K8s基础
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base
#使用glusterfs做存储，不懂glusterfs的请参考其他文章
命名空间
容器
临时容器
root@ubuntu-200430-1:~# kubectl create deployment nginx-deployment --image=nginx:1.25.2-alpine deployment.apps/nginx-deployment created root@ubuntu-200430-1:~# kubectl get deploy NAME READY UP-TO-DATE AVAILABLE AGE nginx-deployment 0/1 1 0 11s
label
给节点打标签label
root@ubuntu-200470-1:~/pod# kubectl get node
NAME STATUS ROLES AGE VERSION
master Ready control-plane 22d v1.24.10
work1 Ready <none> 22d v1.24.10
work2 Ready <none> 22d v1.24.10
#给节点1 work1打上 nodename=node01
root@ubuntu-200470-1:~/pod# kubectl label nodes work1 nodename=node01
node/work1 labeled
#查看效果
root@ubuntu-200470-1:~/pod# kubectl get node --show-labels=true
NAME STATUS ROLES AGE VERSION LABELS
master Ready control-plane 22d v1.24.10 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=master,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node.kubernetes.io/exclude-from-external-load-balancers=
work1 Ready <none> 22d v1.24.10 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=work1,kubernetes.io/os=linux,nodename=node01
work2 Ready <none> 22d v1.24.10 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=work2,kubernetes.io/os=linux
#使用 例如在dp
apiVersion: apps/v1
kind: Deployment
metadata:
name: dep-nginx-sel-node
spec:
replicas: 1
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
ver: beta
spec:
containers:
- name: nginx
image: nginx:1.25.2-alpine
imagePullPolicy: IfNotPresent
nodeSelector:
nodename: node01
label svc
oot@ubuntu-200470-1:~/oct19# kubectl get svc nginx --show-labels NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE LABELS nginx ClusterIP None <none> 80/TCP 6h15m app=nginxlabelstest root@ubuntu-200470-1:~/oct19# kubectl label svc nginx version=1 service/nginx labeled root@ubuntu-200470-1:~/oct19# kubectl get svc nginx --show-labels NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE LABELS nginx ClusterIP None <none> 80/TCP 6h15m app=nginxlabelstest,version=1 root@ubuntu-200470-1:~/oct19# kubectl label svc nginx version- service/nginx unlabeled root@ubuntu-200470-1:~/oct19# kubectl get svc nginx --show-labels NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE LABELS nginx ClusterIP None <none> 80/TCP 6h16m app=nginxlabelstest root@ubuntu-200470-1:~/oct19#
k8s 配置管理
configmap
ConfigMap 存储 Nginx 配置文件
#创建并查看ConfigMap
cat my-nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 1
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.25.2-alpine
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
#在k8s集群拉起一个nginx的pod并加载ConfigMap，通过默认8080去访问。
编写nginx的yaml文件，并加载ConfigMap
root@ubuntu-200470-1:~/oct21# cat my-nginx-cm.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 1
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.25.2-alpine
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
volumeMounts:
- name: config-volume
mountPath: /etc/nginx/conf.d
volumes:
- name: config-volume
configMap:
name: nginx-conf
root@ubuntu-200470-1:~/oct21# kubectl apply -f my-nginx-cm.yaml
deployment.apps/my-nginx configured
root@ubuntu-200470-1:~/oct21# kubectl get pod
NAME READY STATUS RESTARTS AGE
dapi-test-pod 0/1 Completed 0 30h
env-valuefrom-64956864d6-sh7hb 0/1 CrashLoopBackOff 138 (3m48s ago) 30h
laravel-deployment-5b44dcf689-lvkhp 1/1 Running 3 (95m ago) 3d9h
my-nginx-7678bcdf4c-qbl6b 1/1 Running 0 15s
mydep-759989964c-tdf5l 1/1 Running 3 (94m ago) 3d6h
mypod 1/1 Running 1 (91m ago) 29h
mypod2 1/1 Running 1 (95m ago) 29h
mysql-deploy-7fdd46c697-4r842 0/1 CreateContainerConfigError 0 3d9h
nginx-deployment-89857df9d-4m8kl 1/1 Running 2 (91m ago) 2d6h
nginx-deployment-89857df9d-fcqm5 1/1 Running 2 (95m ago) 2d6h
nginx-deployment-89857df9d-gwdql 1/1 Running 2 (94m ago) 2d6h
nginx-deployment-89857df9d-kg595 1/1 Running 2 (95m ago) 2d6h
nginx-deployment-89857df9d-nbqhm 1/1 Running 2 (90m ago) 2d6h
secret-env-pod 0/1 Unknown 0 29h
web-0 1/1 Running 2 (91m ago) 2d5h
web-1 1/1 Running 2 (91m ago) 2d5h
web-2 1/1 Running 2 (93m ago) 2d4h
wordpress-deploy-5d6679b4c4-tcmpd 1/1 Running 3 (94m ago) 3d9h
