---
layout: default
navsection: api
navmenu: API Methods
title: "containers"

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{% comment %}
Copyright (C) The Arvados Authors. All rights reserved.

SPDX-License-Identifier: CC-BY-SA-3.0
{% endcomment %}

API endpoint base: @https://{{ site.arvados_api_host }}/arvados/v1/containers@

Object type: @dz642@

Example UUID: @zzzzz-dz642-0123456789abcde@

h2. Resource

A container is work order to be dispatched to an Arvados cluster to perform some computational work.  A container is created in response to a container request.  See "computing with Crunch":{{site.baseurl}}/api/execution.html for details.

Each Container offers the following attributes, in addition to the "Common resource fields":{{site.baseurl}}/api/resources.html:

table(table table-bordered table-condensed).
|_. Attribute|_. Type|_. Description|_. Notes|
|state|string|The allowed states are "Queued", "Locked", "Running", "Cancelled" and "Complete".|See "Container states":#container_states for more details.|
|started_at|datetime|When this container started running.|Null if container has not yet started.|
|finished_at|datetime|When this container finished.|Null if container has not yet finished.|
|log|string|UUID or portable data hash of a collection containing the log messages produced when executing the container.|PDH after the container is finished, otherwise UUID or null.|
|environment|hash|Environment variables and values that should be set in the container environment (@docker run --env@). This augments and (when conflicts exist) overrides environment variables given in the image's Dockerfile.|Must be equal to a ContainerRequest's environment in order to satisfy the ContainerRequest.|
|cwd|string|Initial working directory.|Must be equal to a ContainerRequest's cwd in order to satisfy the ContainerRequest|
|command|array of strings|Command to execute.| Must be equal to a ContainerRequest's command in order to satisfy the ContainerRequest.|
|output_path|string|Path to a directory or file inside the container that should be preserved as this container's output when it finishes.|Must be equal to a ContainerRequest's output_path in order to satisfy the ContainerRequest.|
|mounts|hash|Must contain the same keys as the ContainerRequest being satisfied. Each value must be within the range of values described in the ContainerRequest at the time the Container is assigned to the ContainerRequest.|See "Mount types":#mount_types for more details.|
|secret_mounts|hash|Must contain the same keys as the ContainerRequest being satisfied. Each value must be within the range of values described in the ContainerRequest at the time the Container is assigned to the ContainerRequest.|Not returned in API responses. Reset to empty when state is "Complete" or "Cancelled".|
|runtime_constraints|hash|Compute resources, and access to the outside world, that are / were available to the container.
Generally this will contain additional keys that are not present in any corresponding ContainerRequests: for example, even if no ContainerRequests specified constraints on the number of CPU cores, the number of cores actually used will be recorded here.|e.g.,
<pre><code>{
  "ram":12000000000,
  "vcpus":2,
  "API":true
}</code></pre>See "Runtime constraints":#runtime_constraints for more details.|
|runtime_status|hash|Information related to the container's run, including its steps. Some keys have specific meaning and are described later in this page.|e.g.,
<pre><code>{
  "error": "This container won't be successful because at least one step has already failed."
}</code></pre>See "Runtime status":#runtime_status for more details.|
|scheduling_parameters|hash|Parameters to be passed to the container scheduler when running this container.|e.g.,<pre><code>{
"partitions":["fastcpu","vfastcpu"]
}</code></pre>See "Scheduling parameters":#scheduling_parameters for more details.|
|output|string|Portable data hash of the output collection.|Null if the container is not yet finished.|
|container_image|string|Portable data hash of a collection containing the docker image used to run the container.||
|progress|number|A number between 0.0 and 1.0 describing the fraction of work done.||
|priority|integer|Range 0-1000.  Indicate scheduling order preference.|Currently assigned by the system as the max() of the priorities of all associated ContainerRequests.  See "container request priority":container_requests.html#priority .|
|exit_code|integer|Process exit code.|Null if state!="Complete"|
|auth_uuid|string|UUID of a token to be passed into the container itself, used to access Keep-backed mounts, etc.  Automatically assigned.|Null if state∉{"Locked","Running"} or if @runtime_token@ was provided.|
|locked_by_uuid|string|UUID of a token, indicating which dispatch process changed state to Locked. If null, any token can be used to lock. If not null, only the indicated token can modify this container.|Null if state∉{"Locked","Running"}|
|runtime_token|string|A v2 token to be passed into the container itself, used to access Keep-backed mounts, etc.|Not returned in API responses.  Reset to null when state is "Complete" or "Cancelled".|

