In the upgrade path for x509 cluster auth, the -clusterAuthMode option "sendKeyfile" has different capitalization for “keyfile” than the rest of our command line options ( “sslPEMKeyFile”, “-keyFile”). Given that we camel-case on the word "file" in all other instances of keyFile, I’d argue that precedence suggests sendKeyfile should instead be sendKeyFile.

Likewise, the option keyfile should be keyFile.

This is pretty minor, but we might as well be as consistent as possible while the feature is fresh.