kubernetes发布tomcat服务,通过deployment,service布署

1.制作tomcat镜像

参考docker tomcat镜像制作

此处直接拉取

查看已有可镜像

先设置docker阿里源，即添加 "registry-mirrors": ["https://mj9kvemk.mirror.aliyuncs.com"]

[root@k8s-master docker]# pwd
/etc/docker
[root@k8s-master docker]# cat daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ],
  "registry-mirrors": ["https://mj9kvemk.mirror.aliyuncs.com"]
}
[root@k8s-master docker]# 

service docker restart

[root@k8s-master docker]# docker pull tomcat:
: Pulling from library/tomcat
e79bb959ec00: Pull complete
d4b7902036fe: Pull complete
1b2a72d4e030: Pull complete
de423484a946: Pull complete
ceaac3b844f7: Pull complete
88f01b722a52: Pull complete
c23be56a9ac1: Pull complete
d852ffd6d31f: Pull complete
11775a3d792d: Pull complete
acd9db02854a: Pull complete
3032f09d91b5: Pull complete
Digest: sha256:84e91645e3176f55e1f2ad63edf657216ed4ef3dde82e381f1b8ceac1145a21c
Status: Downloaded newer image for tomcat:
[root@k8s-master docker]# docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
tomcat                                                  f1332ae3f570         days ago          463MB
k8s.gcr.io/kube-proxy                v1.14.0             5cd54e388aba         days ago          .1MB
k8s.gcr.io/kube-scheduler            v1.14.0             00638a24688b         days ago          .6MB
k8s.gcr.io/kube-controller-manager   v1.14.0             b95b1efa0436         days ago          158MB
k8s.gcr.io/kube-apiserver            v1.14.0             ecf910f40d6e         days ago          210MB
quay.io/coreos/flannel               v0.11.0-amd64       ff281650a721         months ago        .6MB
k8s.gcr.io/coredns                   1.3.               eb516548c180         months ago        .3MB
k8s.gcr.io/etcd                      3.3.              2c4adeb21b4f         months ago        258MB
k8s.gcr.io/pause                     3.1                 da86e6ba6ca1         months ago       742kB
[root@k8s-master docker]# 

2.利用docker启动镜像，验证可用性

[root@k8s-master docker]# docker run -d -p : --name mytomcat_1 tomcat:
c8a00a7aab85ee3b342fb7cd1515a464bde1195397432173b6126f4242244ef9
[root@k8s-master docker]# docker ps -a|grep tomcat
c8a00a7aab85        tomcat:               "catalina.sh run"         minutes ago       Up  minutes                 0.0.0.0:->/tcp   mytomcat_1
[root@k8s-master docker]# 

chrome验证 http://192.168.111.130:58080/

3.发布k8s集群

创建一个deployment

（可参考https://blog.csdn.net/wucong60/article/details/81699196）

kubernetes yaml语法，横杠表示数组，缩进表示层级，缩进不能有tab,参考Kubernetes之YAML文件

[root@k8s-master ~]# pwd
/root
[root@k8s-master ~]# cat deployment-hello.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: hello
spec:
  replicas:
  template:
    metadata:
      labels:
        run: hello
    spec:
      containers:
       - name: hello
         image: tomcat:8 #确保node节点上有该镜像且可正常运行，注意是node节点机器上，不是master机器
         imagePullPolicy: IfNotPresent ##Always,IfNotPresent,Never
         ports:
         - name: http
           containerPort: 

kubectl 创建pod

[root@k8s-master ~]# kubectl create -f deployment-hello.yaml
deployment.extensions/hello created

deployments详情

root@k8s-master ~]# kubectl get deployments #查看deploy是否成功
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
hello   /                            55s

[root@k8s-master ~]# kubectl get rs ##因为deployment是三层架构，看rs是否成功,我们看自动创建4个rs.名称后面的字符串是 模板的哈希值。是不会发生变化的，最后pod的是随机值
NAME DESIRED CURRENT READY AGE
hello-68df45bc79 4 4 0 8m29s

