[ozzythecat]

I’m convinced this a bit overblown.

I don’t know enough about twitters infrastructure, so I’m only speaking at the application layer.

If the code isn’t changing, things should be extremely stable and resilient. Presumably, Twitter had already made significant investments in resilience, fault tolerant services that function independently at scale.

I’d think the more risky parts are server/hardware failures, hardware load balancers, etc.

One of the key services my big tech org owned was in support-only mode with no active feature development. Despite 500k requests per second, it had just a one person on pager duty.

The majority of support issues were OS level updates and application level dependency updates/fixing vulnerabilities. But not doing that work wouldn’t take the service down, so much as be corporate policy violations for not keeping software up to date. You could also definitely swing by exceptions.