目錄
kubectl常用命令
| 命令 | 作用 |
|---|---|
| kubectl cluster-info | 查看集群信息 |
| kubectl describe pod -n kube-system kube-flannel-ds-amd64-trpqq | 查看kube-system名稱空間里pod的描述信息 |
| kubectl get pods -n NAME_SPACE | #查看指定命名空間的pod |
| kubectl create deployment NAME --image=image [--dry-run] [options] | 創建deployment, dry-run為true就是測試不執行 |
| kubectl expose deployment nginx-deploy --name=nginx --port=80 --target-port=80 --protocol=TCP | 為deployment創建service, --name為service的名字, --port為暴露端口, --target-port為目標pod端口 |
| dig -t A nginx.default.svc.cluster.local @10.96.0.10 | 驗證是否能正確解析service, @后邊的ip為k8s的dns地址 |
| kubectl describe svc nginx | 查看service名字為nginx的描述信息 |
| kubectl get pods --show-labels | 查看pod的標簽 |
| kubectl scale deployment nginx-deploy --replicas=3 | 擴容或縮容, --replicas為數量 |
| kubectl run -it test --image=busybox -- sh; wget -O - -q nginx-deploy | nginx-deploy是svc名字, 驗證svc是不是好用 |
| kubectl rollout undo deployment myapp-deploy --to-revision=1 | 回滾到指定版本, 默認回滾到上一版本 |
資源清單配置
apiVersion: v1
kind: Pod
metadata:
name: pod-demo
namespace: default
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
- name: busybox
image: busybox
command:
- "/bin/sh"
- "-c"
- "sleep 5"
kubectl create -f test.yaml
kubectl delete -f test.yaml
kubectl describe pod pod-demo
kubectl describe pod pod-demo
kubectl exec -it pod-demo -c myapp -- /bin/sh
lable使用
過濾lable
kubectl get pods -l app --show-labels
給pod打標簽
kubectl label pods http-7f8cbdf584-dbmkn release=canary
根據label過濾pod
kubectl get pods -l release, app
kubectl get pods -l release=stable, app=myapp
kubectl get pods -l release!=canary
kubectl get pods -l "release in (canary, beta, alpha)"
apiVersion: v1
kind: Pod
metadata:
name: pod-demo #name必須小寫
namespace: default
labels:
app: myapp
tier: frontend
annotations:
create-by: tianpei.wang
spec:
containers:
- name: myapp
image: nginx
ports:
- name: http
containerPort: 80
- name: https
containerPort: 443
- name: busybox
image: busybox
imagePullPolicy: IfNotPresent
command: ["/bin/sh", "-c", "sleep 60"]
nodeSelector:
kubernetes.io/hostname: node01
Pod存活性和可用性驗證
liveness存活驗證鈎子
exec
apiVersion: v1
kind: Pod
metadata:
name: liveness-exec-pod
namespace: default
spec:
containers:
- name: liveness-exec-containers
image: busybox:latest
imagePullPolicy: IfNotPresent
command: ["/bin/sh","-c","touch /tmp/healthy; sleep 30; rm -f /tmp/healthy; sleep 3600"]
livenessProbe:
exec:
command: ["test", "-e", "/tmp/healthy"]
initialDelaySeconds: 1 #延遲一秒探測
periodSeconds: 3 #三秒為一個探測周期
httpGet
apiVersion: v1
kind: Pod
metadata:
name: liveness-httpget-pod
namespace: default
spec:
containers:
- name: liveness-httpget-containers
image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
livenessProbe:
httpGet:
port: http
path: /index.html
initialDelaySeconds: 1
periodSeconds: 3
liveness可用性驗證鈎子
httpGet
apiVersion: v1
kind: Pod
metadata:
name: readiness-httpget-pod
namespace: default
spec:
containers:
- name: readiness-httpget-containers
image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
readinessProbe:
httpGet:
port: http
path: /index.html
initialDelaySeconds: 1
periodSeconds: 3
lifecycle-poststart錯誤示例
apiVersion: v1
kind: Pod
metadata:
name: poststart-pod
namespace: default
spec:
containers:
- name: busybox-httpd
image: busybox:latest
imagePullPolicy: IfNotPresent
lifecycle:
postStart:
exec:
command: ["/bin/sh", "-c", "mkdir -p /data/web/html; echo 'Home Page' >>/data/web/html/index.html"]
command: ["/bin/httpd"]
args: ["-f", "-h /data/web/html"]
使用上述yaml創建pod會報錯
Warning FailedPostStartHook 8s (x2 over 26s) kubelet, node01 Exec lifecycle hook ([/bin/sh -c mkdir -p /data/web/html; echo 'Home Page' >>/data/web/html/index.html]) for Container "busybox-httpd" in Pod "poststart-pod_default(92846bc9-ca3f-11e9-9c47-0242ac110046)" failed - error: command '/bin/sh -c mkdir -p /data/web/html; echo 'Home Page' >>/data/web/html/index.html' exited with 126: , message: "cannot exec in a stopped state: unknown\r\n"
原因是由於,優先去執行containers下的command, 然后才會去執行lifecycle下的command, 所以導致/data/web/html目錄還未創建
service, deployment, replicaset和pod之間的關系
