https://v1-29.docs.kubernetes.io/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade

https://kodekloud.com/community/t/upgrading-kubeadm-to-version-not-displayed-by-madison-command/422910/2

cat /etc/apt/sources.list.d/kubernetes.list
deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.29/deb/ /

---

kubectl get deployments -n admin2406 –sort-by=.metadata.name \
-o=custom-columns=’DEPLOYMENT:metadata.name,CONTAINER_IMAGE:spec.template.spec.containers[0].image,READY_REPLICAS:status.readyReplicas,NAMESPACE:metadata.namespace’ > /opt/admin2406_data

---

mysql-alpha-pvc

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mysql-alpha-pvc
namespace: alpha
spec:
accessModes:

• ReadWriteOnce
  resources:
  requests:
  storage: 1Gi
  storageClassName: slow

---

kubectl create deployment nginx-deploy –image=nginx:1.16 –dry-run=client -o yaml > nginx-deploy.yaml

---

kubectl get pod -n kube-system

kubectl describe pod etcd-bbsvibmk8m -n kube-system

export ETCDCTL_API=3
etcdctl snapshot save –cacert=/etc/kubernetes/pki/etcd/ca.crt –cert=/etc/kubernetes/pki/etcd/server.crt –key=/etc/kubernetes/pki/etcd/server.key –endpoints=127.0.0.1:2379 /root/etcd-backup.db

---

kubectl run secret-1401 -n admin1401 –image busybox –dry-run=client -o yaml –command — sleep 4800 > admin.yaml

apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: secret-1401
name: secret-1401
namespace: admin1401
spec:
volumes:

• name: secret-volume
  secret:
  secretName: dotfile-secret
  containers:
• command:
  • sleep
  • “4800”
    image: busybox
    name: secret-admin
    volumeMounts:
  • name: secret-volume
    readOnly: true
    mountPath: /etc/secret-volume

---

apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: web-proj-268
name: web-proj-268
spec:
replicas: 1
selector:
matchLabels:
app: web-proj-268
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: web-proj-268
spec:
containers:
– image: nginx:1.16
name: nginx
resources: {}
status: {}

kubectl set image deployment web-proj-268 nginx=nginx:1.17 –record=true

kubectl rollout history deployment web-proj-268

---

kubectl create deployment web-003 –image=nginx –replicas=3

---

kubectl run web-load-5461 –image=nginx:1.17 –labels=”tier=web”
kubectl run web-load-5461 –image=nginx:1.17 –labels tier=web

---

https://linchpiner.github.io/k8s-multi-container-pods.html

apiVersion: v1
kind: Pod
metadata:
name: pod-multi
spec:
containers:

• name: container1
  image: nginx
• name: container2
  image: busybox
  command: [“sleep”, “4800”]

---

kubectl run front-end-helper –image=busybox -it –rm –restart=Never — /bin/sh -c ‘echo binaries downloaded successfully’ > front-end-helper-log.txt

---

kubectl create namespace defence

apiVersion: v1
kind: Pod
metadata:
name: delta-pod
namespace: defence
spec:
containers:

• name: delta-pod image: nginx:1.17 env:
  • name: env
    value: “dev”
  • name: tier
    value: “front”

---

apiVersion: v1
kind: Pod
metadata:
name: admin-pod
namespace: default
spec:
containers:

• command:
  • sleep
  • “3200”
    image: busybox
    name: admin-pod
    securityContext:
    capabilities:
    add: [“SYS_TIME”]

---

kubectl expose rc nginx –port=80 –target-port=8000
kubectl expose pod web-pod –name=web-pod-svc –port=80
kubectl exec -it nslookup — nslookup web-pod-svc

---

kubectl get node -o jsonpath='{.items[*].status.nodeInfo.osImage}’

---

apiVersion: v1
kind: PersistentVolume
metadata:
name: pv-rnd
spec:
storageClassName: manual
capacity:
storage: 100Mi
accessModes:
– ReadWriteMany
hostPath:
path: “/pv/host_data-rnd”

---

node01 not responding

kubectl describe node node01

ssh node01

systemctl status kubelet

systemctl start kubelet

---

get nodes -o wide -o jsonpath='{.items[*].status.addresses[?(@.type==”InternalIP”)].address}’

static pod :

ps -ef | grep kubelet
more /var/lib/kubelet/config.yaml | grep static
staticPodPath: /etc/kubernetes/manifests
cd /etc/kubernetes/manifests/

remove static.yaml

ssh node01

ps -ef | grep kubelet
more /var/lib/kubelet/config.yaml | grep static
staticPodPath: /etc/kubernetes/manifests

cd /etc/kubernetes/manifests/

vi static.yaml
pod oluştur

---

kubectl -n kube-system logs kube-controller-manager-bbsvibmk8m
kubectl -n kube-system describe pod kube-controller-manager-bbsvibmk8m
kubectl -n kube-system get pod

