Red Hat CLUSTER SUITE FOR ENTERPRISE LINUX 5.1 Instrukcja Użytkownika Pobierz pdf (Strona 13)

Introduction to Linux Clustering

When a cluster node fails, the services that are running on it need to be migrated to

other machines. The cluster management software will look at a list of other nodes

called the “failover domain”, and will select one from the list to run the service.

The list can also be prioritised if desired – both the order of what servers should be

used in a failure, as well as whether or not the service should be moved back to a

higher priority node when one becomes avaliable.

In the event of the service running out of online hosts in the failover domain, the

service will be stopped until a node comes back online.

● Fencing devices

A fencing device is used to power off or reset unresponsive/crashed cluster nodes.

This is typically something like a network controlled power strip, or a out-of-band

management card in the server.

5.1.2 LUCI AND RICCI

Luci does not have to be run on the cluster itself, although that is the recommended method

as you can cluster luci and thus be able to always administrate the cluster.

The ricci daemon runs on all the nodes and allows Luci to communicate with the nodes to

configure them.

Luci is smart enough to install the packages it requires via yum on the nodes when you add

them to the cluster which makes setup easier.

5.1.3 SYSTEM-CONFIG-CLUSTER

Luci seems to be replacing system-config-cluster as the favourite program to use, but at this

stage system-config-cluster is a capable GTK GUI application for cluster configuration.

You can run it on any cluster node, once you save your changes you can then click a button

to send out the new configuration to all the cluster nodes.

5.1.4 LOAD BALANCING

Redhat Cluster Suite is focused on providing HA servers and doesn't provide any special

features for doing load balancing.

However, you can setup load balancing by the following method:

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 32 33

Brak uwag

Red Hat CLUSTER SUITE FOR ENTERPRISE LINUX 5.1 Instrukcja Użytkownika Strona 13