I have a cluster of 3 Cassandra pods running on Kubernetes. I want to do automatic backup of my data and for that I need to run nodetool snaphot command inside of each container and I need to invoke it remotely. What is the correct way to do it from architectural point of view? Do I need modify cassandra image to have ssh deamon in it or do I need to have helper containers in cassandra pods or to do this by 'kubectl exec' Kubernetes API calls? Other options?