k8s集群创建pod,rc,service服务并实现滚动发布自动扩缩容
上一篇博客介绍了如何搭建一套k8s集群k8s集群搭建部署教程本篇介绍用k8s部署应用k8s集群中创建podmaster节点创建pod先创建目录[root@server1 ~]# mkdir -p k8s_yaml/pod创建yaml文件[root@server1 ~]# cd k8s_yaml/pod/[root@server1 pod]# vi k8s_pod.yamlapiVersion: v
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上一篇博客介绍了如何搭建一套k8s集群
k8s集群搭建部署教程
本篇介绍用k8s部署应用
k8s集群创建pod
master节点创建pod
先创建目录
[root@server1 ~]# mkdir -p k8s_yaml/pod
创建yaml文件
[root@server1 ~]# cd k8s_yaml/pod/
[root@server1 pod]# vi k8s_pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx
labels:
app: web
spec:
containers:
- name: nginx
image: 192.168.56.132:5000/nginx:1.13
ports:
- containerPort: 80
创建nginx pod
[root@server1 pod]# kubectl create -f k8s_pod.yaml
pod/nginx created
查看pod
[root@server1 pod]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx 0/1 ImagePullBackOff 0 3m7s
将master上的nginx镜像打包上传到node1和node2
打包master镜像
[root@server1 pod]# docker save docker.io/pseudecoder/centos-nginx -o /mnt/nginx.tar
上传nginx镜像到node1和node2节点
[root@server1 pod]# scp /mnt/nginx.tar server2:/mnt/
[root@server1 pod]# scp /mnt/nginx.tar server3:/mnt/
node节点加载镜像
[root@server2 ~]# docker load -i /mnt/nginx.tar
5f70bf18a086: Loading layer [==================================================>] 1.024 kB/1.024 kB
ee1dd2cb6df2: Loading layer [==================================================>] 204.2 MB/204.2 MB
d4f57322e1a5: Loading layer [==================================================>] 3.072 kB/3.072 kB
62c84ccc943b: Loading layer [==================================================>] 74.89 MB/74.89 MB
aafdd9551301: Loading layer [==================================================>] 1.697 MB/1.697 MB
772fd97d8860: Loading layer [==================================================>] 2.048 kB/2.048 kB
385103b6bdaf: Loading layer [==================================================>] 45.57 kB/45.57 kB
Loaded image: docker.io/pseudecoder/centos-nginx:latest
[root@server3 ~]# docker load -i /mnt/nginx.tar
5f70bf18a086: Loading layer [==================================================>] 1.024kB/1.024kB
ee1dd2cb6df2: Loading layer [==================================================>] 204.2MB/204.2MB
d4f57322e1a5: Loading layer [==================================================>] 3.072kB/3.072kB
62c84ccc943b: Loading layer [==================================================>] 74.89MB/74.89MB
aafdd9551301: Loading layer [==================================================>] 1.697MB/1.697MB
772fd97d8860: Loading layer [==================================================>] 2.048kB/2.048kB
385103b6bdaf: Loading layer [==================================================>] 45.57kB/45.57kB
Loaded image: pseudecoder/centos-nginx:latest
给nginx镜像打标签
[root@server2 ~]# docker tag docker.io/pseudecoder/centos-nginx:latest 192.168.56.132:5000/nginx:1.13
[root@server3 ~]# docker tag docker.io/pseudecoder/centos-nginx:latest 192.168.56.132:5000/nginx:1.13
将node节点上的镜像push到master私有镜像仓库
[root@server2 ~]# docker push 192.168.56.132:5000/nginx:1.13
The push refers to repository [192.168.56.132:5000/nginx]
5f70bf18a086: Pushed
385103b6bdaf: Pushed
772fd97d8860: Pushed
aafdd9551301: Pushed
62c84ccc943b: Pushed
d4f57322e1a5: Pushed
ee1dd2cb6df2: Pushed
1.13: digest: sha256:3dfe5891f891b3c0af86290e33db9591959acf80cf8067dcfc99e962b2a8d2f6 size: 2604
[root@server3 system]# docker push 192.168.56.132:5000/nginx:1.13
