2.09 Static Pods

Static Pods are pods managed directly by the kubelet, independent of the kube-apiserver or other control plane components.

Key Concept

Normally, the kubelet relies on the kube-apiserver and scheduler for instructions.
However, even without these components (no master, etcd, or controllers), the kubelet can operate independently by creating pods from manifest files placed in a designated directory on the node.

The kubelet periodically checks a configured Pod Manifest Path (e.g., /etc/kubernetes/manifests) for pod definition files.
When a file is added → the kubelet creates the pod.
When the file is updated → the kubelet recreates the pod.
When the file is removed → the pod is automatically deleted.
The kubelet ensures the pod stays running and restarts it if it crashes.

You can configure the static pod path in two ways:

Directly in the kubelet service:

--pod-manifest-path=/etc/kubernetes/manifests

Through the Kubelet Config File:
```
staticPodPath: /etc/kubernetes/manifests
```
The kubelet continuously monitors this directory and manages any pod definitions within it.

When working outside a cluster (no API server), view static pods using CRI commands:
```
  docker ps 
```
When the node is part of a cluster, view static pods as mirror pods in the API server:
```
kubectl get pods
```
Static pods appear as read-only mirror pods in the API server.
Their names are automatically appended with the node name,

The kubelet can receive instructions to create pods from two different sources:

From pod definition files located in the static pod directory.
From HTTP API requests sent by the kube-apiserver.
This allows the kubelet to manage both static pods and regular pods at the same time.
When a node running the kubelet is part of a cluster, the API server becomes aware of the static pods it creates.
The kubelet automatically generates a mirror object for each static pod within the API server.
These mirror pods appear like regular pods in the cluster, but they are read-only representations.
You can view their details, but you cannot edit or delete them through the API server.
To modify or remove a static pod, you must update or delete its manifest file from the node’s designated manifest directory.

Static Pods are ideal for deploying control plane components, such as:

static-pods-control-plane

They restart automatically if they crash, making them reliable for bootstrapping clusters.
This is exactly how kubeadm sets up the control plane — by running its core components as static pods stored under /etc/kubernetes/manifests.

Static Pods	DaemonSets
Created by the kubelet	Created by the kube-apiserver (DaemonSet Controller)
Deploy Control Plane components as static pods	Deploy Monitoring Agents or Logging Agents on all nodes
Ignored by the kube-scheduler	Ignored by the kube-scheduler