Modern Deployment Methods¶

The two popular modern deployment methods are:

blue/green deployment
canary rollout

Choices of tools

There're different tools supporting the blue/green and canary rollout:

Ingress
Istio
Knative
Argo Rollout
Flagger
...

Blue/Green Deployment¶

For a blue/green deployment, two working deployments are deployed but only one is public.

Pre-launch¶

The latest version is deployed into the environment, but not receiving any public traffic.

graph TD

traffic(Traffic) --100%--> stable(Stable)
traffic --0%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style stable stroke:blue,stroke-width:2px
style latest stroke:green,stroke-width:2px

By seting up specific routing rules (route by header, cookies, etc), the latest deployment can be access secretly for testing.

graph TD

traffic(Traffic) --100%--> stable(Stable)
traffic --secret path--> latest(Latest)
traffic --0%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style stable stroke:blue,stroke-width:2px
style latest stroke:green,stroke-width:2px

Launch¶

If all the testing results are good, the latest version will be rolled out.

graph TD

traffic(Traffic) --0%--> stable(Stable)
traffic --100%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style stable stroke:blue,stroke-width:2px
style latest stroke:green,stroke-width:2px

Roll Back¶

If a defect is found in the latest version, the we can adjust the traffic routing to roll back to the stable version.

The latest version is still up and running and leaves us the environment to do further trouble shoot.

graph TD

traffic(Traffic) --100%--> stable(Stable)
traffic --secret path--> latest(Latest)
traffic --0%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style stable stroke:blue,stroke-width:2px
style latest stroke:red,stroke-width:3px

Canary Rollout¶

For a canary rollout, multiple working deployments are deployed and all can receive public.

Multiple versions

With canary rollout, you can have multiple versions with different features running and receiving public traffic at the same time with a limited impact on overall users.

Pre-launch¶

The latest version is deployed into the environment, but not receiving any public traffic.

graph TD

traffic(Traffic) --100%--> stable(Stable)
traffic --0%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style latest stroke:orange,stroke-width:2px

By setup specific routing rules (by header, cookies, etc), the latest deployment can be access secretly for testing.

graph TD

traffic(Traffic) --100%--> stable(Stable)
traffic --secret path--> latest(Latest)
traffic --0%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style latest stroke:orange,stroke-width:2px

Launch¶

If all the testing results are good, the latest version will be gradually rolled out.

80-20¶

graph TD

traffic(Traffic) --80%--> stable(Stable)
traffic --20%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style latest stroke:orange,stroke-width:2px

50-50¶

graph TD

traffic(Traffic) --50%--> stable(Stable)
traffic --50%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style latest stroke:orange,stroke-width:2px

20-80¶

graph TD

traffic(Traffic) --20%--> stable(Stable)
traffic --80%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style latest stroke:orange,stroke-width:2px

100-0¶

graph TD

traffic(Traffic) --100%--> stable(Stable)
traffic --0%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style latest stroke:orange,stroke-width:2px

Roll Back¶

If a defect is found in the latest version, the we can adjust the traffic routing to roll back to the stable version.

The latest version is still up and running and leaves us the environment to do further trouble shoot.

graph TD

traffic(Traffic) --100%--> stable(Stable)
traffic --secret path--> latest(Latest)
traffic --0%--> latest(Latest)

subgraph stable
    ins1(Instance 1)
    ins2(Instance 2)
end

subgraph latest
    ins3(Instance 1)
    ins4(Instance 2)
end

subgraph Service
  stable
  latest
end

style latest stroke:orange,stroke-width:2px

Comparison¶

Featue	Blue Green	Canary
Traffic	Only one service facing public	Can have more than one service facing public
Rollback	Switch traffic to stable version	Reduce the traffic of version with defect to 0%, keep other version(s) keep receiving traffic
Requirement	Applicable to most services	Backward compatible is required
Limitation	The potential defect will impact all public traffic	Not suitable for new feature, new endpoints including frontend packed css and js chunks