k8s常用操作和常见问题
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| 阿里云国际，腾讯云国际，低至75折。AWS 93折 免费开户实名账号 代冲值 优惠多多 微信号：monov8 飞机：@monov6 |
写在前面
本文记录k8s的常见操作毕竟好记性不如烂笔头。
1常用操作
1.1pod查看日志
dongyunqi@dongyunqi-virtual-machine:~/test$ kubectl logs busy-pod
ubuntu, on
因为pod中只有一个容器所以不需要指定容器当有多个容器时需要指定容器如下:
dongyunqi@dongyunqi-virtual-machine:~/test$ kubectl logs ngx-num1-pod -c ngx1111
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
...
1.2查询POD
可以直接查看也可以通过label过滤查看如下
dongyunqi@mongodaddy:~/k8s$ kubectl get pod
NAME READY STATUS RESTARTS AGE
ngx-dep-name-dcc8b7bfd-7lbrq 1/1 Running 0 17m
ngx-dep-name-dcc8b7bfd-9m2rs 1/1 Running 0 17m
ngx-dep-name-dcc8b7bfd-wp4zt 1/1 Running 0 17m
redis-ds-5jf5x 1/1 Running 1 (4h34m ago) 40h
redis-ds-n8p45 1/1 Running 1 (4h34m ago) 40h
5可以根据POD的label来过滤POD支持使用==、!=、in、notin等表达式如下
dongyunqi@mongodaddy:~/k8s$ kubectl get pod -l 'app in (ngx, nginx, ngx-dep-pod)'
NAME READY STATUS RESTARTS AGE
ngx-dep-name-577dd8d59b-4xkd2 1/1 Running 0 3m34s
ngx-dep-name-577dd8d59b-dcx8k 1/1 Running 0 3m34s
ngx-dep-name-577dd8d59b-f2kxp 1/1 Running 0 3m34s
dongyunqi@mongodaddy:~/k8s$ kubectl get pod -l 'app=ngx-dep-pod'
NAME READY STATUS RESTARTS AGE
ngx-dep-name-577dd8d59b-4xkd2 1/1 Running 0 3m59s
ngx-dep-name-577dd8d59b-dcx8k 1/1 Running 0 3m59s
ngx-dep-name-577dd8d59b-f2kxp 1/1 Running 0 3m59s
1.3查看pod中运行的容器
1.3.1describe
dongyunqi@mongodaddy:~/k8s$ kubectl describe pod ngx-dep-name-dcc8b7bfd-7lbrq | grep Events -A 100
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 34m default-scheduler Successfully assigned default/ngx-dep-name-dcc8b7bfd-7lbrq to mongomummy # pod分配的Node
Normal Pulled 34m kubelet Container image "nginx:alpine" already present on machine # 创建容器使用的镜像
Normal Created 34m kubelet Created container nginx # 创建容器显示的是容器的名称
Normal Started 34m kubelet Started container nginx
dongyunqi@mongodaddy:~/k8s$ kubectl describe pod ngx-dep-name-dcc8b7bfd-7lbrq | grep Containers: -A 100
Containers: # 所有的容器信息
nginx: # 容器的名称
Container ID: docker://87afa9c8b6c1a9c8434a5dcbe39eb55863ecff4c91a68b408a3fd5f11b18a86f
Image: nginx:alpine # 容器使用的镜像
Image ID: docker-pullable://nginx@sha256:eb05700fe7baa6890b74278e39b66b2ed1326831f9ec3ed4bdc6361a4ac2f333
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Thu, 12 Jan 2023 14:59:05 +0800
Ready: True
Restart Count: 0 # 容器重启的此时
Environment: <none>
Mounts:
/etc/nginx/conf.d from ngx-conf-vol (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-wlbhf (ro)
1.3.2jsonpath过滤
dongyunqi@mongodaddy:~/k8s$ kubectl get pods ngx-dep-name-dcc8b7bfd-7lbrq -o jsonpath={.spec.containers[*].name}
nginx
1.4通过events排查异常POD
当POD运行异常时如一直PENDING可通过kubectl describe查看异常信息
dongyunqi@mongodaddy:~/k8s$ kubectl describe pod ngx-dep-name-dcc8b7bfd-7lbrq | grep Events -A 100
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 34m default-scheduler Successfully assigned default/ngx-dep-name-dcc8b7bfd-7lbrq to mongomummy # pod分配的Node
Normal Pulled 34m kubelet Container image "nginx:alpine" already present on machine # 创建容器使用的镜像
Normal Created 34m kubelet Created container nginx # 创建容器显示的是容器的名称
Normal Started 34m kubelet Started container nginx
这里展示的正常如果是发生错误则在Message列会有对应的提示。如下是我从网上找的一个比较典型的错误信息
0/5 nodes are available: 1 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate, 4 Insufficient memory.
