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Commands: job plan
The job plan command is used to dry-run a job update to determine its effects.

Command: job plan

Alias: nomad plan

The job plan command can be used to invoke the scheduler in a dry-run mode with new jobs or when updating existing jobs to determine what would happen if the job is submitted. Job files must conform to the job specification format.

Usage

nomad job plan [options] <path>

The job plan command requires a single argument, specifying the path to a file containing an HCL job specification. This file will be read and the resulting parsed job will be validated. If the supplied path is "-", the job file is read from STDIN. Otherwise it is read from the file at the supplied path or downloaded and read from URL specified. Nomad downloads the job file using go-getter and supports go-getter syntax.

Plan invokes a dry-run of the scheduler to determine the effects of submitting either a new or updated version of a job. The plan will not result in any changes to the cluster but gives insight into whether the job could be run successfully and how it would affect existing allocations.

A job modify index is returned with the plan. This value can be used when submitting the job using nomad job run -check-index, which will check that the job was not modified between the plan and run command before invoking the scheduler. This ensures the job has not been modified since the plan.

A structured diff between the local and remote job is displayed to give insight into what the scheduler will attempt to do and why.

If the job has specified the region, the -region flag and NOMAD_REGION environment variable are overridden and the job's region is used.

Plan will return one of the following exit codes:

  • 0: No allocations created or destroyed.
  • 1: Allocations created or destroyed.
  • 255: Error determining plan results.

The plan command will set the vault_token of the job based on the following precedence, going from highest to lowest: the -vault-token flag, the $VAULT_TOKEN environment variable and finally the value in the job file.

When ACLs are enabled, this command requires a token with the submit-job capability for the job's namespace.

General Options

@include 'general_options.mdx'

Plan Options

  • -diff: Determines whether the diff between the remote job and planned job is shown. Defaults to true.

  • -policy-override: Sets the flag to force override any soft mandatory Sentinel policies.

  • -json: Parses the job file as JSON. If the outer object has a Job field, such as from "nomad job inspect" or "nomad run -output", the value of the field is used as the job.

  • -hcl1: If set, HCL1 parser is used for parsing the job spec. Takes precedence over -hcl2-strict.

  • -hcl2-strict: Whether an error should be produced from the HCL2 parser where a variable has been supplied which is not defined within the root variables. Defaults to true, but ignored if -hcl1 is defined.

  • -vault-token: Used to validate if the user submitting the job has permission to run the job according to its Vault policies. A Vault token must be supplied if the vault block allow_unauthenticated is disabled in the Nomad server configuration. If the -vault-token flag is set, the passed Vault token is added to the jobspec before sending to the Nomad servers. This allows passing the Vault token without storing it in the job file. This overrides the token found in the $VAULT_TOKEN environment variable and the vault_token field in the job file. This token is cleared from the job after planning and cannot be used within the job executing environment. Use the vault block when templating in a job with a Vault token.

  • -vault-namespace: If set, the passed Vault namespace is stored in the job before sending to the Nomad servers.

  • -var=<key=value>: Variable for template, can be used multiple times.

  • -var-file=<path>: Path to HCL2 file containing user variables.

  • -verbose: Increase diff verbosity.

Examples

Plan a new job that has not been previously submitted:

$ nomad job plan example.nomad.hcl
+ Job: "example"
+ Task Group: "cache" (1 create)
  + Task: "redis" (forces create)

Scheduler dry-run:
- All tasks successfully allocated.

Job Modify Index: 0
To submit the job with version verification run:

nomad job run -check-index 0 example.nomad.hcl

When running the job with the check-index flag, the job will only be run if the
job modify index given matches the server-side version. If the index has
changed, another user has modified the job and the plan's results are
potentially invalid.

Increase the count of an existing without sufficient cluster capacity:

$ nomad job plan example.nomad.hcl
+/- Job: "example"
+/- Task Group: "cache" (7 create, 1 in-place update)
  +/- Count: "1" => "8" (forces create)
      Task: "redis"

Scheduler dry-run:
- WARNING: Failed to place all allocations.
  Task Group "cache" (failed to place 3 allocations):
    * Resources exhausted on 1 nodes
    * Dimension "cpu" exhausted on 1 nodes

Job Modify Index: 15
To submit the job with version verification run:

nomad job run -check-index 15 example.nomad.hcl

When running the job with the check-index flag, the job will only be run if the
job modify index given matches the server-side version. If the index has
changed, another user has modified the job and the plan's results are
potentially invalid.

Update an existing job such that it would cause a rolling update:

$ nomad job plan example.nomad.hcl
+/- Job: "example"
+/- Task Group: "cache" (3 create/destroy update)
  +/- Task: "redis" (forces create/destroy update)
    +/- Config {
      +/- image:           "redis:2.8" => "redis:7"
          port_map[0][db]: "6379"
    }

Scheduler dry-run:
- All tasks successfully allocated.
- Rolling update, next evaluation will be in 10s.

Job Modify Index: 7
To submit the job with version verification run:

nomad job run -check-index 7 example.nomad.hcl

When running the job with the check-index flag, the job will only be run if the
job modify index given matches the server-side version. If the index has
changed, another user has modified the job and the plan's results are
potentially invalid.

Add a task to the task group using verbose mode:

$ nomad job plan -verbose example.nomad.hcl
+/- Job: "example"
+/- Task Group: "cache" (3 create/destroy update)
  + Task: "my-website" (forces create/destroy update)
    + Driver:      "docker"
    + KillTimeout: "5000000000"
    + Config {
      + image:            "node:6.2"
      + port_map[0][web]: "80"
    }
    + Resources {
      + CPU:      "500"
      + DiskMB:   "300"
      + MemoryMB: "256"
      + Network {
        + MBits: "10"
        + Dynamic Port {
          + Label: "web"
        }
      }
    }
    + LogConfig {
      + MaxFileSizeMB: "10"
      + MaxFiles:      "10"
    }
    + Service {
      + Name:      "website"
      + PortLabel: "web"
      + Check {
          Command:  ""
        + Interval: "10000000000"
        + Name:     "alive"
          Path:     ""
          Protocol: ""
        + Timeout:  "2000000000"
        + Type:     "tcp"
      }
    }
    Task: "redis"

Scheduler dry-run:
- All tasks successfully allocated.
- Rolling update, next evaluation will be in 10s.

Job Modify Index: 7
To submit the job with version verification run:

nomad job run -check-index 7 example.nomad.hcl

When running the job with the check-index flag, the job will only be run if the
job modify index given matches the server-side version. If the index has
changed, another user has modified the job and the plan's results are
potentially invalid.

When using the nomad job plan command in automated environments, such as in CI/CD pipelines, it is useful to output the plan result for manual validation and also store the check index on disk so it can be used later to guarantee that a job deployment will match the expected changes described in the plan result.

This can be done by parsing the command output and redirecting the index to a file. For example, in Linux environments the tee command can be used for this purpose:

$ nomad job plan -no-color example.nomad.hcl | tee /dev/stderr | grep 'Job Modify Index:' | awk -F': ' '{ print $2 }' > check-index || true

The -no-color flag prevents style characters from impacting parsing. Colored output may be helpful when analyzing the plan result, so the -force-color flag can be used. This will affect how parsing is done to avoid hidden control characters. Adding || true at the end prevents undesired failures since nomad job plan returns a non-zero exit code if a change is detected.