使用argo-rollouts实现金丝雀发布

什么是 argo rollouts

Argo-Rollout是一个 Kubernetes Controller 和对应一系列的 CRD，提供更强大的 Deployment 能力。包括灰度发布、蓝绿部署、更新测试(experimentation)、渐进式交付(progressive delivery)等特性。

支持特性如下：

• 蓝绿色更新策略
• 金丝雀更新策略
• 细粒度，加权流量转移
• 自动回 rollback 和 promotion
• 手动判断
• 可定制的指标查询和业务 KPI 分析
• 入口控制器集成：NGINX，ALB
• 服务网格集成：Istio，Linkerd，SMI
• Metric provider 集成：Prometheus，Wavefront，Kayenta，Web，Kubernetes Jobs

Argo 原理和 Deployment 差不多，只是加强 rollout 的策略和流量控制。当 spec.template 发送变化时，Argo-Rollout 就会根据 spec.strategy 进行 rollout，通常会产生一个新的 ReplicaSet，逐步 scale down 之前的 ReplicaSet 的 pod 数量。

安装

按着官方文档进行安装，官方地址为：https://argoproj.github.io/argo-rollouts/installation/#kubectl-plugin-installation

（1）在 Kubernetes 集群中安装 argo-rollouts

kubectl create namespace argo-rollouts
kubectl apply -n argo-rollouts -f https://raw.githubusercontent.com/argoproj/argo-rollouts/stable/manifests/install.yaml

（2）安装 argo-rollouts 的 kubectl plugin

curl -LO https://github.com/argoproj/argo-rollouts/releases/latest/download/kubectl-argo-rollouts-linux-amd64
chmod +x ./kubectl-argo-rollouts-linux-amd64
mv ./kubectl-argo-rollouts-linux-amd64 /usr/local/bin/kubectl-argo-rollouts

金丝雀发布

灰度发布包含 Replica Shifting 和 Traffic Shifting 两个过程。

• Replica Shifting：版本替换
• Traffic Shifting：流量接入

这里使用官方的 demo 来进行测试。例子：https://argoproj.github.io/argo-rollouts/getting-started/

Replica Shifting

部署应用

使用如下命令部署示例：

kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/basic/rollout.yaml
kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/basic/service.yaml

我们先看看第一个 rollout.yaml 的具体内容，如下：

apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
  name: rollouts-demo
spec:
  replicas: 5
  strategy:
    canary:
      steps:
        - setWeight: 20
        - pause: {}
        - setWeight: 40
        - pause: { duration: 10 }
        - setWeight: 60
        - pause: { duration: 10 }
        - setWeight: 80
        - pause: { duration: 10 }
  revisionHistoryLimit: 2
  selector:
    matchLabels:
      app: rollouts-demo
  template:
    metadata:
      labels:
        app: rollouts-demo
    spec:
      containers:
        - name: rollouts-demo
          image: argoproj/rollouts-demo:blue
          ports:
            - name: http
              containerPort: 8080
              protocol: TCP
          resources:
            requests:
              memory: 32Mi
              cpu: 5m

可以看到除了apiVersion，kind以及strategy之外，其他和 Deployment 无异。

strategy字段定义的是发布策略，其中：

• setWeight：设置流量的权重
• pause：暂停，如果里面没有跟duration: 10则表示需要手动更新，如果跟了表示等待多长时间会自动跟新。

而 service.yaml 文件定义的就是普通的 service，如下：

apiVersion: v1
kind: Service
metadata:
  name: rollouts-demo
spec:
  ports:
  - port: 80
    targetPort: http
    protocol: TCP
    name: http
  selector:
    app: rollouts-demo

