kubernetes(K8S)基础管理
2021-07-02 本文已影响0人
一个小运维
以下内容基于前面的搭建，上篇文章为k8s的搭建部署：https://www.jianshu.com/p/2316b60a0b41
kubectl 命令
命令说明
| 命令格式 | 命令说明 |
|---|---|
| kubectl run 资源名称 -参数 --image=镜像名称:标签 | 创建资源对象，常用参数-i交互，-t终端 |
| kubectl get 查询资源 可选参数 -o wide 显示主机信息 | 常用查询的资源 node|deployment|pod |
| kubectl exec -it 容器id 执行的命令 | 同 docker exec 指令，进入容器内 |
| kubectl describe 资源类型 资源名称 | 查询资源的详细信息 |
| kubectl attach | 同 docker attach 指令，连接容器 |
| kubectl logs 容器id | 查看容器控制台的标准输出 |
| kubectl delete 资源类型 资源名称 | 删除指定的资源 |
| kubectl create|apply -f 资源文件 | 执行指定的资源文件 |
命令示例
# get 查询信息
[root@master ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready master 19h v1.17.6
node-0001 Ready <none> 16h v1.17.6
[root@master ~]# kubectl get pod
No resources found in default namespace.
[root@master ~]# kubectl get namespaces
NAME STATUS AGE
default Active 9h
kube-node-lease Active 9h
kube-public Active 9h
kube-system Active 9h
[root@master ~]# kubectl -n kube-system get pod
NAME READY STATUS RESTARTS AGE
kube-flannel-ds-amd64-hf2jp 1/1 Running 0 41m
kube-flannel-ds-amd64-rtl4l 1/1 Running 0 41m
... ...
# describe 查询详细信息
[root@master ~]# kubectl -n kube-system describe pod kube-flannel-ds-amd64-rtl4l
Name: kube-proxy-4tbp6
Namespace: kube-system
... ...
# 使用run启动容器
[root@master ~]# kubectl run testos -it --image=192.168.1.100:5000/myos:v1804
[root@testos-79778b4895-s8mxl /]#
# 启动服务
[root@master ~]# kubectl run testweb --image=192.168.1.100:5000/myos:httpd
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/testweb created
# 访问节点
[root@master ~]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP
testos-79778b4895-s8mxl 1/1 Running 1 6m33s 10.244.3.2 ... ...
testweb-7bf98b9576-v566c 1/1 Running 0 4m24s 10.244.4.2 ... ...
[root@master ~]# curl http://10.244.4.2/info.php
<pre>
Array
(
[REMOTE_ADDR] => 10.244.0.0
[REQUEST_METHOD] => GET
[HTTP_USER_AGENT] => curl/7.29.0
[REQUEST_URI] => /info.php
)
php_host: testweb-7bf98b9576-v566c
1229
# 进入容器
[root@master ~]# kubectl exec -it testos-79778b4895-s8mxl -- /bin/bash
[root@testos-79778b4895-s8mxl /]#
[root@master ~]# kubectl attach -it testos-79778b4895-s8mxl
[root@testos-79778b4895-s8mxl /]#
# 查看终端日志
[root@master ~]# kubectl logs testweb-7bf98b9576-v566c
AH00558: httpd: Could not reliably determine the server fully qualified domain name, using 10.244.4.2. Set the 'ServerName' directive globally to suppress this message
# 执行指定的资源文件
[root@master flannel]# kubectl apply -f kube-flannel.yml
# 删除资源，直接删除POD会自动重建
[root@master ~]# kubectl delete pod testos-79778b4895-s8mxl
pod "testos-79778b4895-s8mxl" deleted
[root@master ~]# kubectl delete deployments testos
deployment.apps "testos" deleted
常用排错命令：
- kubectl -n 命令空间 get pod #命令空间可以通过 kubectl get namespace 命令查看
- kubectl describe deployment 资源名称 #查看资源详细信息
kubectl describe "deployment-rs-pod" #查看容器详细信息 "deployment-rs-pod"为容器名称 - kubectl logs 容器名称
资源文件
在k8s集群中，latest标签是不会被缓存，如果想缓存可以使用其他标签
[root@master ~]# curl http://192.168.1.100:5000/v2/myos/tags/list
{"name":"myos","tags":["nginx","php-fpm","v1804","httpd"]}
pod 资源文件
[root@master config]# vim mypod.yaml
---
kind: Pod
apiVersion: v1
metadata:
name: mypod
spec:
containers:
- name: mylinux
image: 192.168.1.100:5000/myos:v1804
stdin: true
tty: true
[root@master ~]# kubectl apply -f mypod.yaml
pod/mypod created
[root@master ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE
mypod 1/1 Running 0 13s
[root@master ~]# kubectl delete -f mypod.yaml
pod "mypod" deleted
[root@master ~]#
deployment 资源文件
[root@master ~]# vim myapache.yaml
--- #资源定义起始标志
kind: Deployment #当前创建资源的类型
apiVersion: apps/v1 #当前格式的版本
metadata: #元数据
name: myapache #deployment的名称
annotations:
kubernetes.io/change-cause: httpd.v1 #定义回滚标记
spec: #详细配置信息
selector: #选择器
matchLabels: #标签选择
myapp: httpd #标签，在pod中定义
replicas: 1 #副本数量
template: #template定义
metadata: #元数据
labels: #标签
myapp: httpd #定义标签，在其它地方被引用
spec: #容器详细定义
containers: #容器定义
- name: webcluster #容器名称
image: 192.168.1.100:5000/myos:httpd #镜像地址
stdin: false #标准输入，默认false，服务容器中可省略
tty: false #终端，默认false，服务容器中可省略
ports: #端口
- protocol: TCP #服务使用的协议
containerPort: 80 #容器监听的端口号
restartPolicy: Always
[root@master ~]# kubectl apply -f myapache.yaml
