Standard NPM package metadata and package requests to a group repository containing an npm proxy repo using S3 storage against the official registry may start returning 500 status responses. This problem only occurs in HA clusters. The initial caching of the npm packages works fine, then later the blobs go missing and nexus responds with 500 for every npm package metadata request and related package requests.
The log messages suggest the the database is referencing a blob which can't be found in the S3 bucket and can't be fetched from the remote anymore either.
We have been able to reproduce this in versions 3.16.x under load testing.
We have made improvements to npm proxy repository request processing in the upcoming 3.17.0 release (
NEXUS-19941), and can no longer reproduce it in that version. This is not a complete fix though, and work to determine the underlying causes is still ongoing. This issue is open to track that work.
For those running 3.16.x, our testing has found that directing all npm traffic to a single node in the HA cluster provides a workaround, so far we haven't been able to reproduce the problem with that setup.