A Basic Single IP address Configuration

The most common, basic configuration is that of a high-availability server which simply provides a single IP address (1.2.3.4) to be failed over[1] between the nodes[2] of our cluster[3]. This is an ActivePassive[4] configuration - the most basic configuration.

/etc/ha.d/ha.cf file

This is for Heartbeat[5] 1.2.x

logfacility daemon         # Log to syslog as facility "daemon"
node paul silas            # List our cluster members
keepalive 1                # Send one heartbeat each second
deadtime 10                # Declare nodes dead after 10 seconds
bcast eth0 eth1            # Broadcast heartbeats on eth0 and eth1 interfaces
ping 1.2.3.254             # Ping our router to monitor ethernet connectivity
auto_failback no           # Don't fail back to paul automatically
respawn hacluster /usr/lib/heartbeat/ipfail  # Failover on network failures

This is for Heartbeat[5] 2.0.x[6] without CRM[7]

logfacility     daemon
keepalive 1
deadtime 10
warntime 5
initdead 120 # depend on your hardware
udpport 694
ping 1.2.3.254
bcast eth0
auto_failback off
node    paul
node    silas
respawn hacluster /usr/lib/heartbeat/ipfail
use_logd yes

This is for Heartbeat[5] 2.0.x[6] with CRM[7]

logfacility     daemon
keepalive 1
deadtime 10
warntime 5
initdead 120 # depend on your hardware
udpport 694
ping 1.2.3.254
bcast eth0
auto_failback off
node    paul
node    silas
use_logd yes
compression     bz2
compression_threshold 2
crm yes

See the ipfail[8] page for more information on ipfail[8].

bcast / mcast / ucast

If you want less broadcast traffic, use ucast[9], which is strictly peer-to-peer. bcast[10] is limited to the logical segment and not routed, while ucast[9]/mcast[11] are potentially routed. ucast[9] duplicates the packets, as it has to be sent to each node and not just broad/multicasted to all of them at the same time.

/etc/ha.d/haresources file

For Heartbeat[5] version 2[6] with CRM[7], you'll need to modify cib.xml instead of this file. Please see the Basic Single IP address Configuration for version 2[12] page for details.

paul    1.2.3.4

The first word (paul) on the line represents the "preferred[13]" host for the service. The remainder of the line is the list of resource[14]s (services) which are part of this ResourceGroup[15]. In this case, there is only one resource[14] -- an IP address. This is a shorthand notation for IPaddr::1.2.3.4. There are many possible variants of how to specify the IP address, to learn about them, see the page on the IPaddr resource agent[16].

Note that this address cannot be used for anything else on these machines. In particular, it has to be controlled only by Heartbeat[5], and cannot be brought up by your operating system at boot time. We call this address a ServiceAddress[17] - which is distinct from an AdministrativeAddress[18], like those brought up by your operating system.

/etc/ha.d/authkeys file

/etc/ha.d/authkeys[19] must be mode 600. See the section on GeneratingAuthkeysAutomatically[20] for information how to generate good keys automatically.

auth 1
1 sha1 PutYourSuperSecretKeyHere

References