[root@k8s-master ~]# kubectl get pods #查看最后一层pod
NAME                     READY   STATUS              RESTARTS   AGE
hello-7d46c7db4c-42bwl   /     ContainerCreating             67s
hello-7d46c7db4c-rg9fq   /     ContainerCreating             67s
hello-7d46c7db4c-tclps   /     ContainerCreating             67s
hello-7d46c7db4c-whvsw   /     ContainerCreating             67s

[root@k8s-master ~]# kubectl describe  deployment hello
Name:                   hello
Namespace:              default
CreationTimestamp:      Wed, 03 Apr 2019 10:18:53 +0800
Labels:                 run=hello
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               run=hello
Replicas:               4 desired | 4 updated | 4 total | 4 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  1 max unavailable, 1 max surge
Pod Template:
  Labels:  run=hello
  Containers:
   hello:
    Image:        tomcat:8
    Port:         8080/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
OldReplicaSets:  <none>
NewReplicaSet:   hello-57b49c67cf (4/4 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  3m30s  deployment-controller  Scaled up replica set hello-57b49c67cf to 4
[root@k8s-master ~]# 

##过两分钟状态就会变为running
[root@k8s-master ~]# kubectl get deployment
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
hello   4/4     4            4           6m52s

[root@k8s-master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
hello-57b49c67cf-6hh59   1/1     Running   0          4m56s
hello-57b49c67cf-6ml78   1/1     Running   0          4m56s
hello-57b49c67cf-8xqgw   1/1     Running   0          4m56s
hello-57b49c67cf-pd826   1/1     Running   0          4m56s
[root@k8s-master ~]# kubectl describe pod hello-57b49c67cf-6hh59
Name:               hello-57b49c67cf-6hh59
Namespace:          default
Priority:           0
PriorityClassName:  <none>
Node:               k8s-node1/192.168.111.131
Start Time:         Wed, 03 Apr 2019 10:18:53 +0800
Labels:             pod-template-hash=57b49c67cf
                    run=hello
Annotations:        <none>
Status:             Running
IP:                 10.244.1.22
Controlled By:      ReplicaSet/hello-57b49c67cf
Containers:
  hello:
    Container ID:   docker://8cd27dd2bb4dffd50f8faf8938870af9fa9489f853498f37277a360e3059c476
    Image:          mytomcat:v8
    Image ID:       docker-pullable://tomcat@sha256:3e3d18321127bb9114f4226f95802d3899aeec4c36df84d0359e5da300e9bc72
    Port:           8080/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Wed, 03 Apr 2019 10:18:57 +0800
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-92rjn (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True
Volumes:
  default-token-92rjn:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-92rjn
    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  5m37s  default-scheduler   Successfully assigned default/hello-57b49c67cf-6hh59 to k8s-node1
  Normal  Pulled     5m34s  kubelet, k8s-node1  Container image "mytomcat:v8" already present on machine
  Normal  Created    5m34s  kubelet, k8s-node1  Created container hello
  Normal  Started    5m33s  kubelet, k8s-node1  Started container hello

如果kubectl get pod状态为ErrImagePull && ImagePullBackOff  ErrImageNeverPull,请确保node上有相应的镜像，若无，则在node机器执行第1，2步

pod发布位置

root@k8s-master ~]# kubectl get pods -o wide
NAME                     READY   STATUS              RESTARTS   AGE     IP       NODE        NOMINATED NODE   READINESS GATES
hello-7d46c7db4c-42bwl   /     ContainerCreating             5m53s   <none>   k8s-node1   <none>           <none>
hello-7d46c7db4c-rg9fq   /     ContainerCreating             5m53s   <none>   k8s-node1   <none>           <none>
hello-7d46c7db4c-tclps   /     ContainerCreating             5m53s   <none>   k8s-node1   <none>           <none>
hello-7d46c7db4c-whvsw   /     ContainerCreating             5m53s   <none>   k8s-node1   <none>           <none>

