Installation guide

Example of Setting Up Apache HTTP Server
This appendix provides an example of setting up a highly available Apache HTTP Server on a Red
Hat Cluster. The example describes how to set up a service to fail over an Apache HTTP Server.
Variables in the example apply to this example only; they are provided to assist setting up a service
that suits your requirements.
Note
This example uses the Clu st er Co n f ig u rat io n T o o l (system-config-cluster). You can
use comparable Co n g a functions to make an Apache HTTP Server highly available on a Red
Hat Cluster.
A.1. Apache HTT P Server Set up Overview
First, configure Apache HTTP Server on all nodes in the cluster. If using a failover domain , assign
the service to all cluster nodes configured to run the Apache HTTP Server. Refer to Section 5.6,
“ Configuring a Failover Domain” for instructions. The cluster software ensures that only one cluster
system runs the Apache HTTP Server at one time. The example configuration consists of installing
the httpd RPM package on all cluster nodes (or on nodes in the failover domain, if used) and
configuring a shared GFS shared resource for the Web content.
When installing the Apache HTTP Server on the cluster systems, run the following command to
ensure that the cluster nodes do not automatically start the service when the system boots:
# chkconfig --del httpd
Rather than having the system init scripts spawn the httpd daemon, the cluster infrastructure
initializes the service on the active cluster node. This ensures that the corresponding IP address and
file system mounts are active on only one cluster node at a time.
When adding an httpd service, a floating IP address must be assigned to the service so that the IP
address will transfer from one cluster node to another in the event of failover or service relocation.
The cluster infrastructure binds this IP address to the network interface on the cluster system that is
currently running the Apache HTTP Server. This IP address ensures that the cluster node running
httpd is transparent to the clients accessing the service.
The file systems that contain the Web content cannot be automatically mounted on the shared
storage resource when the cluster nodes boot. Instead, the cluster software must mount and unmount
the file system as the httpd service is started and stopped. This prevents the cluster systems from
accessing the same data simultaneously, which may result in data corruption. Therefore, do not
include the file systems in the /etc/fstab file.
A.2. Configuring Shared St orage
To set up the shared file system resource, perform the following tasks as root on one cluster system:
1. On one cluster node, use the interactive parted utility to create a partition to use for the
document root directory. Note that it is possible to create multiple document root directories
on different disk partitions.
Example of Set t ing Up Apache HT T P Server
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