执行上面命令部署后，会在default命名空间下创建 5 个 pod，如下：

# kubectl get pod
NAME                                    READY   STATUS    RESTARTS   AGE
nfs-client-prosioner-598d477ff6-fmgwf   1/1     Running   2          17d
rollouts-demo-7bf84f9696-4glv6          1/1     Running   0          78s
rollouts-demo-7bf84f9696-7kqt6          1/1     Running   0          78s
rollouts-demo-7bf84f9696-8k9hw          1/1     Running   0          78s
rollouts-demo-7bf84f9696-9cz2r          1/1     Running   0          78s
rollouts-demo-7bf84f9696-jvzvd          1/1     Running   0          78s

可以使用kubectl-argo-rollouts get rollout rollouts-demo命令来查看部署状态，如下：

# kubectl-argo-rollouts get rollout rollouts-demo
Name:            rollouts-demo
Namespace:       default
Status:          ✔ Healthy
Strategy:        Canary
  Step:          8/8
  SetWeight:     100
  ActualWeight:  100
Images:          argoproj/rollouts-demo:blue (stable)
Replicas:
  Desired:       5
  Current:       5
  Updated:       5
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS     AGE   INFO
⟳ rollouts-demo                            Rollout     ✔ Healthy  114s
└──# revision:1
   └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  ✔ Healthy  114s  stable
      ├──□ rollouts-demo-7bf84f9696-4glv6  Pod         ✔ Running  114s  ready:1/1
      ├──□ rollouts-demo-7bf84f9696-7kqt6  Pod         ✔ Running  114s  ready:1/1
      ├──□ rollouts-demo-7bf84f9696-8k9hw  Pod         ✔ Running  114s  ready:1/1
      ├──□ rollouts-demo-7bf84f9696-9cz2r  Pod         ✔ Running  114s  ready:1/1
      └──□ rollouts-demo-7bf84f9696-jvzvd  Pod         ✔ Running  114s  ready:1/1

可以看到该版本被标记为stable，而且 STATUS 为healthy。还可以在命令后面加一个--watch来实时监控服务状态，完整命令为kubectl argo rollouts get rollout rollouts-demo --watch。

更新应用

接下来对应用进行更新。对应用进行更新和更新用 Deployment 部署的应用一样，更新镜像即可。argo rollouts 插件有一个set image命令来更新镜像，如下：

kubectl argo rollouts set image rollouts-demo \
  rollouts-demo=argoproj/rollouts-demo:yellow

更新过后，我们可以通过观察kubectl argo rollouts get rollout rollouts-demo --watch服务状态，如下：

Name:            rollouts-demo
Namespace:       default
Status:          ॥ Paused
Message:         CanaryPauseStep
Strategy:        Canary
  Step:          1/8
  SetWeight:     20
  ActualWeight:  20
Images:          argoproj/rollouts-demo:blue (stable)
                 argoproj/rollouts-demo:yellow (canary)
Replicas:
  Desired:       5
  Current:       5
  Updated:       1
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS     AGE    INFO
⟳ rollouts-demo                            Rollout     ॥ Paused   9m12s
├──# revision:2
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  ✔ Healthy  44s    canary
│     └──□ rollouts-demo-789746c88d-l4gmd  Pod         ✔ Running  44s    ready:1/1
└──# revision:1
   └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  ✔ Healthy  9m12s  stable
      ├──□ rollouts-demo-7bf84f9696-4glv6  Pod         ✔ Running  9m12s  ready:1/1
      ├──□ rollouts-demo-7bf84f9696-8k9hw  Pod         ✔ Running  9m12s  ready:1/1
      ├──□ rollouts-demo-7bf84f9696-9cz2r  Pod         ✔ Running  9m12s  ready:1/1
      └──□ rollouts-demo-7bf84f9696-jvzvd  Pod         ✔ Running  9m12s  ready:1/1