The push refers to repository [192.168.56.132:5000/nginx]
5f70bf18a086: Pushed
385103b6bdaf: Pushed
772fd97d8860: Pushed
aafdd9551301: Pushed
62c84ccc943b: Pushed
d4f57322e1a5: Pushed
ee1dd2cb6df2: Pushed
1.13: digest: sha256:3dfe5891f891b3c0af86290e33db9591959acf80cf8067dcfc99e962b2a8d2f6 size: 2604
master上创建nginx pod
[root@server1 pod]# kubectl create -f k8s_pod.yaml
pod/nginx created
查看pod
[root@server1 pod]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx 0/1 ContainerCreating 0 118s
查看pod详细信息
[root@server1 pod]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx 1/1 Running 0 2m40s 10.244.2.7 server3.example.com <none> <none>
查看nginx pod状态及内容
可以看到nginx是正常启动的
[root@server1 pod]# curl -I 10.244.2.7
HTTP/1.1 200 OK
Server: nginx
Date: Sun, 28 Jun 2020 14:50:43 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 26 Jan 2016 15:51:10 GMT
Connection: keep-alive
Vary: Accept-Encoding
ETag: "56a795ee-264"
Accept-Ranges: bytes
在创建一个nginx pod
[root@server1 pod]# cp k8s_pod.yaml k8s_pod2.yaml
[root@server1 pod]# ls
k8s_pod2.yaml k8s_pod.yaml
[root@server1 pod]# vim k8s_pod2.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx2
labels:
app: web
spec:
containers:
- name: nginx
image: 192.168.56.132:5000/nginx:1.13
ports:
- containerPort: 80
[root@server1 pod]# kubectl create -f k8s_pod2.yaml
pod/nginx2 created
查看nginx2 pod
[root@server1 pod]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 73s
nginx2 1/1 Running 0 12m
[root@server1 pod]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx 1/1 Running 0 107s 10.244.2.8 server3.example.com <none> <none>
nginx2 1/1 Running 0 13m 10.244.1.2 server2.example.com <none> <none>
访问nginx2
[root@server1 pod]# curl -I 10.244.1.2
HTTP/1.1 200 OK
Server: nginx
Date: Mon, 29 Jun 2020 14:54:42 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 26 Jan 2016 15:51:10 GMT
Connection: keep-alive
Vary: Accept-Encoding
ETag: "56a795ee-264"
Accept-Ranges: bytes
创建Replication Controller服务
Replication Controller简称RC，它能够保证Pod持续运行，并且在任何时候都有指定数量的Pod副本，在此基础上提供一些高级特性，比如滚动升级和弹性伸缩
编辑rc配置文件
[root@server1 rc]# vim k8s_rc.yml
apiVersion: v1
kind: ReplicationController
metadata: #设置rc的元数据
name: nginx
spec: #设置rc的具体规格
replicas: 3 #设置Pod的具体数量
selector: #通过selector来匹配相应的Pod的label
app: myweb
template: #设置Pod的模板
metadata:
labels:
app: myweb
spec:
containers:
- name: myweb
image: 192.168.56.132:5000/nginx:1.13
ports:
- containerPort: 80
创建rc
[root@server1 rc]# kubectl create -f k8s_rc.yml
replicationcontroller/nginx created
查看刚才创建的rc
[root@server1 rc]# kubectl get rc
NAME DESIRED CURRENT READY AGE
nginx 3 3 3 2m55s
查看pod,以下pod就是刚才创建rc时创建的pod
[root@server1 rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-bg98z 1/1 Running 0 3m52s
nginx-j825s 1/1 Running 0 3m52s
nginx-nzf6v 1/1 Running 0 3m52s
当删除其中一个Pod或者删除全部Pod的时候，RC会自动再次创建Pod，直到满足配置文件中定义的个数
删除一个pod，看是否会自动创建
[root@server1 rc]# kubectl delete pod nginx-bg98z
pod "nginx-bg98z" deleted
查看pod，已经自动创建，数量仍然是3个
[root@server1 rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-9ttf6 1/1 Running 0 98s
nginx-j825s 1/1 Running 0 27m
nginx-nzf6v 1/1 Running 0 27m
弹性伸缩
弹性伸缩就是在现有环境不能满足业务需求的时候，进行的扩容或缩容
1.缩容Pod
[root@server1 rc]# kubectl scale replicationcontroller nginx --replicas=2
replicationcontroller/nginx scaled
查看nginx pod已经缩减至两个
[root@server1 rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-j825s 1/1 Running 0 31m
