docs: add Kubernetes CKS study notes

2026-08-04 23:18:45 +02:00
parent a6ee7a2b07
commit 91a1849009
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--- a/exams/exam-3.md
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+# Task 1
+
+```bash
+sysctl net.ipv4.ip_forward=1
+sysctl net.bridge.bridge-nf-call-iptables=1
+
+# it is already persistent: /etc/sysctl.d/k8s.conf
+```
+
+# Task 2
+
+```bash
+kubectl create serviceaccount pvviewer
+kubectl create clusterrole pvviewer-role --verb=list --resource=persistentVolumes
+kubectl create clusterrolebinding pvviewer-role-binding --clusterrole=pvviewer-role --serviceaccount=default:pvviewer
+k run pvviewer --image=redis -o yaml --dry-run > p.yaml
+
+# edit -> add serviceAccount -> apply
+
+```
+
+# Task 3
+
+```bash
+cat sc.yaml
+apiVersion: storage.k8s.io/v1
+kind: StorageClass
+metadata:
+  name: rancher-sc
+provisioner: rancher.io/local-path
+volumeBindingMode: WaitForFirstConsumer
+```
+
+# Task 4
+
+```bash
+kubectl create configmap app-config -n cm-namespace --from-litera
+l=ENV=production --from-literal=LOG_LEVEL=info
+
+k get deployments.apps -n cm-namespace cm-webapp -o yaml | yq .spec
+progressDeadlineSeconds: 600
+replicas: 1
+revisionHistoryLimit: 10
+selector:
+  matchLabels:
+    app: cm-webapp
+strategy:
+  rollingUpdate:
+    maxSurge: 25%
+    maxUnavailable: 25%
+  type: RollingUpdate
+template:
+  metadata:
+    labels:
+      app: cm-webapp
+  spec:
+    containers:
+      - env:
+          - name: LOG_LEVEL
+            valueFrom:
+              configMapKeyRef:
+                key: LOG_LEVEL
+                name: app-config
+          - name: ENV
+            valueFrom:
+              configMapKeyRef:
+                key: ENV
+                name: app-config
+        image: nginx
+        imagePullPolicy: Always
+        name: nginx
+        resources: {}
+        terminationMessagePath: /dev/termination-log
+        terminationMessagePolicy: File
+    dnsPolicy: ClusterFirst
+    restartPolicy: Always
+    schedulerName: default-scheduler
+    securityContext: {}
+    terminationGracePeriodSeconds: 30
+```
+
+# Task 5
+
+```bash
+cat pc.yaml 
+apiVersion: scheduling.k8s.io/v1
+kind: PriorityClass
+metadata:
+  name: low-priority
+value: 50000
+```
+
+# Task 6
+
+```bash
+cat np.yaml 
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: ingress-to-nptest
+spec:
+  podSelector: 
+    matchLabels:
+      run: np-test-1
+  ingress:
+   - ports: 
+     - protocol: TCP
+       port: 80
+  policyTypes:
+  - Ingress
+```
+
+# Task 7
+
+```bash
+k taint node node01 kodekloud:NoSchedule
+k run dev-redis --image redis:alpine
+k run prod-redis --image redis:alpine -o yaml --dry-run > p7.yaml
+
+cat p7.yaml 
+apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    run: prod-redis
+  name: prod-redis
+spec:
+  containers:
+  - image: redis:alpine
+    name: prod-redis
+    resources: {}
+  dnsPolicy: ClusterFirst
+  restartPolicy: Always
+  tolerations:
+  - key: "kodekloud"
+    operator: "Exists"
+    effect: "NoSchedule"
+```
+
+# Task 8
+
+```bash
+# k get storageClasses
+# fix accessMode
+kubectl get pvc app-pvc -n storage-ns -o yaml > pvc.yaml
+
+cat pvc.yaml  | yq .spec
+accessModes:
+  - ReadWriteOnce
+resources:
+  requests:
+    storage: 1Gi
+volumeMode: Filesystem
+
+```
+
+# Task 9
+
+```bash
+# fix port to api server in kubeconfig
+
+```
+
+# Task 10
+
+```bash
+k scale deployment nginx-deploy --replicas=3
+
+# /etc/kubernetes/manifests/controller-manager ... typo in command
+```
+
+# Task 11
+
+```bash
+# hpa
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: api-hpa
+  namespace: api
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: api-deployment
+  minReplicas: 1
+  maxReplicas: 20
+  metrics:
+  - type: Pods
+    pods:
+      metric:
+        name: requests_per_second
+      target:
+        type: AverageValue
+        averageValue: "1000"
+```
+
+# Task 12
+
+```bash
+# httproute
+cat httproute.yaml 
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: web-route
+spec:
+  parentRefs:
+  - name: web-gateway
+  rules:
+  - matches:
+    - path:
+        type: PathPrefix
+        value: /
+    backendRefs:
+    - name: web-service
+      port: 80
+      weight: 80
+    - name: web-service-v2
+      port: 80
+      weight: 20
+```
+
+# Task 13
+
+```bash
+helm install webpage-server-02 /root/new-version/
+helm uninstall webpage-server-01
+```
+
+# Task 14
+
+```bash
+k get cm -n kube-system kubeadm-config -o yaml
+echo "172.17.0.0/16" > /root/pod-cidr.txt
+```