Allocations HTTP API

The /allocation endpoints are used to query for and interact with allocations.

List Allocations

This endpoint lists all allocations.

Method	Path	Produces
`GET`	`/v1/allocations`	`application/json`

The table below shows this endpoint's support for blocking queries and required ACLs.

Blocking Queries	ACL Required
`YES`	`namespace:read-job`

Parameters

prefix (string: "")- Specifies a string to filter allocations based on an ID prefix. Because the value is decoded to bytes, the prefix must have an even number of hexadecimal characters (0-9a-f). This is specified as a query string parameter.
next_token (string: "") - This endpoint supports paging. The next_token parameter accepts a string which identifies the next expected allocation. This value can be obtained from the X-Nomad-NextToken header from the previous response.
per_page (int: 0) - Specifies a maximum number of allocations to return for this request. If omitted, the response is not paginated. The value of the X-Nomad-NextToken header of the last response can be used as the next_token of the next request to fetch additional pages.
filter (string: "") - Specifies the expression used to filter the results. Consider using pagination or a query parameter to reduce resource used to serve the request.
namespace (string: "default") - Specifies the namespace to search. Specifying * would return all allocations across all the authorized namespaces.
resources (bool: false) - Specifies whether or not to include the AllocatedResources field in the response.
task_states (bool: true) - Specifies whether or not to include the TaskStates field in the response. TaskStates are included by default but can represent a large percentage of the overall response size. Clusters with a large number of allocations may set task_states=false to significantly reduce the size of the response.
reverse (bool: false) - Specifies the list of returned allocations should be sorted in the reverse order. By default allocations are returned sorted in chronological order (older evaluations first), or in lexicographical order by their ID if the prefix query parameter is used.

Sample Request

$ curl \
    https://localhost:4646/v1/allocations

$ curl \
    https://localhost:4646/v1/allocations?prefix=a8198d79

$ curl \
    https://localhost:4646/v1/allocations?namespace=*&prefix=a8198d79

Sample Response

[
  {
    "ClientDescription": "Tasks are running",
    "ClientStatus": "running",
    "CreateIndex": 10,
    "CreateTime": 1636017249798459000,
    "DeploymentStatus": {
      "Canary": false,
      "Healthy": true,
      "ModifyIndex": 15,
      "Timestamp": "2021-11-04T10:14:22.054814+01:00"
    },
    "DesiredDescription": "",
    "DesiredStatus": "run",
    "DesiredTransition": {
      "ForceReschedule": null,
      "Migrate": null,
      "Reschedule": null
    },
    "EvalID": "cb20d15d-861f-8d8d-8253-e93932beea2e",
    "FollowupEvalID": "",
    "ID": "5457f16d-0f87-8e6b-5e91-0c7da3a41eb7",
    "JobID": "example",
    "JobType": "service",
    "JobVersion": 0,
    "ModifyIndex": 15,
    "ModifyTime": 1636017262190928000,
    "Name": "example.cache[0]",
    "Namespace": "default",
    "NodeID": "f476d2b4-02dc-c216-d031-273396727347",
    "NodeName": "linux",
    "PreemptedAllocations": null,
    "PreemptedByAllocation": "",
    "RescheduleTracker": null,
    "TaskGroup": "cache",
    "TaskStates": {
      "redis": {
        "Events": [
          {
            "Details": {},
            "DiskLimit": 0,
            "DisplayMessage": "Task received by client",
            "DownloadError": "",
            "DriverError": "",
            "DriverMessage": "",
            "ExitCode": 0,
            "FailedSibling": "",
            "FailsTask": false,
            "GenericSource": "",
            "KillError": "",
            "KillReason": "",
            "KillTimeout": 0,
            "Message": "",
            "RestartReason": "",
            "SetupError": "",
            "Signal": 0,
            "StartDelay": 0,
            "TaskSignal": "",
            "TaskSignalReason": "",
            "Time": 1636017249803624000,
            "Type": "Received",
            "ValidationError": "",
            "VaultError": ""
          },
          {
            "Details": {
              "message": "Building Task Directory"
            },
            "DiskLimit": 0,
            "DisplayMessage": "Building Task Directory",
            "DownloadError": "",
            "DriverError": "",
            "DriverMessage": "",
            "ExitCode": 0,
            "FailedSibling": "",
            "FailsTask": false,
            "GenericSource": "",
            "KillError": "",
            "KillReason": "",
            "KillTimeout": 0,
            "Message": "Building Task Directory",
            "RestartReason": "",
            "SetupError": "",
            "Signal": 0,
            "StartDelay": 0,
            "TaskSignal": "",
            "TaskSignalReason": "",
            "Time": 1636017249805254000,
            "Type": "Task Setup",
            "ValidationError": "",
            "VaultError": ""
          },
          {
            "Details": {},
            "DiskLimit": 0,
            "DisplayMessage": "Task started by client",
            "DownloadError": "",
            "DriverError": "",
            "DriverMessage": "",
            "ExitCode": 0,
            "FailedSibling": "",
            "FailsTask": false,
            "GenericSource": "",
            "KillError": "",
            "KillReason": "",
            "KillTimeout": 0,
            "Message": "",
            "RestartReason": "",
            "SetupError": "",
            "Signal": 0,
            "StartDelay": 0,
            "TaskSignal": "",
            "TaskSignalReason": "",
            "Time": 1636017252049956000,
            "Type": "Started",
            "ValidationError": "",
            "VaultError": ""
          }
        ],
        "Failed": false,
        "FinishedAt": null,
        "LastRestart": null,
        "Restarts": 0,
        "StartedAt": "2021-11-04T09:14:12.04996Z",
        "State": "running",
        "TaskHandle": null
      }
    }
  }
]

