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Suppose you need to run 2 or more apache instances on 1 machine (for whatever reason)

Here is how you can do this in a way without the need to modify init scripts, compile a second instance, do some dirty hacks, ...

The SuSE apache package and scripts are already ready to achieve this.

In this example I'm going to run 2 instances (each on their own ip address)

If you install the apache2 package it will (by default) put all its configuration files under /etc/apache2. The apache is started via the startup script (/etc/init.d/apache2 - rcapache2).

The default configuration makes apache listen on all ip addresses, since we want to run a second instance of apache on a separate address we need to limit the first instance to its own address. This can be done by modifying the /etc/apache2/listen.conf file and specify on which address apache should listen. (e.g listen on ip 1.1.1.1)

Listen 1.1.1.1:80

After you made a change to this configuration file you need to restart apache. Verify if apache is now only listening on the specified ip.

# lsof -i tcp:80
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
httpd2-pr 6010 root 3u IPv4 18189 TCP 1.1.1.1:http (LISTEN)

Now we can continue with the configuration of our second instance.
Create a separate configuration directory for this instance

# cp -pr /etc/apache2 /etc/myapache2
# cp -p /etc/sysconfig/apache2 /etc/sysconfig/myapache2

Modify the necessary values like paths,etc... in the configuration files in /etc/myapache2/{httpd,default-server}.conf and the /etc/sysconfig/myapache2 file.

Don't forget to modify /etc/myapache2/listen.conf, where you need to specify the ip address (on which this instance should listen)

Listen 2.2.2.2:80

In the /etc/myapache2/default-server.conf add the following line (at the top)

PidFile /var/run/myapache2.pid

Otherwise the both apache instances will use the same pid file.

As a final step you now need to create a small wrapper script (around rcapache2) where you point the following variables to the directories of the 2nd instance

#!/bin/bash

export sysconfdir=/etc/myapache2
export sysconfig_apache=/etc/sysconfig/myapache2
export pidfile=/var/run/myapache2.pid
export logdir=/var/log/myapache2
export homedir=/var/lib/myapache2

rcapache2 $1

(offcourse this script needs some error handling)
Don't forget to make the script executable

That's it.

Now you can start both instances

rcapache2 start
/path/to/wrapper-script start