DaemonSet

As explained in Acing the Certified Kubernetes Administrator Exam, Second Edition

A DaemonSet is a Kubernetes workload resource that ensures a pod runs on each eligible node.

A DaemonSet is a Kubernetes workload resource that ensures one pod runs on every eligible node. If its pod is deleted, the DaemonSet recreates it on a node missing that pod. section 4.1.1

Use a DaemonSet when a node-level component must run continuously across the cluster:

• Run kube-proxy and container network interface components on each node. section 1.8
• Inspect DaemonSets with kubectl get ds or kubectl get ds -A; compare desired, current, ready, and available counts. section 1.8
• Inspect a DaemonSet pod's assigned node in its YAML by locating nodeName; retrieve pod names with kubectl get po -A. section 4.1.1

Distinguish kubelet from a DaemonSet

kubelet is a Linux background process managed on the host rather than by Kubernetes as a DaemonSet. Check it with systemctl list-unit-files --type service | grep kubelet -A3 -B3, then start it with systemctl start kubelet if it is stopped. section 1.8

Figure 1.13 DaemonSets ensure that a single pod is running on each node in the cluster. kube-proxy and CNI both run as a DaemonSet.

Use the diagram to visualize the one-pod-per-node placement pattern, including kube-proxy and CNI workloads. section 1.8

How Acing the Certified Kubernetes Administrator Exam, Second Edition covers it

How deep it goes

Explains one-pod-per-node scheduling, respawning, nodeName inspection, and kubectl verification, but not manifest construction.

Examples

Uses kube-proxy, CNI, kindnet, kubectl output, and kubelet systemd listings as operational examples.

What it assumes

Assumes basic Kubernetes pods and nodes, while clarifying the difference between Kubernetes DaemonSets and Linux background processes.

What you can do after

Diagnose DaemonSet coverage with kubectl and distinguish missing DaemonSet pods from a stopped host-level kubelet.

How it connects

Connects DaemonSets with pods, node names, node selectors, kube-proxy, CNI, and kubelet.

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Also explained in

• 

  liveBookmanning.com
  Kubernetes in Action, Second EditionA DaemonSet is a Kubernetes resource that ensures a pod instance runs on each eligible node or selected subset of nodes.
• 

  liveBookmanning.com
  Logs and TelemetryA DaemonSet is a Kubernetes workload controller that ensures a Pod runs on each eligible node or on a selected set of nodes.

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Related concepts

• kube-proxyused by · kube-proxy is a Kubernetes node component that maintains network rules forwarding service traffic to appropriate application pods.
• Kubernetes resourcekind of · A Kubernetes resource is a persistent API-managed object representing the desired or observed state of a workload, configuration, or other cluster entity.
• node selectorconfigured by · A node selector is a Kubernetes scheduling constraint that restricts a pod or workload to nodes having specified matching labels.
• podproduces · A Kubernetes Pod is the smallest deployable unit in Kubernetes, grouping one or more co-located containers that share networking and other resources.
• pod templatehas part · A pod template is a declarative specification embedded in a Kubernetes workload that defines the metadata, containers, and configuration of pods it creates.
• workloaduses · A workload is the amount, pattern, or set of work, tasks, or processing activity assigned to or carried out by a person, application, or computing system.

This explainer was generated by Manning's knowledge graph from the text of Acing the Certified Kubernetes Administrator Exam, Second Edition. The section links point to the parts of the book it draws on.