Live Migration of Workloads

Rosetta Stone: VMware

In VMware this is called VMotion.

VMware uses the concept of Datastores. VMware Datastores can be thought of as LUNs, which may or may not belong to a Datastore Cluster.

Differences

  • Different paradigm.

  • PV PVC provides it to a VM when it needs it, getting it from a StorageClass.

  • Datastore → Cluster structure

Mapping

  • Datastore Cluster (or VM attached directly to Datastore) = StorageClass defines volume, claims against it.

Datastore Clusters are a collection of Datastores and use SDRS for placement of the .VMDK files on specific Datastores. Storage Distributed Resource Scheduler (SDRS) can only be applied to Datastore Clusters, and is used to automate this process.

Migrating workloads between compute nodes and storage types is a crucial feature of any modern hypervisor. OpenShift Virtualization allows the simple and easy process of migrating your virtual machine compute and storage from one place to another.

In this module, you will perform three migration tasks:

Accessing the OpenShift Cluster

Web Console

{openshift_cluster_console_url}[{openshift_cluster_console_url},window=_blank]

CLI Login
oc login -u {openshift_cluster_admin_username} -p {openshift_cluster_admin_password} --server={openshift_api_server_url}
Cluster API

{openshift_api_server_url}[{openshift_api_server_url},window=_blank]

OpenShift Username
{openshift_cluster_admin_username}
OpenShift Password
{openshift_cluster_admin_password}

Compute Migration to a random node

During maintenance or troubleshooting, you might need to migrate a VM to a different node. Live migration is the process of moving a running Virtual Machine Instance (VMI) to a different node without disruption.

Rosetta Stone: VMware

This feature is similar to VMware’s Compute vMotion feature, and Distributed Resource Scheduler (DRS) for VM placement.

In this lab, you will be performing a live migration of Virtual Machine from one compute node to another. To do this, you will access a running VM, determine its current node, and then migrate it to another node.

Requirements

  • The underlying PVC must use ReadWriteMany (RWX) access mode

  • The pod network must not be configured with the bridge binding type.

  • Ports 49152 and 49153 must be available in the VM’s virt-launcher pod; live migration fails if these ports are specified in a masquerade network interface.

  • CPU model must match on the source and destination node - you can not live migrate from Intel to AMD

Instructions

  1. Ensure you are logged in to the OpenShift Console as the admin user from your web browser and continue to the next step.

  2. From the left side panel, navigate to Virtualization → Virtual Machines. Under All projects, select the live-migrate namespace and click on the Virtual Machine named live-migrate-vm1.

  3. The Virtual Machine is currently powered off. Click the blue Play button to Start the Virtual Machine.

    01 vm start 001
    Figure 1. Start the Virtual Machine

  4. The Virtual Machine will schedule, start and move into the Running state as seen below.

    01 vm start 002
    Figure 2. Running Virtual Machine

    To see the node the Virtual Machine is currently running on, look at the General box on the right hand side of the VirtualMachine details page for the Node name. In the example, the node is worker-cluster-m2ssq-1.
    01 image compute 002
    Figure 3. Virtual machine details

  5. To migrate the Virtual Machine to another node, click on the Actions menu, hover over Migration, and then click Compute.

    01 image compute 003
    Figure 4. Initiate migration

  6. Leave the default selection, which is to Automatically migrate to any Node.

    01 image compute 004
    Figure 5. Configure migration

  7. Click Migrate Virtual Machine

  8. Wait a few moments and the Virtual Machine status will change from Running to Migrating.

    01 image compute 006
    Figure 6. VM is migrating

  9. A few moments after that, the Virtual Machine will return to a Running state.

    Looking back at the General box on the right hand side of the VirtualMachine details page, you can see that the node has changed.
    01 image compute 007
    Figure 7. VM is running

  10. The VM has migrated to a new worker node while still running.

Compute Migration to a specific node

During maintenance or troubleshooting, you might need to migrate a Virtual Machine to a specific node in the cluster.

The requirements for this type of migration are the same as the previous lesson.

Instructions

  1. Ensure you are logged in to the OpenShift Console as the admin user from your web browser and continue to the next step.

  2. From the left side panel, navigate to Virtualization → Virtual Machines.

  3. Under All projects, select the live-migrate namespace and click on the Virtual Machine named live-migrate-vm1.

  4. The Virtual Machine should already be Running from the last lesson. If it is not, click the blue Play button to Start the Virtual Machine and wait for it to enter the Running state.

