Overview:

DaemonSets ensure that a copy of a Pod runs on all (or specific) Nodes in a cluster.

Use Cases:

• Running logging or monitoring agents (e.g., Fluentd, Prometheus Node Exporter).

• Running system-level tasks.

Example DaemonSet YAML Manifest:

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: daemonset-example
spec:
  selector:
    matchLabels:
      app: example
  template:
    metadata:
      labels:
        app: example
    spec:
      containers:
      - name: example-container
        image: busybox
        command:
        - /bin/sh
        - -c
        - "while true; do echo Hello from DaemonSet; sleep 3600; done"

Steps to Deploy:

1. Apply the DaemonSet:

   kubectl apply -f daemonset.yaml

2. Verify DaemonSet Pods:

   kubectl get pods -o wide

3. Check Node Placement:

   kubectl describe daemonset daemonset-example

Activity:

Deploy a DaemonSet to run a logging agent on all cluster Nodes. Verify the Pods are running on each Node.