2.3. Setting Up the Nodes

After identifying the cluster hardware components described in Section 2.1 Choosing a Hardware Configuration, set up the basic cluster hardware and connect the nodes to the optional console switch and network switch or hub. Follow these steps:

  1. In all nodes, install the required network adapters and host bus adapters. Refer to Section 2.3.1 Installing the Basic Cluster Hardware for more information about performing this task.

  2. Set up the optional console switch and connect it to each node. Refer to Section 2.3.3 Setting Up a Console Switch for more information about performing this task.

    If a console switch is not used, then connect each node to a console terminal.

  3. Set up the network switch or hub and use network cables to connect it to the nodes and the terminal server (if applicable). Refer to Section 2.3.4 Setting Up a Network Switch or Hub for more information about performing this task.

After performing the previous tasks, install Red Hat Enterprise Linux as described in Section 2.4 Installing and Configuring Red Hat Enterprise Linux.

2.3.1. Installing the Basic Cluster Hardware

Nodes must provide the CPU processing power and memory required by applications.

In addition, nodes must be able to accommodate the SCSI or Fibre Channel adapters, network interfaces, and serial ports that the hardware configuration requires. Systems have a limited number of pre-installed serial and network ports and PCI expansion slots. Table 2-10 helps determine how much capacity the employed node systems require.

Cluster Hardware ComponentSerial PortsEthernet PortsPCI Slots
SCSI or Fibre Channel adapter to shared disk storage  One for each bus adapter
Network connection for client access and Ethernet heartbeat pings  One for each network connection 
Point-to-point Ethernet connection for 2-node clusters (optional) One for each connection 
Terminal server connection (optional)One  

Table 2-10. Installing the Basic Cluster Hardware

Most systems come with at least one serial port. If a system has graphics display capability, it is possible to use the serial console port for a power switch connection. To expand your serial port capacity, use multi-port serial PCI cards. For multiple-node clusters, use a network power switch.

Also, ensure that local system disks are not on the same SCSI bus as the shared disks. For example, use two-channel SCSI adapters, such as the Adaptec 39160-series cards, and put the internal devices on one channel and the shared disks on the other channel. Using multiple SCSI cards is also possible.

Refer to the system documentation supplied by the vendor for detailed installation information. Refer to Appendix A Supplementary Hardware Information for hardware-specific information about using host bus adapters in a cluster.

2.3.2. Shared Storage considerations

In a cluster, shared disks can be used to store cluster service data. Because this storage must be available to all nodes running the cluster service configured to use the storage, it cannot be located on disks that depend on the availability of any one node.

There are some factors to consider when setting up shared disk storage in a cluster:

After setting up the shared disk storage hardware, partition the disks and create file systems on the partitions. Refer to Section 2.5.3.1 Partitioning Disks, and Section 2.5.3.2 Creating File Systems for more information on configuring disks.

2.3.3. Setting Up a Console Switch

Although a console switch is not required for cluster operation, it can be used to facilitate node management and eliminate the need for separate monitors, mouses, and keyboards for each cluster node. There are several types of console switches.

For example, a terminal server enables connection to serial consoles and management of many nodes from a remote location. For a low-cost alternative, use a KVM (keyboard, video, and mouse) switch, which enables multiple nodes to share one keyboard, monitor, and mouse. A KVM switch is suitable for configurations in which GUI access to perform system management tasks is preferred.

Set up the console switch according to the documentation provided by the vendor.

After the console switch has been set up, connect it to each cluster node. The cables used depend on the type of console switch. For example, a Cyclades terminal server uses RJ45 to DB9 crossover cables to connect a serial port on each node to the terminal server.

2.3.4. Setting Up a Network Switch or Hub

A network switch or hub, although not required for operating a two-node cluster, can be used to facilitate cluster and client system network operations. Clusters of more than two nodes require a switch or hub.

Set up a network switch or hub according to the documentation provided by the vendor.

After setting up the network switch or hub, connect it to each node by using conventional network cables. A terminal server, if used, is connected to the network switch or hub through a network cable.