Using HP Serviceguard for Linux to Provide High Availability for LAMP, December 2005

Edit the package configuration file (lamp_single_pkg.config) and change the

PACKAGE_NAME and NODE_NAME fields according to the comments given in that file

template. The next set of editable fields in the package configuration file defines the path

to the package control file. Enter the path to the package control script for both the

RUN_SCRIPT and HALT_SCRIPT. In the package configuration file used in the

development of this white paper, these entries look as follows.

PACKAGE_NAME lamp_single

NODE_NAME node1

NODE_NAME node2

RUN_SCRIPT /usr/local/cmcluster/conf/http_pkg/lamp_single_pkg.cntl

RUN_SCRIPT_TIMEOUT NO_TIMEOUT

HALT_SCRIPT /usr/local/cmcluster/conf/http_pkg/lamp_single_pkg.cntl

HALT_SCRIPT_TIMEOUT NO_TIMEOUT

The following sets of fields define the service variables required to start monitor services

for both Apache and MySQL. Since in this configuration both Apache and MySQL run as

a consolidated stack both MySQL and Apache monitor services need to be listed in this

file. The sample field entries are shown below.

SERVICE_NAME http.monitor

SERVICE_FAIL_FAST_ENABLED NO

SERVICE_HALT_TIMEOUT 300

SERVICE_NAME mysql.monitor

SERVICE_FAIL_FAST_ENABLED NO

SERVICE_HALT_TIMEOUT 300

Next, edit the package control script (lamp_single_pkg.cntl). Other scripts from both

original toolkits are called from this package control script. In a typical package control

script, calls to the toolkit.sh file can be made in two ways. One way to do this is to

enable the HA_APP_SERVER variable. This causes Serviceguard to make a call to the

toolkit.sh file in the current directory, in this case the Apache package directory. This is

one of the reasons for keeping the package configuration file and the package control

file in the Apache package directory. Another way to call the toolkit.sh is by making

explicit calls in the customer defined run and halt command functions. Since explicit

paths can be used here, it is not mandatory for the toolkit.sh file to reside in the current

directory. This feature can be used for calling the toolkit.sh for MySQL.

The two calling methods shown above can be merged so that both Apache and MySQL

toolkit.sh files can be called from the same package control script and both services can

run as part of the same package.

Various lines in the package control script (lamp_single_pkg.cntl) need to change:

VGCHANGE="vgchange -a y"

VG[0] ="vg01"

VG[1] ="vg02"

Where, VG[0] specifies the volume group for the shared Apache DocumentRoot directory

and VG[1] is the volume group for the MySQL database and configuration files.

LV[0]="/dev/vg01/lvol0"; FS[0]="/Apache"; FS_TYPE[0]="ext3";

FS_MOUNT_OPT[0]="-o rw"