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Deployment YAML方式创建Nginx服务

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08/04
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replication controller

Replication Controller为Kubernetes的一个核心内容，应用托管到Kubernetes之后，需要保证应用能够持续的运行，Replication Controller就是这个保证的key，主要的功能如下：

1.确保pod数量：它会确保Kubernetes中有指定数量的Pod在运行。如果少于指定数量的pod，Replication Controller会创建新的，反之则会删除掉多余的以保证Pod数量不变。
2.确保pod健康：当pod不健康，运行出错或者无法提供服务时，Replication Controller也会杀死不健康的pod，重新创建新的。
3.弹性伸缩 ：在业务高峰或者低峰期的时候，可以通过Replication Controller动态的调整pod的数量来提高资源的利用率。同时，配置相应的监控功能（Hroizontal Pod Autoscaler），会定时自动从监控平台获取Replication Controller关联pod的整体资源使用情况，做到自动伸缩。
4.滚动升级：滚动升级为一种平滑的升级方式，通过逐步替换的策略，保证整体系统的稳定，在初始化升级的时候就可以及时发现和解决问题，避免问题不断扩大。

Deployment

Deployment同样为Kubernetes的一个核心内容，主要职责同样是为了保证pod的数量和健康，90%的功能与Replication Controller完全一样，可以看做新一代的Replication Controller。但是，它又具备了Replication Controller之外的新特性：

1.Replication Controller全部功能：Deployment继承了上面描述的Replication Controller全部功能。
2.事件和状态查看：可以查看Deployment的升级详细进度和状态。
3.回滚：当升级pod镜像或者相关参数的时候发现问题，可以使用回滚操作回滚到上一个稳定的版本或者指定的版本。
4.版本记录: 每一次对Deployment的操作，都能保存下来，给予后续可能的回滚使用。
5.暂停和启动：对于每一次升级，都能够随时暂停和启动。
6.多种升级方案：Recreate：删除所有已存在的pod,重新创建新的; RollingUpdate：滚动升级，逐步替换的策略，同时滚动升级时，支持更多的附加参数，例如设置最大不可用pod数量，最小升级间隔时间等等。


1、创建deployment
[root@linux-node1 ~]# vim nginx-deployment.yaml#使用yaml的方式进行创建应用
apiVersion: apps/v1#apiVersion是当前配置格式的版本
kind: Deployment#kind是要创建的资源类型，这里是Deploymnet
metadata:#metadata是该资源的元数据，name是必须的元数据项
name: nginx-deployment
labels:
app: nginx
spec:#spec部分是该Deployment的规则说明
replicas: 3 #relicas指定副本数量，默认为1
selector:
matchLabels:
app: nginx
template:#template定义Pod的模板，这是配置的重要部分
metadata: #metadata定义Pod的元数据，至少要顶一个label，label的key和value可以任意指定
labels:
app: nginx
spec:#spec描述的是Pod的规则，此部分定义pod中每一个容器的属性，name和image是必需的
containers:
- name: nginx
image: nginx:1.13.12
ports:
- containerPort: 80[root@linux-node1 ~]# kubectl create -f nginx-deployment.yaml #创建nginx-deployment应用
deployment.apps "nginx-deployment" created2、查看deployment[root@linux-node1 ~]# kubectl get deployment
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
net-test 2 2 2 2 32m
nginx-deployment 3 3 3 0 10s[root@linux-node1 ~]# kubectl describe deployment nginx-deployment #查看deployment详情
Name: nginx-deployment
Namespace: default
CreationTimestamp: Thu, 16 Aug 2018 16:13:37 +0800
Labels: app=nginx
Annotations: deployment.kubernetes.io/revision=1
Selector: app=nginx
Replicas: 3 desired | 3 updated | 3 total | 0 available | 3 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=nginx
Containers:
nginx:
Image: nginx:1.13.12
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available False MinimumReplicasUnavailable
Progressing True ReplicaSetUpdated
OldReplicaSets: <none>
NewReplicaSet: nginx-deployment-6c45fc49cb (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 1m deployment-controller Scaled up replica set nginx-deployment-6c45fc49cb to 3