Read Allocation

This endpoint reads information about a specific allocation.

Method	Path	Produces
`GET`	`/v1/allocation/:alloc_id`	`application/json`

The table below shows this endpoint's support for blocking queries and required ACLs.

Blocking Queries	ACL Required
`YES`	`namespace:read-job`

Parameters

:alloc_id (string: <required>)- Specifies the UUID of the allocation. This must be the full UUID, not the short 8-character one. This is specified as part of the path.

Sample Request

$ curl \
    https://localhost:4646/v1/allocation/5456bd7a-9fc0-c0dd-6131-cbee77f57577

Sample Response

{
  "ID": "a8198d79-cfdb-6593-a999-1e9adabcba2e",
  "EvalID": "5456bd7a-9fc0-c0dd-6131-cbee77f57577",
  "Name": "example.cache[0]",
  "NodeID": "fb2170a8-257d-3c64-b14d-bc06cc94e34c",
  "PreviousAllocation": "516d2753-0513-cfc7-57ac-2d6fac18b9dc",
  "NextAllocation": "cd13d9b9-4f97-7184-c88b-7b451981616b",
  "RescheduleTracker": {
    "Events": [
      {
        "PrevAllocID": "516d2753-0513-cfc7-57ac-2d6fac18b9dc",
        "PrevNodeID": "9230cd3b-3bda-9a3f-82f9-b2ea8dedb20e",
        "RescheduleTime": 1517434161192946200,
        "Delay": "5000000000"
      }
    ]
  },
  "JobID": "example",
  "Job": {
    "Region": "global",
    "ID": "example",
    "ParentID": "",
    "Name": "example",
    "Type": "service",
    "Priority": 50,
    "AllAtOnce": false,
    "Datacenters": ["dc1"],
    "Constraints": null,
    "Affinities": null,
    "TaskGroups": [
      {
        "Name": "cache",
        "Count": 1,
        "Constraints": null,
        "Affinities": null,
        "RestartPolicy": {
          "Attempts": 10,
          "Interval": 300000000000,
          "Delay": 25000000000,
          "Mode": "delay"
        },
        "Spreads": null,
        "Tasks": [
          {
            "Name": "redis",
            "Driver": "docker",
            "User": "",
            "Config": {
              "port_map": [
                {
                  "db": 6379
                }
              ],
              "image": "redis:7"
            },
            "Env": null,
            "Services": [
              {
                "Name": "redis-cache",
                "PortLabel": "db",
                "Tags": ["global", "cache"],
                "Checks": [
                  {
                    "Name": "alive",
                    "Type": "tcp",
                    "Command": "",
                    "Args": null,
                    "Path": "",
                    "Protocol": "",
                    "PortLabel": "",
                    "Interval": 10000000000,
                    "Timeout": 2000000000,
                    "InitialStatus": ""
                  }
                ]
              }
            ],
            "Vault": null,
            "Templates": null,
            "Constraints": null,
            "Affinities": null,
            "Resources": {
              "CPU": 500,
              "MemoryMB": 10,
              "DiskMB": 0,
              "Networks": [
                {
                  "Device": "",
                  "CIDR": "",
                  "IP": "",
                  "MBits": 10,
                  "ReservedPorts": null,
                  "DynamicPorts": [
                    {
                      "Label": "db",
                      "Value": 0
                    }
                  ]
                }
              ]
            },
            "Spreads": null,
            "DispatchPayload": null,
            "Meta": null,
            "KillTimeout": 5000000000,
            "LogConfig": {
              "MaxFiles": 10,
              "MaxFileSizeMB": 10
            },
            "Artifacts": null,
            "Leader": false
          }
        ],
        "EphemeralDisk": {
          "Sticky": false,
          "SizeMB": 300,
          "Migrate": false
        },
        "Meta": null
      }
    ],
    "Update": {
      "Stagger": 10000000000,
      "MaxParallel": 0
    },
    "Periodic": null,
    "ParameterizedJob": null,
    "Payload": null,
