How to update SQL Server 2005 clustered instances? We have a 3 node cluster with an instance running on each. 
Windows 2003 R2 32bit (16GB) / SQL Server 2005

I want to bring them all up to build 9.00.5266 (SP 4 + CU3) (1 Node is already updated)
The links and articles I have found haven't been very helpful in terms of order installation and gotchas.

Our test cluster nodes were already at 9.00.5266. (My predecessor did that before I arrived).

I updated the test cluster instances to 9.00.5292 (Cluster only has 2 nodes)
Although I got there, this did not go as expected....

The plan was :


Move all instances to node2
Update the instances on node1
Reboot node1
Move all instances to node1
Update the instances on node2
Reboot node2
Move an instance to node1


I got to step 5. Then the installer said I had to use the active node. That means that the instance must go offline.

Is this a pitfall of SQL Server 2005 or am I doing this wrong?

Why did the first update work?

There are only few hotfixes available after build 9.00.5292 (All via links from MS upon request) so I can't experiment any further without reinstalling the test cluster.

I'm sure there are a couple of DBAs out there that have experience with updating SQL Server 2005 clustered instances. [Smile]

Most helpful links found:

SQL Server failover cluster rolling patch and service pack process(2008+ only. No link to 2005) [Sad]
[How to install SQL Server 2005 SP3]3
I think this is a pitfall. I recall SQL 2005 and older versions requires active nodes to be updated. SQL 2008 and later versions allow passive node updates like the walkthrough you described. A posting from Linchi Shea explains it well.