@Sergey_Zelenov that configuration indeed gets passed to Mongo as part of /etc/mongodb-config/mongod.conf configuration file. Make sure that you do not have a conflicting configuration field in your cr.yml that might override that value you are setting like I did (ref).
The thing is that Mongo’s quiet mode does not silence the NETWORK spam, and you cannot disable the network component from systemLog as it is already set to 0 by default, the least verbose level (ref).
It seems to be a Mongo limitation, which has been raised quite a bit and which would require changes to the source code. Considering the Percona operator is behind by a couple majors, it doesn’t seem like there would be a short term solution following that path.
However, I envision it might be possible to effectively do what we want by creating another container you’d pipe the mongo logs to which would be in charge of eliminating the noise, if we cannot update whatever connects to the db without a long-lived connection as I mentioned here.