Updating hardware on nodes running on vSphere | Updating clusters

Updating virtual hardware on vSphere
Scheduling an update for virtual hardware on vSphere

You must ensure that your nodes running in vSphere are running on the hardware version supported by OpenShift Container Platform. Currently, hardware version 15 or later is supported for vSphere virtual machines in a cluster.

You can update your virtual hardware immediately or schedule an update in vCenter.

Version 4.12 of OpenShift Container Platform requires VMware virtual hardware version 15 or later.

Updating virtual hardware on vSphere

To update the hardware of your virtual machines (VMs) on VMware vSphere, update your virtual machines separately to reduce the risk of downtime for your cluster.

Updating the virtual hardware for control plane nodes on vSphere

To reduce the risk of downtime, it is recommended that control plane nodes be updated serially. This ensures that the Kubernetes API remains available and etcd retains quorum.

Prerequisites

You have cluster administrator permissions to execute the required permissions in the vCenter instance hosting your OpenShift Container Platform cluster.
Your vSphere ESXi hosts are version 7.0U2 or later.

Procedure

List the control plane nodes in your cluster.

$ oc get nodes -l node-role.kubernetes.io/master

Example output

NAME                    STATUS   ROLES    AGE   VERSION
control-plane-node-0    Ready    master   75m   v1.25.0
control-plane-node-1    Ready    master   75m   v1.25.0
control-plane-node-2    Ready    master   75m   v1.25.0

Note the names of your control plane nodes.

Mark the control plane node as unschedulable.
```
$ oc adm cordon <control_plane_node>
```
Shut down the virtual machine (VM) associated with the control plane node. Do this in the vSphere client by right-clicking the VM and selecting Power → Shut Down Guest OS. Do not shut down the VM using Power Off because it might not shut down safely.
Update the VM in the vSphere client. Follow Upgrade the Compatibility of a Virtual Machine Manually in the VMware documentation for more information.
Power on the VM associated with the control plane node. Do this in the vSphere client by right-clicking the VM and selecting Power On.

Wait for the node to report as Ready:

$ oc wait --for=condition=Ready node/<control_plane_node>

Mark the control plane node as schedulable again:
```
$ oc adm uncordon <control_plane_node>
```
Repeat this procedure for each control plane node in your cluster.

Updating the virtual hardware for compute nodes on vSphere

To reduce the risk of downtime, it is recommended that compute nodes be updated serially.

Multiple compute nodes can be updated in parallel given workloads are tolerant of having multiple nodes in a NotReady state. It is the responsibility of the administrator to ensure that the required compute nodes are available.

Prerequisites

You have cluster administrator permissions to execute the required permissions in the vCenter instance hosting your OpenShift Container Platform cluster.
Your vSphere ESXi hosts are version 7.0U2 or later.

Procedure

List the compute nodes in your cluster.

$ oc get nodes -l node-role.kubernetes.io/worker

Example output

NAME              STATUS   ROLES    AGE   VERSION
compute-node-0    Ready    worker   30m   v1.25.0
compute-node-1    Ready    worker   30m   v1.25.0
compute-node-2    Ready    worker   30m   v1.25.0

Note the names of your compute nodes.

Mark the compute node as unschedulable:
```
$ oc adm cordon <compute_node>
```
Evacuate the pods from the compute node. There are several ways to do this. For example, you can evacuate all or selected pods on a node:
```
$ oc adm drain <compute_node> [--pod-selector=<pod_selector>]
```
See the "Understanding how to evacuate pods on nodes" section for other options to evacuate pods from a node.
Shut down the virtual machine (VM) associated with the compute node. Do this in the vSphere client by right-clicking the VM and selecting Power → Shut Down Guest OS. Do not shut down the VM using Power Off because it might not shut down safely.
Update the VM in the vSphere client. Follow Upgrade the Compatibility of a Virtual Machine Manually in the VMware documentation for more information.
Power on the VM associated with the compute node. Do this in the vSphere client by right-clicking the VM and selecting Power On.

Wait for the node to report as Ready:

$ oc wait --for=condition=Ready node/<compute_node>

Mark the compute node as schedulable again:
```
$ oc adm uncordon <compute_node>
```
Repeat this procedure for each compute node in your cluster.

Updating the virtual hardware for template on vSphere

Prerequisites

You have cluster administrator permissions to execute the required permissions in the vCenter instance hosting your OpenShift Container Platform cluster.
Your vSphere ESXi hosts are version 7.0U2 or later.

Procedure

If the RHCOS template is configured as a vSphere template follow Convert a Template to a Virtual Machine in the VMware documentation prior to the next step.

Once converted from a template, do not power on the virtual machine.
Update the VM in the vSphere client. Follow Upgrade the Compatibility of a Virtual Machine Manually in the VMware documentation for more information.
Convert the VM in the vSphere client from a VM to template. Follow Convert a Virtual Machine to a Template in the vSphere Client in the VMware documentation for more information.

Additional resources

Understanding how to evacuate pods on nodes

Scheduling an update for virtual hardware on vSphere

Virtual hardware updates can be scheduled to occur when a virtual machine is powered on or rebooted. You can schedule your virtual hardware updates exclusively in vCenter by following Schedule a Compatibility Upgrade for a Virtual Machine in the VMware documentation.

When scheduling an upgrade prior to performing an upgrade of OpenShift Container Platform, the virtual hardware update occurs when the nodes are rebooted during the course of the OpenShift Container Platform upgrade.