4.8. Configuring shared block storage

Procedure

1. Create a shared block volume:

   $ az disk create -g <resource_group> -n <shared_block_volume_name> --size-gb <disk_size> --max-shares <number_vms> -l <location>

   For example, the following command creates a shared block volume named shared-block-volume.vhd in the resource group sharedblock within the Azure Availability Zone westcentralus.

   $ az disk create -g sharedblock-rg -n shared-block-volume.vhd --size-gb 1024 --max-shares 3 -l westcentralus
   
   {
     "creationData": {
       "createOption": "Empty",
       "galleryImageReference": null,
       "imageReference": null,
       "sourceResourceId": null,
       "sourceUniqueId": null,
       "sourceUri": null,
       "storageAccountId": null,
       "uploadSizeBytes": null
     },
     "diskAccessId": null,
     "diskIopsReadOnly": null,
     "diskIopsReadWrite": 5000,
     "diskMbpsReadOnly": null,
     "diskMbpsReadWrite": 200,
     "diskSizeBytes": 1099511627776,
     "diskSizeGb": 1024,
     "diskState": "Unattached",
     "encryption": {
       "diskEncryptionSetId": null,
       "type": "EncryptionAtRestWithPlatformKey"
     },
     "encryptionSettingsCollection": null,
     "hyperVgeneration": "V1",
     "id": "/subscriptions/12345678910-12345678910/resourceGroups/sharedblock-rg/providers/Microsoft.Compute/disks/shared-block-volume.vhd",
     "location": "westcentralus",
     "managedBy": null,
     "managedByExtended": null,
     "maxShares": 3,
     "name": "shared-block-volume.vhd",
     "networkAccessPolicy": "AllowAll",
     "osType": null,
     "provisioningState": "Succeeded",
     "resourceGroup": "sharedblock-rg",
     "shareInfo": null,
     "sku": {
       "name": "Premium_LRS",
       "tier": "Premium"
     },
     "tags": {},
     "timeCreated": "2020-08-27T15:36:56.263382+00:00",
     "type": "Microsoft.Compute/disks",
     "uniqueId": "cd8b0a25-6fbe-4779-9312-8d9cbb89b6f2",
     "zones": null
   }

2. Verify the shared block volume:

   $ az disk show -g <resource_group> -n <shared_block_volume_name>

   For example, the following command shows details for the shared block volume shared-block-volume.vhd within the resource group sharedblock-rg.

   $ az disk show -g sharedblock-rg -n shared-block-volume.vhd
   
   {
     "creationData": {
       "createOption": "Empty",
       "galleryImageReference": null,
       "imageReference": null,
       "sourceResourceId": null,
       "sourceUniqueId": null,
       "sourceUri": null,
       "storageAccountId": null,
       "uploadSizeBytes": null
     },
     "diskAccessId": null,
     "diskIopsReadOnly": null,
     "diskIopsReadWrite": 5000,
     "diskMbpsReadOnly": null,
     "diskMbpsReadWrite": 200,
     "diskSizeBytes": 1099511627776,
     "diskSizeGb": 1024,
     "diskState": "Unattached",
     "encryption": {
       "diskEncryptionSetId": null,
       "type": "EncryptionAtRestWithPlatformKey"
     },
     "encryptionSettingsCollection": null,
     "hyperVgeneration": "V1",
     "id": "/subscriptions/12345678910-12345678910/resourceGroups/sharedblock-rg/providers/Microsoft.Compute/disks/shared-block-volume.vhd",
     "location": "westcentralus",
     "managedBy": null,
     "managedByExtended": null,
     "maxShares": 3,
     "name": "shared-block-volume.vhd",
     "networkAccessPolicy": "AllowAll",
     "osType": null,
     "provisioningState": "Succeeded",
     "resourceGroup": "sharedblock-rg",
     "shareInfo": null,
     "sku": {
       "name": "Premium_LRS",
       "tier": "Premium"
     },
     "tags": {},
     "timeCreated": "2020-08-27T15:36:56.263382+00:00",
     "type": "Microsoft.Compute/disks",
     "uniqueId": "cd8b0a25-6fbe-4779-9312-8d9cbb89b6f2",
     "zones": null
   }

3. Create three network interfaces. Run the following command three times by using a different <nic_name> for each node:

   $ az network nic create \
       -g <resource_group> -n <nic_name> --subnet <subnet_name> \
       --vnet-name <virtual_network> --location <location> \
       --network-security-group <network_security_group> --private-ip-address-version IPv4

   For example, the following command creates a network interface with the name shareblock-nodea-vm-nic-protected.