deployment.apps/myapache created
[root@master ~]# kubectl get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
myapache 1/1 1 1 19s
[root@master ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE
myapache-69b494dc5c-bff95 1/1 Running 0 28s
[root@master ~]#
集群调度
扩容与缩减
[root@master ~]# kubectl get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
myapache 1/1 1 1 113s
[root@master ~]# kubectl scale deployment myapache --replicas=3
deployment.apps/myapache scaled
[root@master ~]# kubectl get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
myapache 3/3 3 3 2m12s
[root@master ~]#
集群更新与回滚
[root@master config]# kubectl rollout history deployment myapache
deployment.apps/myapache
REVISION CHANGE-CAUSE
1 <none>
[root@master ~]# curl http://10.244.3.5
this is apache
[root@master ~]# kubectl edit deployments.apps myapache
deployment.apps/myapache edited
[root@master ~]# curl http://10.244.2.6
this is nginx
[root@master ~]# kubectl rollout history deployment myapache
deployment.apps/myapache
REVISION CHANGE-CAUSE
1 <none>
2 <none>
[root@master ~]# kubectl rollout undo deployment myapache --to-revision=1
deployment.apps/myapache rolled back
[root@master ~]# curl http://10.244.3.6
this is apache
[root@master ~]#
节点标签选择器
使用 nodeName 参数让容器运行在指定节点上
[root@master ~]# vim myapache.yaml
---
kind: Deployment
apiVersion: apps/v1
metadata:
name: myapache
spec:
selector:
matchLabels:
myapp: httpd
replicas: 1
template:
metadata:
labels:
myapp: httpd
spec:
nodeName: node-0001 # 新增一行
containers:
- name: webcluster
image: 192.168.1.100:5000/myos:httpd
stdin: false
tty: false
ports:
- protocol: TCP
containerPort: 80
restartPolicy: Always
[root@master ~]# kubectl delete -f myapache.yaml
deployment.apps "myapache" deleted
[root@master ~]# kubectl apply -f myapache.yaml
deployment.apps/myapache created
[root@master ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
myapache-xxx 1/1 Running 0 3m49s 10.244.3.9 node-0001
使用 标签 让容器运行在一些节点上
[root@master ~]# kubectl delete -f myapache.yaml
deployment.apps "myapache" deleted
[root@master ~]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master Ready master 10h v1.17.6 kubernetes.io/hostname=master ... ...
node-0001 Ready <none> 10h v1.17.6 kubernetes.io/hostname=node-0001 ... ...
node-0002 Ready <none> 10h v1.17.6 kubernetes.io/hostname=node-0002 ... ...
node-0003 Ready <none> 10h v1.17.6 kubernetes.io/hostname=node-0003 ... ...
[root@master ~]# kubectl label nodes node-0002 node-0003 disktype=ssd
node/node-0002 labeled
node/node-0003 labeled
[root@master ~]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master Ready master 10h v1.17.6 kubernetes.io/hostname=master ... ...
node-0001 Ready <none> 10h v1.17.6 kubernetes.io/hostname=node-0001 ... ...
node-0002 Ready <none> 10h v1.17.6 disktype=ssd ... ...
node-0003 Ready <none> 10h v1.17.6 disktype=ssd ... ...
[root@master ~]# vim myapache.yaml
---
kind: Deployment
apiVersion: apps/v1
metadata:
name: myapache
spec:
selector:
matchLabels:
myapp: httpd
replicas: 1
template:
metadata:
labels:
myapp: httpd
spec:
nodeSelector: # 新添加
disktype: ssd # 新添加
containers:
- name: webcluster
image: 192.168.1.100:5000/myos:httpd
stdin: false
tty: false
ports:
- protocol: TCP
containerPort: 80
restartPolicy: Always
[root@master ~]# kubectl scale deployment myapache --replicas=3
deployment.apps/myapache scaled
[root@master ~]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
myapache-xxx 1/1 Running 0 9s 10.244.1.7 node-0003 <none>
myapache-xxx 1/1 Running 0 9s 10.244.2.8 node-0002 <none>
myapache-xxx 1/1 Running 0 21s 10.244.2.7 node-0002 <none>
[root@master ~]# kubectl delete -f myapache.yaml
deployment.apps "myapache" deleted
[root@master ~]# kubectl label nodes node-0002 node-0003 disktype-
node/node-0002 labeled
node/node-0003 labeled
[root@master ~]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master Ready master 10h v1.17.6 kubernetes.io/hostname=master ... ...
node-0001 Ready <none> 10h v1.17.6 kubernetes.io/hostname=node-0001 ... ...
node-0002 Ready <none> 10h v1.17.6 kubernetes.io/hostname=node-0002 ... ...
node-0003 Ready <none> 10h v1.17.6 kubernetes.io/hostname=node-0003 ... ...
