – no error
  • 404 – no such exec instance
  • 500 - server error

3. Going further

3.1 Inside docker run

As an example, the docker run command line makes the following API calls:

  • Create the container

  • If the status code is 404, it means the image doesn’t exist:
    • Try to pull it.
    • Then, retry to create the container.

  • Start the container.

  • If you are not in detached mode:

  • Attach to the container, using logs=1 (to have stdout and stderr from the container’s start) and stream=1

  • If in detached mode or only stdin is attached, display the container’s id.

3.2 Hijacking

In this version of the API, /attach, uses hijacking to transport stdin, stdout, and stderr on the same socket.

To hint potential proxies about connection hijacking, Docker client sends connection upgrade headers similarly to websocket.

Upgrade: tcp
Connection: Upgrade

When Docker daemon detects the Upgrade header, it switches its status code from 200 OK to 101 UPGRADED and resends the same headers.

3.3 CORS Requests

To set cross origin requests to the Engine API please give values to --api-cors-header when running Docker in daemon mode. Set * (asterisk) allows all, default or blank means CORS disabled

$ docker -d -H="192.168.1.9:2375" --api-cors-header="http://foo.bar"
API, Docker, rcli, REST, documentation