可以看到多了一个revision:2，而且该版本被标记为canary，而且状态是Status: Paused，canary 接入流量为 20%。

部署之所以处于Paused阶段，是因为我们在 rollout.yaml 中定义了发布第一个版本后会暂停，这时候需要手动接入接下来的更新。

argo rollouts 提供了promote来进行后续的更新，命令如下：

kubectl argo rollouts promote rollouts-demo

然后我们可以在 watch 界面，看到如下的更新过程。

Name:            rollouts-demo
Namespace:       default
Status:          ॥ Paused
Message:         CanaryPauseStep
Strategy:        Canary
  Step:          3/8
  SetWeight:     40
  ActualWeight:  40
Images:          argoproj/rollouts-demo:blue (stable)
                 argoproj/rollouts-demo:yellow (canary)
Replicas:
  Desired:       5
  Current:       5
  Updated:       2
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS         AGE    INFO
⟳ rollouts-demo                            Rollout     ॥ Paused       15m
├──# revision:2
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  ✔ Healthy      6m46s  canary
│     ├──□ rollouts-demo-789746c88d-l4gmd  Pod         ✔ Running      6m46s  ready:1/1
│     └──□ rollouts-demo-789746c88d-67dwp  Pod         ✔ Running      19s    ready:1/1
└──# revision:1
   └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  ✔ Healthy      15m    stable
      ├──□ rollouts-demo-7bf84f9696-4glv6  Pod         ✔ Running      15m    ready:1/1
      ├──□ rollouts-demo-7bf84f9696-8k9hw  Pod         ✔ Running      15m    ready:1/1
      ├──□ rollouts-demo-7bf84f9696-9cz2r  Pod         ✔ Running      15m    ready:1/1
      └──□ rollouts-demo-7bf84f9696-jvzvd  Pod         ◌ Terminating  15m    ready:1/1

因为后续的更新在 pause 阶段只暂停 10s，所以会依次自动更新完，不需要手动介入，待更新完后整体的状态如下：

Name:            rollouts-demo
Namespace:       default
Status:          ✔ Healthy
Strategy:        Canary
  Step:          8/8
  SetWeight:     100
  ActualWeight:  100
Images:          argoproj/rollouts-demo:yellow (stable)
Replicas:
  Desired:       5
  Current:       5
  Updated:       5
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS        AGE    INFO
⟳ rollouts-demo                            Rollout     ✔ Healthy     17m
├──# revision:2
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  ✔ Healthy     8m35s  stable
│     ├──□ rollouts-demo-789746c88d-l4gmd  Pod         ✔ Running     8m35s  ready:1/1
│     ├──□ rollouts-demo-789746c88d-67dwp  Pod         ✔ Running     2m8s   ready:1/1
│     ├──□ rollouts-demo-789746c88d-k7mfk  Pod         ✔ Running     106s   ready:1/1
│     ├──□ rollouts-demo-789746c88d-glbfb  Pod         ✔ Running     94s    ready:1/1
│     └──□ rollouts-demo-789746c88d-d7m4f  Pod         ✔ Running     83s    ready:1/1
└──# revision:1
   └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  • ScaledDown  17m

可以看到第一个版本已经下线，第二个版本的状态为Healthy，而且镜像被标记为stable。

终止更新

如果在更新应用的过程中，最新的应用有问题，需要终止更新需要怎么做呢？

我们先使用下面命令发布新版本应用，如下：

kubectl argo rollouts set image rollouts-demo \
  rollouts-demo=argoproj/rollouts-demo:red

