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Command: job action

Alias: nomad action

The job action command allows operators to execute predefined actions declared in Nomad job specifications. These actions can be defined at task level and are intended for specific operational tasks, such as clearing a cache, or migrating a database.

An action may self-terminate upon completion (for example, echoing a string), or run for an indeterminate amount of time (for example, watching a blocking query). In the latter case, an action can be terminated via escape character (such as cmd+c / ctrl+c)

When ACLs are enabled, this command requires a token with the alloc-exec, read-job, and list-jobs capabilities for the allocation's namespace. If the task driver does not have file system isolation (as with raw_exec), this command requires the alloc-node-exec, alloc-exec, read-job, and list-jobs capabilities for the allocation's namespace.

Usage

nomad job action [options] <action>

The job action command requires an action name and accepts two ways of specifying where it should run:

  • by passing the job name and known allocation ID along with the name of the action
  • by passing the job, task group, and task name along with the name of the action (when the allocation ID is not known). A random allocation will be selected if multiple are available.

The action name provided must be defined within a task in the job specification provided. With sufficient privileges, an execution context will be opened and the defined action command will be run. No further input is possible, save for the escape character to terminate execution, so interactive commands are not supported.

General Options

  • -address=<addr>: The address of the Nomad server. Overrides the NOMAD_ADDR environment variable if set. Defaults to http://127.0.0.1:4646.

  • -region=<region>: The region of the Nomad server to forward commands to. Overrides the NOMAD_REGION environment variable if set. Defaults to the Agent's local region.

  • -namespace=<namespace>: The target namespace for queries and actions bound to a namespace. Overrides the NOMAD_NAMESPACE environment variable if set. If set to '*', subcommands which support this functionality query all namespaces authorized to user. Defaults to the "default" namespace.

  • -no-color: Disables colored command output. Alternatively, NOMAD_CLI_NO_COLOR may be set. This option takes precedence over -force-color.

  • -force-color: Forces colored command output. This can be used in cases where the usual terminal detection fails. Alternatively, NOMAD_CLI_FORCE_COLOR may be set. This option has no effect if -no-color is also used.

  • -ca-cert=<path>: Path to a PEM encoded CA cert file to use to verify the Nomad server SSL certificate. Overrides the NOMAD_CACERT environment variable if set.

  • -ca-path=<path>: Path to a directory of PEM encoded CA cert files to verify the Nomad server SSL certificate. If both -ca-cert and -ca-path are specified, -ca-cert is used. Overrides the NOMAD_CAPATH environment variable if set.

  • -client-cert=<path>: Path to a PEM encoded client certificate for TLS authentication to the Nomad server. Must also specify -client-key. Overrides the NOMAD_CLIENT_CERT environment variable if set.

  • -client-key=<path>: Path to an unencrypted PEM encoded private key matching the client certificate from -client-cert. Overrides the NOMAD_CLIENT_KEY environment variable if set.

  • -tls-server-name=<value>: The server name to use as the SNI host when connecting via TLS. Overrides the NOMAD_TLS_SERVER_NAME environment variable if set.

  • -tls-skip-verify: Do not verify TLS certificate. This is highly not recommended. Verification will also be skipped if NOMAD_SKIP_VERIFY is set.

  • -token: The SecretID of an ACL token to use to authenticate API requests with. Overrides the NOMAD_TOKEN environment variable if set.

Action Options

  • -job: (Required) Specifies the job containing the predefined action.

  • -alloc: Specifies the allocation within which the action is to be executed. If omitted, -group and -task must be provided, and a random allocation for the group will be selected.

  • -task: Specifies the task within the job where the action is defined. This is required either if -alloc provided and your group has multiple tasks, or if you specify a -group.

  • -group: Specifies the task group within the job. If present, a random allocation is selected. If omitted, -alloc must be provided.

  • -i: Pass stdin to the action, defaults to true. Pass -i=false to disable explicitly.

  • -t: Allocate a pseudo-tty, defaults to true if stdin is detected to be a tty session. Pass -t=false to disable explicitly.

  • -e <escape_char>: Sets the escape character for sessions with a pty, defaults to '~'. The escape character is only recognized at the beginning of a line. The escape character followed by a dot (.) closes the connection. Setting the character to none disables any escapes and makes the session fully transparent.

Examples

Execute an action within a specific task in a job:

$ nomad action \
  -group=my-group \
  -task=my-task \
  -job=my-job \
  weather

Toronto: ☁️   +3°C

Execute an action within a specific allocation:

$ nomad action \
  -alloc=f200a789-6da4-504c-d131-6181764f101e \
  -job=actions-demo \
  echo-time

Running for 0 seconds
Running for 1 seconds
Running for 2 seconds
Running for 3 seconds
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