I am attempting to get RabbitMQ to run in Nomad using Docker. However I have stumbled into some problems related to permissions. When attempting to run the Job in Nomad I either get this error:

sed: preserving permissions for ‘/etc/rabbitmq/sedpR1m3w’: Operation not permitted
sed: preserving permissions for ‘/etc/rabbitmq/sedEc0Idz’: Operation not permitted
/usr/local/bin/docker-entrypoint.sh: line 250: /etc/rabbitmq/rabbitmq.conf: Permission denied
touch: cannot touch '/etc/rabbitmq/rabbitmq.conf': Permission denied

WARNING: '/etc/rabbitmq/rabbitmq.conf' is not writable, but environment variables have been provided which request that we write to it
  We have copied it to '/tmp/rabbitmq.conf' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead.

/usr/local/bin/docker-entrypoint.sh: line 250: /tmp/rabbitmq.conf: Permission denied

or this error:

chmod: changing permissions of '/var/lib/rabbitmq/.erlang.cookie': Operation not permitted

I have setup volumes so that RabbitMQ data can be preserved. These volumes is pointing to an SMB share on a Windows Server box elsewhere on the network.
I have added the following to /etc/ftstab for auto mounting:

//DC02/Nomad /mnt/winshare cifs credentials=/home/linuxnomad/.smbcreds,uid=995,gid=993,file_mode=0777,dir_mode=0777 0 0

This is what the Job spec looks like:

job "rabbitmq03" {
  datacenters = ["techtest"]
  type        = "service"
  
  constraint {
    attribute = "${attr.kernel.name}"
    value     = "linux"
  }

    constraint {
    attribute = "${attr.unique.hostname}"
    value     = "nomadlinux03"
  }
  
  group "rabbitmq" {
    network {
        mode = "cni/prod"
      hostname = "RabbitMqNOMAD03"
    }
    
    service {
      name         = "${JOB}"
      port         = 5672
      address_mode = "alloc"
      check {
        type         = "http"
            port         = 15672
        path         = "/api/health/checks/local-alarms"
        interval     = "3s"
        timeout      = "2s"
        address_mode = "alloc"
        header {
          Authorization = ["Basic Z3Vlc3Q6Z3Vlc3Q="]
        }
      }
    }

    task "rabbitmq" {
      driver = "docker"
      
      config {
        privileged     = false
        image          = "rabbitmq:3.8.12-management"
        auth_soft_fail = true
        
        volumes = [
          "/mnt/winshare/RabbitMQ03/data:/var/lib/rabbitmq/mnesia",
          "/mnt/winshare/RabbitMQ03/config:/etc/rabbitmq",
          "/mnt/winshare/RabbitMQ03/log:/var/log/rabbitmq"
        ]
      }

      env {
        HOSTNAME = "RabbitMqNOMAD"
        RABBITMQ_DEFAULT_USER = "guest"
        RABBITMQ_DEFAULT_PASS = "guest"
        RABBITMQ_ERLANG_COOKIE = "testsecret"    
      }

      resources {
        cpu    = 1001
        memory = 6144
      }
    }
  }
}

I did make sure to mount the SMB share with the Nomad user rights, so my expectation would be that it’s fine, but perhaps I’m missing something?