Blue Green and Canary Deployment

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• These aren’t built-in like RollingUpdate or Recreate that we saw in Deployment but can be implemented using Deployments and Services.

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Blue Green Deployment

• Run two versions of your app:
  • Blue = old version (e.g., v1)
  • Green = new version (e.g., v2)
• 100% traffic goes to blue at first
• You will take below steps:
  1. Deploy green version (new deployment)
  2. Run tests on green version
  3. Once satisfied, switch traffic from blue to green

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How to switch

• Pods have labels like version: v1 or version: v2
• Service routes traffic using label selectors
  • Initially: selector: version=v1
  • After testing: change to selector: version=v2
• Now the service routes all traffic to the green (new) deployment

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Canary Deployment

• Canary deployment allows you deploy a new version of the app is deployed alongside the existing version.
• Only a small portion of the traffic is routed to the new version while the majority stays to on the stable version
• This allows testing the new version with real traffic before fully rolling it out.

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Limitation

• Traffic splitting is based on the number of pods.
• Precise traffic control is not possible with basic Deployments and Services.

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⬅️ Labels And Selectors | Jobs ➡️