分批发布是一种通用的发布方式，但是在Kubernetes集群中，要实现分批发布，需要控制各种状态，维护service流量，以及各种label配置，十分麻烦。阿里云容器服务提供一种基于 CRD 的分批发布方式，大大方便发布流程。

使用kubectl进行分批发布

新集群默认安装了alicloud-application-controller，老集群请先手动安装，安装方式，

kubectl create -f alicloud-application-controller.yml

apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: alicloud-application-controller  labels:    owner: aliyun    app: alicloud-application-controller  namespace: kube-systemspec:  replicas: 1  selector:    matchLabels:      owner: aliyun      app: alicloud-application-controller  template:    metadata:      labels:        owner: aliyun        app: alicloud-application-controller      annotations:        scheduler.alpha.kubernetes.io/critical-pod: ''    spec:      tolerations:      - effect: NoSchedule        operator: Exists        key: node-role.kubernetes.io/master      - effect: NoSchedule        operator: Exists        key: node.cloudprovider.kubernetes.io/uninitialized      containers:        - name: alicloud-application-controller          image: registry.cn-hangzhou.aliyuncs.com/acs/aliyun-app-lifecycle-manager:0.1-c8d5da8          imagePullPolicy: IfNotPresent      serviceAccount: admin

我们这里以下面这个StatefulSet为例子演示分批发布的流程，

apiVersion: apps/v1kind: StatefulSetmetadata:  name: webspec:  selector:    matchLabels:      app: nginx # has to match .spec.template.metadata.labels  serviceName: "nginx"  replicas: 3 # by default is 1  template:    metadata:      labels:        app: nginx # has to match .spec.selector.matchLabels    spec:      terminationGracePeriodSeconds: 10      containers:      - name: nginx        image: registry.cn-hangzhou.aliyuncs.com/xianlu/old-nginx        ports:        - containerPort: 80          name: web

这是一个含有三个实例的nginx 实例，为了暴露此容器，我们使用Service来暴露，Service的Yaml如下

apiVersion: v1kind: Servicemetadata:  name: nginx  labels:    app: nginxspec:  ports:  - port: 80    name: web  selector:    app: nginx  type: LoadBalancer

这里通过SLB 暴露nginx 服务。

为了保证用户的Yaml安全性，分批发布需要使用Secret来存储最终的yaml，这里需要将yaml执行一下base64操作，再存储。这个是StatefulSet的Secret Yaml

apiVersion: v1kind: Secretmetadata:  name: myststype: Opaquedata:  yaml: 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

下面的为Service的Secret Yaml

apiVersion: v1kind: Secretmetadata:  name: mysvctype: Opaquedata:  yaml: YXBpVmVyc2lvbjogdjEKa2luZDogU2VydmljZQptZXRhZGF0YToKICBuYW1lOiBuZ2lueAogIGxhYmVsczoKICAgIGFwcDogbmdpbngKc3BlYzoKICBwb3J0czoKICAtIHBvcnQ6IDgwCiAgICBuYW1lOiB3ZWIKICBzZWxlY3RvcjoKICAgIGFwcDogbmdpbngKICB0eXBlOiBMb2FkQmFsYW5jZXI=

分别将上面的两个Secret 创建出来，kubectl create -f xxxxx

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可以看到两个Secret都已经创建完毕，下面就可以来创建分批发布的 CRD。分批发布的 CRD 格式如下，

apiVersion: alicloud.com/v1beta1kind: BatchReleasemetadata:  name: example-batch-release  annotations:    aliyun.batchnum: "2"spec:  statefulSetSecretName: mysts  serviceSecretName: mysvc

�aliyun.batchnum: 代表分几批发布，目前默认是2批

statefulSetSecretName: 表示存储StatefulSet的Secret 名称serviceSecretName: 表示存储Service的Secret 名称使用kubectl create -f xxx 创建此CRD分批发布可以看到，描述资源都已经创建出来了。

[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get stsNAME      DESIRED   CURRENT   AGEweb       3         3         6m[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get pods -o=wideNAME      READY     STATUS    RESTARTS   AGE       IP             NODEweb-0     1/1       Running   0          7m        172.16.2.2     cn-hangzhou.i-bp199b7a244chaux4ozhweb-1     1/1       Running   0          6m        172.16.2.131   cn-hangzhou.i-bp199b7a244chaux4oziweb-2     1/1       Running   0          6m        172.16.1.136   cn-hangzhou.i-bp199b7a244chaux4ozg[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get svcNAME         TYPE           CLUSTER-IP      EXTERNAL-IP      PORT(S)        AGEkubernetes   ClusterIP      172.19.0.1      
    
