Cloud Technology Blog

1. 컨트롤 플레인 노드 업그레이드

master node 에서 실행
yum install -y kubeadm-1.26.x-0 --disableexcludes=kubernetes

다운로드 결과 조회
kubeadm version

업그레이드 계획 확인
sudo kubeadm upgrade plan v.1.2x.x

2. kubeadm upgrade

sudo kubeadm upgrade apply v1.2x.x

결과 확인
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.26.x". Enjoy!

[upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets if you haven't already done so.

3. node drain

kubectl drain <node-to-drain> --ignore-daemonsets

4. kubelet and kubectl upgrade

yum install -y kubelet-1.2x.x-0 kubectl-1.2x.x-0 --disableexcludes=kubernetes

5. kubelet reolad and uncordon

sudo systemctl daemon-reload
sudo systemctl restart kubelet

kubectl uncordon <node-to-drain>

6. workernode upgrade

wokernode 에서
yum install -y kubeadm-1.2x.x-0 --disableexcludes=kubernetes

sudo kubeadm upgrade node

7. node drain and kubelet/kubectl upgrade

kubectl drain <node-to-drain> --ignore-daemonsets

yum install -y kubelet-1.2x.x-0 kubectl-1.2x.x-0 --disableexcludes=kubernetes

8. kubelet restart

sudo systemctl daemon-reload
sudo systemctl restart kubelet

kubectl uncordon <node-to-drain>

방법 : 

1. ETCD backup

##backup

ETCDCTL_API=3 etcdctl --endpoints=https://127.0.0.1:2379 \
  --cacert=<trusted-ca-file> \
  --cert=<cert-file> \
  --key=<key-file> \
  snapshot save <backup-file-location>

2. ETCD restore

ETCDCTL_API=3 etcdctl  \
--data-dir <data-dir-location> \   ## 변경될 etcd 위치(to-be)
snapshot restore snapshotdb        ## 복구시킬 저장된 스냅샷 경로(as-is)

3. etcd.yaml 파일 수정

sudo vim /etc/kubernetes/manifests/etcd/yaml

- hostPath : 
  path : [새로만든 경로로 수정]

조건 : redis 이름과  imgae 를 사용하는 POD를 생성 후 /data/redis 경로에 마운트

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: non-persistent-redis
  name: non-persistent-redis
spec:
  containers:
  - image: redis
    name: redis-container
    volumeMounts:
      - mountPath: /data/redis
        name: redis-mount
  volumes:
    - name: redis-mount

주제 : 조건에 맞는 파드를 생성하라

조건 : 

• pod name : nginx
• env : var = value
• 생성 후 env 확인

kubectl run nginx --image=nginx --restart=Never --env=var1=value1 --dry-run=client -o yaml

[위 명령어로 생성되는 yaml 파일을 아래와 같이 수정]
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: nginx
  name: nginx
spec:
  containers:
  - env:
    - name: var1
      value: value1
    image: nginx
    name: nginx
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Never


[생성 후 pod 의 env 확인 방법]
kubectl exec -it nginx -- env
kubectl exec -it nginx -- sh -c 'echo $varl'
kubectl describe nginx | grep value1

https://kubernetes.io/ko/docs/tasks/inject-data-application/define-environment-variable-container/

주제 : 명령어를 사용하여 POD 실행

조건 : 

• 이름 : nginx
• nodeselector : disk = ssd
• image = nginx

kubectl run nginx-name --image=nginx --dry-run=cliend -o yaml

[위명령어를치면 yaml 파일이 나오는데 아래와 같이 수정 하면 됨]
apiVersion: v1
kind: Pod
metadata:
  name: nginx-name
spec:
  containers:
  - image: nginx
    name: nginx
  nodeSelector:
    disk: ssd