Kubernetes Cookbook - Second Edition

Pod as DaemonSets

If a Kubernetes DaemonSet is created, the defined Pod will be deployed in every single node. It is guaranteed that the running containers occupy equal resources in each node. In this scenario, the container usually works as the daemon process.

For example, the following template has an Ubuntu image container that keeps checking its memory usage half a minute at a time:

1. To build it as a DaemonSet, execute the following code block:

$ cat daemonset-free.yamlapiVersion: apps/v1kind: DaemonSetmetadata:  name: ram-checkspec:  selector:    matchLabels:      name: checkRam  template:    metadata:      labels:        name: checkRam    spec:      containers:      - name: ubuntu-free        image: ubuntu        command: ["/bin/bash","-c","while true; do free; sleep 30; done"]      restartPolicy: ...