How Do I Add a Node to a VMS Cluster?

The simple answer is to log in as a privileged user, such as SYSTEM, and do a “@CLUSTER_CONFIG”. This works just fine if you’re going to boot a new cluster member which will share the current system disk (which is a neat VMS feature, BTW).

But what if you’re adding a shiny new Itanium box to your VAX cluster? They can’t share the same system disk. No problem, just run CLUSTER_CONFIG on the Itanium box and specify the cluster number and the cluster password.

When systems attempt to cluster, they swap the cluster number and a 32-bit hash of the password. If they agree, they’re in the same cluster. If they don’t both match, they’re in separate clusters.

Don’t have the cluster number and password? Did “Fred” set up this cluster 20 years ago and you haven’t see him since?

No need to panic. It’s not possible to recover the password because of the hashing, but you can get something almost as good.

On the existing cluster, look for file CLUSTER_AUTHORIZE.DAT in directory SYS$SYSTEM. If you do a DUMP/RECORD on it, you’ll see something like:

Record number 1 (00000001), 512 (0200) bytes, RFA(0001,0000,0000)
00000000 00000000 5A528B9A 00000001 ……RZ…….. 000000

The first 32 bits of the file is the cluster number (cluster 1 in this example), and the next 32 bits is the password hash.

Just drop this file into SYS$COMMON:[SYSEXE] on the new cluster node, and it’ll come right up. After you set the appropriate SYSGEN parameters. Back to the manual for that…