During scale up, pods (nodes) are added to the rack following the rack order defined in the list in the CR. The Operator distributes the nodes equally across all racks. If any pods remain after equal distribution, they are distributed following the rack order.
Consider a cluster of two racks and five pods. After equal pod distribution, both racks would have two pods, with one left over as a remainder. The remaining pod would go to Rack 1, resulting in Rack 1 having three pods and Rack 2 having two pods. If the cluster size is scaled up to six pods, a new pod would be added to Rack 2.
Scaling down follows the rack order and removes pods with the goal of equal distribution.
In above example of two racks and six pods, scaling down to four pods will result in two racks with two pods each. The third pod (third replica) on Rack 1 goes down first, followed by the third pod on Rack 2.
For this example, the cluster is deployed using a CR file named
spec.size field in the CR file to scale the cluster up or down to the specified number of pods.
Use kubectl to apply the change.
kubectl apply -f aerospike-cluster.yaml
Check the pods.
$ kubectl get pods -n aerospike
NAME READY STATUS RESTARTS AGE
aerocluster-0-0 1/1 Running 0 3m6s
aerocluster-0-1 1/1 Running 0 3m6s
aerocluster-0-2 1/1 Running 0 30s
aerocluster-0-3 1/1 Running 0 30s