» vault Stanza

The vault stanza allows a task to specify that it requires a token from a HashiCorp Vault server. Nomad will automatically retrieve a Vault token for the task and handle token renewal for the task. If specified at the group level, the configuration will apply to all tasks within the group. If specified at the job level, the configuration will apply to all tasks within the job. If multiple vault stanzas are specified, they are merged with the task stanza taking the highest precedence, then the group, then the job.

job "docs" {
  group "example" {
    task "server" {
      vault {
        policies = ["cdn", "frontend"]

        change_mode   = "signal"
        change_signal = "SIGUSR1"
      }
    }
  }
}

The Nomad client will make the Vault token available to the task by writing it to the secret directory at secret/vault_token and by injecting a VAULT_TOKEN environment variable.

If Vault token renewal fails due to a Vault outage, the Nomad client will attempt to retrieve a new Vault token. When the new Vault token is retrieved, the contents of the file will be replaced and action will be taken based on the change_mode.

If Nomad is unable to renew the Vault token (perhaps due to a Vault outage or network error), the client will retrieve a new Vault token. If successful, the contents of the secrets file are updated on disk, and action will be taken according to the value set in the change_mode parameter.

If a vault stanza is specified, the template stanza can interact with Vault as well.

» vault Parameters

• change_mode (string: "restart") - Specifies the behavior Nomad should take if the Vault token changes. The possible values are:

  • "noop" - take no action (continue running the task)
  • "restart" - restart the task
  • "signal" - send a configurable signal to the task

• change_signal (string: "") - Specifies the signal to send to the task as a string like "SIGUSR1" or "SIGINT". This option is required if the change_mode is signal.

• env (bool: true) - Specifies if the VAULT_TOKEN environment variable should be set when starting the task.

• policies (array<string>: []) - Specifies the set of Vault policies that the task requires. The Nomad client will generate a a Vault token that is limited to those policies.

» vault Examples

The following examples only show the vault stanzas. Remember that the vault stanza is only valid in the placements listed above.

» Retrieve Token

This example tells the Nomad client to retrieve a Vault token. The token is available to the task via the canonical environment variable VAULT_TOKEN and written to disk at secrets/vault_token. The resulting token will have the "frontend" Vault policy attached.

vault {
  policies = ["frontend"]
}

» Signal Task

This example shows signaling the task instead of restarting it.

vault {
  policies = ["frontend"]

  change_mode   = "signal"
  change_signal = "SIGINT"
}