print log messages to journald

[andreasgerstmayr]

Currently only systemd-related messages are in the journal, but not the actual log output of the systemd services, for example pmproxy:

[root@ci-vm-10-0-139-91 lemon]# journalctl -e -u pmproxy
-- Logs begin at Wed 2020-09-09 12:10:27 EDT, end at Wed 2020-09-09 13:16:21 EDT. --
Sep 09 13:16:21 lemon systemd[1]: Starting Proxy for Performance Metrics Collector Daemon...
Sep 09 13:16:21 lemon pmproxy[21091]: Starting pmproxy ...
Sep 09 13:16:21 lemon systemd[1]: Started Proxy for Performance Metrics Collector Daemon.

[root@ci-vm-10-0-139-91 lemon]# cat /var/log/pcp/pmproxy/pmproxy.log 
Log for pmproxy on lemon started Wed Sep  9 13:16:21 2020

pmproxy: PID = 21091, PDU version = 2, user = pcp (993)
pmproxy request port(s):
  sts fd   port  family address
  === ==== ===== ====== =======
  ok    14       unix   /run/pcp/pmproxy.socket
  ok    15 44322 inet   INADDR_ANY
  ok    19 44322 ipv6   INADDR_ANY
  ok    20 44323 inet   INADDR_ANY
  ok    21 44323 ipv6   INADDR_ANY
[Wed Sep  9 13:16:21] pmproxy(21091) Info: OpenSSL 1.1.1g FIPS  21 Apr 2020 - no certificates found
[Wed Sep  9 13:16:21] pmproxy(21091) Info: Redis slots, command keys, schema version setup

[kmcdonell]

Sorry Andreas, I disagree.

We should use less of systemd/journald not more ... in over 20 years I cannot recall one instance in which systemd has helped PCP nor one instance in which I've wished PCP logs info was in journald's sphere of influence.

The PCP logs (pmproxy and pmcd in particular) contain a lot of information that has no place in a system-level log ... it did not go to syslog for a bunch of reasons, it should not go to joutrnald for all the same reasons.

[andreasgerstmayr]

We should use less of systemd/journald not more

Given that systemd is the default in most popular linux distributions, I think we should strive to make the experience using systemd+PCP the best possible. journalctl is the first thing to look at if any systemd service doesn't work as expected.

I think most of the problems of integrating PCP with systemd stem from the issue that systemd wants to do things which PCP is doing, for example PMCD starting PMDAs and pmlogger starting individual pmlogger processes. In the case of pmproxy, systemd could start the pmproxy binary directly, pmproxy can run in the foreground and log to stdout/stderr. afaics that's the most common way systemd services are configured & that way it works without issues from my experience.