Host Volumes

Dynamic Host Volumes is a simple driver built into Nomad which allocates storage from a local directory on the host. This is useful for testing and simple development environments; however, the volume will only be available on a single server.

Nomad Configuration

The location where the host volume plugin should create the volumes can be set using the host_volumes_dir parameter in client section of the nomad.hcl:

client {
  host_volumes_dir = "/srv/host_volumes"
}

By default Nomad stores them under the data_dir

Example Usage in Knot

Below is an example of how to use the dynamic host volume driver. This configuration should be added to the Volumes section of a template or as a standalone volume:

volumes:
  - name: "test-volume"
    type: "host"
    plugin_id: "mkdir"
    parameters:
      mode: "0755"
      uid: 1000
      gid: 1000

Example Usage in a Nomad Job

The volume is referenced from a job by its name using a volume stanza in the group, then mounted into the task with a volume_mount stanza:

job "example" {
  datacenters = ["dc1"]

  group "example" {
    count = 1

    volume "data" {
      type      = "host"
      source    = "test-volume"
      read_only = false
    }

    task "example" {
      driver = "docker"
      config {
        image = "paularlott/knot-ubuntu:24.04"
      }

      volume_mount {
        volume      = "data"
        destination = "/data"
      }

      resources {
        cores  = 1
        memory = 512
      }
    }
  }
}