灰度发布在不同场景中实现方式不同，如果当前灰度机器仅对测试开放，可以定义一个新的deployment来配合service来实现。如果需要切入一部分随机真实用户的流量，可以将生产机器中一台机器作为灰度机器，通过灰度后再升级其它的机器。

# nginx-v1.15.yaml 与 nginx-v1.14.yaml 一致，仅仅修改了镜像文件
[root@hdss7-21 ~]# kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.15.yaml --record=true && kubectl rollout pause deployment nginx-deploy -n app
[root@hdss7-21 ~]# kubectl rollout history deployment nginx-deploy -n app
REVISION  CHANGE-CAUSE
1         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.12.yaml --record=true
2         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.13.yaml --record=true
3         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.14.yaml --record=true
4         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.15.yaml --record=true
[root@hdss7-21 ~]# kubectl get rs -n app -l tier=slb -L version  # 存在两个ReplicaSet对外提供服务
NAME                      DESIRED   CURRENT   READY   AGE     VERSION
nginx-deploy-5597c8b45    0         0         0       177m    v1.12
nginx-deploy-6695fd9655   1         1         1       2m22s   v1.15
nginx-deploy-6bd88df699   0         0         0       176m    v1.13
nginx-deploy-7c5976dcd9   5         5         5       23m     v1.14
[root@hdss7-21 ~]# kubectl get pod -n app -l partition=website -L version -w # 新老共存
NAME                            READY   STATUS    RESTARTS   AGE   VERSION
nginx-deploy-6695fd9655-tcm76   1/1     Running   0          17s   v1.15
nginx-deploy-7c5976dcd9-4tnv4   1/1     Running   0          21m   v1.14
nginx-deploy-7c5976dcd9-bpjc2   1/1     Running   0          20m   v1.14
nginx-deploy-7c5976dcd9-gv8qm   1/1     Running   0          20m   v1.14
nginx-deploy-7c5976dcd9-ttlqx   1/1     Running   0          21m   v1.14
nginx-deploy-7c5976dcd9-xq2qs   1/1     Running   0          21m   v1.14

# 手动暂停
[root@hdss7-21 ~]# kubectl rollout resume deployment nginx-deploy -n app && kubectl rollout pause deployment nginx-deploy -n app
[root@hdss7-21 ~]# kubectl get pod -n app -l partition=website -L version -w
NAME                            READY   STATUS    RESTARTS   AGE     VERSION
nginx-deploy-6695fd9655-jmb94   1/1     Running   0          19s     v1.15
nginx-deploy-6695fd9655-tcm76   1/1     Running   0          6m19s   v1.15
nginx-deploy-7c5976dcd9-4tnv4   1/1     Running   0          27m     v1.14
nginx-deploy-7c5976dcd9-gv8qm   1/1     Running   0          26m     v1.14
nginx-deploy-7c5976dcd9-ttlqx   1/1     Running   0          27m     v1.14
nginx-deploy-7c5976dcd9-xq2qs   1/1     Running   0          27m     v1.14
# 升级剩余所有机器
[root@hdss7-21 ~]# kubectl rollout resume deployment nginx-deploy -n app