k8s-deployments

为了满足不同业务场景，k8s开发了Deployment、ReplicaSet、DaemonSet、StatefuleSet、Job 等多种 Controllerdeploymentsdeployments创建流程运行deployments查看deployments查看replicaset查看pod总结流程Deployments YAML创建yaml伸缩 Scale Up/Downk8s的Failo

mrlxxx

412人浏览 · 2020-07-14 18:30:57

mrlxxx · 2020-07-14 18:30:57 发布

为了满足不同业务场景，k8s开发了Deployment、ReplicaSet、DaemonSet、StatefuleSet、Job 等多种 Controller

deployments创建流程

运行deployments

运行一个deployments，镜像为nginx，副本数为2

kubectl run nginx --image=nginx --replicas=2

查看deployments

kubectl get deployments.apps nginx 
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   2/2     2            2           59s

使用describe查看

kubectl describe deployments.apps nginx
Name:                   nginx
Namespace:              default
CreationTimestamp:      Tue, 14 Jul 2020 17:46:01 +0800
Labels:                 run=nginx
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               run=nginx
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=nginx
  Containers:
   nginx:
    Image:        nginx
    Port:         <none>
    Host Port:    <none>
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   nginx-6db489d4b7 (2/2 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  100s  deployment-controller  Scaled up replica set nginx-6db489d4b7 to 2

这里告诉我们创建了一个 NewReplicaSet: nginx-6db489d4b7 (2/2 replicas created)，证明deoloyments是通过replicaset管理pod

查看replicaset

kubectl describe replicasets.apps  nginx-6db489d4b7

Name:           nginx-6db489d4b7
Namespace:      default
Selector:       pod-template-hash=6db489d4b7,run=nginx
Labels:         pod-template-hash=6db489d4b7
                run=nginx
Annotations:    deployment.kubernetes.io/desired-replicas: 2
                deployment.kubernetes.io/max-replicas: 3
                deployment.kubernetes.io/revision: 1
Controlled By:  Deployment/nginx
Replicas:       2 current / 2 desired
Pods Status:    2 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:  pod-template-hash=6db489d4b7
           run=nginx
  Containers:
   nginx:
    Image:        nginx
    Port:         <none>
    Host Port:    <none>
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Events:
  Type    Reason            Age    From                   Message
  ----    ------            ----   ----                   -------
  Normal  SuccessfulCreate  3m56s  replicaset-controller  Created pod: nginx-6db489d4b7-ghzd9
  Normal  SuccessfulCreate  3m56s  replicaset-controller  Created pod: nginx-6db489d4b7-7f6jb

Controlled By: Deployment/nginx 这里表示是replicasets是由deployment、nginx创建

查看pod

 kubectl get pod
NAME                     READY   STATUS    RESTARTS   AGE
nginx-6db489d4b7-7f6jb   1/1     Running   0          7m18s
nginx-6db489d4b7-ghzd9   1/1     Running   0          7m18s


kubectl describe pod nginx-6db489d4b7-7f6jb
Name:         nginx-6db489d4b7-7f6jb
Namespace:    default
Priority:     0
Node:         node1/192.168.1.20
Start Time:   Tue, 14 Jul 2020 17:46:01 +0800
Labels:       pod-template-hash=6db489d4b7
              run=nginx
Annotations:  <none>
Status:       Running
IP:           10.244.1.19
IPs:
  IP:           10.244.1.19
Controlled By:  ReplicaSet/nginx-6db489d4b7
Containers:
  nginx:
    Container ID:   docker://277b9ca9091bd2690c0524ef8a74696aa7bfad8f3f4ccf56062c221277c00894
    Image:          nginx
    Image ID:       docker-pullable://nginx@sha256:a93c8a0b0974c967aebe868a186e5c205f4d3bcb5423a56559f2f9599074bbcd
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Tue, 14 Jul 2020 17:46:12 +0800
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-hvq4p (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  default-token-hvq4p:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-hvq4p
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason     Age    From               Message
  ----    ------     ----   ----               -------
  Normal  Scheduled  7m26s  default-scheduler  Successfully assigned default/nginx-6db489d4b7-7f6jb to node1
  Normal  Pulling    7m26s  kubelet, node1     Pulling image "nginx"
  Normal  Pulled     7m15s  kubelet, node1     Successfully pulled image "nginx"
  Normal  Created    7m15s  kubelet, node1     Created container nginx
  Normal  Started    7m15s  kubelet, node1     Started container nginx

Controlled By: ReplicaSet/nginx-6db489d4b7 表示是由ReplicaSet/nginx-6db489d4b7创建pod

总结流程

用户通过kubectl创建deployment
deployment创建replicaset
repliset创建pod

Deployments YAML

创建yaml

vim  nginx.yml


apiVersion: apps/v1					##文件格式版本
kind: Deployment					##资源类型
metadata:							##资源的元数据
  labels:							##标签
    app: nginx
  name: nginx						##名称
spec: 								##规格
  replicas: 3						##副本数
  selector:
    matchLabels:
      app: nginx
  template:							##pod模板
    metadata:						##pod元数据
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx				##pod使用的镜像
        name: nginx

