<database>.sytem.namespaces deprecated in mongo 4.2+

[kwisatz]

The replication lag check for instance tries to run a find query on local.system.namespaces which mongo answers with

  "errmsg" : "not authorized on local to execute command { find: \"system.namespaces\", filter: {}, …

The problem is most likely not authorization though, but deprecation (CMIIW).
See https://docs.mongodb.com/manual/reference/system-collections/#%3Cdatabase%3E.system.namespaces

The find query should be replaced by a call to listCollections which is covered by the clusterMonitor role.

[joekinley]

Running into this myself, and it is quite annoying. Any plans to fix this?

[joekinley]

Okay, for anyone stumbling over this, there is a PR that fixes this issue (https://github.com/mzupan/nagios-plugin-mongodb/pull/247/files), which I tried, and can confirm that it works.