0/5是说5个容器都不可用1 node(s) had taint {node-role.kubernetes.io/master: }其中一个是因为有污点 , 4 Insufficient memory 另外四个是因为内存不足了这样我们就可以对症下药了。
1.5查看API对向所属的namespace
dongyunqi@mongodaddy:~/k8s$ kubectl get service -A | egrep 'NAMESP|ngx-svc'| awk '{print $1}'
NAMESPACE
default
1.6获取k8s集群节点信息
dongyunqi@mongodaddy:~/k8s$ kubectl get node -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
mongodaddy Ready control-plane,master 6h36m v1.23.3 192.168.64.131 <none> Ubuntu 22.04.1 LTS 5.15.0-57-generic docker://20.10.12
mongomummy Ready <none> 6h31m v1.23.3 192.168.64.132 <none> Ubuntu 22.04.1 LTS 5.15.0-57-generic docker://20.10.12
1.7获取所有命名空间
yunqi@mongodaddy:~/k8s$ kubectl get namespaces
NAME STATUS AGE
default Active 21h
kube-flannel Active 20h
kube-node-lease Active 21h
kube-public Active 21h
kube-system Active 21h
nginx-ingress Active 13h
1.8POD已经RUNNING但是不READY
出现这种现象的原因一般都是配置了健康检查机制容器已经启动成功了但是容器内的应用健康检查没有通过即容器内的应用没有启动成功如下
dongyunqi@mongodaddy:~/k8s$ kubectl get pod -n nginx-ingress
NAME READY STATUS RESTARTS AGE
ngx-kic-dep-67c7cf6d5f-dg5cw 0/1 Running 0 43s
此时可以查看应用日志来定位具体问题如下实例
dongyunqi@mongodaddy:~/k8s$ kubectl logs ngx-kic-dep-67c7cf6d5f-dg5cw -n nginx-ingress
I0114 03:23:11.052364 1 main.go:213] Starting NGINX Ingress Controller Version=2.2.2 GitCommit=a88b7fe6dbde5df79593ac161749afc1e9a009c6 Date=2022-05-24T00:33:34Z Arch=linux/amd64 PlusFlag=false
....
2023/01/14 03:23:11 [notice] 12#12: OS: Linux 5.15.0-57-generic
2023/01/14 03:23:11 [notice] 12#12: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2023/01/14 03:23:11 [notice] 12#12: start worker processes
2023/01/14 03:23:11 [notice] 12#12: start worker process 13
I0114 03:23:11.115502 1 leaderelection.go:248] attempting to acquire leader lease nginx-ingress/nginx-ingress-leader-election...
W0114 03:23:11.117925 1 reflector.go:324] pkg/mod/k8s.io/client-go@v0.23.6/tools/cache/reflector.go:167: failed to list *v1alpha1.TransportServer: the server could not find the requested resource (get transportservers.k8s.nginx.org)
E0114 03:23:11.118154 1 reflector.go:138] pkg/mod/k8s.io/client-go@v0.23.6/tools/cache/reflector.go:167: Failed to watch *v1alpha1.TransportServer: failed to list *v1alpha1.TransportServer: the server could not find the requested resource (get transportservers.k8s.nginx.org)
W0114 03:23:11.137598 1 reflector.go:324] pkg/mod/k8s.io/client-go@v0.23.6/tools/cache/reflector.go:167: failed to list *v1.Policy: the server could not find the requested resource (get policies.k8s.nginx.org)
以上的错误实例是在部署ingress controller时因为一些ingress controller没有初始化完成导致出现错误。
1.9查询k8s都有哪些API对象
dongyunqi@mongodaddy:~/k8s$ kubectl api-resources|egrep -w 'Ingress|KIND'
NAME SHORTNAMES APIVERSION NAMESPACED KIND
ingresses ing networking.k8s.io/v1 true Ingress
dongyunqi@mongodaddy:~/k8s$ kubectl api-resources
NAME SHORTNAMES APIVERSION NAMESPACED KIND
bindings v1 true Binding
componentstatuses cs v1 false ComponentStatus
...
2常用问题
2.1POD一直ContainerCreating
通过kubectl describe pod {pod名称}查看错误原因,如下就是因为网络插件出现问题导致
dongyunqi@mongodaddy:~/k8s$ kubectl describe pod busy-pod
Name: busy-pod
...
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 4m5s default-scheduler Successfully assigned default/busy-pod to mongomummy
Warning FailedCreatePodSandBox 4m5s kubelet Failed to create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "81294866bfbdb13363f63bab5b2a87434994b7890ec03e601869cb586d1fad87" network for pod "busy-pod": networkPlugin cni failed to set up pod "busy-pod_default" network: open /run/flannel/subnet.env: no such file or directory
Warning FailedCreatePodSandBox 4m3s kubelet Failed to create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "533c9ceee9a99087be62bb1efdc624cf72f81397443cd908252abc4cea7b7c1b" network for pod "busy-pod": networkPlugin cni failed to set up pod "busy-pod_default" network: open /run/flannel/subnet.env: no such file or directory
...
只需要在k8s集群中创建网络插件就行了具体可以参考这篇文章 。
| 阿里云国内75折 回扣 微信号：monov8 |
| 阿里云国际，腾讯云国际，低至75折。AWS 93折 免费开户实名账号 代冲值 优惠多多 微信号：monov8 飞机：@monov6 |