go-micro 基于k8s做服务发现

go-micro 基于k8s做服务发现

go-micro 可以基于k8s做服务发现，需要开启RBAC

制作镜像

micro-hello 是基于go-micro框架的服务

Dokerfile

FROM alpine

ADD micro-hello /micro-hello
ENTRYPOINT /micro-hello --registry kubernetes

执行命令生成镜像

~# docker build . -t micro-hello-default-k8s:latest

创建serviceAccount

serviceAccount.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: micro-services

• 执行命令 kubectl apply -f serviceAccount.yaml
• 查看serviceAccount是否创建成功

~$ kubectl get sa
NAME             SECRETS   AGE
default          1         4d20h
micro-services   1         3h24m

~$ kubectl describe sa micro-services
Name:                micro-services
Namespace:           default
Labels:              <none>
Annotations:         <none>
Image pull secrets:  <none>
Mountable secrets:   micro-services-token-qbhfz
Tokens:              micro-services-token-qbhfz
Events:              <none>

创建clusterRole

clusterrole.yaml

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: micro-registry
rules:
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - list
  - patch
  - watch

• 执行命令 kubectl apply -f clusterrole.yaml
• 检查clusterRole的状态

~$ kubectl get clusterrole
NAME                                                                   CREATED AT
admin                                                                  2021-08-20T09:30:09Z
calico-kube-controllers                                                2021-08-20T09:38:15Z
calico-node                                                            2021-08-20T09:38:16Z
cluster-admin                                                          2021-08-20T09:30:08Z
edit                                                                   2021-08-20T09:30:09Z
kubeadm:get-nodes                                                      2021-08-20T09:30:19Z
micro-registry                                                         2021-08-24T09:06:28Z

~$ kubectl describe clusterrole micro-registry
Name:         micro-registry
Labels:       <none>
Annotations:  <none>
PolicyRule:
  Resources  Non-Resource URLs  Resource Names  Verbs
  ---------  -----------------  --------------  -----
  pods       []                 []              [list patch watch]

创建 rolebinging

rulebinging.yaml

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: micro-registry
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: micro-registry
subjects:
- kind: ServiceAccount
  name: micro-services
  namespace: default

• 执行命令 kubectl apply -f rulebinging.yaml
• 检查roleBind的状态

~$ kubectl get rolebinding
NAME             ROLE                         AGE
micro-registry   ClusterRole/micro-registry   21h

~$ kubectl describe rolebinding micro-registry
Name:         micro-registry
Labels:       <none>
Annotations:  <none>
Role:
  Kind:  ClusterRole
  Name:  micro-registry
Subjects:
  Kind            Name            Namespace
  ----            ----            ---------
  ServiceAccount  micro-services  default

部署镜像

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: micro-hello-default
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: micro-hello-default
  template:
    metadata:
      labels:
        app: micro-hello-default
    spec:
      serviceAccountName: micro-services
      containers:
      - name: hello
        image: micro-hello-default-k8s:test

• 执行命令 kubectl apply -f deployment.yaml
• 检查pods是否允许正常

~$ kubectl get pods -n default
NAME                                   READY   STATUS    RESTARTS        AGE
micro-client-79fb798cd5-sjrcc          1/1     Running   0               99m
micro-hello-default-7cf4bd79d7-gtdpc   1/1     Running   0               3h21m
nginx-deployment-748c6fff66-kmtjw      1/1     Running   1 (4h42m ago)   21h

~$ kubectl logs -f micro-hello-default-7cf4bd79d7-gtdpc
2021-08-25 03:12:07  file=v3@v3.6.0/service.go:199 level=info Starting [service] micro-hello
2021-08-25 03:12:07  file=server/rpc_server.go:820 level=info Transport [http] Listening on [::]:33989
2021-08-25 03:12:07  file=server/rpc_server.go:840 level=info Broker [http] Connected to 127.0.0.1:35617
2021-08-25 03:12:07  file=server/rpc_server.go:654 level=info Registry [kubernetes] Registering node: micro-hello-1196f798-8218-4c81-a646-196292ddefc0

如果出现下面的错误，一般是因为权限问题，检查一下配置设置的是否正确

2019/06/27 12:54:13 K8s: request failed with code 403
2019/06/27 12:54:13 K8s: request failed with body:
2019/06/27 12:54:13 {"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"pods \"micro-hello-default-7cf4bd79d7-gtdpc\" is forbidden: User \"system:serviceaccount:micro-services:default\" cannot patch resource \"pods\" in API group \"\" in the namespace \"default\"","reason":"Forbidden","details":{"name":"micro-hello-default-7cf4bd79d7-gtdpc","kind":"pods"},"code":403}
2019/06/27 12:54:13 Server register error: K8s: error