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RedHat Cluster Suite And Conga - Linux Clustering
This how to describes an easy step by step installation of the RedHat Cluster Suite on three CentOS nodes and prepare them as nodes of a cluster. You will also install the Management suite which is web based and is known as Conga.
You will use three nodes to form the cluster and one node as the cluster management node and as a cluster node it will not take part. All the nodes and the management node should be resolvable either by host file entries or by DNS.
Cluster Nodes:
cnode1:
eth0-192.168.2.151/24 - external-lan
eth1-192.168.1.200/26 - internal-lan cluster
cnode2:
eth0-192.168.2.152/24 - external-lan
eth1-192.168.1.201/26 - internal-lan cluster
cnode3:
eth0-192.168.2.153/24 - external-lan
eth1-192.168.1.202/26 - internal-lan cluster
Cluster Management Node:
centos:
eth0-192.168.2.150/24
As the cluster, its management interface and the service deamons use tcp, for the purpose of this article you can disable the firewalls at these nodes.
OS - All Nodes:
CentOS 6 Minimal
Cluster Nodes - Software Installation:
yum groupinstall "High Availability"
yum install ricci
Cluster Management Node - Software Installation:
yum groupinstall "High Availability Management"
yum install ricci
Copy this initial sample cluster config file into /etc/cluster/cluster.conf at all the nodes cnode1, cnode2, cnode3.
<?xml version="1.0"?> <cluster config_version="1" name="cl1"> <clusternodes> <clusternode name="cnode1" nodeid="1"/> <clusternode name="cnode2" nodeid="2"/> <clusternode name="cnode3" nodeid="3"/> </clusternodes> </cluster>
This initial file states that the cluster name is cl1 and defines the cluster nodes.
Now some services have to be configured and started at the nodes first and then at the management node as below.
Cluster Nodes:
chkconfig iptables off
chkconfig ip6tables off
chkconfig ricci on
chkconfig cman on
chkconfig rgmanager on
chkconfig modclusterd on
Create a password for the ricci service user with
passwd ricci
service iptables stop
service ip6tables stop
service ricci start
service cman start
service rgmanager start
service modclusterd start
Cluster Management Node:
chkconfig iptables off
chkconfig ip6tables off
chkconfig luci on
chkconfig ricci on
service iptables stop
service ip6tables stop
service luci start
service ricci start
luci service is the management service that presents the web based cluster interface via https at port 8084 and can be accessed in any browser at
https://<cluster management node FQDN or hostname:8084>/
ricci service is the underlying daemon that helps in cluster configuration sync and file copy, service start, stop etc. and uses tcp port 11111.
cman, rgmanager and modclusterd are the actual cluster services which futher start other services that actually make the clustering happen and keep it live.
Open a browser and enter the conga node url which in tis case is https://centos:8084/
After clicking 'ok' to the initial warning information you will be presented with the login screen. Enter the root user and root password of that system and start the interface.
Now click Add cluster and add the first node cnode1 and the ricci password, click 'ok' and it will detect the other two nodes also, add the ricci passwords and the cluster will be added to the Cluster Management interface. The cluster can be managed and configured from this interface. Care should be taken as the cluster.conf file sometimes does not get synced to all cluster nodes, they will get fenced due to version misconfiguration. At such times copy the cluster.conf file from node1 to all the other nodes. If all the nodes are in sync then the uptime is shown in the cluster nodes list.
Getting a cluster, configuring and managing, your cluster is up, live and configured in no time and later other clusters can be added into this management interface for easy maintenance.
- Bellamkonda Sudhakar