                443/TCP        4hnginx        LoadBalancer   172.19.12.163   120.55.148.238   80:32065/TCP   7m[root@iZbp11x2k7by5gfy6pkrl1Z ~]# curl 120.55.148.238old
    

可以看到，nginx 的StatefulSet和对应的Service 都已经创建出来，并且curl 是可以直接访问。

下面我们开始分批发布一个新版本的StatefulSet，这里我们新的StatefulSet Yaml 模板如下

apiVersion: apps/v1kind: StatefulSetmetadata:  name: webspec:  selector:    matchLabels:      app: nginx # has to match .spec.template.metadata.labels  serviceName: "nginx"  replicas: 3 # by default is 1  template:    metadata:      labels:        app: nginx # has to match .spec.selector.matchLabels    spec:      terminationGracePeriodSeconds: 10      containers:      - name: nginx        image: registry.cn-hangzhou.aliyuncs.com/xianlu/new-nginx        ports:        - containerPort: 80          name: web

可以看到，新老StatefulSet的区别在于，更换了新版本的镜像。

同样，我们需要创建一个Secret 来存储这个新的StatefulSet

apiVersion: v1kind: Secretmetadata:  name: my-new-ststype: Opaquedata:  yaml: 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

然后我们更新刚才创建的 CRD，将statefulSetSecretName改成新的StatefulSet名称。

修改后的CRD Yaml 如下:

[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get BatchRelease example-batch-release -o=yamlapiVersion: alicloud.com/v1beta1kind: BatchReleasemetadata:  annotations:    aliyun.batchnum: "2"  clusterName: ""  creationTimestamp: 2018-07-31T08:17:17Z  generation: 1  name: example-batch-release  namespace: default  resourceVersion: "43484"  selfLink: /apis/alicloud.com/v1beta1/namespaces/default/batchreleases/example-batch-release  uid: 2386ddfd-949a-11e8-a3c2-00163e086528spec:  serviceSecretName: mysvc  statefulSetSecretName: my-new-sts

[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl describe BatchRelease example-batch-releaseName:         example-batch-releaseNamespace:    defaultLabels:       
    
     Annotations:  aliyun.batchnum=2API Version:  alicloud.com/v1beta1Kind:         BatchReleaseMetadata:  Cluster Name:  Creation Timestamp:  2018-07-31T08:17:17Z  Generation:          1  Resource Version:    43484  Self Link:           /apis/alicloud.com/v1beta1/namespaces/default/batchreleases/example-batch-release  UID:                 2386ddfd-949a-11e8-a3c2-00163e086528Spec:  Service Secret Name:       mysvc  Stateful Set Secret Name:  my-new-stsStatus:  Control:  Release:    Batch _ Order:  1    Progress:       finished    Status:         WaitingForConfirm  Resources:    Service:      Name:       nginx      Namespace:  default      Status:     Updating    Stateful Set:      Name:       web      Namespace:  default      Status:     UpdatingEvents:  Type    Reason             Age   From               Message  ----    ------             ----  ----               -------  Normal  CreateSubResource  2m    aliyun-controller  Create StatefulSet resource sucessfully  Normal  CreateSubResource  2m    aliyun-controller  Create service resource sucessfully  Normal  Synced             2m    aliyun-controller  Batch CRD synced successfully  Normal  UpdateResource     1m    aliyun-controller  Begin to update StatefulSet web with partition 2  Normal  UpdateResource     1m    aliyun-controller  Waiting StatefulSet default:web ready, readyReplicas 2 replicas 3 times 1  Normal  UpdateResource     1m    aliyun-controller  Waiting StatefulSet default:web ready, readyReplicas 2 replicas 3 times 2  Normal  UpdateResource     1m    aliyun-controller  Begin to update service with new selector map[app:nginx aliyun.version:2]  Normal  UpdateResource     1m    aliyun-controller  Update StatefulSet and Service sucessfully, waiting confirm[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get pods -o=wideNAME      READY     STATUS    RESTARTS   AGE       IP             NODEweb-0     1/1       Running   0          2m        172.16.2.132   cn-hangzhou.i-bp199b7a244chaux4oziweb-1     1/1       Running   0          2m        172.16.2.3     cn-hangzhou.i-bp199b7a244chaux4ozhweb-2     1/1       Running   0          1m        172.16.1.138   cn-hangzhou.i-bp199b7a244chaux4ozg[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get svcNAME         TYPE           CLUSTER-IP     EXTERNAL-IP      PORT(S)        AGEkubernetes   ClusterIP      172.19.0.1     
     
