volume_mount Block

The volume_mount block allows the task to specify how a group volume should be mounted into the task.

job "docs" {
  group "example" {
    volume "certs" {
      type = "host"
      read_only = true
      source = "ca-certificates"
    }

    task "example" {
      volume_mount {
        volume      = "certs"
        destination = "/etc/ssl/certs"
        propagation_mode = "private"
      }
    }
  }
}

The Nomad client will make the volumes available to tasks according to this configuration, and it will fail the allocation if the client configuration updates to remove a volume that it depends on.

volume_mount Parameters

• volume (string: "") - Specifies the group volume that the mount is going to access.

• destination (string: "") - Specifies where the volume should be mounted inside the task's allocation.

• read_only (bool: false) - When a group volume is writeable, you may specify that it is read_only on a per mount level using the read_only option here.

• propagation_mode (string: "private") - Specifies the mount propagation mode for nested volumes. Possible values are:

  • private - the task is not allowed to access nested mounts.

  • host-to-task - allows new mounts that have been created outside of the task to be visible inside the task.

  • bidirectional - allows the task to both access new mounts from the host and also create new mounts. This mode requires ReadWrite permission.

    Warning: bidirectional propagation mode can be dangerous to use and cause problems in the host operating system if a task creates a mount but does not clean it up properly before exiting.

For examples of how to use HCL2 interpolation for fine-grained control of volumes, see Volume Interpolation.