kubernetes Pod控制器 Deployment
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Kubernetes
Deployment简述
Deployment 为 Pod 和 ReplicaSet 提供了一个声明式定义(declarative)方法，用来替代以前的ReplicationController 来方便的管理应用。典型的应用场景包括：
定义Deployment来创建Pod和ReplicaSet
滚动升级和回滚应用
扩容和缩容
暂停和继续Deployment
您只需要在 Deployment 中描述您想要的目标状态是什么，Deployment controller 就会帮您将 Pod 和ReplicaSet 的实际状态改变到您的目标状态。您可以定义一个全新的 Deployment 来创建 ReplicaSet 或者删除已有的 Deployment 并创建一个新的来替换。
Deployment用例:
使用Deployment来创建ReplicaSet。ReplicaSet在后台创建pod。
检查启动状态，看它是成功还是失败。
通过更新Deployment的PodTemplateSpec字段来声明Pod的新状态
创建一个新的ReplicaSet，Deployment会按照控制的速率将pod从旧的ReplicaSet移动到新的ReplicaSet中。
如果当前状态不稳定，回滚到之前的Deployment revision。每次回滚都会更新Deployment的revision。
扩容Deployment以满足更高的负载。
暂停Deployment来应用PodTemplateSpec的多个修复，然后恢复上线。
根据Deployment 的状态判断上线是否hang住了。
清除旧的不必要的 ReplicaSet。
image.png
总结
用户通过 kubectl 创建 Deployment。
Deployment 创建 ReplicaSet。
ReplicaSet 创建 Pod。
对象的命名方式是：子对象的名字 = 父对象名字 + 随机字符串或数字。
image.jpg
Deployment资源清单
Deployment 也需要apiVersion，kind和metadata这些配置项
[root@k8s-master01 learning]# kubectl explain deploymentKIND: Deployment VERSION: extensions/v1beta1 DESCRIPTION: DEPRECATED - This group version of Deployment is deprecated by apps/v1beta2/Deployment. See the release notes for more information. Deployment enables declarative updates for Pods and ReplicaSets. FIELDS: apiVersion <string> APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#resources kind <string> Kind is a string value representing the REST resource this object represents. Servers may infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds metadata <Object> Standard object metadata. spec <Object> Specification of the desired behavior of the Deployment. status <Object> Most recently observed status of the Deployment.
spec字段参数
Replicas: 可选字段，指定期望的pod数量，默认是1
Selector: 可选字段, 用来指定 label selector ，圈定Deployment管理的pod范围
如果被指定: 必须匹配 .spec.template.metadata.labels，否则它将被API拒绝
如果未指定: .spec.selector.matchLabels 默认是.spec.template.metadata.labels
在Pod的template跟.spec.template不同或者数量超过了.spec.replicas规定的数量的情况下，Deployment会杀掉label跟selector不同的Pod
Template: 必须字段, 划分Pod的范围，Deployment中的pod template必须指定适当的label
strategy: 可选字段, 指定新的Pod替换旧的Pod的策略,可以是"Recreate"或者是 "RollingUpdate"。默认值是"RollingUpdate"
maxSurge: 可选字段，用来指定可以超过期望的Pod数量的最大个数,默认是25%,之前是1
maxUnavailable: 可选字段，用来指定不可用Pod数量的最大个数,默认是25%,之前是1
Recreate: 重建式更新，就是删一个建一个
rollingUpdate：滚动更新，简单定义 更新期间pod最多有几个等
revisionHistoryLimit: 可选字段，指定保留的旧的ReplicaSet数量,默认是10
rollbackTo: 可选字段，设置该参数将触发回退操作，每次回退完成后，该值就会被清除
revision: 可选字段，用来指定回退到的revision。默认是0,意味着回退到上一个revision。
progressDeadlineSeconds: 可选字段，用来指定在系统报告Deployment的failed progressing——表现为resource的状态中type=Progressing、Status=False、 Reason=ProgressDeadlineExceeded前可以等待的Deployment进行的秒数
minReadySeconds: 可选字段，指定没有任何容器crash的Pod并被认为是可用状态的最小秒数。默认是0（Pod在ready后就会被认为是可用状态）
paused: 可选字段，用来指定暂停和恢复Deployment。Paused和没有paused的Deployment之间的唯一区别就是，所有对paused deployment中的PodTemplateSpec的修改都不会触发新的rollout。Deployment被创建之后默认是非paused。
定义资源清单
