OpenRC service management on Alpine: rc-update, rc-service, runlevels and rc-status

Goal

Enable a service to start at boot, start/stop it immediately, and check what is actually running, on Alpine Linux 3.2x, and know where boot-time OpenRC logging goes (or does not go) by default.

Prerequisites

Root access; the package providing the service already installed via apk add.

Steps

1. Understand the two-command split: Alpine's documentation states "the init system manages the services, startup and shutdown of your computer," and separates runtime control from boot-time configuration. Manipulating a running service uses rc-service; enabling it for boot uses rc-update. Installing a package does not do either automatically.
2. Control a service right now: rc-service sshd start, rc-service sshd stop, or rc-service sshd status. These take effect immediately and do not touch boot configuration; stopping sshd or networking over an SSH session can cut that session off.
3. Enable a service to start at boot: rc-update add sshd default adds it to the default runlevel — the documentation's own example. Omitting the runlevel name (rc-update add sshd) targets whichever runlevel is currently active. "Enabling a service means putting it in a runlevel," and "a runlevel is simply a directory in" /etc/runlevels, containing a symlink to the service's script in /etc/init.d.
4. Disable it: rc-update delete sshd removes it from the current runlevel; rc-update delete sshd -a removes it from every runlevel it is in, the documented way to fully unhook a service.
5. See everything configured across runlevels: rc-update show -v lists services per runlevel, including -v for ones not assigned to any. See everything actually running in the current runlevel: rc-status, which lists services in the active runlevel by default, or rc-status boot for a named one.
6. If boot-time script output needs to be captured for troubleshooting, be aware it is not captured by default. The upstream OpenRC default /etc/rc.conf states that rc_logger "launches a logging daemon to log the entire rc process to" /var/log/rc.log (on Linux, not the sysinit runlevel), and ships it commented out (#rc_logger="NO"); check the file on the host, then set rc_logger="YES". This captures OpenRC's own startup sequence, not necessarily an individual daemon's runtime stdout/stderr, which depends on that daemon's own logging (commonly to syslog via a separately installed and enabled syslog service).

Expected result

rc-update show -v lists the service under the intended runlevel; rc-status shows it as started once enabled and either booted or manually started; after enabling rc_logger, /var/log/rc.log exists and contains boot-sequence entries from the next boot onward.

Limits and test basis

rc-service <name> start run on a service not in any runlevel works for that boot only and reverts on the next reboot unless also added with rc-update; conversely, rc-update add alone does not start the service immediately. Removing a service from all runlevels with rc-update delete -a does not stop it if it is currently running — stop it explicitly first if a full teardown is intended.