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/v1beta1
kind: Deployment
metadata:
name: alicloud-application-controller
labels:
owner: aliyun
app: alicloud-application-controller
namespace: kube-system
spec:
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/v1
kind: StatefulSet
metadata:
name: web
spec:
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: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
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: v1
kind: Secret
metadata:
name: mysts
type: Opaque
data:
yaml: 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
下面的为Service的Secret Yaml
apiVersion: v1
kind: Secret
metadata:
name: mysvc
type: Opaque
data:
yaml: YXBpVmVyc2lvbjogdjEKa2luZDogU2VydmljZQptZXRhZGF0YToKICBuYW1lOiBuZ2lueAogIGxhYmVsczoKICAgIGFwcDogbmdpbngKc3BlYzoKICBwb3J0czoKICAtIHBvcnQ6IDgwCiAgICBuYW1lOiB3ZWIKICBzZWxlY3RvcjoKICAgIGFwcDogbmdpbngKICB0eXBlOiBMb2FkQmFsYW5jZXI=
分别将上面的两个Secret 创建出来，kubectl create -f xxxxx
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/v1beta1
kind: BatchRelease
metadata:
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 sts
NAME DESIRED CURRENT AGE
web 3 3 6m
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get pods -o=wide
NAME READY STATUS RESTARTS AGE IP NODE
web-0 1/1 Running 0 7m 172.16.2.2 cn-hangzhou.i-bp199b7a244chaux4ozh
web-1 1/1 Running 0 6m 172.16.2.131 cn-hangzhou.i-bp199b7a244chaux4ozi
web-2 1/1 Running 0 6m 172.16.1.136 cn-hangzhou.i-bp199b7a244chaux4ozg
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 172.19.0.1 <none> 443/TCP 4h
nginx LoadBalancer 172.19.12.163 120.55.148.238 80:32065/TCP 7m
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# curl 120.55.148.238
old
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/v1
kind: StatefulSet
metadata:
name: web
spec:
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: v1
kind: Secret
metadata:
name: my-new-sts
type: Opaque
data:
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=yaml
apiVersion: alicloud.com/v1beta1
kind: BatchRelease
metadata:
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-a3c2-00163e086528
spec:
serviceSecretName: mysvc
statefulSetSecretName: my-new-sts
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl describe BatchRelease example-batch-release
Name: example-batch-release
Namespace: default
Labels: <none>
Annotations: aliyun.batchnum=2
API Version: alicloud.com/v1beta1
Kind: BatchRelease
Metadata:
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-a3c2-00163e086528
Spec:
Service Secret Name: mysvc
Stateful Set Secret Name: my-new-sts
Status:
Control:
Release:
Batch _ Order: 1
Progress: finished
Status: WaitingForConfirm
Resources:
Service:
Name: nginx
Namespace: default
Status: Updating
Stateful Set:
Name: web
Namespace: default
Status: Updating
Events:
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=wide
NAME READY STATUS RESTARTS AGE IP NODE
web-0 1/1 Running 0 2m 172.16.2.132 cn-hangzhou.i-bp199b7a244chaux4ozi
web-1 1/1 Running 0 2m 172.16.2.3 cn-hangzhou.i-bp199b7a244chaux4ozh
web-2 1/1 Running 0 1m 172.16.1.138 cn-hangzhou.i-bp199b7a244chaux4ozg
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 172.19.0.1 <none> 443/TCP 5h
nginx LoadBalancer 172.19.2.184 101.37.107.187 80:32173/TCP 2m
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# curl 101.37.107.187
new
[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-release
batchrelease.alicloud.com "example-batch-release" edited
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get pods -o=wide
NAME READY STATUS RESTARTS AGE IP NODE
web-0 1/1 Running 0 7m 172.16.2.132 cn-hangzhou.i-bp199b7a244chaux4ozi
web-1 1/1 Running 0 7m 172.16.2.3 cn-hangzhou.i-bp199b7a244chaux4ozh
web-2 1/1 Running 0 3s 172.16.1.139 cn-hangzhou.i-bp199b7a244chaux4ozg
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 172.19.0.1 <none> 443/TCP 5h
nginx LoadBalancer 172.19.2.184 101.37.107.187 80:32173/TCP 7m
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# curl 101.37.107.187
old
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=wide
NAME READY STATUS RESTARTS AGE IP NODE
web-0 1/1 Running 0 3s 172.16.2.138 cn-hangzhou.i-bp199b7a244chaux4ozi
web-1 1/1 Running 0 13s 172.16.2.12 cn-hangzhou.i-bp199b7a244chaux4ozh
web-2 1/1 Running 0 2m 172.16.1.153 cn-hangzhou.i-bp199b7a244chaux4ozg
[root@iZbp11x2k7by5gfy6pkrl1Z ~]# kubectl get BatchRelease example-batch-release -o=yaml
apiVersion: alicloud.com/v1beta1
kind: BatchRelease
metadata:
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-a3c2-00163e086528
spec:
serviceSecretName: mysvc
statefulSetSecretName: my-new-sts
status:
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=yaml
apiVersion: alicloud.com/v1beta1
kind: BatchRelease
metadata:
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-a3c2-00163e086528
spec:
serviceSecretName: mysvc
statefulSetSecretName: my-new-sts
status:
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-system
NAME TYPE DATA AGE
example-batch-release.v1 Opaque 4 18m
example-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。