[root@k8s-master01 learning]# vim deployment-demo.yaml apiVersion: apps/v1beta2 kind: Deployment metadata: name: deploy-demo namespace: learning spec: replicas: 2 selector: matchLabels: app: deploy-demo tag: learn-deploy strategy: rollingUpdate: maxSurge: 1 maxUnavailable: 0 type: RollingUpdate template: metadata: labels: app: deploy-demo tag: learn-deploy spec: containers: - name: deploy-demo image: nginx:1.10 imagePullPolicy: IfNotPresent ports: - name: http containerPort: 80 livenessProbe: failureThreshold: 3 httpGet: path: /index.html port: 80 scheme: HTTP initialDelaySeconds: 20 periodSeconds: 2 successThreshold: 1 timeoutSeconds: 1 readinessProbe: failureThreshold: 3 httpGet: path: /index.html port: 80 scheme: HTTP initialDelaySeconds: 20 periodSeconds: 2 successThreshold: 2 timeoutSeconds: 1
常用命令
查看资源
[root@k8s-master01 learning]# kubectl apply -f deployment-demo.yaml deployment.apps/deploy-demo created# 查看创建的deployments[root@k8s-master01 learning]# kubectl get deployments. -n learning NAME READY UP-TO-DATE AVAILABLE AGE
deploy-demo 2/2 2 2 2m4s# 查看deployment管理的replicaset[root@k8s-master01 learning]# kubectl get replicasets. -n learning NAME DESIRED CURRENT READY AGE
deploy-demo-5c64bd4959 2 2 2 2m11s# 查看replicaset管理的pod[root@k8s-master01 learning]# kubectl get pods -n learning NAME READY STATUS RESTARTS AGE
deploy-demo-5c64bd4959-5ltxf 1/1 Running 0 2m18s
deploy-demo-5c64bd4959-b6pth 1/1 Running 0 2m18s# 查看详细信息 [root@k8s-master01 learning]# kubectl describe deployments. -n learning deploy-demo Name: deploy-demoNamespace: learningCreationTimestamp: Mon, 28 Jan 2019 20:01:31 +0800Labels: <none>Annotations: deployment.kubernetes.io/revision: 1
kubectl.kubernetes.io/last-applied-configuration:
{"apiVersion":"apps/v1beta2","kind":"Deployment","metadata":{"annotations":{},"name":"deploy-demo","namespace":"learning"},"spec":{"replic...
Selector: app=deploy-demo,tag=learn-deploy
Replicas: 2 desired | 2 updated | 2 total | 2 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 0 max unavailable, 1 max surge
Pod Template:
Labels: app=deploy-demo
tag=learn-deploy
Containers:
deploy-demo:
Image: nginx:1.10
Port: 80/TCP
Host Port: 0/TCP
Liveness: http-get http://:80/index.html delay=20s timeout=1s period=2s #success=1 #failure=3
Readiness: http-get http://:80/index.html delay=20s timeout=1s period=2s #success=2 #failure=3
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: deploy-demo-5c64bd4959 (2/2 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 6m46s deployment-controller Scaled up replica set deploy-demo-5c64bd4959 to 2修改Pod数量
1. 修改配置文件,然后apply -f2. edit在线编辑3. 打补丁的方式
[root@k8s-master01 learning]# kubectl patch deployments. -n learning deploy-demo -p '{"spec":{"replicas":5}}'deployment.extensions/deploy-demo patched
[root@k8s-master01 learning]# kubectl get pods -n learning NAME READY STATUS RESTARTS AGE
deploy-demo-5c64bd4959-89spz 1/1 Running 0 3m33s
deploy-demo-5c64bd4959-hxg6b 1/1 Running 0 33s
deploy-demo-5c64bd4959-k7dnr 1/1 Running 0 3m9s
deploy-demo-5c64bd4959-pz2wb 1/1 Running 0 33s
deploy-demo-5c64bd4959-vl55c 1/1 Running 0 33s升级版本
1. 修改配置文件,然后apply -f2. edit在线编辑3. sed image修改 [root@k8s-master01 ~]# kubectl set image deployment deploy-demo deploy-demo=nginx:1.13 -n learning deployment.extensions/deploy-demo image updated [root@k8s-master01 ~]# kubectl get deployments. -n learning -o wideNAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR deploy-demo 5/5 3 5 41m deploy-demo nginx:1.13 app=deploy-demo,tag=learn-deploy# 升级版本 查看升级过程# 修改配置文件升级,观察升级过程,可以看出是先增加一个,当新增加的状态为running后才进行删除一个,删除后在增加,直到升级完成[root@k8s-master01 learning]# sed -i 's/ image: nginx:1.10/ image: