|VACM: Users and Programmers Manual|
VA 1000 nodes use a dedicated cluster management bus (CMBus) to monitor and control the individual nodes in a cluster. The nodes are connected in a daisy-chained configuration, using the Console ports on the back of the nodes. This connection between the nodes forms the cluster management bus. It also serves as a built-in KVM switch, allowing one monitor, keyboard, and mouse to connect to any one of the nodes in the cluster.
For practical purposes, a typical cluster of VA 1000 nodes will be limited to one rack. One of the nodes is used to control the cluster, and will have the VACM nexxus installed on it. The VA 1000's CMBus is formed by connecting the Console port 1 connector from one unit to the Console port 2 connector of the next unit. This is repeated for all nodes in the cluster. A console adapter can be connected to the unused Console connector on either end of the cluster. (An additional console adapter connected to the other end of the cluster may help improve the console's video quality in clusters with more than six nodes.)
The CMBus relies on each node having a unique CMBus address. Nodes determine their addresses dynamically the first time that power is applied. The address is saved in a local EEPROM, so it is not forgotten if power is removed.
NOTE: Because the addresses are determined the first time power is applied, it is very important to use the following procedure to power up the cluster for the first time.
To configure a rack of VA 1000 nodes and apply power for the first time:
Place all the VA 1000 nodes in the rack (or stack less than 6 high)
Make sure the power switches are in the off (0) position.
Daisy-chain the Console ports using console cables.
Connect a Console Adapter to either end of the daisy-chain.
Attach a keyboard, mouse, and monitor to the Console Adapter.
Connect Ethernet and any other interface cables to the nodes.
Connect power to all the nodes, but do not turn them on.
Finally, power up each node in the cluster, using the following procedure:
Set the power switch on the rear of the node to the On (1) position.
Press and release the front panel Power switch two times within a three second period. Both the blue Power and green Console LED's light up.
Wait for the node to boot to the login prompt before starting the next node.
To configure VA 1000 nodes under VACM, you need to know the CMBus address of the node. To determine the address of a node, use the following procedure:
Press and hold the Power switch down for at least 5 seconds.
Release the Power switch.
The two rightmost LED's will flash once, indicating the start of the CMBus address transmission.
The three rightmost LED's will flash individually to indicate the CMBus address. From left to right, the LED's represent 100's, 10's, and 1's of the address.
Finally, the two rightmost LED's blink together once more to indicate the end of the address transmission.