Kubernetes 之 ReplicaSet

ReplicaSet 定义

ReplicaSet 是 Kubernetes 中的一种副本控制器，其主要作用是控制其管理的 Pod 的预设副本数量。它会持续监听这些 Pod 的运行状态，在Pod发生故障时执行重启策略，当 Pod 数量减少时会重新启动新的 Pod 副本。但官方推荐不要直接使用 ReplicaSet，推荐用Deployment 取而代之，Deployment 是 ReplicaSet 的父集。ReplicaSet 无法灵活性升级回退和扩缩容，但 Deployment 支持了这两大功能。

ReplicaSet 使用

apiVersion: apps/v1
kind: ReplicaSet
metadata:name: rs-nginxnamespace: defaultlabels:app: rs-nginx
spec:replicas: 2selector:matchLabels:app: pod-nginxtemplate:metadata:labels:app: pod-nginxspec:containers:- name: nginximage: docker.io/k8s-test:v1.0imagePullPolicy: IfNotPresentports:- containerPort: 80

root@k8s-master1:~# kubectl get pods -owide
NAME             READY   STATUS    RESTARTS   AGE   IP               NODE          NOMINATED NODE   READINESS GATES
rs-nginx-hljsk   1/1     Running   0          9s    10.244.194.120   k8s-worker1   <none>           <none>
rs-nginx-t85wr   1/1     Running   0          9s    10.244.126.22    k8s-worker2   <none>           <none>
root@k8s-master1:~# kubectl delete pods rs-nginx-hljsk
pod "rs-nginx-hljsk" deleted
root@k8s-master1:~# kubectl get pods -owide
NAME             READY   STATUS    RESTARTS   AGE   IP               NODE          NOMINATED NODE   READINESS GATES
rs-nginx-t85wr   1/1     Running   0          41s   10.244.126.22    k8s-worker2   <none>           <none>
rs-nginx-xsmdm   1/1     Running   0          4s    10.244.194.121   k8s-worker1   <none>           <none>
root@k8s-master1:~# kubectl get rs
NAME       DESIRED   CURRENT   READY   AGE
rs-nginx   2         2         2       64s