What is Blue-Green Deployment?
Blue-green deployment, told as a story about two identical rides, taking turns.
While fixing the ride, no guests can get on.For as long as the repair takes, the ride simply has to stay closed.
You can't keep letting guests ride something that's mid-repair.Fixing it while guests are still riding is even more dangerous.
Twin rides, running one at a time.While one takes guests, the other gets fully repaired.
Flip the sign, and the switch is done.The line that went to green now heads to blue instead.
Keeping two rides running costs twice as much.Switching back is easy — but the guest-log gap that built up in between needs care.
Blue-green deployment = keeping two identical rides, fully repairing the idle one while the other keeps taking guests, then switching with no downtime by just flipping the sign.
A deployment strategy that prepares a whole second environment identical to the live one, tests it fully, and then switches all traffic over at once. If something goes wrong, flipping the arrow back reverts it instantly.
When grown-ups say it
- Blue-green deployment
- Running twin rides, one at a time. One serves, one's repaired — the roles swap.
- Zero-downtime deployment
- A deployment with almost no downtime. Guests barely notice the switch happening.
- Switchover
- The moment the sign gets flipped. One flip sends every guest to the new side.
- Instant rollback
- Flipping the sign back to where it was. Reverting is much simpler than with a canary
- vs. canary
- Switching everything, versus showing it to a few first. Canary starts at 1% and grows from there
- Downtime
- Time when no guests can get on. Blue-green cuts this down to almost nothing.
- Twin-environment cost
- The cost of keeping two rides running. It always takes double the space and staff.
- Rollback
- Back to yesterday's version, right away. → back to yesterday's version, fast