get shell of the pod running Cassandra via GKE

Question

I have created a GKE cluster of Cassandra and I want to run nodetool on each node to back up the data. I am unable to figure out how to do it.

So far, I have SSHed to the node on the kubernetes cluster and I lost from that point onwards. I did docker ps -a and can see the containers. How do I get to each container/pod and take back up?

Answer 1

@Manu Chadha

I am not sure which method you used to install Cass on GKE, but with the cass-operator tag I am going to assume you used the Cass Operator.

This is how i get to pods (NEED POD NAME):

kubectl -n cass-operator get pods
NAME                             READY   STATUS    RESTARTS   AGE
cass-operator-557f6689df-qftdf   1/1     Running   0          14m
cluster1-dc1-default-sts-0       2/2     Running   0          11m
cluster1-dc1-default-sts-1       2/2     Running   0          11m
cluster1-dc1-default-sts-2       2/2     Running   0          11m

Next I can get to bash with pod name:

kubectl -n cass-operator exec --stdin cluster1-dc1-default-sts-0 -- /bin/bash

From bash I can use nodetool or dsetool

You can also execute these directly like this:

kubectl -n cass-operator exec -it -c cassandra cluster1-dc1-default-sts-0 -- nodetool status

I am updating to answer the last question about backups. Backups are done a bit different with cass-operator. Be sure to include backup enabled in your yaml:

# Sized to work on 3 k8s workers nodes with 1 core / 4 GB RAM
# See neighboring example-cassdc-full.yaml for docs for each parameter
apiVersion: cassandra.datastax.com/v1beta1
kind: CassandraDatacenter
metadata:
  name: dc1
spec:
  clusterName: cluster1
  serverType: dse
  serverVersion: "6.8.4"
  managementApiAuth:
    insecure: {}
  size: 3
  storageConfig:
    cassandraDataVolumeClaimSpec:
      storageClassName: server-storage
      accessModes:
        - ReadWriteOnce
      resources:
        requests:
          storage: 25Gi
  config:
    cassandra-yaml:
      backup_service:
        enabled: true
    jvm-server-options:
      initial_heap_size: "800M"
      max_heap_size: "800M"
      additional-jvm-opts:
        # As the database comes up for the first time, set system keyspaces to RF=3
        - "-Ddse.system_distributed_replication_dc_names=dc1"
        - "-Ddse.system_distributed_replication_per_dc=3"

Follow the documented steps for GKE and Google Blog Storage:

https://docs.datastax.com/en/dse/6.8/dse-admin/datastax_enterprise/operations/opsBackupRestoreCreateBackupStore.html

https://docs.datastax.com/en/dse/6.8/dse-admin/datastax_enterprise/operations/opsCqlCreateBackupStore.html

Answer 2

Try the steps on this article, get your pods:

kubectl get pvc

And then:

kubectl exec cassandra-pod -- nodetool status

Change cassandra-pod with the pod name.