然后更新动作会在第一次更新的时候处于Paused状态，现在我们可以用abort来终止发布，如下：

kubectl argo rollouts abort rollouts-demo

待执行完命令后，可以在 watch 页面，看到如下信息：

Name:            rollouts-demo
Namespace:       default
Status:          ✖ Degraded
Message:         RolloutAborted: Rollout is aborted
Strategy:        Canary
  Step:          0/8
  SetWeight:     0
  ActualWeight:  0
Images:          argoproj/rollouts-demo:yellow (stable)
Replicas:
  Desired:       5
  Current:       5
  Updated:       0
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS        AGE    INFO
⟳ rollouts-demo                            Rollout     ✖ Degraded    21m
├──# revision:3
│  └──⧉ rollouts-demo-6f75f48b7            ReplicaSet  • ScaledDown  90s    canary
├──# revision:2
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  ✔ Healthy     13m    stable
│     ├──□ rollouts-demo-789746c88d-l4gmd  Pod         ✔ Running     13m    ready:1/1
│     ├──□ rollouts-demo-789746c88d-67dwp  Pod         ✔ Running     6m46s  ready:1/1
│     ├──□ rollouts-demo-789746c88d-k7mfk  Pod         ✔ Running     6m24s  ready:1/1
│     ├──□ rollouts-demo-789746c88d-glbfb  Pod         ✔ Running     6m12s  ready:1/1
│     └──□ rollouts-demo-789746c88d-nntc9  Pod         ✔ Running     18s    ready:1/1
└──# revision:1
   └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  • ScaledDown  21m

最终应用会回退到稳定版本。

但是我们可以看到 Status 是Degraded状态而并非Healthy状态，我们有必须要将其变成Healthy状态。最简单的办法就是执行如下命令重新发布一下版本：

kubectl argo rollouts set image rollouts-demo \
  rollouts-demo=argoproj/rollouts-demo:yellow

执行过后，可以看到其状态立即变成 Healthy，并且没有创建新的副本、新的版本，如下：

Name:            rollouts-demo
Namespace:       default
Status:          ✔ Healthy
Strategy:        Canary
  Step:          8/8
  SetWeight:     100
  ActualWeight:  100
Images:          argoproj/rollouts-demo:yellow (stable)
Replicas:
  Desired:       5
  Current:       5
  Updated:       5
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS        AGE  INFO
⟳ rollouts-demo                            Rollout     ✔ Healthy     40m
├──# revision:4
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  ✔ Healthy     32m  stable
│     ├──□ rollouts-demo-789746c88d-l4gmd  Pod         ✔ Running     32m  ready:1/1
│     ├──□ rollouts-demo-789746c88d-67dwp  Pod         ✔ Running     26m  ready:1/1
│     ├──□ rollouts-demo-789746c88d-k7mfk  Pod         ✔ Running     25m  ready:1/1
│     ├──□ rollouts-demo-789746c88d-glbfb  Pod         ✔ Running     25m  ready:1/1
│     └──□ rollouts-demo-789746c88d-nntc9  Pod         ✔ Running     19m  ready:1/1
├──# revision:3
│  └──⧉ rollouts-demo-6f75f48b7            ReplicaSet  • ScaledDown  20m
└──# revision:1
   └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  • ScaledDown  40m

回退应用

有时候在应用上线过后，有些 BUG 并没有发现，这时候要回退怎么办呢？argo rollouts 有一个undo命令，可以进行回退。

比如我们要将版本回退到第一个版本，则执行一下命令：

kubectl-argo-rollouts undo  rollouts-demo --to-revision=1

然后通过 watch 界面可以看到如下信息：

Name:            rollouts-demo
Namespace:       default
Status:          ॥ Paused
Message:         CanaryPauseStep
Strategy:        Canary
  Step:          1/8
  SetWeight:     20
  ActualWeight:  20
Images:          argoproj/rollouts-demo:blue (canary)
                 argoproj/rollouts-demo:yellow (stable)
Replicas:
  Desired:       5
  Current:       5
  Updated:       1
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS        AGE  INFO
⟳ rollouts-demo                            Rollout     ॥ Paused      45m
├──# revision:5
│  └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  ✔ Healthy     45m  canary
│     └──□ rollouts-demo-7bf84f9696-bn2lz  Pod         ✔ Running     36s  ready:1/1
├──# revision:4
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  ✔ Healthy     36m  stable
│     ├──□ rollouts-demo-789746c88d-l4gmd  Pod         ✔ Running     36m  ready:1/1
│     ├──□ rollouts-demo-789746c88d-67dwp  Pod         ✔ Running     30m  ready:1/1
│     ├──□ rollouts-demo-789746c88d-k7mfk  Pod         ✔ Running     29m  ready:1/1
│     └──□ rollouts-demo-789746c88d-glbfb  Pod         ✔ Running     29m  ready:1/1
└──# revision:3
   └──⧉ rollouts-demo-6f75f48b7            ReplicaSet  • ScaledDown  25m

