Manage CPU and Memory

You can use the KubeVirt CPU Hotplug and KubeVirt Memory Hotplug feature in Palette, which allows the Virtual Machine (VM) to add and remove virtual CPUs and increase or decrease memory while the VM is active. By default, live migration is automatically enabled to apply the changes without rebooting the VM.

Limitations

• CPU and memory hotplug is not currently supported by the ARM64 architecture.
• The current CPU and memory hotplug implementation requires the live migration of the VM workload.

Prerequisites

• A VM deployed and active in Palette.

Manage CPU and Memory

Select the tab that corresponds to the method you want to use to enable CPU or memory hotplug in your VM.

UI

1. Log in to Palette.

2. From the left Main Menu, select Clusters, and then select the cluster with the VM you want to update.

3. Select the Virtual Machines tab, then select the necessary VM and open its Details tab.

   

4. Change the desired CPU sockets, CPU cores, or memory size. Toggle the Run Live Migration switch to enable the changes through live migration. If you don't toggle the switch, the changes are applied next time the VM is restarted.

   

   info

   Memory changes expose an additional Save & Restart button. This button allows you to save the changes and immediately restart the VM to apply the changes. Otherwise, the changes are applied through live migration.

5. Select Save.

YAML

1. Log in to Palette.

2. From the left Main Menu, select Clusters, and then select the cluster with the VM you want to update.

3. Select the Virtual Machines tab, then select the necessary VM and open its YAML tab.

   

4. In the VM YAML configuration editor, navigate to the VM object configuration and update the number of CPU sockets or memory. Consider the following examples for reference.

   spec:
     template:
       spec:
         domain:
           cpu:
             sockets: 5

   spec:
     template:
       spec:
         domain:
           memory:
             guest: 2Gi

5. In the bottom-left corner, select Save. Palette applies your updates.

6. To track the update process, in the YAML configuration editor, select Reload and monitor for a status update similar to the following example.

   status:
     conditions:
       - lastProbeTime: null
         lastTransitionTime: null
         status: "True"
         type: LiveMigratable
       - lastProbeTime: null
         lastTransitionTime: null
         status: "True"
         type: HotVCPUChange

Validate

UI

1. Log in to Palette.

2. From the left Main Menu, select Clusters, and then select the cluster with the VM you want to update.

3. Select the Virtual Machines tab, then select the necessary VM and open its Console tab.

4. Log in to the VM using the appropriate credentials specified in the YAML template. The provided templates contain the default credentials for the VM in the cloudInitNoCloud.userData section.

5. Verify that the VM has the expected number of CPUs or memory size. Use the following commands to verify the number of CPUs, memory size, and number of CPU cores. Keep in mind that the commands may vary based on the OS.

   To verify the number of CPUs and cores, issue the following command.

    lscpu

   To verify the memory size, issue the following command.

   free --human

YAML

1. Log in to Palette.

2. From the left Main Menu, select Clusters, and then select the cluster with the VM where you enabled the CPU or memory hotplug.

3. Select the Virtual Machines tab, then select the necessary VM and open its YAML tab.

4. In the VM YAML configuration editor, navigate to the VM object and status configurations and verify that they specify the expected number of CPUs or memory size. Consider the following example for reference.

   spec:
     template:
       spec:
         domain:
           cpu:
             cores: 1
             sockets: 5
             threads: 1
    ...
    status:
      currentCPUTopology:
        cores: 1
        sockets: 5
        threads: 1