Place replicas within the same domain in OpenShift vSphere within a synchronous DR setup
Once your Portworx cluster is operational, the replica 2 volumes will distribute their replicas across the two cluster domains. You can control this behavior using the Metro DR domain protection
flag, which is enabled by default.
You can run the following command to check if the protection flag is enabled in your setup:
PX_POD=$(oc get pods -l name=portworx -n <portworx-namespace> -o jsonpath='{.items[0].metadata.name}') \
oc exec $PX_POD -n <portworx-namespace> -- /opt/pwx/bin/pxctl cluster options list | grep Metro
If you want the volume replica of a specific volume (for example, monitoring data volumes) to be created within the same cluster domain, label the volume with disable-domain-protection
. This label disables the Metro DR domain protection
flag at the individual volume level, rather than at the cluster level.
The volumes with the disable-domain-protection
label will not be protected by Synchronous DR. In the event of a disaster, you might lose the data associated with these volumes.
To force both the replica provision in the same cluster domain use the VPS.
If you do not want to enforce this behavior and the goal is to simply relax the Metro DR domain protection, then you can skip step 1 and use only disable-domain-protection: "true"
in the StorageCluster spec.
-
Create a custom volume placement strategy for
replicaAffinity
, so that volume replicas are always in the same cluster domain:apiVersion: portworx.io/v1beta2
kind: VolumePlacementStrategy
metadata:
name: vps-domain-filter
spec:
replicaAffinity:
- matchExpressions:
- key: domain
operator: In
values:
- <domain-name>Replace
<domain-name>
with the domain name where you want the replicas to be placed. -
Create the following StorageClass:
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: disable-domain-protection-sc
provisioner: pxd.portworx.com
parameters:
repl: "2"
disable-domain-protection : "true"
placement_strategy: "vps-domain-filter"
allowVolumeExpansion: trueIf you are not using the VPS, then remove
placement_strategy: "vps-domain-filter"
from the above spec. -
Save and apply the above spec:
oc apply -f <your-storageclass>.yaml
-
Create a PVC which references the StorageClass you created above, specifying the StorageClass:
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: <application>-pvc
spec:
storageClassName: disable-domain-protection-sc
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 2Gi -
Save and apply your PVC with the oc apply command:
oc apply -f <your-storageclass>.yaml
The above PVC will have its replicas placed within the same cluster domain.