    "Spreads": null,
    "Meta": null,
    "VaultToken": "",
    "Status": "pending",
    "StatusDescription": "",
    "CreateIndex": 52,
    "ModifyIndex": 52,
    "JobModifyIndex": 52
  },
  "TaskGroup": "cache",
  "Resources": {
    "CPU": 500,
    "MemoryMB": 10,
    "DiskMB": 300,
    "Networks": [
      {
        "Device": "lo0",
        "CIDR": "",
        "IP": "127.0.0.1",
        "MBits": 10,
        "ReservedPorts": null,
        "DynamicPorts": [
          {
            "Label": "db",
            "Value": 23116
          }
        ]
      }
    ]
  },
  "SharedResources": {
    "CPU": 0,
    "MemoryMB": 0,
    "DiskMB": 300,
    "Networks": null
  },
  "TaskResources": {
    "redis": {
      "CPU": 500,
      "MemoryMB": 10,
      "DiskMB": 0,
      "Networks": [
        {
          "Device": "lo0",
          "CIDR": "",
          "IP": "127.0.0.1",
          "MBits": 10,
          "ReservedPorts": null,
          "DynamicPorts": [
            {
              "Label": "db",
              "Value": 23116
            }
          ]
        }
      ]
    }
  },
  "Metrics": {
    "NodesEvaluated": 1,
    "NodesFiltered": 0,
    "NodesAvailable": {
      "dc1": 1
    },
    "NodesInPool": 1,
    "ClassFiltered": null,
    "ConstraintFiltered": null,
    "NodesExhausted": 0,
    "ClassExhausted": null,
    "DimensionExhausted": null,
    "Scores": {
      "fb2170a8-257d-3c64-b14d-bc06cc94e34c.binpack": 0.6205732522109244
    },
    "AllocationTime": 31729,
    "CoalescedFailures": 0
  },
  "DesiredStatus": "run",
  "DesiredDescription": "",
  "ClientStatus": "running",
  "ClientDescription": "",
  "TaskStates": {
    "redis": {
      "State": "running",
      "Failed": false,
      "FinishedAt": "0001-01-01T00:00:00Z",
      "LastRestart": "0001-01-01T00:00:00Z",
      "Restarts": 0,
      "StartedAt": "2017-07-25T23:36:26.106431265Z",
      "Events": [
        {
          "Type": "Received",
          "Time": 1495747371795703800,
          "FailsTask": false,
          "RestartReason": "",
          "SetupError": "",
          "DriverError": "",
          "ExitCode": 0,
          "Signal": 0,
          "Message": "",
          "KillTimeout": 0,
          "KillError": "",
          "KillReason": "",
          "StartDelay": 0,
          "DownloadError": "",
          "ValidationError": "",
          "DiskLimit": 0,
          "FailedSibling": "",
          "VaultError": "",
          "TaskSignalReason": "",
          "TaskSignal": "",
          "DriverMessage": ""
        },
        {
          "Type": "Driver",
          "Time": 1495747371798867200,
          "FailsTask": false,
          "RestartReason": "",
          "SetupError": "",
          "DriverError": "",
          "ExitCode": 0,
          "Signal": 0,
          "Message": "",
          "KillTimeout": 0,
          "KillError": "",
          "KillReason": "",
          "StartDelay": 0,
          "DownloadError": "",
          "ValidationError": "",
          "DiskLimit": 0,
          "FailedSibling": "",
          "VaultError": "",
          "TaskSignalReason": "",
          "TaskSignal": "",
          "DriverMessage": "Downloading image redis:7"
        },
        {
          "Type": "Started",
          "Time": 1495747379525667800,
          "FailsTask": false,
          "RestartReason": "",
          "SetupError": "",
          "DriverError": "",
          "ExitCode": 0,
          "Signal": 0,
          "Message": "",
          "KillTimeout": 0,
          "KillError": "",
          "KillReason": "",
          "StartDelay": 0,
          "DownloadError": "",
          "ValidationError": "",
          "DiskLimit": 0,
          "FailedSibling": "",
          "VaultError": "",
          "TaskSignalReason": "",
          "TaskSignal": "",
          "DriverMessage": ""
        }
      ]
    }
  },
  "PreviousAllocation": "",
  "CreateIndex": 54,
  "ModifyIndex": 57,
  "AllocModifyIndex": 54,
  "CreateTime": 1495747371794276400,
  "ModifyTime": 1495747371794276400
}

