Mastering Kubernetes - Second Edition

Using DaemonSet to distribute Cassandra

A better solution to the problem of assigning Cassandra pods to different nodes is to use a DaemonSet. A DaemonSet has a pod template like a replication controller. But a DaemonSet has a node selector that determines on which nodes to schedule its pods. It doesn't have a certain number of replicas, it just schedules a pod on each node that matches its selector. The simplest case is to schedule a pod on each node in the Kubernetes cluster. But the node selector can also use match expressions against labels to deploy to a particular subset of nodes. Let's create a DaemonSet for deploying our Cassandra cluster onto the Kubernetes cluster:

apiVersion: apps/v1 kind: DaemonSet metadata: name: cassandra-daemonset ...