一 为什么使用控制器
pod控制器
作用：1.pod类型资源删除，不会重建
2.控制器可以帮助用户监控，并保证节点上运行定义好的pod副本数
3.pod超过或低于用户期望，控制器会创建、删除pod副本数量
控制器类型：
- RS控制器:按照用户期望的副本数量，创建pod, 用户写yaml，定义RS控制器，去定义pod模板，pod按照这个模板去运行
- deployment控制器
- DaemonSet
二 详解rs控制器原理
RS控制器原理：副本数保障、标签选择器
2.1 创建RS控制器
bash
[root@k8s-master ~]# cat rs-nginx.yml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: nginx-rs
namespace: lxy
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
name: nginx-pod
labels:
app: nginx
spec:
containers:
- name: nginx-containers
image: nginx:1.14.0
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
bash
kubectl create -f rs-nginx.yml
kubectl -n lxy get rs -owide
kubectl -n lxy get pods -l app=nginx -owide
2.2 删除Pod,查看rs如何保障副本数
删掉一个pod,但是会马上创建一个
2.3 pod和rs关系
kubectl -n lxy describe rs nginx-rs
2.4 修改RS控制器
1.对yaml修改副本数，修改资源配置：kubectl apply -f rs-nginx.yml
2.编辑RS控制器：kubectl -n lxy edit rs nginx-rs (有些是无法修改)
三 Deploy控制器与弹性扩缩容
kubectl scale --help
kubectl -n lxy scale --replicas=X rs nginx-rs
bash
root@k8s-master ~]# kubectl -n lxy get pods -owide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-2 1/1 Running 2 5d17h 10.2.20.143 k8s-node13 <none> <none>
nginx-rs-2zhzn 1/1 Running 0 7h25m 10.2.231.96 k8s-node12 <none> <none>
nginx-rs-7p64w 1/1 Running 0 7h25m 10.2.20.146 k8s-node13 <none> <none>
[root@k8s-master ~]# kubectl -n lxy scale --replicas=4 rs nginx-rs
replicaset.apps/nginx-rs scaled
[root@k8s-master ~]# kubectl -n lxy get pods -owide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-2 1/1 Running 2 5d17h 10.2.20.143 k8s-node13 <none> <none>
nginx-rs-2zhzn 1/1 Running 0 7h34m 10.2.231.96 k8s-node12 <none> <none>
nginx-rs-7p64w 1/1 Running 0 7h34m 10.2.20.146 k8s-node13 <none> <none>
nginx-rs-8jf8p 1/1 Running 0 4s 10.2.20.150 k8s-node13 <none> <none>
nginx-rs-k9dvr 1/1 Running 0 4s 10.2.20.149 k8s-node13 <none> <none>
[root@k8s-master ~]# kubectl -n lxy scale --replicas=2 rs nginx-rs
replicaset.apps/nginx-rs scaled
[root@k8s-master ~]# kubectl -n lxy get pods -owide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-2 1/1 Running 2 5d17h 10.2.20.143 k8s-node13 <none> <none>
nginx-rs-2zhzn 1/1 Running 0 7h34m 10.2.231.96 k8s-node12 <none> <none>
nginx-rs-7p64w 1/1 Running 0 7h34m 10.2.20.146 k8s-node13 <none> <none>
nginx-rs-8jf8p 0/1 Terminating 0 12s 10.2.20.150 k8s-node13 <none> <none>
nginx-rs-k9dvr 0/1 Terminating 0 12s 10.2.20.149 k8s-node13 <none> <none>获取当前rs资源的Yaml: kubectl -n lxy get rs nginx-rs -oyaml
四 Deploy与rs原理
kubectl -n kube-system get deploy coredns -o yaml
bash
[root@k8s-master ~]# cat deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
namespace: lxy
spec:
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.14.2
ports:
- containerPort: 80
resources:
limits:
cpu: 100m
memory: 200Mi
requests:
cpu: 100m
memory: 200Mi
bash
[root@k8s-master ~]# kubectl get deployments.apps -owide -n lxy
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
nginx-deployment 2/2 2 2 110s nginx nginx:1.14.2 app=nginx
[root@k8s-master ~]# kubectl get rs -n lxy
NAME DESIRED CURRENT READY AGE
nginx-deployment-58df99679c 2 2 2 115s
nginx-rs 2 2 2 8h
[root@k8s-master ~]# kubectl get pods -l app=nginx -n lxy
NAME READY STATUS RESTARTS AGE
nginx-deployment-58df99679c-tqxps 1/1 Running 0 119s
nginx-deployment-58df99679c-zhvcj 1/1 Running 0 119s
nginx-rs-2zhzn 1/1 Running 0 8h
nginx-rs-7p64w 1/1 Running 0 8hpod和rs和deployment关系
kubectl describe pods nginx-deployment-AAA-XX
kubectl describe rs nginx-deployment-AAA
五 滚动更新详解原理
蓝绿更新：起一个新的Pod+删除一个旧pod,接替就是滚动更新
六 更新镜像版本其他玩法
1.kubectl edit rs资源
2. kubectl scale --replicas=xxx rs rs名
3.edit 编辑deployment资源
4.deployment提供了 修改镜像版本 参数 kubectl set image
七 版本更新与回滚详解
因为rs控制器还在，数据还在 kubectl get rs -owide -w / kubectl get rs -owide -n lxy
bash
#查看版本是1.14.2
kubectl get deployments.apps -n lxy -owide
#修改版本为1.14.1
kubectl -n lxy set image deployment nginx-deployment nginx=nginx:1.14.1
#这时候在查看是1.14.1，使用命令回归后，恢复成1.14.2
kubectl rollout undo deployment nginx-deployment -n lxy八 详解版本记录号玩法
1.kubectl create -f last-deploy-nginx.yml --record ----创建的时候，记录版本号
2.查看deploy版本信息
kubectl rollout history deployment last-nginx-deployment
kubectl rollout status deployment last-nginx-deployment
kubectl rollout history deployment last-nginx-deployment --revision=2（指定那个版本的镜像信息）
3.指定回滚到哪个版本
kubectl rollout undo deployment last-nginx-deployment --to-revision=1
九.DaemonSet 每个节点上运行一个Pod的副本
经典用法：
- 每个节点运行集群的守护进程
- 每个节点上运行日志收集守护进程 zabbix-agent /elk efk
- 每个节点上运行监控守护进程
1.查看系统网络插件部署方式是Daemonset
2.根据标签选择器来保证每个node部署一个Pod的calico网络插件
kubectl -n kube-system get pod -owide --show-labels | grep calico
kubectl -n kube-system get ds --show-labels
3.daemonset 和 node 的关系，Node的亲和性
kubectl -n kube-system get ds calico-node -oyaml
4.可以看到nodeSelector中的信息，kubectl get nodes -owide --show-labels
可以看到labels 中含有该信息，是为node的亲和性
