If found if kamailio started from command line like `kamailio -DD -E` and present `log_engine_type="systemd"`, then i can see messages from `sd_journal_print` and `xlog` functions.
When I start kamailio with same config as systemd service then I not see messages from `sd_journal_print` and `xlog` functions.
When I disable `log_engine_type="systemd"` then i can see output of `sd_journal_print` and `xlog` functions again. Think some issue exist here.
That is exactly what I find as well. I'm re-researching this as well as the new `systemdops.so` module to support `sd_notify()` in 0c48e1621c88bf1d390e4cfb82e52b2d6339b837. Both of them seem to suffer from the same issue -- the way Kamailio is forking interferes with the core using certain modules, as they relate to sending messages to systemd.