PGDGroup parting v1.2.0

Suggest edits

Deletion and finalizers

When deleting a PGD Group, the operator will start parting every node in the group first. It will connect to an active instance and part every node in the target group. Once a node is parted, the node will not participate in replication and consensus operations. To make sure the node is correctly parted before being deleted, the operator uses the k8s.pgd.enterprisedb.io/partNodes finalizer. Please refer to the kubernetes documentation on finalizers for context.

Note

If a namespace holding a PGD Group is deleted directly, the operator cannot ensure the deleting and parting sequence is carried out correctly. Before deleting a namespace, it is recommended to delete all the contained PGD groups.

Time limit

When parting a node, the operator needs to connect to an active instance to execute the bdr.part_node function. To avoid this operation hanging, a time limit for the finalizer is used; by default, it is 300 seconds. After the time limit expires, the finalizer will be removed, and the node will be deleted anyway, potentially leaving stale metadata in the global PGD catalog. This time limit can be configured through spec.failingFinalizerTimeLimitSeconds, which is specified in seconds.

Skip finalizer

For testing purposes only, the operator also provides an annotation to skip the finalizer: k8s.pgd.enterprisedb.io/noFinalizers. When this annotation is added to a PGDGroup, the finalizer will be skipped when the PGDGroup is being deleted, and the nodes will not be parted from the PGD cluster.

PGDGroup cleanup

Clean up parted nodes

Once the PGDGroup is deleted from Kubernetes and all the nodes belonging to this group are parted, the group information is still available in the pgd metadata like bdr.node_group. The PGD4K operator defines a CRD named PGDGroupCleanup to help drop the PGDGroup and clean up the parted nodes belonging to this group, if any.

In the example below, the PGDGroupCleanup executes locally from region-a, and will clean up all parted nodes of region-b, with the prerequisite that all the nodes must be in the PARTED state. It will then drop the PGDGroup region-b.

apiVersion: pgd.k8s.enterprisedb.io/v1beta1
kind: PGDGroupCleanup
metadata:
  name: region-b-cleanup
spec:
  executor: region-a
  target: region-b

Please note that if the target group (region-b in the example) contains nodes not in a PARTED state, the Group Cleanup will stop in phase PGDGroupCleanup - Waiting for nodes in target PGDGroup to be parted. In cases of extreme need, we can add the force option.

Warning

Using force can leave the PGD cluster in an inconsistent state. Use it only to recover from failures in which you can't part the group nodes any other way.

apiVersion: pgd.k8s.enterprisedb.io/v1beta1
kind: PGDGroupCleanup
metadata:
  name: region-b-cleanup
spec:
  force: true
  executor: region-a
  target: region-b
← Prev

Monitoring

↑ Up

EDB Postgres® AI for CloudNativePG™ Global Cluster

Next →

SQLMutations