Merge pull request #48655 from abhilasha2418/daemonSet

Create new task for building basic daemon set

Author: k8s-ci-robot

content/en/docs/tasks/manage-daemon/create-daemon-set.md

@@ -0,0 +1,65 @@
+---
+title: Building a Basic DaemonSet  
+content_type: task  
+weight: 5  
+---
+<!-- overview -->
+
+This page demonstrates how to build a basic {{< glossary_tooltip text="DaemonSet" term_id="daemonset" >}} that runs a Pod on every node in a Kubernetes cluster.
+It covers a simple use case of mounting a file from the host, logging its contents using
+an [init container](/docs/concepts/workloads/pods/init-containers/), and utilizing a pause container.
+
+## {{% heading "prerequisites" %}}
+
+{{< include "task-tutorial-prereqs.md" >}}
+
+A Kubernetes cluster with at least two nodes (one control plane node and one worker node) to demonstrate the behavior of DaemonSets.
+
+## Define the DaemonSet
+
+In this task, a basic DaemonSet is created which ensures that the copy of a Pod is scheduled on every node.
+The Pod will use an init container to read and log the contents of `/etc/machine-id` from the host,
+while the main container will be a `pause` container, which keeps the Pod running.
+
+{{% code_sample file="application/basic-daemonset.yaml" %}}
+
+1. Create a DaemonSet based on the (YAML) manifest:
+
+  ```shell
+  kubectl apply -f https://k8s.io/examples/application/basic-daemonset.yaml
+  ```
+
+1. Once applied, you can verify that the DaemonSet is running a Pod on every node in the cluster:
+
+  ```shell
+  kubectl get pods -o wide
+  ```
+
+  The output will list one Pod per node, similar to:
+
+  ```
+  NAME                                READY   STATUS    RESTARTS   AGE    IP       NODE
+  example-daemonset-xxxxx             1/1     Running   0          5m     x.x.x.x  node-1
+  example-daemonset-yyyyy             1/1     Running   0          5m     x.x.x.x  node-2
+  ```
+
+1. You can inspect the contents of the logged `/etc/machine-id` file by checking the log directory mounted from the host:
+
+  ```shell
+  kubectl exec <pod-name> -- cat /var/log/machine-id.log
+  ```
+  
+  Where `<pod-name>` is the name of one of your Pods.
+
+## {{% heading "cleanup" %}}
+
+  ```
+  kubectl delete --cascade=foreground --ignore-not-found --now daemonsets/example-daemonset
+  ```
+
+This simple DaemonSet example introduces key components like init containers and host path volumes,
+which can be expanded upon for more advanced use cases. For more details refer to
+[DaemonSet](/docs/concepts/workloads/controllers/daemonset/).
+
+
+

content/en/examples/application/basic-daemonset.yaml

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+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: example-daemonset
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: example
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: example
+    spec:
+      containers:
+      - name: pause
+        image: registry.k8s.io/pause
+      initContainers:
+      - name: log-machine-id
+        image: busybox:1.37
+        command: ['sh', '-c', 'cat /etc/machine-id > /var/log/machine-id.log']
+        volumeMounts:
+        - name: machine-id
+          mountPath: /etc/machine-id
+          readOnly: true
+        - name: log-dir
+          mountPath: /var/log
+      volumes:
+      - name: machine-id
+        hostPath:
+          path: /etc/machine-id
+          type: File
+      - name: log-dir
+        hostPath:
+          path: /var/log