pod管理调度约束、与健康状态检查
pod的管理
[root@k8s-master ~]# vim pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
创建pod
[root@k8s-master ~]# kubectl create -f pod.yaml
查看pod信息
[root@k8s-master ~]# kubectl get all
po/nginx-pod
1/1 Running 0 1m
查看pod的详细信息
[root@k8s-master ~]# kubectl describe po/nginx-pod
删除创建的pod
[root@k8s-master ~]# kubectl delete -f pod.yaml
POD的资源管理
[root@k8s-master ~]# vim pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
resources:
requests:
memory: "64Mi"
cpu: "250m"
limits:
memory: "128Mi"
cpu: "500m"
[root@k8s-master ~]# kubectl create -f pod.yaml
[root@k8s-master ~]# kubectl describe po/nginx-pod
Limits:
cpu: 500m
memory: 128Mi
pod调度约束与重启策略
[root@k8s-master ~]# vim pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
labels:
app: nginx
spec:
nodeName: 192.168.30.22
nodeSelector:
env_role: dev
containers:
- name: nginx
image: nginx
[root@k8s-master ~]# kubectl create -f pod.yaml
我们指定的是pod在22主机上创建，自然也会分配到这个主机上
[root@k8s-master ~]# kubectl get pod -o wide
nginx-pod 1/1 Running 0 2m 172.17.11.3 192.168.30.22
查看主机名标签
[root@k8s-master ~]# kubectl describe node 192.168.30.22
Name: 192.168.30.22
Roles: <none>
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/hostname=192.168.30.22
添加标签
[root@k8s-master ~]# kubectl label nodes 192.168.30.22 env_role=dev
再次查看主机名标签已经把env_role=dev添加进去
[root@k8s-master ~]# kubectl describe node 192.168.30.22
Name: 192.168.30.22
Roles: <none>
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
env_role=dev
kubernetes.io/hostname=192.168.30.22
根据我们的约束再次创建pod已经又放在22主机上了
[root@k8s-master ~]# kubectl get pod -o wide
nginx-pod2 1/1 Running 0 1m 172.17.11.5 192.168.30.22
pod健康状态检查
提供 Probe 机制，有以下两种类型：
l livenessProbe
如果检查失败，将杀死容器，根据Pod的restartPolicy来操作。
l readinessProbe
如果检查失败，Kubernetes会把Pod从service endpoints中剔除。
Probe 支持以下三种检查方法：
l httpGet
发送HTTP请求，返回200-400范围状态码为成功。
l exec
执行Shell命令返回状态码是0为成功。
l tcpSocket
发起TCP Socket建立成功。
[root@k8s-master ~]# vim pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
livenessProbe:
httpGet:
path: /index.html
port: 80
[root@k8s-master ~]# kubectl create -f pod.yaml
查看详细信息，可以看到这里容器访问80端口的信息
[root@k8s-master ~]# kubectl describe po/nginx-pod
Restart Count: 0
Liveness: http-get http://:80/index.html delay=0s timeout=1s period=10s #success=1 #failure=3
Environment: <none>
通过日志可以看到这里使用kube-probe来访问
[root@k8s-master ~]# kubectl logs nginx-pod -f
172.17.80.1 - - [08/Jul/2019:10:08:14 +0000] "GET /index.html HTTP/1.1" 200 612 "-" "kube-probe/1.9" "-"
172.17.80.1 - - [08/Jul/2019:10:08:24 +0000] "GET /index.html HTTP/1.1" 200 612 "-" "kube-probe/1.9" "-"
再开一个窗口，进入容器删除index.html看看日志的变化
[root@k8s-master ~]# kubectl exec -it nginx-pod bash
root@nginx-pod:/# cd /usr/share/nginx/html/
root@nginx-pod:/usr/share/nginx/html# ls
50x.html index.html
root@nginx-pod:/usr/share/nginx/html# rm index.html
root@nginx-pod:/usr/share/nginx/html# exit
这边10秒后显示404找不到页面了
2019/07/08 10:17:14 [error] 6#6: *55 open() "/usr/share/nginx/html/index.html" failed (2: No such file or directory), client: 172.17.80.1, server: localhost, request: "GET /index.html HTTP/1.1", host: "172.17.80.4:80"
172.17.80.1 - - [08/Jul/2019:10:17:14 +0000] "GET /index.html HTTP/1.1" 404 153 "-" "kube-probe/1.9" "-"
172.17.80.1 - - [08/Jul/2019:10:17:24 +0000] "GET /index.html HTTP/1.1" 404 153 "-" "kube-probe/1.9" "-"
查看pod的详细信息，已经输出404页面，但是它还会再创建一个容器并启动
[root@k8s-master ~]# kubectl describe pod nginx-pod
Warning Unhealthy 22s (x3 over 42s) kubelet, 192.168.30.23 Liveness probe failed: HTTP probe failed with statuscode: 404
Normal Created 5m (x2 over 14m) kubelet, 192.168.30.23 Created container
Normal Started 5m (x2 over 14m) kubelet, 192.168.30.23 Started container
进入容器再看，容器又有了
root@nginx-pod:~# cd /usr/share/nginx/html
root@nginx-pod:/usr/share/nginx/html# ls
50x.html index.html