nginx:1.11/g' deployment-demo.yaml [root@k8s-master01 learning]# kubectl apply -f deployment-demo.yaml & kubectl get pods -n learning -w -o wide -l app=deploy-demoNAME READY STATUS RESTARTS AGE deploy-demo-5c64bd4959-48frt 1/1 Running 0 45s deploy-demo-5c64bd4959-rprrl 1/1 Running 0 45s deployment.apps/deploy-demo configured deploy-demo-5d56cdb4cd-llf4m 0/1 Pending 0 0s deploy-demo-5d56cdb4cd-llf4m 0/1 Pending 0 0s deploy-demo-5d56cdb4cd-llf4m 0/1 ContainerCreating 0 0s deploy-demo-5d56cdb4cd-llf4m 0/1 Running 0 2s deploy-demo-5d56cdb4cd-llf4m 1/1 Running 0 23s deploy-demo-5c64bd4959-48frt 1/1 Terminating 0deploy-demo-5d56cdb4cd-trtfz 0/1 Pending 0 0s deploy-demo-5d56cdb4cd-trtfz 0/1 Pending 0 0s deploy-demo-5d56cdb4cd-trtfz 0/1 ContainerCreating 0 0s deploy-demo-5c64bd4959-48frt 0/1 Terminating 0 68s deploy-demo-5d56cdb4cd-trtfz 0/1 Running 0 1s deploy-demo-5c64bd4959-48frt 0/1 Terminating 0 69s deploy-demo-5c64bd4959-48frt 0/1 Terminating 0 69s deploy-demo-5c64bd4959-48frt 0/1 Terminating 0 73s deploy-demo-5c64bd4959-48frt 0/1 Terminating 0 73s deploy-demo-5d56cdb4cd-trtfz 1/1 Running 0 24s deploy-demo-5c64bd4959-rprrl 1/1 Terminating 0 92s deploy-demo-5c64bd4959-rprrl 0/1 Terminating 0 93s deploy-demo-5c64bd4959-rprrl 0/1 Terminating 0 101s deploy-demo-5c64bd4959-rprrl 0/1 Terminating 0 101s# 查看升级后的rs[root@k8s-master01 learning]# kubectl get rs -n learning -o wideNAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR deploy-demo-5c64bd4959 0 0 0 5m7s deploy-demo nginx:1.10 app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy deploy-demo-5d56cdb4cd 2 2 2 4m22s deploy-demo nginx:1.11 app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy
回滚到上个版本
只要 Deployment 的 rollout 被触发就会创建一个 revision。也就是说当且仅当 Deployment 的 Pod template（如.spec.template）被更改，例如更新template 中的 label 和容器镜像时，就会创建出一个新的 revision
# 查看最近的历史版本[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo deployment.extensions/deploy-demo REVISION CHANGE-CAUSE1 <none>2 <none>3 <none># 查看历史版本信息[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo --revision=2deployment.extensions/deploy-demo with revision #2Pod Template: Labels: app=deploy-demo pod-template-hash=5d56cdb4cd tag=learn-deploy Containers: deploy-demo: Image: nginx:1.11 Port: 80/TCP Host Port: 0/TCP Liveness: http-get http://:80/index.html delay=20s timeout=1s period=2s #success=1 #failure=3 Readiness: http-get http://:80/index.html delay=20s timeout=1s period=2s #success=2 #failure=3 Environment: <none> Mounts: <none> Volumes: <none># 回退历史版本，默认是回退到上一个版本[root@k8s-master01 learning]# kubectl rollout undo deployment -n learning deploy-demo deployment.extensions/deploy-demo rolled back# 第二个版本已经不存在了,已经成了最新的第四个版本[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo deployment.extensions/deploy-demo REVISION CHANGE-CAUSE1 <none>3 <none>4 <none># 通过这里可以看到已经回退到了1.11版本[root@k8s-master01 learning]# kubectl get rs -n learning -o wide NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR deploy-demo-57cdd6d965 0 0 0 2m19s deploy-demo nginx:1.12 app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy deploy-demo-5c64bd4959 0 0 0 10m deploy-demo nginx:1.10 app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy deploy-demo-5d56cdb4cd 2 2 2 9m44s deploy-demo nginx:1.11 app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy
回滚到指定版本