                 443/TCP        5hnginx        LoadBalancer   172.19.2.184   101.37.107.187   80:32173/TCP   2m[root@iZbp11x2k7by5gfy6pkrl1Z ~]# curl 101.37.107.187new[root@iZbp11x2k7by5gfy6pkrl1Z ~]#
     
    

我们可以通过event 看到 CRD 的所有事件。同时可以看到，nginx的3个pod，已经有一个 pod发生了改变，变成了最新镜像，同时 curl对应的service，会发现流量已经指向了新的pod。这样用户就可以快速试错了。

下面我们来演示如何快速回滚，如果流量打到新的 pod后发现有问题，需要回滚，那么我们需要编辑CRD,

将Status 的action 置为rollback 就可以快速回滚。

[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl edit BatchRelease example-batch-releasebatchrelease.alicloud.com "example-batch-release" edited[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get pods -o=wideNAME      READY     STATUS    RESTARTS   AGE       IP             NODEweb-0     1/1       Running   0          7m        172.16.2.132   cn-hangzhou.i-bp199b7a244chaux4oziweb-1     1/1       Running   0          7m        172.16.2.3     cn-hangzhou.i-bp199b7a244chaux4ozhweb-2     1/1       Running   0          3s        172.16.1.139   cn-hangzhou.i-bp199b7a244chaux4ozg[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get svcNAME         TYPE           CLUSTER-IP     EXTERNAL-IP      PORT(S)        AGEkubernetes   ClusterIP      172.19.0.1     
    
                443/TCP        5hnginx        LoadBalancer   172.19.2.184   101.37.107.187   80:32173/TCP   7m[root@iZbp11x2k7by5gfy6pkrl1Z ~]# curl 101.37.107.187old
    

可以看到原来web-2所在的pod已经被回滚到了老镜像，现在curl service 也都是老的服务了。

发布第二批

发布第二批需要在action 置为continue 就可以

[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get pods -o=wideNAME      READY     STATUS    RESTARTS   AGE       IP             NODEweb-0     1/1       Running   0          3s        172.16.2.138   cn-hangzhou.i-bp199b7a244chaux4oziweb-1     1/1       Running   0          13s       172.16.2.12    cn-hangzhou.i-bp199b7a244chaux4ozhweb-2     1/1       Running   0          2m        172.16.1.153   cn-hangzhou.i-bp199b7a244chaux4ozg[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get BatchRelease example-batch-release -o=yamlapiVersion: alicloud.com/v1beta1kind: BatchReleasemetadata:  annotations:    aliyun.batchnum: "2"  clusterName: ""  creationTimestamp: 2018-07-31T09:44:58Z  generation: 1  name: example-batch-release  namespace: default  resourceVersion: "58066"  selfLink: /apis/alicloud.com/v1beta1/namespaces/default/batchreleases/example-batch-release  uid: 6321dcaf-94a6-11e8-a3c2-00163e086528spec:  serviceSecretName: mysvc  statefulSetSecretName: my-new-stsstatus:  control: {}  release:    batch_order: "2"    progress: finished    status: WaitingForConfirm  resources:    Service:      name: nginx      namespace: default      status: Updating    StatefulSet:      name: web      namespace: default      status: Updating

可以看到StatefulSet的三个 pod都被更新了。

这个时候就可以确认发布了

置为confirm 就确定了这次发布。

[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get BatchRelease example-batch-release -o=yamlapiVersion: alicloud.com/v1beta1kind: BatchReleasemetadata:  annotations:    aliyun.batchnum: "2"  clusterName: ""  creationTimestamp: 2018-07-31T09:44:58Z  generation: 1  name: example-batch-release  namespace: default  resourceVersion: "58542"  selfLink: /apis/alicloud.com/v1beta1/namespaces/default/batchreleases/example-batch-release  uid: 6321dcaf-94a6-11e8-a3c2-00163e086528spec:  serviceSecretName: mysvc  statefulSetSecretName: my-new-stsstatus:  control: {}  release:    progress: finished    status: Success  resources:    Service:      name: nginx      namespace: default      status: Success    StatefulSet:      name: web      namespace: default      status: Success[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get secret -l owner=aliyun -n=kube-systemNAME                       TYPE      DATA      AGEexample-batch-release.v1   Opaque    4         18mexample-batch-release.v2   Opaque    4         56s

可以看到，所有的确认版本历史都会被记录到secret里面，方便到时候跨版本回滚。