正常情况下

[root@k8s-master ~]# kubectl get pods
NAME                  READY   STATUS    RESTARTS   AGE
hello-665548d-5fcbf   /     Running             11m
hello-665548d-h69xx   /     Running             11m
hello-665548d-jl6m6   /     Running             11m
hello-665548d-zd7kw   /     Running             11m

创建一个service

[root@k8s-master ~]# cat service-hello.yaml
apiVersion: v1
kind: Service
metadata:
  name: service-hello
  labels:
  name: service-hello
spec:
  type: NodePort      #这里代表是NodePort类型的,另外还有ingress,LoadBalancer
  ports:
  - port:           #这里的端口和clusterIP(kubectl describe service service-hello中的IP的port)对应，即在集群中所有机器上curl 10.98.166.242:80可访问发布的应用服务。
    targetPort:   #端口一定要和container暴露出来的端口对应，nodejs暴露出来的端口是8081，所以这里也应是8081
    protocol: TCP
    nodePort:    # 所有的节点都会开放此端口30000--32767，此端口供外部调用。
  selector:
    run: hello         #这里选择器一定要选择容器的标签，之前写name:kube-node是错的。
[root@k8s-master ~]# pwd
/root
[root@k8s-master ~]# 

kubectl create -f  创建对像，删除用kubectl delete -f

[root@k8s-master ~]# kubectl create -f service-hello.yaml
service/service-hello created

[root@k8s-master ~]# kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 4h24m
service-hello NodePort 10.98.166.242 <none> 80:31111/TCP 42s
[root@k8s-master ~]#

root@k8s-master ~]# kubectl get services -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 4h25m <none>
service-hello NodePort 10.98.166.242 <none> 80:31111/TCP 104s run=hello

[root@k8s-master ~]# kubectl describe service service-hello
Name:                     service-hello
Namespace:                default
Labels:                   <none>
Annotations:              <none>
Selector:                 run=hello
Type:                     NodePort
IP:                       10.98.166.242
Port:                     <unset>  80/TCP
TargetPort:               8080/TCP
NodePort:                 <unset>  31111/TCP
Endpoints:                10.244.1.22:8080,10.244.1.23:8080,10.244.1.24:8080 + 1 more...
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>
[root@k8s-master ~]#

service创建后，自动生成endpoints,每个pod ip都在里面,简单认为：动态存储pod名字与pod ip对应关系的list，并提供将请求转发到实际pod上的能力 kubernets之endpoints

[root@k8s-master ~]# kubectl get endpoints
NAME            ENDPOINTS                                                        AGE
kubernetes      192.168.111.130:                                             20h
service-hello   10.244.1.22:,10.244.1.23:,10.244.1.24: +  more...   15h
[root@k8s-master ~]# kubectl describe endpoint service-hello
error: the server doesn't have a resource type "endpoint"
[root@k8s-master ~]# kubectl describe endpoints service-hello
Name:         service-hello
Namespace:    default
Labels:       <none>
Annotations:  endpoints.kubernetes.io/last-change-trigger-time: --03T02::57Z
Subsets:
  Addresses:          10.244.1.22,10.244.1.23,10.244.1.24,10.244.1.25
  NotReadyAddresses:  <none>
  Ports:
    Name     Port  Protocol
    ----     ----  --------
    <unset>    TCP

Events:
  Type     Reason                  Age                From                 Message
  ----     ------                  ----               ----                 -------
  Warning  FailedToUpdateEndpoint  48m (x2 over 69m)  endpoint-controller  Failed to update endpoint default/service-hello: Operation cannot be fulfilled on endpoints "service-hello": the object has been modified; please apply your changes to the latest version and try again
[root@k8s-master ~]# 

4.验证发布

http://192.168.111.130:31111/ 或者http://192.168.111.131:31111/