/etc/kubernetes/manifests önemli kube-controller-manager

---

taint :

kubectl describe nodes | grep -i taint
kubectl taint node bbsvibmk8m cpu=high:NoSchedule

kubectl get nodes -o json | jq “.items[] | {name:.metadata.name}”
{
“name”: “bbsvibmk8m”
}
{
“name”: “bbsvibmk8s1”
}
{
“name”: “bbsvibmk8s2”
}

kubectl get nodes -o json | jq “.items[] | {name:.metadata.name, tainst:.spec.taints}”
{
“name”: “bbsvibmk8m”,
“tainst”: [
{
“effect”: “NoSchedule”,
“key”: “cpu”,
“value”: “high”
},
{
“effect”: “NoSchedule”,
“key”: “node-role.kubernetes.io/control-plane”
}
]
}
{
“name”: “bbsvibmk8s1”,
“tainst”: null
}
{
“name”: “bbsvibmk8s2”,
“tainst”: null
}

---

kubectl create namespace airfusion

kubectl run nginx –image=nginx –namespace airfusion

vim netpool.yaml

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: my-net-pool
namespace: airfusion
spec:
podSelector: {}
policyTypes:

• Ingress
  ingress:
• from:
  • podSelector: {}
    ports:
  • protocol: TCP
    port: 80

---

kubectl run audit-web-app –image nginx

vim srvc.yaml

apiVersion: v1
kind: Service
metadata:
name: audit-web-app-service
spec:
type: NodePort
selector:
run: audit-web-app
ports:

• protocol: TCP
  port: 8080
  targetPort: 8080
  nodePort: 30002

---

taint and toleration

untaint :
kubectl taint nodes bbsvibmk8m cpu=high:NoSchedule-
node/bbsvibmk8m untainted

kubectl taint nodes bbsvibmk8s1 env_type=production:NoSchedule

apiVersion: v1
kind: Pod
metadata:
name: prod-pod-nginx
labels:
run: prod-pod-nginx
spec:
containers:
– name: prod-pod-nginx
image: nginx
tolerations:
– key: “env_type”
operator: “Equal”
value: “production”
effect: “NoSchedule”

---

kubectl get deployment | awk ‘{print $1}’ | tail -n +2

---

apiVersion: v1
kind: Pod
metadata:
name: pod-jxc56fv
spec:
securityContext:
runAsUser: 1000
runAsGroup: 2000
fsGroup: 2000
containers:

• name: pod-jxc56fv
  image: redis:alpine

kubectl exec -it pod-jxc56fv whoami

---

yetki verilmesi

openssl genrsa -out k8admin.key 2048

openssl req -new -key k8admin.key -out k8admin.csr -subj “/CN=k8admin/O=dev”

csr.yaml

apiVersion: certificates.k8s.io/v1
kind: CertificateSigningRequest
metadata:
name: k8admin
spec:
request: cat k8admin.csr | base64 | tr -d “\n”
signerName: kubernetes.io/kube-apiserver-client
usages:

• client auth

kubectl get csr

kubectl certificate approve k8admin

rol.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
namespace: space
name: pod-reader
rules:

• apiGroups: [“”] # “” indicates the core API group
  resources: [“pods”]
  verbs: [“get”, “watch”, “list”,”update”,”delete”]

rb.yaml

apiVersion: rbac.authorization.k8s.io/v1

This role binding allows “jane” to read pods in the “default” namespace.

You need to already have a Role named “pod-reader” in that namespace.

kind: RoleBinding
metadata:
name: read-pods
namespace: space
subjects:

You can specify more than one “subject”

• kind: User
  name: k8admin # “name” is case sensitive
  apiGroup: rbac.authorization.k8s.io
  roleRef:
  # “roleRef” specifies the binding to a Role / ClusterRole
  kind: Role #this must be Role or ClusterRole
  name: pod-reader # this must match the name of the Role or ClusterRole you wish to bind to
  apiGroup: rbac.authorization.k8s.io

kubectl auth can-i get pod –as=k8admin -n space
kubectl auth can-i list pod –as=k8admin -n space

---

pv – pvc – pod

vi pv.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
name: mypvlog
labels:
type: local
spec:
storageClassName: manual
capacity:
storage: 100Mi
accessModes:
– ReadWriteMany
hostPath:
path: /pv/log/

pvc.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: pv-claim-log
spec:
storageClassName: manual
accessModes:
– ReadWriteMany
resources:
requests:
storage: 50Mi

pod. yaml

apiVersion: v1
kind: Pod
metadata:
name: my-nginx-pod
spec:
volumes:
– name: task-pv-storage
persistentVolumeClaim:
claimName: pv-claim-log
containers:
– name: task-pv-container
image: nginx
ports:
– containerPort: 80
name: “http-server”
volumeMounts:
– mountPath: “/log”
name: task-pv-storage

