Starting and Stopping an OpenACS instance.

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The simplest way to start and stop and OpenACS site is to run the startup shell script provided, /var/lib/aolserver/$OPENACS_SERVICE_NAME/etc/daemontools/run. This runs as a regular task, and logs to the logfile. To stop the site, kill the script.

A more stable way to run OpenACS is with a "keepalive" mechanism of some sort, so that whenever the server halts or is stopped for a reset, it restarts automatically. This is recommended for development and production servers.

The Reference Platform uses Daemontools to control AOLserver. A simpler method, using init, is here.

Daemontools must already be installed. If not, install it.
Each service controlled by daemontools must have a directory in /service. That directory must have a file called run. It works like this:
- The init program starts every time the computer is booted.
- A line in init's configuration file, /etc/inittab, tells init to run, and to restart if necessary, svscanboot.
- svscanboot checks the directory /service every few seconds.
- If it sees a subdirectory there, it looks for a file in the subdirectory called run. If it finds a run file, it creates a supervise process
- supervise executes the run script. Whenever the run script stops, supervise executes it again. It also creates additional control files in the same directory.
Hence, the AOLserver instance for your development server is started by the file /service/$OPENACS_SERVICE_NAME/run. But we use a symlink to make it easier to add and remove stuff from the /service, so the actual location is /var/lib/aolserver/$OPENACS_SERVICE_NAMEetc/daemontools/run.
Daemontools creates additional files and directories to track status and log. A daemontools directory is included in the OpenACS tarball at /var/lib/aolserver/$OPENACS_SERVICE_NAME/etc/daemontools. To use it, first ill any existing AOLserver instances. As root, link the daemontools directory into the /service directory. Daemontools' svscan process checks this directory every five seconds, and will quickly execute run.
```
[$OPENACS_SERVICE_NAME etc]$ killall nsd
nsd: no process killed
[$OPENACS_SERVICE_NAME etc]$ emacs /var/lib/aolserver/$OPENACS_SERVICE_NAME/etc/daemontools/run
[$OPENACS_SERVICE_NAME etc]$ exit

[root root]# ln -s /var/lib/aolserver/$OPENACS_SERVICE_NAME/etc/daemontools/ /service/$OPENACS_SERVICE_NAME
```
Verify that AOLserver is running.
```
[root root]# ps -auxw | grep nsd
$OPENACS_SERVICE_NAME   5562 14.4  6.2 22436 15952 ?       S    11:55   0:04 /usr/local/aolserver/bin/nsd -it /var/lib/aolserver/$OPENACS_SERVICE_NAME/etc/config.tcl -u serve
root      5582  0.0  0.2  3276  628 pts/0    S    11:55   0:00 grep nsd
[root root]#
```
The user $OPENACS_SERVICE_NAME can now control the service $OPENACS_SERVICE_NAME with these commands:
- svc -d /service/$OPENACS_SERVICE_NAME - Bring the server down
- svc -u /service/$OPENACS_SERVICE_NAME - Start the server up and leave it in keepalive mode.
- svc -o /service/$OPENACS_SERVICE_NAME - Start the server up once. Do not restart it if it stops.
- svc -t /service/$OPENACS_SERVICE_NAME - Stop and immediately restart the server.
- svc -k /service/$OPENACS_SERVICE_NAME - Sends the server a KILL signal. This is like KILL -9. AOLserver exits immediately. If svc -t fails to fully kill AOLserver, use this option. This does not take the server out of keepalive mode, so it should still bounce back up immediately.

Install a script to automate the stopping and starting of AOLserver services via daemontools. You can then restart a service via restart-aolserver $OPENACS_SERVICE_NAME

[root root]# cp /var/lib/aolserver/$OPENACS_SERVICE_NAME/packages/acs-core-docs/www/files/restart-aolserver-daemontools.txt /usr/local/bin/restart-aolserver
[root root]# chmod 755 /usr/local/bin/restart-aolserver
[root root]#

At this point, these commands will work only for the root user. Grant permission for the web group to use svc commands on the $OPENACS_SERVICE_NAME server.
```
[root root]# /usr/local/bin/svgroup web /service/$OPENACS_SERVICE_NAME
[root root]#
```
Verify that the controls work. You may want to tail -f /var/lib/aolserver/$OPENACS_SERVICE_NAME/log/$OPENACS_SERVICE_NAME-error.log in another window, so you can see what happens when you type these commands.
Most of this information comes from Tom Jackson's AOLserver+Daemontools Mini-HOWTO.

Table 6.1. How it Works

Program	Invoked by this program ...	... using this file	Where to find errors	Log goes to	Use these commands to control it
svscanboot	init	/etc/inittab	ps -auxw \| grep readproctitle	n/a
aolserver	supervise (a child of svscanboot)	/service/$OPENACS_SERVICE_NAME/run	/var/lib/aolserver/$OPENACS_SERVICE_NAME/log/error.log	/var/lib/aolserver/$OPENACS_SERVICE_NAME/log/$OPENACS_SERVICE_NAME.log	svc -k /service/$OPENACS_SERVICE_NAME
postgresql	Redhat init scripts during boot	/etc/init.d/postgresql	/usr/local/pgsql/data/server.log		service postgresql start (Red Hat), /etc/init.d/postgresql start (Debian)

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