nginx-nzf6v 1/1 Running 0 31m
2.扩容Pod
[root@server1 rc]# kubectl scale replicationcontroller nginx --replicas=3
replicationcontroller/nginx scaled
查看nginx pod已经扩容至3个了
[root@server1 rc]# kubectl get rc nginx
NAME DESIRED CURRENT READY AGE
nginx 3 3 3 34m
滚动升级
新建一个rc文件
[root@server1 rc]# cp k8s_rc.yml k8s_rc2.yml
[root@server1 rc]# vim k8s_rc2.yml
apiVersion: v1
kind: ReplicationController
metadata: #设置rc的元数据
name: nginx2
spec: #设置rc的具体规格
replicas: 3 #设置Pod的具体数量
selector: #通过selector来匹配相应的Pod的label
app: myweb2
template: #设置Pod的模板
metadata:
labels:
app: myweb2
spec:
containers:
- name: myweb
image: 192.168.56.132:5000/nginx:1.15
ports:
- containerPort: 80
本次新建nginx版本为nginx-1.15，在node1和node2上下载nginx-1.15并上传至镜像仓库
[root@server2 ~]# docker load -i /mnt/nginx.tar
Loaded image: pseudecoder/centos-nginx:latest
[root@server3 ~]# docker load -i /mnt/nginx.tar
Loaded image: pseudecoder/centos-nginx:latest
将nginx打上1.15的标签
[root@server2 ~]# docker tag pseudecoder/centos-nginx:latest 192.168.56.132:5000/nginx:1.15
[root@server3 ~]# docker tag pseudecoder/centos-nginx:latest 192.168.56.132:5000/nginx:1.15
将nginx镜像推至镜像仓库
[root@server2 ~]# docker push 192.168.56.132:5000/nginx:1.15
The push refers to repository [192.168.56.132:5000/nginx]
1.15: digest: sha256:3dfe5891f891b3c0af86290e33db9591959acf80cf8067dcfc99e962b2a8d2f6 size: 2604
删除原有nginx pod,创建带记录点方式的nginx pod
[root@server1 rc]# kubectl delete ReplicationController nginx
replicationcontroller "nginx" deleted
创建deployment文件
[root@server1 rc]# cp k8s_rc.yml k8s_deploy.yml
[root@server1 rc]# cp k8s_rc2.yml k8s_deploy2.yml
apiVersion: apps/v1
kind: Deployment
metadata: #设置rc的元数据
name: nginx-deployment
spec: #设置rc的具体规格
replicas: 3 #设置Pod的具体数量
selector: #通过selector来匹配相应的Pod的label
matchLabels:
app: nginx-deployment
template: #设置Pod的模板
metadata:
labels:
app: nginx-deployment
spec:
containers:
- name: nginx-deployment
image: 192.168.56.132:5000/nginx:1.13
ports:
- containerPort: 80
创建带记录点方式的deployment，这条命令将开始记录所有对Depolyment的操作
[root@server1 rc]# kubectl create -f k8s_deploy.yml --record
deployment.apps/nginx-deployment created
查询创建的Depolyment
[root@server1 rc]# kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
nginx-deployment 3/3 3 3 5m38s
查询当前所在的记录点
[root@server1 rc]# kubectl rollout history deployment nginx-deployment
deployment.apps/nginx-deployment
REVISION CHANGE-CAUSE
1 kubectl create --filename=k8s_deploy.yml --record=true
升级/更新这个Depolyment，这里我们更新images
[root@server1 rc]# vim k8s_deploy.yml
apiVersion: apps/v1
kind: Deployment
metadata: #设置rc的元数据
name: nginx-deployment
spec: #设置rc的具体规格
replicas: 3 #设置Pod的具体数量
selector: #通过selector来匹配相应的Pod的label
matchLabels:
app: nginx-deployment
template: #设置Pod的模板
metadata:
labels:
app: nginx-deployment
spec:
containers:
- name: nginx-deployment
image: docker.io/pseudecoder/centos-nginx #更换源Images
ports:
- containerPort: 80
升级nginx
[root@server1 rc]# kubectl apply -f k8s_deploy.yml
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
deployment.apps/nginx-deployment configured
看下升级前后pod的变化
升级前：
[root@server1 rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-deployment-5dcf8b988c-2php9 1/1 Running 0 12m
nginx-deployment-5dcf8b988c-8nplm 1/1 Running 0 12m
nginx-deployment-5dcf8b988c-hxb24 1/1 Running 0 12m
升级后：
