Deployment

https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

You describe a desired state in a Deployment, and the Deployment Controller changes the actual state to the desired state at a controlled rate. You can define Deployments to create new ReplicaSets, or to remove existing Deployments and adopt all their resources with new Deployments.

Create Deployment

Imperatively

$ kubectl create deployment web --image=nginx:1.14.2
$ kubectl scale deployment web --replicas=5

Declaratively

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: web
  name: web
spec:
  replicas: 1
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - image: nginx:1.14.2
        name: nginx

ReplicaSets and Failures

Pod Failures

Rescheduled and a new Pod is created

Node Failures

• Transient failure

• permanent failure

kube-contorller-manager 有一个timeout的设置

pod-eviction-timeout （默认5min） Node如果失联超过5分钟，就会触发在其上运行的Pod的终止和重建。

Update Deployment

Update Strategy

https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#strategy

RollingUpdate (Default)

A new ReplicaSet starts scaling up and the old ReplicaSet starts scaling down

创建一个deployment

$ kubectl create deployment web --image=nginx:1.14 --replicas 3

Update image

$ kubectl set image deployment/web nginx=nginx:1.14.2

Rolling Back

查看rollout history

$ kubectl rollout history deployment web

查看revision history

$ kubectl rollout history deployment web --revision=1

rollout

$ kubectl rollout undo deployment web --to-revision=1

Recreate

Terminates all pods in the current ReplicaSet, set prior to scaling up the new ReplicaSet

(used when applications don’t support running different versions concurrently)

Restarting a Deployment

$ kubectl rollout restart deployment hello-world

Scale Deployment

$ kubectl scale deployment web --replicas 5