首先 revision 为 1 的版本标记没有，重新创建了一个为 5 的标记，而且第一步处于暂停状态，然后我们执行promote命令继续后续的更新，如下：

kubectl argo rollouts promote rollouts-demo

然后我们可以看到如下信息：

Name:            rollouts-demo
Namespace:       default
Status:          ✔ Healthy
Strategy:        Canary
  Step:          8/8
  SetWeight:     100
  ActualWeight:  100
Images:          argoproj/rollouts-demo:blue (stable)
Replicas:
  Desired:       5
  Current:       5
  Updated:       5
  Ready:         5
  Available:     5

NAME                                       KIND        STATUS        AGE    INFO
⟳ rollouts-demo                            Rollout     ✔ Healthy     48m
├──# revision:5
│  └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  ✔ Healthy     48m    stable
│     ├──□ rollouts-demo-7bf84f9696-bn2lz  Pod         ✔ Running     3m21s  ready:1/1
│     ├──□ rollouts-demo-7bf84f9696-xn6dr  Pod         ✔ Running     56s    ready:1/1
│     ├──□ rollouts-demo-7bf84f9696-w58vm  Pod         ✔ Running     44s    ready:1/1
│     ├──□ rollouts-demo-7bf84f9696-fns8d  Pod         ✔ Running     33s    ready:1/1
│     └──□ rollouts-demo-7bf84f9696-qt6f9  Pod         ✔ Running     22s    ready:1/1
├──# revision:4
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  • ScaledDown  39m
└──# revision:3
   └──⧉ rollouts-demo-6f75f48b7            ReplicaSet  • ScaledDown  27m

从Images可以看到回退到我们最初版本为blue的镜像了。

Traffic Shifting

上面我们并没有接入外部流量，仅仅是在内部使用展示了金丝雀部署过程，下面我们接入外部流量进行测试。

Argo-Rollout 主要集成了Ingress和ServiceMesh两种流量控制方法。

目前 Ingress 支持 ALB 和 NGINX ingress。但是我使用的是 nginx ingress。

(1) 部署应用

我们依然使用官方的例子进行展示。

首先删除上面的例子。

kubectl delete -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/basic/rollout.yaml
kubectl delete -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/basic/service.yaml

然后重新部署一个官方的例子，如下：

kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/nginx/rollout.yaml
kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/nginx/services.yaml
kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/nginx/ingress.yaml

这个例子包含 1 个 rollout，2 个 service，1 个 ingress。

它们的配置文件分别如下。

rollout.yaml，为了便与测试，我将权重改为了 50

apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
  name: rollouts-demo
spec:
  replicas: 1
  strategy:
    canary:
      canaryService: rollouts-demo-canary
      stableService: rollouts-demo-stable
      trafficRouting:
        nginx:
          stableIngress: rollouts-demo-stable
      steps:
        - setWeight: 50
        - pause: {}
  revisionHistoryLimit: 2
  selector:
    matchLabels:
      app: rollouts-demo
  template:
    metadata:
      labels:
        app: rollouts-demo
    spec:
      containers:
        - name: rollouts-demo
          image: argoproj/rollouts-demo:blue
          ports:
            - name: http
              containerPort: 8080
              protocol: TCP
          resources:
            requests:
              memory: 32Mi
              cpu: 5m

services.yaml

apiVersion: v1
kind: Service
metadata:
  name: rollouts-demo-canary
spec:
  ports:
    - port: 80
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app: rollouts-demo
    # This selector will be updated with the pod-template-hash of the canary ReplicaSet. e.g.:
    # rollouts-pod-template-hash: 7bf84f9696

