Volume Lifecycle Basics with CSI

This section provides instructions for managing Portworx CSI volumes on Nomad.

Dynamic volume creation

The following steps will allow you to dynamically provision a Portworx CSI volume:

1. Create a file named volume.hcl with the following content:

   id           = "volume-1"
   name         = "database"
   type         = "csi"
   plugin_id    = "portworx"
   capacity_min = "1G"
   capacity_max = "1G"
   
   capability {
     access_mode     = "single-node-writer"
     attachment_mode = "file-system"
   }

2. Create a volume using thevolume.hcl file you just created:

   nomad volume create volume.hcl

3. Verify the volume creation; if successful, the status should be xxxxx:

   nomad volume status

Registering pre-provisioned volumes

To register a pre-provisioned volume, you must first create a volume on one of the nodes. This example uses the Portworx job to find which alloc to run your commands on.

1. Get the status of the Portworx job:

   nomad job status portworx

   Grab a running allocation ID from the table listed with the previous command. This example uses 8d76fdfc from the output:

   Allocations
   ID        Node ID   Task Group  Version  Desired  Status   Created    Modified
   8d76fdfc  58c745d0  portworx    0        run      running  10d5h ago  10d5h ago
   a75f6340  e374e687  portworx    0        run      running  10d5h ago  10d5h ago
   ff166433  6e130136  portworx    0        run      running  10d5h ago  10d5h ago

2. Create a volume by executing the following pxctl command in the 8d76fdfc allocation:

   nomad alloc exec 8d76fdfc /opt/pwx/bin/pxctl volume create volume1
   Volume successfully created: 1055712112955862813

   Note the volume ID in the command output above. This will be used in a future step. It is 1055712112955862813 in this example.

   note

   If the command above failed with Access denied token is empty, you must setup a pxctl context on that machine.

3. Create a volume registration file volume-register.hcl:

   id           = "volume-2"
   name         = "database"
   type         = "csi"
   plugin_id    = "portworx"
   external_id  = "1055712112955862813"
   
   capability {
     access_mode     = "single-node-writer"
     attachment_mode = "file-system"
   }

4. Register the pre-provisioned volume with the following command:

   nomad volume register volume-register.hcl

Sharedv4 volume creation

Perform the following steps to dynamically provision a sharedv4 Portworx CSI volume:

1. Create a file volume-shared.hcl with the following content:

   id           = "volume-2"
   name         = "database"
   type         = "csi"
   plugin_id    = "portworx"
   capacity_min = "1G"
   capacity_max = "1G"
   
   capability {
     access_mode     = "multi-node-multi-writer"
     attachment_mode = "file-system"
   }

2. Create a volume using the above file:

   nomad volume create volume-shared.hcl

3. List the volume status to see it:

   nomad volume status

Run a Nomad job with Portworx volumes

1. Create a nomad job configuration file job.hcl with the following contents:

   job "mysql-server" {
     datacenters = ["dc1"]
     type        = "service"
   
     group "mysql-server" {
       count = 1
   
       volume "database" {
         attachment_mode = "file-system"
         access_mode     = "single-node-writer"
         type            = "csi"
         read_only       = false
         source          = "volume-1"
       }
   
       network {
         port "db" {
           static = 3306
         }
       }
   
       restart {
         attempts = 10
         interval = "5m"
         delay    = "25s"
         mode     = "delay"
       }
   
       task "mysql-server" {
         driver = "docker"
   
         volume_mount {
           volume      = "database"
           destination = "/srv"
           read_only   = false
         }
   
         env {
           MYSQL_ROOT_PASSWORD = "password"
         }
   
         config {
           image = "hashicorp/mysql-portworx-demo:latest"
           args  = ["--datadir", "/srv/mysql"]
           ports = ["db"]
         }
   
         resources {
           cpu    = 500
           memory = 1024
         }
   
         service {
           name = "mysql-server"
           port = "db"
   
           check {
             type     = "tcp"
             interval = "10s"
             timeout  = "2s"
           }
         }
       }
     }
   }

2. Create a job with the above configuration:

   nomad job run job.hcl

3. Check the status of your job. It should be running shortly after the image pull has finished:

   nomad job status mysql-server

4. This setup can be cleaned up by stopping the job and and deleting the volume:

   nomad job stop mysql-server 
   nomad volume delete volume-1