---

fix to node01

kubectl get node
kubectl describe node node01

ssh node01
systemctl status kubelet.service

hata devam ederse ; journalctl

/var/lib/kubelet/config.yaml

sertifikaya bak ve config dosyasını düzelt

/etc/kubernet/pki

systemctl daemon-reload
systemctl restart kubelet

---

multiple pod

apiVersion: v1
kind: Pod
metadata:
name: nginx
namespace: development
spec:
containers:

• name: nginx
  image: nginx
• name: redis
  image: redis

---

fix the pod

kubectl describe pod pod01
kubectl describe node node01 | grep -i taint
kubectl get pod nginx-pod -o yaml > pod.yaml

spec -> containers ile aynı hizada
tolerations:

• key: “color”
  operator: “Equal”
  value: “blue”
  effect: “NoSchedule”

---

kubectl create deployment nginx-deploy –image nginx –replicas 8 –dry-client=run -o yaml

---

replicaset :

kubectl get pod –show-labels

run=dev-pod-nginx

apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: rs-nginx
labels:
app: rs-nginx
tier: dev-pod-nginx
spec:
replicas: 8
selector:
matchLabels:
run: dev-pod-nginx
template:
metadata:
labels:
tier: frontend
spec:
containers:
– name: dev-pod-nginx
image: ginx

---

Daemonset

kubectl taint node bbsvibmk8s1 env=qa:NoSchedule

apiVersion: apps/v1
kind: DaemonSet
metadata:
name: ssd-monitor
spec:
selector:
matchLabels:
app: ssd-monitor
template:
metadata:
labels:
app: ssd-monitor
spec:
nodeSelector:
disk: ssd
containers:
– name: web
image: nginx:latest

---

custom-column
kubectl get nodes -o custom-columns=”NAMESPACE:.metadata.name,AVALIABLE_MEMORY:.status.allocatable.memory,AVALIABLE_CPU:status.capacity.cpu”

---

init container

apiVersion: v1
kind: Pod
metadata:
name: nginx-k8s
labels:
app.kubernetes.io/name: MyApp
spec:
containers:

• name: nginx-container image: nginx volumeMounts:
  • name: config-vol
    mountPath: “/usr/share/nginx/html”
    volumes:
• name: git-volume
  gitRepo:
  repository: “https://github.com/jhawithu/k8s-nginx.git”
  initContainers:
• name: git-k8s
  image: alpine/git

custom-column
kubectl get nodes -o custom-columns=”NAMESPACE:.metadata.name,AVALIABLE_MEMORY:.status.allocatable.memory,AVALIABLE_CPU:status.capacity.cpu”

---

init container

apiVersion: v1
kind: Pod
metadata:
name: nginx-k8s
labels:
app.kubernetes.io/name: MyApp
spec:
containers:

• name: nginx-container image: nginx volumeMounts:
  • name: config-vol
    mountPath: “/usr/share/nginx/html”
    volumes:
• name: git-volume
  gitRepo:
  repository: “https://github.com/jhawithu/k8s-nginx.git”
  initContainers:
• name: git-k8s
  image: alpine/git

---

kubectl run nginx-resolver –image=nginx
kubectl expose pod nginx-resolver –name=nginx-resolver-service –port=80 –target-port=80 –type=ClusterIP

kubectl run test-nslookup –image=busybox:1.28 –rm -it –restart=Never — nslookup nginx-resolver-service
kubectl run test-nslookup –image=busybox:1.28 –rm -it –restart=Never — nslookup nginx-resolver-service > /root/CKA/nginx.svc

kubectl get pod nginx-resolver -o wide
kubectl run test-nslookup –image=busybox:1.28 –rm -it –restart=Never — nslookup > /root/CKA/nginx.pod

---

kubectl apply -f – <<EOF
apiVersion: v1
kind: ServiceAccount
metadata:
name: pvviewer
EOF

kubectl create sa pvviewer

kubectl create clusterrole pvviewer-role –verb=list –resource=persistentvolumes

kubectl create clusterrolebinding pvviewer-role-binding –clusterrole=pvviewer-role –serviceaccount=default:pvviewer

apiVersion: v1
kind: Pod
metadata:
labels:
run: pvviewer
name: pvviewer
spec:
containers:

• image: redis
  name: pvviewer
  serviceAccountName: pvviewer

---

kubectl run hr-pod –image=redis:alpine –namespace=hr –labels=environment=production,tier=frontend

---

key: env_type, value: production, operator: Equal and effect: NoSchedule

kubectl taint node node01 env_type=production:NoSchedule

kubectl run dev-redis –image=redis:alpine

kubectl get pods -o wide

---

apiVersion: v1
kind: Pod
metadata:
name: prod-redis
spec:
containers:

• name: prod-redis
  image: redis:alpine
  tolerations:
• effect: NoSchedule
  key: env_type
  operator: Equal
  value: production

kubectl get pods -o wide | grep prod-redis

---

kubectl config set-context gce –user=cluster-admin