[root@server1 rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-deployment-f9548676b-dwwzb 1/1 Running 0 37s
nginx-deployment-f9548676b-wsqx9 1/1 Running 0 87s
nginx-deployment-f9548676b-zgtdp 1/1 Running 0 59s
pod的名字已经变了
如果发现更改有问题，可以进行回滚操作
[root@server1 rc]# kubectl rollout history deployment nginx-deployment
deployment.apps/nginx-deployment
REVISION CHANGE-CAUSE
1 kubectl create --filename=k8s_deploy.yml --record=true
2 kubectl create --filename=k8s_deploy.yml --record=true
回退到版本1
[root@server1 rc]# kubectl rollout undo deployment nginx-deployment --to-revision=1
deployment.apps/nginx-deployment rolled back
再次查看nginx pod，已经回到升级前
[root@server1 rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-deployment-5dcf8b988c-88w2t 1/1 Running 0 2m48s
nginx-deployment-5dcf8b988c-ctgbk 1/1 Running 0 2m46s
nginx-deployment-5dcf8b988c-vpg89 1/1 Running 0 2m30s
创建service
Kubernetes中一个应用服务会有一个或多个实例（Pod,Pod可以通过rs进行多复本的建立）,每个实例（Pod）的IP地址由网络插件动态随机分配（Pod重启后IP地址会改变）。为屏蔽这些后端实例的动态变化和对多实例的负载均衡，引入了Service这个资源对象
创建service目录
[root@server1 k8s_yaml]# mkdir service
[root@server1 k8s_yaml]# cd service
[root@server1 service]# vim k8s_service.yml
apiVersion: v1
kind: Service
metadata:
name: nginx-service
labels:
run: nginx
spec:
selector:
app: nginx
ports:
- port: 80
假如有3个app: nginx Pod运行在3个不同的Node中，那么此时客户端访问任意一个Node的30001端口都能访问到这个nginx服务。
删掉之前创建的deployment
[root@server1 service]# kubectl delete deployment nginx-deployment
deployment.apps "nginx-deployment" deleted
创建nginx service
[root@server1 service]# kubectl apply -f k8s_service.yml
service/nginx-service created
查看service信息
[root@server1 service]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 34d
nginx-service NodePort 10.103.179.58 <none> 80:30001/TCP 2m16s
创建一个nginx rc服务
[root@server1 rc]# kubectl create -f k8s_rc.yml
replicationcontroller/nginx created
为nginx创建SVC
（1）使用命令行方式创建
[root@server1 service]# kubectl expose rc nginx --target-port=80 --type=NodePort --port=80
service/nginx exposed
[root@server1 service]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 39d
nginx NodePort 10.102.191.188 <none> 80:30650/TCP 22s
（2）使用yml文件创建svc
[root@server1 service]# kubectl delete svc nginx
service "nginx" deleted
[root@server1 service]# vim k8s_service.yml
apiVersion: v1
kind: Service
metadata:
name: nginx-service
labels:
run: nginx
spec:
selector:
app: nginx #service通过selector和pod建立关联
ports:
- port: 80 #设置Service对外提供服务的端口
nodePort: 30001 #此宿主机端口可不指定,系统将自动从3万~65535分配
type: NodePort
[root@server1 service]# kubectl apply -f k8s_service.yml
service/nginx-service created
[root@server1 service]# kubectl get svc -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 39d <none>
nginx-service NodePort 10.105.32.89 <none> 80:30001/TCP 29s app=nginx
检查svc是否正确的识别到了已存在的pod
[root@server1 service]# kubectl get ep nginx
NAME ENDPOINTS AGE
nginx 10.244.1.10:80,10.244.1.11:80,10.244.2.22:80 13m
什么是endpoint?
endpoint可以简单理解成路由导向的终点，因为 svc 是将许多个动态的 ip 映射成一个静态的 ip。那么就可以把这些动态的 pod ip 称为 svc 的endpoint。
通过svc访问各nginx pod
[root@server1 service]# kubectl exec nginx-lrpdz -- curl http://10.101.218.89:80
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0<!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>
100 612 100 612 0 0 7728 0 --:--:-- --:--:-- --:--:-- 7746
这里我们采用nodeport的方式创建service可以使容器内的应用暴露出来，外部用户可以直接访问容器内部应用
通过访问宿主机IP+nodeport端口访问容器内部应用
这样就达到了外部访问容器内部的需求。
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