    01 image compute 002
    Figure 8. Virtual machine details

  5. To migrate the Virtual Machine to another node, click on the Actions menu, hover over Migration, and then click Compute.

    01 image compute 003
    Figure 9. Initiate migration

  6. You will be presented with the Select the target Node to migrate your VirtualMachine to window.

    01 image compute 004
    Figure 10. Configure migration

  7. Select Specific Node, which will then display the list of available nodes. Select the check the box next to a worker node and click Migrate Virtual Machine

    01 image compute 005
    Figure 11. Select worker node

  8. You will see the Virtual Machine status changes from Running to Migrating.

    01 image compute 006
    Figure 12. VM is migrating

  9. A few moments after that, the Virtual Machine status will return to a Running state.

    Looking back at the General box on the right hand side of the VirtualMachine details page, you can see that the node has changed, specifically to the one you selected from the list.
01 image compute 007
Figure 13. VM is running

Storage Migration

Storage environments often have their own lifecycles and performance profiles, so it is important to be able to move Virtual Machines between storage devices for lifecycle and performance management. OpenShift Virtualization allows the migration of PVCs from one StorageClass to another while the virtual machine is running.

Rosetta Stone: VMware

This feature is similar to VMware’s Storage vMotion feature.

This also includes the Storage Distributed Resource Scheduler (SDRS) for disk placement.

Requirements

  • The Migration Toolkit for Containers (MTC) Operator must be installed for storage class migrations

MTC has been deprecated and engineering is working on removing the MTC requirement for storage class migrations.

This feature is targeting 4.21 and engineering plans to backport it to 4.20.z.

You can follow VM Storage Migration for more information.

Instructions

  1. Ensure you are logged in to the OpenShift Console as the admin user and continue to the next step.

  2. From the left side panel, navigate to Virtualization → Virtual Machines.

    Under All projects, select the live-migrate namespace and click on the Virtual Machine named live-migrate-vm1.

    01 image storage 001
    Figure 14. Virtual machine details

  3. Click on the Configuration tab and select Storage. You can see that the Virtual Machine currently has a single 30GB bootable disk that is using the Storage class called ocs-external-storagecluster-ceph-rbd.

    01 image storage 002
    Figure 15. View storage details

  4. Click on the Console tab. If necessary, click the blue Connect button.

    Login to the Virtual Machine using Copy to clipboard and Paste to console with the User name and Password credentials from above the console window.

  5. Run a command, such as top or ping, that will continue running as we perform the remainder of this exercise.

    01 image storage 003
    Figure 16. Run command on console

  6. Click on the Actions menu, hover over Migration and click on Storage.

    01 image storage 004
    Figure 17. Initiate storage migration

  7. In the Migrate VirtualMachine storage window, review the options, keep the defaults and click Next.

    01 image storage 005
    Figure 18. Migration details

  8. For the Destination StorageClass, select the new StorageClass called custom-storage-class and click Next.

    01 image storage 006
    Figure 19. Select destination StorageClass

  9. Review the final storage migration configuration and click Migrate VirtualMachine storage.

    01 image storage 007
    Figure 20. Review migration details

  10. The next window will show you the status of the storage migration. It is safe to close the window by clicking the X in the top corner, or you may click on the link to View storage migrations. Do not click the Stop button.

    01 image storage 008
    Figure 21. Migration has started

  11. To view the storage migration status, navigate to Migration for Virtualization from the left side panel and click Storage migrations. The migration plan will start in the Pending state, move to Running and then to Completed.

    It may take over a minute for the migration to start, and five or more minutes for the migration to complete in the lab environment.
    01 image storage 009
    Figure 22. Migration is running

  12. Once the migration is Complete, from the left side panel, navigate back to Virtualization → Virtual Machines.

    Under All projects, select the live-migrate namespace and click on the Virtual Machine named live-migrate-vm1.

    Click on the Configuration tab and select Storage. You can see that the name of the Source has changed and the Storage class is now custom-storage-class, which is what you selected for the storage migration.

    01 image storage 010
    Figure 23. VM has been migrated

  13. Moving back to the Console tab, you will see that your ping is still running and was uninterrupted during the migration.

    01 image storage 011
    Figure 24. No interruption during storage migration

Stop the live-migrate-vm1 VM using virtctl from your Terminal window to ensure you have enough resources for the next labs.

virtctl stop live-migrate-vm1 -n live-migrate

VM live-migrate-vm1 was scheduled to stop