Lab Solution DaemonSets optional

In this lesson we inspect existing DaemonSets in the cluster and then create a simple fluentd logging DaemonSet by generating YAML from a Deployment and converting it to a DaemonSet. The steps below reproduce the commands, outputs, and edits needed to complete the lab.

1) How many DaemonSets exist in the cluster (all namespaces)?

Run:

kubectl get daemonsets --all-namespaces

Example output:

NAMESPACE     NAME               DESIRED  CURRENT  READY  UP-TO-DATE  AVAILABLE  NODE SELECTOR                AGE
kube-system   kube-flannel-ds    1        1        1      1           1          <none>                      24m
kube-system   kube-proxy         1        1        1      1           1          kubernetes.io/os=linux      24m

From the output above, there are two DaemonSets in the cluster:

kube-flannel-ds
kube-proxy

Summary table

DaemonSet Name	Namespace	Desired	Ready	Node Selector
`kube-flannel-ds`	`kube-system`	1	1	`<none>`
`kube-proxy`	`kube-system`	1	1	`kubernetes.io/os=linux`

2) Which namespace are the DaemonSets created in?

Check the NAMESPACE column shown by kubectl get daemonsets --all-namespaces above. Both kube-flannel-ds and kube-proxy are in the kube-system namespace. Select kube-system when prompted in the lab.

3) Which of the following is a DaemonSet?

From the list shown earlier, kube-flannel-ds and kube-proxy are DaemonSets. Other components such as scheduler, coredns, or etcd-master are not DaemonSets (they may be Deployments, static pods, or other controller types).

4) On how many nodes are the pods scheduled by the DaemonSet `kube-proxy`?

Describe the DaemonSet in the kube-system namespace:

kubectl describe daemonset kube-proxy -n kube-system

Relevant excerpt (trimmed):

Name:                                kube-proxy
Selector:                            k8s-app=kube-proxy
Node-Selector:                       kubernetes.io/os=linux
Labels:                              k8s-app=kube-proxy
Desired Number of Nodes Scheduled:   1
Current Number of Nodes Scheduled:   1
Number of Nodes Scheduled with Up-to-date Pods: 1
Number of Nodes Scheduled with Available Pods: 1
Pods Status:                         1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:      k8s-app=kube-proxy
  Service Account:  kube-proxy
  Containers:
    kube-proxy:
      Image:        k8s.gcr.io/kube-proxy:v1.20.0
      Command:
        /usr/local/bin/kube-proxy
        --config=/var/lib/kube-proxy/config.conf
        --hostname-override=$(NODE_NAME)
      Environment:
        NODE_NAME: (v1:spec.nodeName)
      Mounts:
        /lib/modules from lib-modules (ro)
        /run/xtables.lock from xtables-lock (rw)

This output shows the DaemonSet is scheduling pods on 1 node. You can verify the cluster has one node with:

kubectl get nodes

Example output:

NAME          STATUS  ROLES                      AGE   VERSION
controlplane  Ready   control-plane,master       26m   v1.20.0

So, in this cluster kube-proxy has pods scheduled on a single node.

5) What image is used by the pod deployed by the `kube-flannel-ds` DaemonSet?

Describe kube-flannel-ds:

kubectl describe daemonset kube-flannel-ds -n kube-system

Relevant excerpt (trimmed):

Name:               kube-flannel-ds
Selector:           app=flannel
Labels:             app=flannel
                    tier=node
Desired Number of Nodes Scheduled: 1
Pods Status: 1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:           app=flannel
                    tier=node
  Service Account:  flannel
  Init Containers:
    install-cni:
      Image:        quay.io/coreos/flannel:v0.13.1-rc1
      Command:
        cp
      Args:
        -f
        /etc/kube-flannel/cni-conf.json
        /etc/cni/net.d/10-flannel.conflist
      Mounts:
        /etc/cni/net.d from cni (rw)
        /etc/kube-flannel/ from flannel-cfg (rw)
  Containers:
    kube-flannel:
      Image:        quay.io/coreos/flannel:v0.13.1-rc1
      Command:
        /opt/bin/flanneld

The kube-flannel container image is quay.io/coreos/flannel:v0.13.1-rc1.

6) Deploy a DaemonSet for fluentd logging

You can author the DaemonSet manifest by hand or generate a resource YAML with kubectl and edit it. One convenient trick when a generator for a DaemonSet is not available is to generate a Deployment manifest and convert it to a DaemonSet by editing the file.

You can generate YAML without creating the resource using --dry-run=client -o yaml. Generate the resource, edit the file to match DaemonSet semantics, and then apply it with kubectl create -f or kubectl apply -f.