运行yaml

kubectl apply -f nginx.yml

查看

kubectl get pod -o wide
NAME                     READY   STATUS              RESTARTS   AGE   IP       NODE    NOMINATED NODE   READINESS GATES
nginx-86c57db685-4579k   0/1     ContainerCreating   0          14s   <none>   node1   <none>           <none>
nginx-86c57db685-psc7m   0/1     ContainerCreating   0          14s   <none>   node2   <none>           <none>
nginx-86c57db685-ssz2p   0/1     ContainerCreating   0          14s   <none>   node1   <none>           <none>

伸缩 Scale Up/Down

上个yaml文件中初始副本数为3个，在文件中直接修改副本数

vim nginx.yml

 修改    replicas: 5

再次执行命令

kubectl apply -f nginx.yml
deployment.apps/nginx configured

查看

kubectl get pod -o wide
NAME                     READY   STATUS    RESTARTS   AGE     IP            NODE    NOMINATED NODE   READINESS GATES
nginx-86c57db685-4579k   1/1     Running   0          4m15s   10.244.1.21   node1   <none>           <none>
nginx-86c57db685-8tv42   1/1     Running   0          47s     10.244.3.18   node2   <none>           <none>
nginx-86c57db685-psc7m   1/1     Running   0          4m15s   10.244.3.17   node2   <none>           <none>
nginx-86c57db685-ssz2p   1/1     Running   0          4m15s   10.244.1.20   node1   <none>           <none>
nginx-86c57db685-wl4tr   1/1     Running   0          47s     10.244.3.19   node2   <none>           <none>

缩减副本数为2个再次查看

vim nginx.yml

修改    replicas: 2

重新执行命令

kubectl apply -f nginx.yml
deployment.apps/nginx configured

查看

kubectl get pod -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
nginx-86c57db685-4579k   1/1     Running   0          6m    10.244.1.21   node1   <none>           <none>
nginx-86c57db685-ssz2p   1/1     Running   0          6m    10.244.1.20   node1   <none>           <none>

k8s的Failover

当前有两个副本运行在node1上，当我们把node1关闭掉之后，在等待一段时间之后，kubernetes会检查到node1不可用，重新在node2上创建pod维持副本数

kubectl get pod -o wide
NAME                     READY   STATUS        RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
nginx-86c57db685-4579k   1/1     Terminating   0          15m   10.244.1.21   node1   <none>           <none>
nginx-86c57db685-7p6gz   1/1     Running       0          90s   10.244.3.20   node2   <none>           <none>
nginx-86c57db685-8fxps   1/1     Running       0          90s   10.244.3.21   node2   <none>           <none>
nginx-86c57db685-ssz2p   1/1     Terminating   0          15m   10.244.1.20   node1   <none>           <none>

重新启动node1后，状态为Terminating的pod会被删除，但是已经运行的pod不会回到node1上

kubectl get nodes
NAME     STATUS   ROLES    AGE     VERSION
master   Ready    master   5d23h   v1.17.0
node1    Ready    <none>   5d23h   v1.17.0
node2    Ready    <none>   5d21h   v1.17.0




kubectl get pod -o wide
NAME                     READY   STATUS        RESTARTS   AGE     IP            NODE    NOMINATED NODE   READINESS GATES
nginx-86c57db685-7p6gz   1/1     Running       0          3m18s   10.244.3.20   node2   <none>           <none>
nginx-86c57db685-8fxps   1/1     Running       0          3m18s   10.244.3.21   node2   <none>           <none>

用label控制pod的位置

默认配置下，Scheduler会将pod调度到所有可用的Node上，如果需要控制pod位置则需要创建label的方式来控制

先删除之前的pod

kubectl delete -f nginx.yml

创建label

kubectl label nodes node1 disktype=ssd

查看label

kubectl get nodes --show-labels

	
node1    Ready    <none>   5d23h   v1.17.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=ssd,kubernetes.io/arch=amd64,kubernetes.io/hostname=node1,kubernetes.io/os=linux

修改yaml文件

在pod模块中加入nodeSelector并且把副本集数量添加到5

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
spec:
  replicas: 5
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
      nodeSelector:
        disktype: ssd

执行yml

kubectl apply -f nginx.yml
deployment.apps/nginx created

查看

kubectl get pod -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
nginx-66fcf948c9-hxgdc   1/1     Running   0          85s   10.244.1.25   node1   <none>           <none>
nginx-66fcf948c9-ls268   1/1     Running   0          85s   10.244.1.22   node1   <none>           <none>
nginx-66fcf948c9-r74rv   1/1     Running   0          85s   10.244.1.24   node1   <none>           <none>
nginx-66fcf948c9-rplwm   1/1     Running   0          85s   10.244.1.23   node1   <none>           <none>
nginx-66fcf948c9-x6ck2   1/1     Running   0          85s   10.244.1.26   node1   <none>           <none>

可以看到5个副本均在node1节点上运行

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