3、查看Pod[root@linux-node1 ~]# kubectl get pod #查看pod在状态，正在创建中，此时应该正在拉取镜像
NAME READY STATUS RESTARTS AGE
net-test-5767cb94df-djt98 1/1 Running 0 22m
net-test-5767cb94df-hcwv7 1/1 Unknown 0 34m
net-test-5767cb94df-zb8m4 1/1 Running 0 34m
nginx-deployment-6c45fc49cb-dmc22 0/1 ContainerCreating 0 2m
nginx-deployment-6c45fc49cb-fd8xm 0/1 ContainerCreating 0 2m
nginx-deployment-6c45fc49cb-sc8sh 0/1 ContainerCreating 0 2m[root@linux-node1 ~]# kubectl describe pod nginx-deployment-6c45fc49cb-dmc22 #查看具体某个pod的状态信息[root@linux-node1 ~]# kubectl get pod -o wide#创建成功，状态为Running
NAME READY STATUS RESTARTS AGE IP NODE
net-test-5767cb94df-djt98 1/1 Running 0 24m 10.2.73.3 192.168.56.13
net-test-5767cb94df-hcwv7 1/1 Unknown 0 36m 10.2.10.2 192.168.56.12
net-test-5767cb94df-zb8m4 1/1 Running 0 36m 10.2.73.2 192.168.56.13
nginx-deployment-6c45fc49cb-dmc22 1/1 Running 0 4m 10.2.73.6 192.168.56.13
nginx-deployment-6c45fc49cb-fd8xm 1/1 Running 0 4m 10.2.73.4 192.168.56.13
nginx-deployment-6c45fc49cb-sc8sh 1/1 Running 0 4m 10.2.73.5 192.168.56.13Deployment、ReplicaSet、Pod 都已经就绪。如果要删除这些资源，执行 kubectl delete deployment nginx-deployment 或者 kubectl delete -f nginx-deployment.yaml。4、测试Pod访问
[root@linux-node1 ~]# curl --head http://10.2.73.6
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Thu, 16 Aug 2018 08:18:14 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Mon, 09 Apr 2018 16:01:09 GMT
Connection: keep-alive
ETag: "5acb8e45-264"
Accept-Ranges: bytes5、更新Deployment[root@linux-node1 ~]# kubectl set image deployment/nginx-deployment nginx=nginx:1.15.2 --record #nginx的版本升级，由1.13.2升级为1.15.2，记录需要加参数--record
deployment.apps "nginx-deployment" image updated[root@linux-node1 ~]# kubectl get deployment -o wide#查看更新后的deployment，可以看到当前4个副本，说明还在滚动升级中
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
net-test 2 2 2 2 39m net-test alpine run=net-test
nginx-deployment 3 4 1 3 6m nginx nginx:1.15.2 app=nginx6、查看更新历史
[root@linux-node1 ~]# kubectl rollout history deployment/nginx-deployment #查看更新历史记录
deployments "nginx-deployment"
REVISION CHANGE-CAUSE
1 <none>
2 kubectl set image deployment/nginx-deployment nginx=nginx:1.15.2 --record=true

7、查看具体某一个版本的升级历史[root@linux-node1 ~]# kubectl rollout history deployment/nginx-deployment --revision=1
deployments "nginx-deployment" with revision #1
Pod Template:
Labels: app=nginx
pod-template-hash=2701970576
Containers:
nginx:
Image: nginx:1.13.12
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>

