Re:AWS Lambda Web Functions
by rahimnathwani on Tuesday October 13, 2026 @02:55PM
(#50076770)
If you scale Cloud Run to zero and then send a request, won't you immediately wake it up and be charged until it powers down in at least 15 minutes?
Re:AWS Lambda Web Functions
by CharlieDigital on Tuesday October 13, 2026 @03:51PM
(#50077634)
When scale to 0, it only bills when actively serving a request. BUT, the instance doesn't go cold immediately; you are only billed while it is serving even if the instance is active.
This diagram helps visualize: https://www.gstatic.com/bricks/image/5eb3c8e9-6159-4e2f-ba98... (gray bar at the top shows when the instance is started and when it ends; blue bars show actual request, and green bars show the billing)
If there's a 10s gap between requests, you are not billed for the 10s gap, but it is still effectively hot; instance does not stop. Request that comes back in 10s later does not have a startup penalty because the instance is still up.
How do you leverage this to build a high throughput system with no cold starts? Just prime it with a short single request (e.g. `/health`) before instance is stopped.
Re:AWS Lambda Web Functions
by rahimnathwani on Tuesday October 13, 2026 @04:12PM
(#50077967)
I assumed you were talking about instance-based billing (what I've always used), but I think you're talking about request-based billing?
Re:AWS Lambda Web Functions
by CharlieDigital on Tuesday October 13, 2026 @04:44PM
(#50078458)
Request based billing indeed.
So if you're at 50% capacity with lots of idle time, it can scale to 0.
Scale to 0 doesn't mean "cold". One easy way to keep both Cloud Run and Container Apps "warm" but functionally scaled to 0 for costs is to just ping it every few minutes with Cloud Scheduler set up on a cron pointing to a health endpoint.