Renewal fails with error: auto-ssl: failed to obtain lock: closed, context: ngx.timer

We are using redis in the backend for storing certificates. We have around 9 lacs certificates in our cache. After every few days we are facing this error and our renewals are failing. We are running around 8 openresty servers. We also noticed sometimes renewal doesn't happen for all the domains present in our cache.

If anyone could provide any help, that would be great.

Thank you in advance.

Start by tracing the renewal work scheduled through ngx.timer and the Redis-backed certificate cache in lua-resty-auto-ssl. Reproduce the closed-lock error with multiple OpenResty servers and a large cache, then verify that renewals complete for all cached domains without lock failures.

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