tips_and_howtos:pacemaker_cluster

This is a quickie to show you how to start do Pacemaker ensured high available Apache with a service IP and KVM virtual host fencing.

Install these to every node and virtual host as well

yum install fence-virt fence-virtd ence-virtd-multicast fence-virtd-libvirt

Install these to pacemaker nodes / guests

yum install pacemaker cman pcs ccs resource-agents

Configure at virtual host, use virbr0, /etc/cluster/fence_xvm.key

fence_virtd -c

Make key

dd if=/dev/random bs=512 count=1 of=/etc/cluster/fence_xvm.key

Configuration should be like this

backends {
 	libvirt {
 		uri = "qemu:///system";
 	}
 }
 listeners {
 	multicast {
 		key_file = "/etc/cluster/fence_xvm.key";
 		interface = "virbr0";
 		port = "1229";
 		address = "225.0.0.12";
 		family = "ipv4";
 	}
 }
 fence_virtd {
 	backend = "libvirt";
 	listener = "multicast";
 	module_path = "/usr/lib64/fence-virt";
 }

Start fencing daemon, insert to your rc.local to get it up after boot

fence_virtd

Test it, you should see your virtual guests

fence_xvm -o list

Copy the /etc/cluster/fence_xvm.key to all guests

Test in GUESTS. if timeouts check if you are using other interface at the virtual host, br0 etc

fence_xvm -o listen

Configure the fencing to your pacemaker cluster later with command

crm configure primitive st-virt stonith:fence_xvm

Do this in one node and copy the /etc/cluster to all nodes

ccs -f /etc/cluster/cluster.conf --addfencedev pcmk agent=fence_pcmk 
ccs -f /etc/cluster/cluster.conf --addmethod pcmk-redirect host1
ccs -f /etc/cluster/cluster.conf --addmethod pcmk-redirect host2
ccs -f /etc/cluster/cluster.conf --addfenceinst pcmk host1 pcmk-redirect port=host1
ccs -f /etc/cluster/cluster.conf --addfenceinst pcmk host2 pcmk-redirect port=host2

Do this in every node

cp /etc/corosync/corosync.conf.example /etc/corosync/corosync.conf
echo "CMAN_QUORUM_TIMEOUT=0">> /etc/sysconfig/cman
chkconfig cman on
chkconfig pacemaker on
service cman start
service pacemaker start
pcs status
pcs config

Set basic properties

pcs property set stonith-enabled=true
pcs property set no-quorum-policy=ignore
pcs resource defaults migration-threshold=1

Set up Apache with HA IP

Be sure that your Apache provides http://localhost/server-status

pcs resource create WebSite ocf:heartbeat:apache configfile=/etc/httpd/conf/httpd.conf statusurl="http://localhost/server-status" op monitor interval=1min
pcs resource create ClusterIP ocf:heartbeat:IPaddr2 ip=1.2.3.4 nic="eth0" cidr_netmask=27 op monitor interval=30s
pcs constraint colocation add WebSite ClusterIP INFINITY
pcs constraint location WebSite prefers host1=50

Finally put the nodes to shoot each other when they've get a problem

crm configure primitive st-virt stonith:fence_xvm
  • tips_and_howtos/pacemaker_cluster.txt
  • Last modified: 2021/10/24 13:51
  • (external edit)