DaemonSet use cases

A DaemonSet's typical jobs are infrastructure tasks requiring an agent on every node:

• Log collection: Fluent Bit, Fluentd, Promtail send the container logs on the node to a central place.
• Monitoring: node-exporter and the Datadog agent collect node metrics.
• Networking: kube-proxy, Calico, Cilium manage the node's network rules.
• Storage: CSI node plugins attach disks to the node.
• Security: tools like Falco watch kernel events.

kubectl get ds -n kube-system
NAME         DESIRED   CURRENT   READY
kube-proxy   3         3         3
calico-node  3         3         3

Since a DaemonSet pod runs on every node, its resource consumption is multiplied by the node count; an agent using 200 MiB of memory on 100 nodes means 20 GiB in total. Also, a priority class is given so critical agents aren't evicted:

      priorityClassName: system-node-critical
      containers:
        - name: fluent-bit
          image: fluent/fluent-bit:3.1
          resources:
            requests: {cpu: 50m, memory: 64Mi}
            limits:   {memory: 128Mi}