root@ubuntu-200470-1:~/oct21# kubectl get pod my-nginx-7678bcdf4c-qbl6b -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
my-nginx-7678bcdf4c-qbl6b 1/1 Running 0 32s 10.234.252.13 work2 <none> <none>
root@ubuntu-200470-1:~/oct21# curl 10.234.252.13:8080
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
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>
root@ubuntu-200470-1:~/oct21# kubectl exec -it my-nginx-7678bcdf4c-qbl6b -- cat /etc/nginx/conf.d/default.conf
server {
listen 8080;
listen [::]:80;
server_name localhost;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
https://www.cnblogs.com/paul8339/p/15424586.html
controllers 控制器
控制器DaemonSet
控制器CronJob
Helm3
k8s-imagePullPolicy拉取策略
imagePullPolicy: Always 总是拉取 pull 以前好像是这个默认值 imagePullPolicy: IfNotPresent 默认值,本地有则使用本地镜像,不拉取 imagePullPolicy: Never 只使用本地镜像，从不拉取
k8s 进入pod shell
kubectl get pods #查看所有正在运行的pod NAME READY STATUS RESTARTS AGE nginx-56b8c64cb4-t97vb 1/1 Running 3 1d kubectl exec -it nginx-56b8c64cb4-t97vb -- /bin/bash #假如当前pod只有一个容器,运行以下命令即可 root@nginx-56b8c64cb4-t97vb:/# ps -ef UID PID PPID C STIME TTY TIME CMD root 1 0 0 14:45 ? 00:00:00 nginx: master process nginx -g daemon off; 假如一个pod里有多个容器,用--container or -c 参数。例如:假如这里有个Pod名为my-pod,这个Pod有两个容器,分别名为main-app 和 helper-app,下面的命令将打开到main-app的shell的容器里。 kubectl exec -it my-pod --container main-app -- /bin/bash
k8s删除pod
1、先删除pod2、再删除对应的deployment否则只是删除pod是不管用的，还会看到pod，因为deployment.yaml文件中定义了副本数量 实例如下： 删除pod [root@test2 ~]# kubectl get pod -n jenkins NAME READY STATUS RESTARTS AGE jenkins2-8698b5449c-grbdm 1/1 Running 0 8s [root@test2 ~]# kubectl delete pod jenkins2-8698b5449c-grbdm -n jenkins pod "jenkins2-8698b5449c-grbdm" deleted 查看pod仍然存储 [root@test2 ~]# kubectl get pod -n jenkins NAME READY STATUS RESTARTS AGE jenkins2-8698b5449c-dbqqb 1/1 Running 0 8s [root@test2 ~]# 删除deployment [root@test2 ~]# kubectl get deployment -n jenkins NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE jenkins2 1 1 1 1 17h [root@test2 ~]# kubectl delete deployment jenkins2 -n jenkins 再次查看pod消失 deployment.extensions "jenkins2" deleted [root@test2 ~]# kubectl get deployment -n jenkins No resources found. [root@test2 ~]# [root@test2 ~]# kubectl get pod -n jenkins No resources found.
[ k8s中正确删除一个pod k8s中正确删除一个pod ]
常见组件安装
安装Metrics server
hpa
coredns状态为ImagePullBackOff问题
kubectl get pods --all-namespaces
kube-system coredns-7f6cbbb7b8-knhl8 0/1 ImagePullBackOff 0 24h
kube-system coredns-7f6cbbb7b8-lt4k5 0/1 ImagePullBackOff 0 24h
解决办法：
确定pod所使用的镜像
kubectl get pods coredns-7f6cbbb7b8-knhl8 -n kube-system -o yaml | grep image
image: registry.aliyuncs.com/google_containers/coredns:v1.8.4
imagePullPolicy: IfNotPresent
- image: registry.aliyuncs.com/google_containers/coredns:v1.8.4
imageID: ""
message: Back-off pulling image "registry.aliyuncs.com/google_containers/coredns:v1.8.4"
root@k8s-master:~# docker pull registry.aliyuncs.com/google_containers/coredns:v1.8.4
Error response from daemon: manifest for registry.aliyuncs.com/google_containers/coredns:v1.8.4 not found: manifest unknown: manifest unknown
拉个latest 再别名
docker pull registry.aliyuncs.com/google_containers/coredns
root@k8s-master:~# docker images | grep coredns
registry.aliyuncs.com/google_containers/coredns latest 8d147537fb7d 3 months ago 47.6MB
强制 改一下 tag
root@k8s-master:~# docker tag 8d147537fb7d registry.aliyuncs.com/google_containers/coredns:v1.8.4
root@k8s-master:~# kubectl get pods --all-namespaces | grep coredns
kube-system coredns-7f6cbbb7b8-knhl8 1/1 Running 0 24h
kube-system coredns-7f6cbbb7b8-lt4k5 1/1 Running 0 24h
root@k8s-master:~#
root@k8s-master:~# kubectl get all -n kube-system
NAME READY STATUS RESTARTS AGE
pod/coredns-7f6cbbb7b8-knhl8 0/1 ImagePullBackOff 0 24h
pod/coredns-7f6cbbb7b8-lt4k5 0/1 ImagePullBackOff 0 24h
docker pull registry.aliyuncs.com/google_containers/coredns
k8s解决coredns 的ImagePullBackOff 和ErrImagePull 问题
https://stackoverflow.com/questions/53559291/kubernetes-coredns-in-crashloopbackoff
Kubernetes CoreDNS 状态是 CrashLoopBackOff 解决思路
CrashLoopBackOff的解决方法
记录一次修复k8s pod长时间处于CrashLoopBackOff状态问题
k8s启动Pod遇到CrashLoopBackOff的解决方法
k8s常见问题
pod无故重启
OOM
