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minikube-kubectl实践使用入门
source link: https://jimolonely.github.io/2019/10/07/cloudcompute/021-kubectl-minikube-hello/
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minikube-kubectl实践使用入门
查看集群信息
$ kubectl cluster-info
Kubernetes master is running at https://192.168.99.100:8443
KubeDNS is running at https://192.168.99.100:8443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
minikube Ready <none> 48m v1.16.0
$ kubectl run nginx --image=gcr.azk8s.cn/google_containers/nginx
kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
deployment.apps/nginx created
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 0/1 1 0 4s
然而并没有应用起来,查看一下状态：
$ kubectl describe pods nginx
Name: nginx-694785858b-dkxrj
Namespace: default
Priority: 0
Node: minikube/10.0.2.15
Start Time: Mon, 07 Oct 2019 11:13:33 +0800
Labels: pod-template-hash=694785858b
run=nginx
Annotations: <none>
Status: Pending
IP:
IPs: <none>
Controlled By: ReplicaSet/nginx-694785858b
Containers:
nginx:
Container ID:
Image: gcr.azk8s.cn/google_containers/nginx
Image ID:
Port: 8080/TCP
Host Port: 0/TCP
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-7dsd7 (ro)
Conditions:
Type Status
Initialized True
Ready False
ContainersReady False
PodScheduled True
Volumes:
default-token-7dsd7:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-7dsd7
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled <unknown> default-scheduler Successfully assigned default/nginx-694785858b-dkxrj to minikube
Normal Pulling 26s kubelet, minikube Pulling image "gcr.azk8s.cn/google_containers/nginx"
看到正在拉取镜像,经过了4分钟左右，终于起来了：
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled <unknown> default-scheduler Successfully assigned default/nginx-694785858b-dkxrj to minikube
Normal Pulling 3m11s kubelet, minikube Pulling image "gcr.azk8s.cn/google_containers/nginx"
Normal Pulled 19s kubelet, minikube Successfully pulled image "gcr.azk8s.cn/google_containers/nginx"
Normal Created 19s kubelet, minikube Created container nginx
Normal Started 19s kubelet, minikube Started container nginx
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 1/1 1 1 3m9s
$ echo -e "\n\n\n\e[92mStarting Proxy. After starting it will not output a response. Please click the first Terminal Tab\n";
$ kubectl proxy
$ curl http://localhost:8001/version
{
"major": "1",
"minor": "16",
"gitVersion": "v1.16.0",
"gitCommit": "2bd9643cee5b3b3a5ecbd3af49d09018f0773c77",
"gitTreeState": "clean",
"buildDate": "2019-09-18T14:27:17Z",
"goVersion": "go1.12.9",
"compiler": "gc",
"platform": "linux/amd64"
}
获取pod名字：
$ export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
$ echo Name of the Pod: $POD_NAME
nginx-6db489d4b7-lbzgr
通过代理访问nginx应用：可以看到首页
$ curl http://localhost:8001/api/v1/namespaces/default/pods/$POD_NAME/proxy/
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-6db489d4b7-lbzgr 1/1 Running 0 5m38s
$ kubectl describe pods
Name: nginx-6db489d4b7-lbzgr
Namespace: default
Priority: 0
Node: minikube/10.0.2.15
Start Time: Mon, 07 Oct 2019 11:25:14 +0800
Labels: pod-template-hash=6db489d4b7
run=nginx
Annotations: <none>
Status: Running
IP: 172.17.0.4
IPs:
IP: 172.17.0.4
Controlled By: ReplicaSet/nginx-6db489d4b7
Containers:
nginx:
Container ID: docker://9ae6de1486054fef58a5e59a19addeaf98cb0f523a60cb7bd146dcdc5def628a
Image: nginx
Image ID: docker-pullable://nginx@sha256:aeded0f2a861747f43a01cf1018cf9efe2bdd02afd57d2b11fcc7fcadc16ccd1
Port: <none>
Host Port: <none>
State: Running
Started: Mon, 07 Oct 2019 11:25:23 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-7dsd7 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-7dsd7:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-7dsd7
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled <unknown> default-scheduler Successfully assigned default/nginx-6db489d4b7-lbzgr to minikube
Normal Pulling 5m51s kubelet, minikube Pulling image "nginx"
Normal Pulled 5m43s kubelet, minikube Successfully pulled image "nginx"
Normal Created 5m43s kubelet, minikube Created container nginx
Normal Started 5m43s kubelet, minikube Started container nginx
查看日志：
$ kubectl logs $POD_NAME
172.17.0.1 - - [07/Oct/2019:03:25:48 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.58.0" "127.0.0.1, 192.168.99.1"
在应用里执行命令
# 查看环境变量
$ kubectl exec $POD_NAME env
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=nginx-6db489d4b7-lbzgr
KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1
KUBERNETES_SERVICE_HOST=10.96.0.1
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT=tcp://10.96.0.1:443
KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP_PORT=443
NGINX_VERSION=1.17.4
NJS_VERSION=0.3.5
