BlogCI/CD
Blue-green and canary deploys from your pipeline
Ship with zero downtime and instant rollback by shifting traffic between versions instead of replacing in place.
Rolling updates replace pods in place — if the new version is bad, you are already partly down. Blue-green and canary deploys keep the old version running and shift traffic instead, so rollback is a routing change measured in seconds, not a redeploy.
Rolling
replace in place
no extra capacity
rollback = redeploy
default, simplest
Blue-green / canary
both versions live
shift traffic
instant rollback
needs 2x briefly
1
Green up
new version deployed
2
Smoke test
green, no live traffic
3
Switch
router -> green
4
Blue idles
instant rollback target
The switch is a selector
At its simplest, blue-green is one Service selector flipping between two ReplicaSets. Argo Rollouts automates the promotion, analysis, and rollback.
rollout.yaml
strategy:canary:steps:- setWeight: 10- pause: { duration: 5m } # watch metrics- setWeight: 50- pause: { duration: 5m }- setWeight: 100
Roll back before users notice
A canary that fails its analysis at 10% weight only ever touched 10% of traffic, and Argo Rollouts aborts automatically. That is the whole value.