deployment
我们已经知道k8s是通过各种controller来管理pod的生命周期。为了满足不同业务场景，k8s开发了Deployment、ReplicaSet、DaemonSet、StatefuleSet、Job 等多种 Controller。我们首先学习最常用的 Deployment。
运行一个deployment
[root@ken ~]# kubectl run httpd-ken1--generator=run-pod/v1 --image=httpd --replicas=2
下面详细分析 Kubernetes 都做了些什么工作。
[root@ken ~]# kubectl get deployment NAME READY UP-TO-DATE AVAILABLE AGE httpd-ken 2/2 2 2 35mkubectl get deplouyment命令可以查看 httpd-ken 的状态，输出显示两个副本正常运行。
接下来我们用 kubectl describe deployment 了解更详细的信息。
[root@ken ~]# kubectl describe deployment httpd-ken Name: httpd-ken Namespace: default CreationTimestamp: Tue, 29 Jan 2019 15:27:40 +0800 Labels: run=httpd-ken Annotations: deployment.kubernetes.io/revision: 1 Selector: run=httpd-ken Replicas: 2 desired | 2 updated | 2 total | 2 available | 0 unavailable StrategyType: RollingUpdate MinReadySeconds: 0 RollingUpdateStrategy: 25% max unavailable, 25% max surge Pod Template: Labels: run=httpd-ken Containers: httpd-ken: Image: httpd Port: <none> Host Port: <none> Environment: <none> Mounts: <none> Volumes: <none> Conditions: Type Status Reason ---- ------ ------ Available True MinimumReplicasAvailable Progressing True NewReplicaSetAvailable OldReplicaSets: <none> NewReplicaSet: httpd-ken-5c949b96f (2/2 replicas created) Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal ScalingReplicaSet 18m deployment-controller Scaled up replica set httpd-ken-5c949b96f to 2
大部分内容都是自解释的，我们重点看最下面部分。这里告诉我们创建了一个 ReplicaSet httpd-ken-5c949b96，Events 是 Deployment 的日志，记录了 ReplicaSet 的启动过程。
通过上面的分析，也验证了 Deployment 通过 ReplicaSet 来管理 Pod 的事实。接着我们将注意力切换到 httpd-ken-5c949b96，执行 kubectl describe replicaset：