h2(#container_states). Container states

table(table table-bordered table-condensed).
|_. State|_. Sgnificance|_. Allowed next|
|Queued|Waiting for a dispatcher to lock it and try to run the container.|Locked, Cancelled|
|Locked|A dispatcher has "taken" the container and is allocating resources for it. The container has not started yet.|Queued, Running, Cancelled|
|Running|Resources have been allocated and the contained process has been started (or is about to start). Crunch-run _must_ set state to Running _before_ there is any possibility that user code will run in the container.|Complete, Cancelled|
|Complete|Container was running, and the contained process/command has exited.|Cancelled|
|Cancelled|The container did not run long enough to produce an exit code. This includes cases where the container didn't even start, cases where the container was interrupted/killed before it exited by itself (e.g., priority changed to 0), and cases where some problem prevented the system from capturing the contained process's exit status (exit code and output).|-|

See "Controlling container reuse":{{site.baseurl}}/admin/controlling-container-reuse.html for details about changing state from @Complete@ to @Cancelled@

h2(#mount_types). {% include 'mount_types' %}

h2(#runtime_constraints). {% include 'container_runtime_constraints' %}

h2(#runtime_status). Runtime status

Runtime status provides container's relevant information about its progress even while it's still in Running state. This is used to avoid reusing containers that have not yet failed but will definitely do, and also for easier workflow debugging.

The following keys have well known meanings:

table(table table-bordered table-condensed).
|_. Key|_. Type|_. Description|_. Notes|
|error|string|The existance of this key indicates the container will definitely fail, or has already failed.|Optional.|
|warning|string|Indicates something unusual happened or is currently happening, but isn't considered fatal.|Optional.|
|activity|string|A message for the end user about what state the container is currently in.|Optional.|
|errorDetails|string|Additional structured error details.|Optional.|
|warningDetails|string|Additional structured warning details.|Optional.|

h2(#scheduling_parameters). {% include 'container_scheduling_parameters' %}

h2. Methods

See "Common resource methods":{{site.baseurl}}/api/methods.html for more information about @create@, @delete@, @get@, @list@, and @update@.

Required arguments are displayed in %{background:#ccffcc}green%.

Supports federated @get@ and @list@.

h2(#create). create

Create a new Container.

Arguments:

table(table table-bordered table-condensed).
|_. Argument |_. Type |_. Description |_. Location |_. Example |
{background:#ccffcc}.|container|object|Container resource|request body||

h3. delete

Delete a Container.

This API requires admin privileges. In normal operation, it should not be used at all. API clients like Workbench might not work correctly when a container request references a container that has been deleted.

Arguments:

table(table table-bordered table-condensed).
|_. Argument |_. Type |_. Description |_. Location |_. Example |
{background:#ccffcc}.|uuid|string|The UUID of the Container in question.|path||

h3. get

Get a Container's metadata by UUID.

Arguments:

table(table table-bordered table-condensed).
|_. Argument |_. Type |_. Description |_. Location |_. Example |
{background:#ccffcc}.|uuid|string|The UUID of the Container in question.|path||

h3. list

List containers.

See "common resource list method.":{{site.baseurl}}/api/methods.html#index

h3. update

Update attributes of an existing Container.

Arguments:

table(table table-bordered table-condensed).
|_. Argument |_. Type |_. Description |_. Location |_. Example |
{background:#ccffcc}.|uuid|string|The UUID of the Container in question.|path||
|container|object||query||

h3. auth

Get the api_client_authorization record indicated by this container's auth_uuid, which belongs to the container's locked_by_uuid.

table(table table-bordered table-condensed).
|_. Argument |_. Type |_. Description |_. Location |_. Example |
{background:#ccffcc}.|uuid|string||path||