Field Reference

Job - A copy of the job at the time that the allocation is created or updated. This is primarily intended for use by the Nomad client when running the allocation, and it may include stale information on some job fields. Up-to-date information about the job status is available from the jobs API; take care to fetch the version of the job associated with this allocation.
TaskStates - A map of tasks to their current state and the latest events that have effected the state. TaskState objects contain the following fields:
- State: The task's current state. It can have one of the following values:
  - TaskStatePending - The task is waiting to be run, either for the first time or due to a restart.
  - TaskStateRunning - The task is currently running.
  - TaskStateDead - The task is dead and will not run again.
- StartedAt: The time the task was last started at. Can be updated through restarts.
- FinishedAt: The time the task was finished at.
- LastRestart: The last time the task was restarted.
- Restarts: The number of times the task has restarted.
- Events - An event contains metadata about the event. The latest 10 events are stored per task. Each event is timestamped (Unix nanoseconds) and has one of the following types:
  - Setup Failure - The task could not be started because there was a failure setting up the task prior to it running.
  - Driver Failure - The task could not be started due to a failure in the driver.
  - Started - The task was started; either for the first time or due to a restart.
  - Terminated - The task was started and exited.
  - Killing - The task has been sent the kill signal.
  - Killed - The task was killed by a user.
  - Received - The task has been pulled by the client at the given timestamp.
  - Failed Validation - The task was invalid and as such it didn't run.
  - Restarting - The task terminated and is being restarted.
  - Not Restarting - the task has failed and is not being restarted because it has exceeded its restart policy.
  - Downloading Artifacts - The task is downloading the artifact(s)
  - specified in the task.
  - Failed Artifact Download - Artifact(s) specified in the task failed to download.
  - Restart Signaled - The task was signaled to be restarted.
  - Signaling - The task was is being sent a signal.
  - Sibling Task Failed - A task in the same task group failed.
  - Leader Task Dead - The group's leader task is dead.
  - Driver - A message from the driver.
  - Task Setup - Task setup messages.
  - Building Task Directory - Task is building its file system.
  Depending on the type the event will have applicable annotations.