Follow these steps:

Generate a Deployment YAML for fluentd (dry run):

kubectl create deployment elasticsearch -n kube-system \
  --image=k8s.gcr.io/fluentd-elasticsearch:1.20 \
  --dry-run=client -o yaml > fluentd.yaml

The generated YAML will look similar to this (trimmed):

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: elasticsearch
  name: elasticsearch
  namespace: kube-system
spec:
  replicas: 1
  selector:
    matchLabels:
      app: elasticsearch
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: elasticsearch
    spec:
      containers:
      - image: k8s.gcr.io/fluentd-elasticsearch:1.20
        name: fluentd-elasticsearch
        resources: {}
status: {}

Edit fluentd.yaml to convert the Deployment into a DaemonSet:
- Change kind: Deployment to kind: DaemonSet.
- Remove replicas and any strategy fields (DaemonSets do not use them).
- Ensure .spec.selector.matchLabels matches .spec.template.metadata.labels.
- Add any necessary tolerations, volumes, and volumeMounts to match your cluster’s logging needs.

Warning: Make sure the DaemonSet selector matches the pod template labels exactly; otherwise kubectl will reject the manifest.

If .spec.selector.matchLabels does not match .spec.template.metadata.labels, applying the manifest will fail. Always keep them in sync when converting Deployments to DaemonSets.

After editing, the manifest might look like this example (trimmed for clarity):

apiVersion: apps/v1
kind: DaemonSet
metadata:
  labels:
    app: elasticsearch
  name: elasticsearch
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: elasticsearch
  template:
    metadata:
      labels:
        app: elasticsearch
    spec:
      tolerations:
      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule
      containers:
      - name: fluentd-elasticsearch
        image: quay.io/fluentd_elasticsearch/fluentd:v2.5.2
        resources:
          limits:
            memory: 200Mi
          requests:
            cpu: 100m
            memory: 200Mi
        volumeMounts:
        - name: varlog
          mountPath: /var/log
        - name: varlibdockercontainers
          mountPath: /var/lib/docker/containers
          readOnly: true

(You can extend this manifest with additional volumes, config maps, or node selectors depending on your logging pipeline and cluster topology.)

Create the DaemonSet from the edited YAML:

kubectl create -f fluentd.yaml

Example output:

daemonset.apps/elasticsearch created

Verify the DaemonSet in the kube-system namespace:

kubectl get daemonsets -n kube-system

Example output after creation:

NAME               DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR                 AGE
elasticsearch      1         1         0       1            0           <none>                       10s
kube-flannel-ds    1         1         1       1            1           <none>                       29m
kube-proxy         1         1         1       1            1           kubernetes.io/os=linux       29m

Note: In this simple example the newly created elasticsearch DaemonSet (the fluentd logging daemon) may take some time to become READY. Add required volumes, volume mounts, tolerations, and node selectors as appropriate for your cluster and logging pipeline.

References

DaemonSet — Kubernetes Concepts
kubectl create — Kubernetes CLI reference
Fluentd images and examples: check the image repository used in your environment (for example, k8s.gcr.io/fluentd-elasticsearch and quay.io/fluentd_elasticsearch/fluentd)

That completes the lab.

Introduction

Core Concepts

Scheduling

Logging & Monitoring

Application Lifecycle Management

Cluster Maintenance

Security

Storage

Networking

Design and Install a Kubernetes Cluster

Install "Kubernetes the kubeadm way"

Troubleshooting

Helm Basics (2025 Updates)

Kustomize Basics (2025 Updates)

Other Topics

Mock Exams

Lab Solution DaemonSets optional

1) How many DaemonSets exist in the cluster (all namespaces)?

2) Which namespace are the DaemonSets created in?

3) Which of the following is a DaemonSet?

4) On how many nodes are the pods scheduled by the DaemonSet `kube-proxy`?

5) What image is used by the pod deployed by the `kube-flannel-ds` DaemonSet?

6) Deploy a DaemonSet for fluentd logging

References

Watch Video

​1) How many DaemonSets exist in the cluster (all namespaces)?

​2) Which namespace are the DaemonSets created in?

​3) Which of the following is a DaemonSet?

​4) On how many nodes are the pods scheduled by the DaemonSet kube-proxy?

​5) What image is used by the pod deployed by the kube-flannel-ds DaemonSet?

​6) Deploy a DaemonSet for fluentd logging

​References

Watch Video

1) How many DaemonSets exist in the cluster (all namespaces)?

2) Which namespace are the DaemonSets created in?

3) Which of the following is a DaemonSet?

4) On how many nodes are the pods scheduled by the DaemonSet `kube-proxy`?

5) What image is used by the pod deployed by the `kube-flannel-ds` DaemonSet?

6) Deploy a DaemonSet for fluentd logging

References