8、查看更新后的Deployment，并进行访问[root@linux-node1 ~]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
net-test-5767cb94df-djt98 1/1 Running 0 30m 10.2.73.3 192.168.56.13
net-test-5767cb94df-hcwv7 1/1 Unknown 0 42m 10.2.10.2 192.168.56.12
net-test-5767cb94df-zb8m4 1/1 Running 0 42m 10.2.73.2 192.168.56.13
nginx-deployment-64749d4b59-djttr 1/1 Running 0 37s 10.2.73.8 192.168.56.13
nginx-deployment-64749d4b59-jp7fw 1/1 Running 0 3m 10.2.73.7 192.168.56.13
nginx-deployment-64749d4b59-q4fsn 1/1 Running 0 33s 10.2.73.9 192.168.56.13
[root@linux-node1 ~]# curl --head http://10.2.73.7
HTTP/1.1 200 OK
Server: nginx/1.15.2#版本已经升级为1.15.2
Date: Thu, 16 Aug 2018 08:24:09 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 24 Jul 2018 13:02:29 GMT
Connection: keep-alive
ETag: "5b572365-264"
Accept-Ranges: bytes9、快速回滚到上一个版本[root@linux-node1 ~]# kubectl rollout undo deployment/nginx-deployment #回滚上一个版本
deployment.apps "nginx-deployment" [root@linux-node1 ~]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
net-test-5767cb94df-djt98 1/1 Running 0 32m 10.2.73.3 192.168.56.13
net-test-5767cb94df-hcwv7 1/1 Unknown 0 43m 10.2.10.2 192.168.56.12
net-test-5767cb94df-zb8m4 1/1 Running 0 43m 10.2.73.2 192.168.56.13
nginx-deployment-6c45fc49cb-b9h84 1/1 Running 0 24s 10.2.73.11 192.168.56.13
nginx-deployment-6c45fc49cb-g4mrg 1/1 Running 0 26s 10.2.73.10 192.168.56.13
nginx-deployment-6c45fc49cb-k29kq 1/1 Running 0 21s 10.2.73.12 192.168.56.13
[root@linux-node1 ~]# curl --head http://10.2.73.10
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Thu, 16 Aug 2018 08:25:35 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Mon, 09 Apr 2018 16:01:09 GMT
Connection: keep-alive
ETag: "5acb8e45-264"
Accept-Ranges: bytes回滚完成，每一次更新或者回滚ip都会变化，所以需要通过vip进行访问，这就引入了service 10、使用service的vip进行访问应用[root@linux-node1 ~]# vim nginx-service.yaml#使用yaml方式创建service
kind: Service
apiVersion: v1
metadata:
name: nginx-service
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 80[root@linux-node1 ~]# kubectl create -f nginx-service.yaml #创建service
service "nginx-service" created[root@linux-node1 ~]# kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.1.0.1 <none> 443/TCP 4h
nginx-service ClusterIP 10.1.213.126 <none> 80/TCP 15s#这个就是vip[root@linux-node2 ~]# curl --head http://10.1.213.126#在node2节点上进行访问vip测试，在node1上无法访问是因为没有安装kube-proxy导致无法访问
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Thu, 16 Aug 2018 08:30:08 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Mon, 09 Apr 2018 16:01:09 GMT
Connection: keep-alive
ETag: "5acb8e45-264"
Accept-Ranges: bytes

11、扩容到5个节点[root@linux-node1 ~]# kubectl scale deployment nginx-deployment --replicas 5#对应用的副本数进行扩容，直接指定副本数为5
deployment.extensions "nginx-deployment" scaled[root@linux-node1 ~]# kubectl get pod#查看pod状态，可以看到已经增加到5个副本
NAME READY STATUS RESTARTS AGE
net-test-5767cb94df-djt98 1/1 Running 0 38m
net-test-5767cb94df-hcwv7 1/1 Unknown 0 50m
net-test-5767cb94df-zb8m4 1/1 Running 0 50m
nginx-deployment-6c45fc49cb-b9h84 1/1 Running 0 6m
nginx-deployment-6c45fc49cb-g4mrg 1/1 Running 0 7m
nginx-deployment-6c45fc49cb-k29kq 1/1 Running 0 6m
nginx-deployment-6c45fc49cb-n9qkx 1/1 Running 0 24s
nginx-deployment-6c45fc49cb-xpx9s 1/1 Running 0 24s

##扩容与减容

#kubectl get deployment ##获取deployment名称
  #kubectl scale deployment nginx-deployment --replicas=3 扩容到3个
  #kubectl scale deployment nginx-deployment --replicas=1 恢复成1个

##动态处理CPU资源

#kubectl autoscale deployment nginx-deployment --min=2 --max=10 --cpu-percent=80