Stop Allocation

This endpoint stops and reschedules a specific allocation.

Method	Path	Produces
`POST` / `PUT`	`/v1/allocation/:alloc_id/stop`	`application/json`

The table below shows this endpoint's support for blocking queries and required ACLs.

Blocking Queries	ACL Required
`NO`	`namespace:alloc-lifecycle`

Parameters

:alloc_id (string: <required>)- Specifies the UUID of the allocation. This must be the full UUID, not the short 8-character one. This is specified as part of the path.
no_shutdown_delay (bool: false) - Ignore the group and task shutdown_delay configuration so that there is no delay between service deregistration and task shutdown. Note that using this parameter will result in failed network connections to the allocation being stopped.

Sample Request

$ curl -X POST \
    https://localhost:4646/v1/allocation/5456bd7a-9fc0-c0dd-6131-cbee77f57577/stop

Sample Response

{
  "EvalID": "5456bd7a-9fc0-c0dd-6131-cbee77f57577",
  "Index": 54
}

Signal Allocation

This endpoint sends a signal to an allocation or task.

Method	Path	Produces
`POST` / `PUT`	`/v1/client/allocation/:alloc_id/signal`	`application/json`

The table below shows this endpoint's support for blocking queries and required ACLs.

Blocking Queries	ACL Required
`NO`	`namespace:alloc-lifecycle`

Parameters

:alloc_id (string: <required>)- Specifies the UUID of the allocation. This must be the full UUID, not the short 8-character one. This is specified as part of the path.

Sample Payload

{
  "Signal": "SIGUSR1",
  "Task": "FOO"
}

If Task is omitted, the signal will be sent to all tasks in the allocation.

Sample Request

$ curl -X POST -d '{"Signal": "SIGUSR1" }' \
    https://localhost:4646/v1/client/allocation/5456bd7a-9fc0-c0dd-6131-cbee77f57577/signal

Sample Response

{}

Restart Allocation

This endpoint restarts an allocation or task in-place.

Method	Path	Produces
`POST` / `PUT`	`/v1/client/allocation/:alloc_id/restart`	`application/json`

The table below shows this endpoint's support for blocking queries and required ACLs.

Blocking Queries	ACL Required
`NO`	`namespace:alloc-lifecycle`

Parameters

:alloc_id (string: <required>)- Specifies the UUID of the allocation. This must be the full UUID, not the short 8-character one. This is specified as part of the path.
TaskName (string: "") - Specifies the individual task to restart. Cannot be used with AllTasks set to true.
AllTasks (bool: false) - If set to true all tasks in the allocation will be restarted, even the ones that already ran. Cannot be set to true if TaskName is defined.

Sample Payload

{
  "TaskName": "FOO"
}

Sample Request

$ curl -X POST -d '{"TaskName": "redis" }' \
    https://localhost:4646/v1/client/allocation/5456bd7a-9fc0-c0dd-6131-cbee77f57577/restart

Sample Response

{}

Exec Allocation

This endpoint executes a command inside the isolation container where an allocation is running. It opens a WebSocket to transmit input to and output from the command.

Method	Path	Produces
`WebSocket`	`/v1/client/allocation/:alloc_id/exec`	WebSocket JSON streams

The table below shows this endpoint's support for blocking queries and required ACLs.

Blocking Queries	ACL Required
`NO`	`namespace:alloc-exec` (and `namespace:alloc-node-exec` if target task uses raw_exec driver)

Parameters

:alloc_id (string: <required>)- Specifies the UUID of the allocation. This must be the full UUID, not the short 8-character one. This is specified as part of the path.
command (string: <required>) - Specifies the command to be executed. This must be a JSON-encoded array of the command to be executed, e.g. ["echo", "hi"] or ["/bin/bash"]. This is specified as a query parameter.
task (string: <required>) - Specifies the task name, as a query parameter.
tty (bool: false) - Specifies whether a TTY is allocated for this task, as a query parameter.
ws_handshake (bool: false) - Specifies whether to expect the authentication token in the first frame, as a query parameter.

