Upgrade a DataStax Enterprise (DSE) cluster With Zero Downtime

User submits a modified MissionControlCluster manifest to the Control Plane Kubernetes cluster.

Cluster-level operator detects the change and modifies the datacenter-level resource.

Datacenter-level operator detects the change and modifies the rack-level resource.

Datacenter-level operator terminates the instance in the rack.

Datacenter-level operator bootstraps a replacement node.

Datacenter-level operator repeats steps c-e for all racks in one datacenter.

Cluster-level operator repeats steps b-e for all datacenters in a cluster, one dc at a time, in the case of a multi-datacenter cluster.

User follows Upgrade SSTables steps, if required.

Modify the existing MissionControlCluster YAML (demo.yaml) in the Control Plane Kubernetes cluster, overwriting the value 6.8.25 in the spec.k8ssandra.cassandra.serverVersion field with 6.8.26:

apiVersion: missioncontrol.datastax.com/v1beta2
kind: MissionControlCluster
metadata:
  name: demo
spec:
  k8ssandra:
    cassandra:
      serverVersion: 6.8.26
...

Submit the version change to the Kubernetes Control Plane cluster with the following command:

kubectl apply -f demo.yaml

Monitor the progress of the upgrade from the Data Plane east cluster, looking at the status of the CassandraDatacenter with this command:

kubectl get cassandradatacenter dc1 -o yaml

status:
  cassandraOperatorProgress: Updating
  conditions:
  - lastTransitionTime: "2022-10-20T16:07:10Z"
    message: ""
    reason: ""
    status: "True"
    type: Healthy
  - lastTransitionTime: "2022-10-20T16:07:10Z"
    message: ""
    reason: ""
    status: "False"
    type: Stopped
...