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Configuration Example
=====================
This example `/etc/finit.conf` can also be split up in multiple `.conf`
files in `/etc/finit.d`. Available, but not yet enabled, services can
be placed in `/etc/finit.d/available` and enabled by an operator using
the [initctl](initctl.md) tool.
See the [contrib/][contrib] directory on GitHub for examples, or take a
peek at systems using Finit, like [Infix OS][infix] and [myLinux][].
> [!TIP]
> As of Finit v4.4, `.conf` lines can be broken up using the standard UNIX
> continuation character (`\`), trailing comments are also supported. The
> latter means you must escape any hashes used in directives and descriptions
> (`\#`). For more on this and examples, see the [finit.conf(5)][] manual or
> the [Configuration](config/index.md) section.
```ApacheConf
# Fallback if /etc/hostname is missing
host default
# Runlevel to start after bootstrap, 'S', default: 2
#runlevel 2
# Support for setting global environment variables, using foo=bar syntax
# be careful though with variables like PATH, SHELL, LOGNAME, etc.
#PATH=/usr/bin:/bin:/usr/sbin:/sbin
# Max file size for each log file: 100 kiB, rotate max 4 copies:
# log => log.1 => log.2.gz => log.3.gz => log.4.gz
log size=100k count=4
# Services to be monitored and respawned as needed
service [S12345] env:-/etc/conf.d/watchdog watchdog $WATCHDOG_OPTS $WATCHDOG_DEV -- System watchdog daemon
service [S12345] env:-/etc/conf.d/syslog syslogd -n $SYSLOGD_OPTS -- System log daemon
service [S12345] <pid/syslogd> env:-/etc/conf.d/klogd klogd -n $KLOGD_OPTS -- Kernel log daemon
service [2345] env:-/etc/conf.d/lldpd lldpd -d $LLDPD_OPTS -- LLDP daemon (IEEE 802.1ab)
# The BusyBox ntpd does not use syslog when running in the foreground
# So we use this trick to redirect stdout/stderr to a log file. The
# log file is rotated with the above settings. The condition declares
# a dependency on a system default route (gateway) to be set. A single
# <!> at the beginning means ntpd does not respect SIGHUP for restart.
service [2345] log:/var/log/ntpd.log <!net/route/default> ntpd -n -l -I eth0 -- NTP daemon
# For multiple instances of the same service, add :ID somewhere between
# the service/run/task keyword and the command.
service :80 [2345] merecat -n -p 80 /var/www -- Web server
service :8080 [2345] merecat -n -p 8080 /var/www -- Old web server
# Alternative method instead of below runparts, can also use /etc/rc.local
#sysv [S] /etc/init.d/keyboard-setup -- Setting up preliminary keymap
#sysv [S] /etc/init.d/acpid -- Starting ACPI Daemon
#task [S] /etc/init.d/kbd -- Preparing console
# Hidden from boot progress, using empty `--` description
#sysv [S] /etc/init.d/keyboard-setup --
#sysv [S] /etc/init.d/acpid --
#task [S] /etc/init.d/kbd --
# Run start scripts from this directory
# runparts /etc/start.d
# Virtual consoles run BusyBox getty, keep kernel default speed
tty [12345] /sbin/getty -L 0 /dev/tty1 linux nowait noclear
tty [2345] /sbin/getty -L 0 /dev/tty2 linux nowait noclear
tty [2345] /sbin/getty -L 0 /dev/tty3 linux nowait noclear
# Use built-in getty for serial port and USB serial
#tty [12345] /dev/ttyAMA0 noclear nowait
#tty [12345] /dev/ttyUSB0 noclear
# Just give me a shell, I need to debug this embedded system!
#tty [12345] console noclear nologin
```
The `service` stanza, as well as `task`, `run` and others are described in
full in the [Services Syntax](config/services.md) section.
Here's a quick overview of some of the most common components needed to start
a UNIX daemon:
```
service [LVLS] <COND> log env:[-]/etc/default/daemon daemon ARGS -- Example daemon
^ ^ ^ ^ ^ ^ ^ ^
| | | | | | | `---------- Optional description
| | | | | | `------------------ Daemon arguments
| | | | | `------------------------- Path to daemon
| | | | `---------------------------------------------------- Optional env. file
| | | `-------------------------------------------------------- Redirect output to log
| | `--------------------------------------------------------------- Optional conditions
| `---------------------------------------------------------------------- Optional Runlevels
`------------------------------------------------------------------------------ Supervised program (daemon)
```
Some components are optional: runlevel(s), condition(s) and description,
making it easy to create simple start scripts and still possible for more
advanced uses as well:
service /usr/sbin/sshd -D
Dependencies are handled using [conditions](conditions.md). One of
the most common conditions is to wait for basic networking to become
available:
service <net/route/default> nginx -- High performance HTTP server
Here is another example where we instruct Finit to not start BusyBox
`ntpd` until `syslogd` has started properly. Finit waits for `syslogd`
to create its PID file, by default `/var/run/syslogd.pid`.
service [2345] log <!pid/syslogd> ntpd -n -N -p pool.ntp.org
service [S12345] syslogd -n -- Syslog daemon
Notice the `log` keyword, BusyBox `ntpd` uses `stderr` for logging when
run in the foreground. With `log` Finit redirects `stdout` + `stderr`
to the system log daemon using the command line `logger(1)` tool.
A service, or task, can have multiple dependencies listed. Here we wait
for *both* `syslogd` to have started and basic networking to be up:
service [2345] log <pid/syslogd,net/route/default> ntpd -n -N -p pool.ntp.org
If either condition fails, e.g. loss of networking, `ntpd` is stopped
and as soon as it comes back up again `ntpd` is restarted automatically.
> [!NOTE]
> Make sure daemons do *not* fork and detach themselves from the controlling
> TTY, usually an `-n` or `-f` flag, or `-D` as in the case of OpenSSH above.
> If it detaches itself, Finit cannot monitor it and will instead try to
> restart it.
[finit.conf(5)]: https://man.troglobit.com/man5/finit.conf.5.html
[infix]: https://kernelkit.github.io
[myLinux]: https://github.com/troglobit/myLinux/
[contrib]: https://github.com/troglobit/finit/tree/master/contrib
|