Request Frames

Request frames represent the stdin stream from the command as well as TTY resize events. When ?ws_handshake=true, the first request frame must contain the authentication token.

The following are valid formats:

# sending authentication token
{"version":1,"auth_token":"fc3c1968-8d31-5c50-9617-3db2e19ef32e"}

# sending stdin data
{"stdin": {"data": "...base64 encoded string of bytes ..."}}

# indicating stdin is closed
{"stdin": {"close": true}}

# indicating that TTY was resized
{"tty_size": {"height": <characters>, "width": <characters>}}

# basic application-level heartbeat
{}

Response Frames

Response frames represent stdout and stderr output from the command as well as exit codes:

# transferring stdout data
{"stdout": {"data": "...base64 encoded string of bytes ..."}}

# signaling that host closed stdout
{"stdout": {"close": true}}

# transferring stderr data
{"stderr": {"data": "...base64 encoded string of bytes ..."}}

# signaling that host closed stderr
{"stderr": {"close": true}}

# signaling process exited
{"exited": true, "result": {"exit_code": <exit_code_int>}}

# basic application-level heartbeat
{}

Sample Request and Response

Request and response frames encompass the full range of terminal emulator inputs and outputs, including the control characters necessary to render interactive applications. The example response includes instances of the ANSI “control sequence introducer” (CSI), which is ASCII code 27 followed by [.

# \x12: form feed, to clear terminal
{"stdin":{"data":"DA=="}}

# "\x1b[H\x1b[2J$ ":
# CSI-H (move cursor to top left corner), CSI-2J (clear entire screen), print "$ "
{"stdout":{"data":"G1tIG1sySiQg"}}

Allocation Services

The endpoint is used to read all services registered within Nomad belonging to the passed allocation ID.

Method	Path	Produces
`GET`	`/allocation/:alloc_id/services`	`application/json`

The table below shows this endpoint's support for blocking queries, consistency modes and required ACLs.

Blocking Queries	Consistency Modes	ACL Required
`YES`	`all`	`namespace:read-job`

Parameters

:alloc_id (string: <required>) - Specifies the service name. This is specified as part of the path.
namespace (string: "default") - Specifies the target namespace.

Sample Request

$ curl \
    https://localhost:4646/v1/allocation/177160af-26f6-619f-9c9f-5e46d1104395/services

Sample Response

[
  {
    "Address": "127.0.0.1",
    "AllocID": "177160af-26f6-619f-9c9f-5e46d1104395",
    "CreateIndex": 14,
    "Datacenter": "dc1",
    "ID": "_nomad-task-177160af-26f6-619f-9c9f-5e46d1104395-redis-example-cache-redis-db",
    "JobID": "example",
    "ModifyIndex": 24,
    "Namespace": "default",
    "NodeID": "7406e90b-de16-d118-80fe-60d0f2730cb3",
    "Port": 29702,
    "ServiceName": "example-cache-redis",
    "Tags": [
      "db",
      "cache"
    ]
  }
]

Allocation Checks

The endpoint is used to read all health checks registered within Nomad belonging to the passed allocation ID.

Method	Path	Produces
`GET`	`/allocation/:alloc_id/checks`	`application/json`

The table below shows this endpoint's support for blocking queries, consistency modes and required ACLs.

Blocking Queries	ACL Required
`NO`	`namespace:read-job``

Parameters

:alloc_id (string: <required>) - Specifies the allocation ID. This is specified as part of the path.

Sample Request

$ curl \
    https://localhost:4646/v1/allocation/177160af-26f6-619f-9c9f-5e46d1104395/checks

Sample Response

{
  "a1ed96606694742bf201a640a607e306": {
    "Check": "redis_probe",
    "Group": "example.cache[0]",
    "ID": "a1ed96606694742bf201a640a607e306",
    "Mode": "healthiness",
    "Output": "nomad: tcp ok",
    "Service": "redis",
    "Status": "success",
    "Timestamp": 1690442203
  }
}