   $ az network nic create \
       -g sharedblock-rg -n sharedblock-nodea-vm-nic-protected --subnet sharedblock-subnet-protected \
       --vnet-name sharedblock-vn --location westcentralus \
       --network-security-group sharedblock-nsg --private-ip-address-version IPv4

4. Create three VMs and attach the shared block volume. Option values are the same for each VM except that each VM has its own <vm_name>, <new_vm_disk_name>, and <nic_name>:

   $ az vm create \
       -n <vm_name> -g <resource_group> --attach-data-disks <shared_block_volume_name> \
       --data-disk-caching None --os-disk-caching ReadWrite --os-disk-name <new_vm_disk_name> \
       --os-disk-size-gb <disk_size> --location <location> --size <virtual_machine_size> \
       --image <image_name> --admin-username <vm_username> --authentication-type ssh \
       --ssh-key-values <ssh_key> --nics <nic_name> --availability-set <availability_set> --ppg <proximity_placement_group>

   For example, the following command creates a VM named sharedblock-nodea-vm:

   $ az vm create \
   -n sharedblock-nodea-vm -g sharedblock-rg --attach-data-disks shared-block-volume.vhd \
   --data-disk-caching None --os-disk-caching ReadWrite --os-disk-name sharedblock-nodea-vm.vhd \
   --os-disk-size-gb 64 --location westcentralus --size Standard_D2s_v3 \
   --image /subscriptions/12345678910-12345678910/resourceGroups/sample-azureimagesgroupwestcentralus/providers/Microsoft.Compute/images/sample-azure-rhel-10.3.0-20200713.n.0.x86_64 --admin-username sharedblock-user --authentication-type ssh \
   --ssh-key-values @sharedblock-key.pub --nics sharedblock-nodea-vm-nic-protected --availability-set sharedblock-as --ppg sharedblock-ppg
   
   {
     "fqdns": "",
     "id": "/subscriptions/12345678910-12345678910/resourceGroups/sharedblock-rg/providers/Microsoft.Compute/virtualMachines/sharedblock-nodea-vm",
     "location": "westcentralus",
     "macAddress": "00-22-48-5D-EE-FB",
     "powerState": "VM running",
     "privateIpAddress": "198.51.100.3",
     "publicIpAddress": "",
     "resourceGroup": "sharedblock-rg",
     "zones": ""
   }

Verification

1. For each VM in your cluster, verify that the block device is available. To do so, connect to the vm by using the ssh command with your VM’s IP address:

   # ssh <ip_address> "hostname ; lsblk -d | grep ' 1T '"

   For example, the following command lists details including the hostname and block device for the VM IP 198.51.100.3:

   # ssh 198.51.100.3 "hostname ; lsblk -d | grep ' 1T '"
   
   nodea
   sdb    8:16   0    1T  0 disk

2. Use the ssh utility to verify that each VM in your cluster uses the same shared disk:

   # ssh <ip_address> "hostname ; lsblk -d | grep ' 1T ' | awk '{print \$1}' | xargs -i udevadm info --query=all --name=/dev/{} | grep '^E: ID_SERIAL='"

   For example, the following command lists details including the hostname and shared disk volume ID for the instance IP address 198.51.100.3:

   # ssh 198.51.100.3 "hostname ; lsblk -d | grep ' 1T ' | awk '{print \$1}' | xargs -i udevadm info --query=all --name=/dev/{} | grep '^E: ID_SERIAL='"
   
   nodea
   E: ID_SERIAL=3600224808dd8eb102f6ffc5822c41d89

   After you verify that each VM connects to the shared disk, you can configure resilient storage for the cluster.