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'httpd' HA using Heartbeat

Step 1: Pre-Configuration Requirements

Assign hostname httpd-primary to primary node with IP address 192.168.230.138 to eth0.
Assign hostname httpd-slave to slave node with IP address 192.168.230.139 to eth0.
[root@httpd-primary ~]# cat /etc/hosts
127.0.0.1   localhost
192.168.230.138         httpd-primary
192.168.230.139         httpd-slave
Primary Server: httpd-primary
[root@httpd-primary ~]# uname -n
httpd-primary
Secondary Server: httpd-slave
[root@httpd-slave ~]# uname -n
httpd-slave
192.168.230.150 is the virtual IP address that will be used for our httpd webserver.
Configure httpd on both server is ‘httpd-primary’ and ‘httpd-slave’
Now lets install Heartbeat on both servers.

Step 2: Install EPEL repo.

[root@httpd-primary ~]# wget http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
Change the ‘https’ to ‘http’ in ‘epel.repo’, if you get an error when you do a ‘yum install heartbeat’
[root@httpd-primary ~]# vim /etc/yum.repos.d/epel.repo
[root@httpd-primary ~]# yum install heartbeat

Step 3: Heartbeat configuration

[root@httpd-primary ~]# cp /usr/share/doc/heartbeat-3.0.4/authkeys /etc/ha.d/
[root@httpd-primary ~]# cp /usr/share/doc/heartbeat-3.0.4/ha.cf /etc/ha.d/
[root@httpd-primary ~]# cp /usr/share/doc/heartbeat-3.0.4/haresources /etc/ha.d/

Step 4:

[root@httpd-primary ~]# vi /etc/ha.d/authkeys
Then add the following lines:
auth 2
2 sha1 anyRandomKeyHere

Step 5: Change the permission of the authkeys file:

chmod 600 /etc/ha.d/authkeys

Step 6: Moving to our second file (ha.cf) which is the most important. So edit the ha.cf file with vi:

vi /etc/ha.d/ha.cf
Add the following lines in the ha.cf file:
logfile /var/log/ha-log
logfacility local0
keepalive 2
deadtime 30
initdead 120
bcast eth0
udpport 694
auto_failback on
node httpd-primary
node httpd-slave

Step 7: update haresources

vi /etc/ha.d/haresources
Add the following line: 
httpd-primary 192.168.230.150 httpd

Step 8: Copy the /etc/ha.d/ directory from httpd-primary to httpd-slave:

scp -r /etc/ha.d/ root@httpd-slave:/etc/

Step 9: As we want httpd highly enabled let’s start configuring httpd:

vi /etc/httpd/conf/httpd.conf
Add this line in httpd.conf:
Listen 192.168.230.150:80

Step 10: Copy the /etc/httpd/conf/httpd.conf file from httpd-primary to httpd-slave:

scp /etc/httpd/conf/httpd.conf root@httpd-slave:/etc/httpd/conf/

Step 11: Create the file index.html on both nodes (httpd-primary & httpd-slave):

On httpd-primary:
echo "`uname -n` apache test server" > /var/www/html/index.html
On httpd-slave:
echo "`uname -n` apache test server" > /var/www/html/index.html

Step 11. Now start heartbeat on the primary httpd-primary and slave httpd-slave:

/etc/init.d/heartbeat start

Step 12. Open web-browser and type in the URL:

http://192.168.230.150
It will show 'httpd-primary apache test server'.

Step 13. Now stop the hearbeat daemon on httpd-primary:

/etc/init.d/heartbeat stop
In your browser type in the URL 
http://192.168.230.150 and press enter.
It will show 'httpd-slave apache test server'.
We don’t need to create a virtual network interface and assign an IP address (192.168.230.150) to it. Heartbeat will do this for you, and start the service (httpd) itself. So don’t worry about this.
NOTE :
A. I had issues due to port access for testing disable ‘iptables’ if you face any issues.
Here are the entries requires for iptables.
iptables -A OUTPUT -o lo -p udp -m udp -d 192.168.230.138 --dport 694 -j ACCEPT
iptables -A INPUT -i lo -p udp -m udp -d 192.168.230.138 --dport 694 -j ACCEPT
iptables -A OUTPUT -o eth0 -p udp -m udp -d 192.168.230.138 --dport 694 -j ACCEPT
iptables -A INPUT -i eth0 -p udp -m udp -d 192.168.230.138 --dport 694 -j ACCEPT

iptables -A OUTPUT -o lo -p udp -m udp -d 192.168.230.139 --dport 694 -j ACCEPT
iptables -A INPUT -i lo -p udp -m udp -d 192.168.230.139 --dport 694 -j ACCEPT
iptables -A OUTPUT -o eth0 -p udp -m udp -d 192.168.230.139 --dport 694 -j ACCEPT
iptables -A INPUT -i eth0 -p udp -m udp -d 192.168.230.139 --dport 694 -j ACCEPT

iptables -A OUTPUT -o eth0 -p tcp -m tcp -d 192.168.230.138 --dport 80 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m tcp -d 192.168.230.138 --dport 80 -j ACCEPT

iptables -A OUTPUT -o eth0 -p tcp -m tcp -d 192.168.230.139 --dport 80 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m tcp -d 192.168.230.139 --dport 80 -j ACCEPT

service iptables save



Useful Links: 
https://wiki.archlinux.org/index.php/Simple_IP_Failover_with_Heartbeat http://www.linuxnix.com/2010/01/heartbeat-clustering.html
https://www.howtoforge.com/high_availability_heartbeat_centos
http://blog.iwayvietnam.com/tuanta/2010/05/19/configuring-a-high-availability-cluster-on-rhel-centos/ 
http://www.howtogeek.com/177621/the-beginners-guide-to-iptables-the-linux-firewall/
http://www.cyberciti.biz/tips/linux-cluster-building-firewall-rules.html 
http://www.linux-ha.org/doc/users-guide/_creating_an_initial_heartbeat_configuration.html
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