Perform Canary Deployments using Argo Rollouts

Projects: c2platform/ansible, c2platform.core, c2platform.mw

The installation steps outlined in the Argo Rollouts documentation  have already been completed by Ansible during the first step of this tutorial: Install and Manage Argo CD with Ansible . This occurs when you execute the command vagrant up c2d-argocd. The PlantUML diagram below depicts the structure set up by Ansible.

Prerequisites

• Install and Manage Argo CD with Ansible: Set up a Kubernetes Cluster, install Argo CD, and manage both using C2 Platform’s Ansible roles for Linux and Kubernetes.

Rollout Status

Using the c2 alias, navigate to the project directory and activate the Python virtual environment, then SSH into the Argo CD container c2d-argocd:

c2
vagrant ssh c2d-argocd

Use the Argo Rollouts Kubectl Plugin to see the current status of the rollout.

kubectl argo rollouts get rollout rollouts-demo --watch \
  --namespace argo-rollouts-demo

This will display five pods, running based on the image argoproj/rollouts-demo:blue.

Access Argo Rollouts Demo UI

Launch Firefox using the configured Firefox profile (see Configure a FireFox Profile ). Navigate to http://1.1.4.25/ , log in as admin with the password supersecret. You should see the Argo Rollouts Demo application. With only “blue” pods running, the app should look like the image below, displaying only blue squares.

Update Rollout

Use kubectl to update the rollout to “yellow”:

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

Name:            rollouts-demo
Namespace:       argo-rollouts-demo
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   6h22m
├──# revision:4
│  └──⧉ rollouts-demo-6cf78c66c5           ReplicaSet  ✔ Healthy  6h4m    canary
│     └──□ rollouts-demo-6cf78c66c5-cmmqb  Pod         ✔ Running  4m49s   ready:1/1
└──# revision:3
  └──⧉ rollouts-demo-687d76d795           ReplicaSet  ✔ Healthy  6h22m   stable
      ├──□ rollouts-demo-687d76d795-4cw2p  Pod         ✔ Running  6h22m   ready:1/1
      ├──□ rollouts-demo-687d76d795-fm82t  Pod         ✔ Running  6h22m   ready:1/1
      ├──□ rollouts-demo-687d76d795-24kbs  Pod         ✔ Running  6h22m   ready:1/1
      └──□ rollouts-demo-687d76d795-dg55c  Pod         ✔ Running  6h22m   ready:1/1

According to the rollout specification, the canary deployment is conducted in steps. The first steps involve setting the weight to 20 and then pausing. Thus, one yellow canary pod is initiated and receives 20% of the traffic.

You can find the rollout specification in group_vars/argocd/argo_rollouts_demo.yml 

  strategy:
    canary:
      steps:
      - setWeight: 20
      - pause: {}
      - setWeight: 40
      - pause: {duration: 10}
      - setWeight: 60
      - pause: {duration: 10}
      - setWeight: 80
      - pause: {duration: 10}

When you navigate to http://1.1.4.25/ , you should see yellow squares starting to appear.

Promote Rollout

kubectl argo rollouts promote rollouts-demo \
  --namespace argo-rollouts-demo

Abort Rollout

Use kubectl to update the rollout to “red”:

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

Abort the rollout

kubectl argo rollouts abort rollouts-demo \
  --namespace argo-rollouts-demo

Aborting the rollout will change its status to “degraded”. To stabilize it again, update the rollout back to yellow:

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

Additional Information

• Argo Rollouts - Kubernetes Progressive Delivery Controller 
  • Installation 
  • Basic Usage 
• argoproj/rollouts-demo