Merge pull request #99578 from lahinson/osdocs-16009-hcp-evictionstrategy

[OSDOCS-16009]: Adding evictionStrategy docs

Author: lahinson

hosted_control_planes/hcp-manage/hcp-manage-virt.adoc

@@ -60,6 +60,8 @@ include::modules/hcp-virt-attach-nvidia-gpus.adoc[leveloffset=+1]
 
 include::modules/hcp-virt-attach-nvidia-gpus-np-api.adoc[leveloffset=+1]
 
+include::modules/hcp-virt-evict-vms.adoc[leveloffset=+1]
+
 include::modules/hcp-topology-spread-constraint.adoc[leveloffset=+1]
 
 [role="_additional-resources"]

modules/hcp-virt-evict-vms.adoc

@@ -0,0 +1,53 @@
+// Module included in the following assemblies:
+//
+// * hosted_control_planes/hcp-manage/hcp-manage-virt.adoc
+
+:_mod-docs-content-type: PROCEDURE
+[id="hcp-virt-evict-vms_{context}"]
+= Evicting KubeVirt virtual machines
+
+In cases where KubeVirt virtual machines (VMs) cannot be live migrated, such as when you use GPU passthrough, the VMs must be evicted at the same time as the `NodePool` resource of the hosted cluster. Otherwise, the compute nodes might be shut down without being drained from the workload. This might also happen when you are upgrading the {VirtProductName} Operator. To achieve a synchronized restart, you can set the `evictionStrategy` parameter on the `hyperconverged` resource to ensure that only VMs that are drained from workloads are rebooted. 
+
+.Procedure
+
+. To learn more about the `hyperconverged` resource and the allowed values for the `evictionStrategy` parameter, enter the following command:
++
+[source,terminal]
+----
+$ oc explain hyperconverged.spec.evictionStrategy
+----
+
+. Patch the `hyperconverged` resource by entering the following command:
++
+[source,terminal]
+----
+$ oc -n openshift-cnv patch hyperconverged kubevirt-hyperconverged \
+  --type=merge \
+  -p '{"spec": {"evictionStrategy": "External"}}'
+----
+
+. Patch the workload update strategy and the workload update methods by entering the following command:
++
+[source,terminal]
+----
+$ oc -n openshift-cnv patch hyperconverged kubevirt-hyperconverged \
+  --type=merge \
+  -p '{"spec": {"workloadUpdateStrategy": {"workloadUpdateMethods": ["LiveMigrate","Evict"]}}}'
+----
++
+By applying this patch, you specify that VMs should be live-migrated if possible, and that only the VMs that cannot be live-migrated should be evicted.
+
+.Verification
+
+* Check whether the patch command was applied properly by entering the following command:
++
+[source,terminal]
+----
+$ oc -n openshift-cnv get hyperconverged kubevirt-hyperconverged -ojsonpath='{.spec.evictionStrategy}'
+----
++
+.Example output
+[source,terminal]
+----
+External
+----