Managing AIX services with the System Resource Controller: lssrc, startsrc/stopsrc, and rc.tcpip

What it is

The System Resource Controller (SRC) is AIX's framework for starting, stopping and monitoring daemons ("subsystems") and collections of them ("groups"), analogous in role to systemd's units but built on the ODM rather than unit files. Each subsystem's definition — the path to its binary, its arguments, whether it restarts on failure — is an object in the SRCsubsys ODM class, inspected with odmget SRCsubsys (optionally piped through grep -p <subsystem> to isolate one entry).

Day-to-day control goes through SRC commands, not direct signals: lssrc -a lists all subsystems and groups with their status; lssrc -s <subsystem> checks one; startsrc -s <subsystem> and stopsrc -s <subsystem> start and stop it under SRC's supervision; refresh -s <subsystem> asks a running subsystem to reread its configuration. What starts automatically at boot is controlled separately, through /etc/inittab (queried and edited with lsitab/mkitab/chitab/rmitab rather than a text editor) — for example the rctcpip entry runs /etc/rc.tcpip, the script that starts the SRC-controlled TCP/IP daemons.

Why it matters

A daemon that is "managed by SRC" but fails to start silently is a known failure mode when its SRCsubsys ODM entry is missing or corrupt: no error message, and even truss or a kernel trace shows nothing unusual, because SRC itself never launched the process. Diagnosing this means checking the ODM entry, not the daemon's own logs. Because boot-time start is governed by /etc/inittab and the scripts it calls (not by systemd-style enable/disable flags), "is this on for next reboot" is answered by lsitab and by the uncommented start lines in scripts such as /etc/rc.tcpip, not by SRC's runtime status.

How to apply

• Check status broadly with lssrc -a before touching an individual daemon.
• Start/stop through SRC (startsrc -s, stopsrc -s) rather than killing or exec'ing the daemon binary directly, so SRC's supervision state stays consistent with reality.
• If a daemon under SRC control won't start and no error appears, inspect its ODM entry: odmget SRCsubsys | grep -p <subsystem>, and correct it with chssys (or recreate a missing entry with mkssys, or by reinstalling the owning fileset) rather than hand-editing the ODM.
• To see or change what starts at boot, use lsitab/mkitab against /etc/inittab, and for TCP/IP daemons started from /etc/rc.tcpip use chrctcp -a <daemon> / chrctcp -d <daemon> (add -S to also start or stop it now); startsrc/stopsrc alone never change boot-time activation.

Pitfalls

• Assuming a silently-failing SRC subsystem will log something; check the ODM entry directly instead.
• Confusing refresh -s (re-read configuration) with a restart; some daemons do not support a live refresh.
• Editing /etc/inittab with a text editor instead of mkitab/chitab, which can leave duplicate or malformed entries.