This article provides a solution for when the page cache is warming up and there is a stuck deployment or site down.
The cache warm up script, at the end of the post-deploy phase, sends requests at such a high rate that certain instances, like 4-cpu ones, cannot cope. Their nginx exhausts the number of workers.
Steps to reproduce:
Start cache warm up operations.
Pages or whole site loads.
The site is unavailable or the response time is too high.
Limit the number of concurrent connections during the cache warm-up. This requires adding the
WARM_UP_CONCURRENCY post-deploy variable to specify the number of warm-up requests that the cache warm-up script can send concurrently. Setting this option can help manage the load on Adobe Commerce’s cloud infrastructure. For steps, see Post-deploy variables > WARM_UP_CONCURRENCY in our developer documentation.
Full-Page Cache in our user guide