PKG_RELEASE=1~buster
HOME=/root
# 进入容器
$ kubectl exec -it $POD_NAME bash
root@nginx-6db489d4b7-lbzgr:/# ls
bin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var
公开访问应用
需要用到service，关于k8s中的服务是个什么概念，看官方介绍：
Kubernetes中的服务是一种抽象，定义了Pod的逻辑集合和访问Pod的策略
查看服务：
$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 44m
暴露80端口：
$ kubectl expose deployment/nginx --type="NodePort" --port 80
service/nginx exposed
$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 65m
nginx NodePort 10.103.123.100 <none> 80:30119/TCP 101s
关于这里的type有4种，具体参考上述文档。
查到其内部端口：
$ export NODE_PORT=$(kubectl get services/nginx -o go-template='{{(index .spec.ports 0).nodePort}}')
$ echo $NODE_PORT
30119
通过暴露的端口访问应用：
$ curl $(minikube ip):$NODE_PORT
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
通过标签查询
$ kubectl get pods -l run=nginx
NAME READY STATUS RESTARTS AGE
nginx-6db489d4b7-lbzgr 1/1 Running 0 71m
$ kubectl get services -l run=nginx
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
nginx NodePort 10.103.123.100 <none> 80:30119/TCP 38m
设置变量：
$ export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
$ echo Name of the Pod: $POD_NAME
Name of the Pod: nginx-6db489d4b7-lbzgr
# 打
$ kubectl label pod $POD_NAME app=v1
pod/nginx-6db489d4b7-lbzgr labeled
# 查看描述
$ kubectl describe pods $POD_NAME
Name: nginx-6db489d4b7-lbzgr
Namespace: default
Labels: app=v1
pod-template-hash=6db489d4b7
run=nginx
# 根据新标签获取
$ kubectl get pods -l app=v1
NAME READY STATUS RESTARTS AGE
nginx-6db489d4b7-lbzgr 1/1 Running 0 76m
通过标签删除服务：
$ kubectl delete service -l run=nginx
service "nginx" deleted
$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 109m
目前就一个应用
~$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 1/1 1 1 82m
扩到3个：
$ kubectl scale deployments/nginx --replicas=3
deployment.apps/nginx scaled
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 3/3 3 3 83m
查看pod：
$ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-6db489d4b7-7ntbs 1/1 Running 0 86s 172.17.0.6 minikube <none> <none>
nginx-6db489d4b7-kqnj4 1/1 Running 0 86s 172.17.0.5 minikube <none> <none>
nginx-6db489d4b7-lbzgr 1/1 Running 0 84m 172.17.0.4 minikube <none> <none>
$ kubectl describe deployments/nginx
Name: nginx
Namespace: default
CreationTimestamp: Mon, 07 Oct 2019 11:25:14 +0800
Labels: run=nginx
Annotations: deployment.kubernetes.io/revision: 1
Selector: run=nginx
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: run=nginx
Containers:
nginx:
Image: nginx
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Progressing True NewReplicaSetAvailable
Available True MinimumReplicasAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-6db489d4b7 (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 2m16s deployment-controller Scaled up replica set nginx-6db489d4b7 to 3
先暴露端口创建服务
$ kubectl expose deployments/nginx --type="NodePort" --port 80
service/nginx exposed
$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 155m
nginx NodePort 10.103.106.245 <none> 80:32396/TCP 6s
获得其端口：
$ kubectl describe services/nginx
Name: nginx
Namespace: default
Labels: run=nginx
Annotations: <none>
Selector: run=nginx
Type: NodePort
IP: 10.103.106.245
Port: <unset> 80/TCP
TargetPort: 80/TCP
NodePort: <unset> 32396/TCP
Endpoints: 172.17.0.4:80,172.17.0.5:80,172.17.0.6:80
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
看到上面endpoints的ip有3个，这时候访问：$ curl $(minikube ip):32396会默认采用轮训策略。
把副本写小一点就好了：
$ kubectl scale deployments/nginx --replicas=2
deployment.apps/nginx scaled
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 2/2 2 2 130m
$ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-6db489d4b7-kqnj4 1/1 Running 0 46m 172.17.0.5 minikube <none> <none>
nginx-6db489d4b7-lbzgr 1/1 Running 0 130m 172.17.0.4 minikube <none> <none>
$ kubectl describe deployments/nginx
Name: nginx
Namespace: default
CreationTimestamp: Mon, 07 Oct 2019 11:25:14 +0800
Labels: run=nginx
Annotations: deployment.kubernetes.io/revision: 1
Selector: run=nginx
Replicas: 2 desired | 2 updated | 2 total | 2 available | 0 unavailable
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 47m deployment-controller Scaled up replica set nginx-6db489d4b7 to 3
Normal ScalingReplicaSet 38s deployment-controller Scaled down replica set nginx-6db489d4b7 to 2
设置新的镜像
$ kubectl set image deployments/nginx nginx=gcr.azk8s.cn/google_containers/nginx:v1.16.1
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 2/2 1 2 162m
查看更新状态
$ kubectl rollout status deployments/nginx
Waiting for deployment "nginx" rollout to finish: 1 out of 2 new replicas have been updated...
$ kubectl rollout undo deployments/nginx
deployment.apps/nginx rolled back
- k8s3
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