---
apiVersion: v1
kind: Service
metadata:
  name: rollouts-demo-stable
spec:
  ports:
    - port: 80
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app: rollouts-demo
    # This selector will be updated with the pod-template-hash of the stable ReplicaSet. e.g.:
    # rollouts-pod-template-hash: 789746c88d

ingress.yaml

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: rollouts-demo-stable
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  rules:
    - host: rollouts-demo.local
      http:
        paths:
          - path: /
            backend:
              # Reference to a Service name, also specified in the Rollout spec.strategy.canary.stableService field
              serviceName: rollouts-demo-stable
              servicePort: 80

从配置文件可以看出 Rollout 里分别用canaryService和stableService分别定义了该应用灰度的 Service Name(rollouts-demo-canary)和当前版本的 Service Name(rollouts-demo-stable)。而且 rollouts-demo-canary 和 rollouts-demo-stable 的 service 的内容是一样的。selector 中暂时没有填上 pod-template-hash，Argo-Rollout Controller 会根据实际的 ReplicaSet hash 来修改该值。

当我们创建完 ingress 后，Rollout Controller 会根据ingress rollouts-demo-stable 内容，自动创建一个ingress用了灰度的流量，名字为<ROLLOUT-NAME>-<INGRESS-NAME>-canary，所以这里多了一个ingress rollouts-demo-rollouts-demo-stable-canary，将流量导向 Canary Service(rollouts-demo-canary)。如下：

# kubectl get ingress
NAME                                        HOSTS                     ADDRESS   PORTS   AGE
rollouts-demo-rollouts-demo-stable-canary   rollout-demo.coolops.cn             80      9m25s
rollouts-demo-stable                        rollout-demo.coolops.cn             80      4m12s

rollouts-demo-rollouts-demo-stable-canary 的内容如下：

# kubectl get ingress rollouts-demo-rollouts-demo-stable-canary -o yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: traefik
    nginx.ingress.kubernetes.io/canary: "true"
    nginx.ingress.kubernetes.io/canary-weight: "0"
  creationTimestamp: "2020-12-09T02:21:52Z"
  generation: 2
  name: rollouts-demo-rollouts-demo-stable-canary
  namespace: default
  ownerReferences:
    - apiVersion: argoproj.io/v1alpha1
      blockOwnerDeletion: true
      controller: true
      kind: Rollout
      name: rollouts-demo
      uid: 4e74913b-5c89-4275-8f4c-768f23c63c34
  resourceVersion: "15681411"
  selfLink: /apis/extensions/v1beta1/namespaces/default/ingresses/rollouts-demo-rollouts-demo-stable-canary
  uid: bc66dfc4-6e98-419b-a288-f67e1233ef3e
spec:
  rules:
    - host: rollout-demo.coolops.cn
      http:
        paths:
          - backend:
              serviceName: rollouts-demo-canary
              servicePort: 80
            path: /

通过域名访问，可以看到如下界面。

(2) 更新应用

现在通过以下命令来进行应用更新操作。

kubectl argo rollouts set image rollouts-demo rollouts-demo=argoproj/rollouts-demo:yellow

然后通过状态窗口可以看到如下信息。

Name:            rollouts-demo
Namespace:       default
Status:          ॥ Paused
Message:         CanaryPauseStep
Strategy:        Canary
  Step:          1/2
  SetWeight:     50
  ActualWeight:  50
Images:          argoproj/rollouts-demo:blue (stable)
                 argoproj/rollouts-demo:yellow (canary)
Replicas:
  Desired:       1
  Current:       2
  Updated:       1
  Ready:         2
  Available:     2

NAME                                       KIND        STATUS     AGE    INFO
⟳ rollouts-demo                            Rollout     ॥ Paused   2m13s
├──# revision:2
│  └──⧉ rollouts-demo-789746c88d           ReplicaSet  ✔ Healthy  89s    canary
│     └──□ rollouts-demo-789746c88d-spn4s  Pod         ✔ Running  89s    ready:1/1
└──# revision:1
   └──⧉ rollouts-demo-7bf84f9696           ReplicaSet  ✔ Healthy  2m     stable
      └──□ rollouts-demo-7bf84f9696-7rwkx  Pod         ✔ Running  2m     ready:1/1

