auth-service: 12 callers identified via traffic logs
All internal. Migration target identified for each.
Write the decom brief and pick a target decom date
2-3 hr
billing-service: still receiving 100 req/min from external partner
Need to coordinate sunset with partner — 90 day notice.
Inventory every known caller
Half a day to a day
search-service: 0 callers in past 7 days
Confirmed via traffic monitor. Safe to drop.
Add deprecation warnings to every response
2-3 hr
Run a brownout: short, scheduled outages
2-3 weeks of brownouts spread out
notification-service: 4 callers, all internal
All caller teams notified. Migration to new service Q3.
Drive the long-tail callers off
2-3 weeks (depends on caller count)
Verify zero traffic for 7 consecutive days
7 days observation
Run the 30-day silence test
30 days observation
Archive the database and the runbooks
1-2 days
Decom day: delete code, drop database, remove DNS
Half a day
Watch for 7 days post-decom for shadow traffic
7 days observation
Run a post-decom retro and update the team's template
30 min retro