# 查看现存的版本[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo deployment.extensions/deploy-demo REVISION CHANGE-CAUSE1 <none>3 <none>4 <none># 回滚到第一个版本[root@k8s-master01 learning]# kubectl rollout undo deployment -n learning deploy-demo --to-revision=1deployment.extensions/deploy-demo rolled back# 可以看到第一个版本已经变成了现在的第五个版本[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo deployment.extensions/deploy-demo REVISION CHANGE-CAUSE3 <none>4 <none>5 <none> [root@k8s-master01 learning]# kubectl get rs -n learning -o wideNAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR deploy-demo-57cdd6d965 0 0 0 5m31s deploy-demo nginx:1.12 app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy deploy-demo-5c64bd4959 2 2 2 13m deploy-demo nginx:1.10 app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy deploy-demo-5d56cdb4cd 0 0 0 12m deploy-demo nginx:1.11 app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy
暂停和恢复
你可以在出发一次或多次更新前暂停一个Deployment，然后再恢复它。这样你就能多次暂停和恢复Deployment，在此期间进行一些修复工作，而不会出发不必要的rollout
1. 更新nginx到1.13版本，并配置暂停deployment [root@k8s-master01 learning]# kubectl set image deployment deploy-demo deploy-demo=nginx:1.13 -n learning && kubectl rollout pause deployment deploy-demo -n learning deployment.extensions/deploy-demo image updated deployment.extensions/deploy-demo paused2. 监控更新的过程，因为pause命令,只是新增了一个资源，并没有去删除旧资源 [root@k8s-master01 learning]# kubectl get pods -n learning NAME READY STATUS RESTARTS AGE deploy-demo-5c64bd4959-rm99c 1/1 Running 0 2m46s deploy-demo-5c64bd4959-x7ctm 1/1 Running 0 2m23s deploy-demo-6b876f975b-6kq4d 1/1 Running 0 83s #新加的# 在rs里面可以清楚的看到[root@k8s-master01 learning]# kubectl get rs -l app=deploy-demo -n learning -o wide -n learning NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR deploy-demo-57cdd6d965 0 0 0 44m deploy-demo nginx:1.12 app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy deploy-demo-5c64bd4959 2 2 2 52m deploy-demo nginx:1.10 app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy deploy-demo-5d56cdb4cd 0 0 0 51m deploy-demo nginx:1.11 app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy deploy-demo-6b876f975b 1 1 1 11m deploy-demo nginx:1.13 app=deploy-demo,pod-template-hash=6b876f975b,tag=learn-deploy3. 确保更新的pod没问题了，继续更新 [root@k8s-master01 learning]# kubectl rollout resume deployment deploy-demo -n learning deployment.extensions/deploy-demo resumed4. 更新后结果 [root@k8s-master01 learning]# kubectl get pods -n learning NAME READY STATUS RESTARTS AGE deploy-demo-6b876f975b-6kq4d 1/1 Running 0 4m17s deploy-demo-6b876f975b-szw4s 1/1 Running 0 53s# 可以看到 都已经到了1.13版本了[root@k8s-master01 learning]# kubectl get rs -l app=deploy-demo -n learning -o wide -n learning NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR deploy-demo-57cdd6d965 0 0 0 46m deploy-demo nginx:1.12 app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy deploy-demo-5c64bd4959 0 0 0 54m deploy-demo nginx:1.10 app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy deploy-demo-5d56cdb4cd 0 0 0 53m deploy-demo nginx:1.11 app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy deploy-demo-6b876f975b 2 2 2 13m deploy-demo nginx:1.13 app=deploy-demo,pod-template-hash=6b876f975b,tag=learn-deploy
作者：baiyongjie
链接：https://www.jianshu.com/p/c0f5b6d70af5
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