然后可以看到rollouts-demo-rollouts-demo-stable-canary的 ingress 的 annotations 中新增了两个参数，如下：

# kubectl get ingress rollouts-demo-rollouts-demo-stable-canary -o yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/canary: "true"
    nginx.ingress.kubernetes.io/canary-weight: "50"
  creationTimestamp: "2020-12-09T03:01:04Z"
  generation: 1
  name: rollouts-demo-rollouts-demo-stable-canary
  namespace: default
  ownerReferences:
  - apiVersion: argoproj.io/v1alpha1
    blockOwnerDeletion: true
    controller: true
    kind: Rollout
    name: rollouts-demo
    uid: 4d956f2a-9e15-4453-b918-926c4a75f884
  resourceVersion: "15686969"
  selfLink: /apis/extensions/v1beta1/namespaces/default/ingresses/rollouts-demo-rollouts-demo-stable-canary
  uid: c9242819-d088-4fc4-bd4d-8870360fa96e
spec:
  rules:
  - host: rollout-demo.coolops.cn
    http:
      paths:
      - backend:
          serviceName: rollouts-demo-canary
          servicePort: 80
        path: /

然后通过网页，可以看到如下的输出展示。

然后可以通过验证结果来判断是否继续还是终止。

如果继续使用如下命令：

kubectl argo rollouts promote rollouts-demo

如果终止使用如下命令：

kubectl argo rollouts abort rollouts-demo

写在最后

目前我还在测试阶段，并没有实际接入使用。通过测试来看，Argo-Rollout 提供更加强大的 Deployment，包含比较适合运维的金丝雀发布和蓝绿发布功能，要使用蓝绿发布，仅需要配置 rollout，如下：

apiVersion: argoproj.io/v1alpha1
kind: Rollout ##部署完rollout后就有了这个kind 资源，这个资源和deployment类似也是管理你的副本集的，所以不能像deployment那样在k8s界面看见，只能通过kubectl命令行
metadata:
  name: rollout-bluegreen
  namespace: rollout-test
spec:
  template:
    spec:
      terminationGracePeriodSeconds: 30
      containers:
        - resources: #{}
            requests:
              cpu: "1"
              memory: "2Gi"
            limits:
              cpu: "2"
              memory: "2Gi"
          terminationMessagePolicy: File
          imagePullPolicy: Always
          name: rollout-bluegreen
          image: argoproj/rollouts-demo:green #nginx:1.17.1
      schedulerName: default-scheduler
      securityContext: {}
      dnsPolicy: ClusterFirst
      restartPolicy: Always
    metadata:
      labels:
        app: rollout-bluegreen
  selector:
    matchLabels:
      app: rollout-bluegreen
  replicas: 2
  strategy:
    blueGreen: ##蓝绿启用配置
      activeService: rollout-bluegreen-active #生效的服务，需要自己创建建本代码最下面service资源。
      previewService: rollout-bluegreen-preview #配置预览服务，同理需要自己创建
      autoPromotionEnabled: true ##是否直接切换，如为true，会在新版本变绿后直接切换到对外服务。
      scaleDownDelayRevisionLimit: 0
      previewReplicaCount: 1 #新版本的pod数量，设为一个从而控制资源消耗
    rollingUpdate:
      maxUnavailable: 25%
      maxSurge: 25%
    type: RollingUpdate
  revisionHistoryLimit: 2
  progressDeadlineSeconds: 600

---
apiVersion: v1
kind: Service
metadata:
  name: rollout-bluegreen-active
  namespace: rollout-test
spec:
  sessionAffinity: None
  selector:
    app: rollout-bluegreen
  ports:
    - protocol: TCP
      port: 80
      targetPort: 8080
  type: LoadBalancer

整体使用还是比较丝滑，如果测试通过后续考虑集成进 CD 中。更多内容可以到https://argoproj.github.io/argo-rollouts/进行学习。