I have a 2 node active/passive cluster running SQL2008 with SP1.

Installation was performed by command line script using a config file.
Started with 1st node with /action = "InstallFailoverCluster". Second node
was installed with a diff config file using the /action= "Add Node". Cluster
operational for over 6 months.

Node 1 has had a hardware failure requiring a re-install of OS and SQL. The
Instance which is also a production instance is now running on second node.

What /action parameter do I use(INSTALLFAILOVERCLUSTER or ADDNODE or
something else) to re-install SQL on the rebuilt node? Will the re-install
have any impact on the second node which is running prod?

Hi Tom,
This is a common encountered scenario. Before you add node to your cluster,
please first make sure that your installed OS and SQL Server 2008 instance
have same versions as your original passive node but now active node.

Then after you add the node to the windows cluster, you can refer to the
following article to re-add the node to the existing cluster:
How to: Add or Remove Nodes in a SQL Server Failover Cluster (Setup)
http://msdn.microsoft.com/en-us/library/ms191545.aspx

For command line, you can refer to the following:
setup.exe /q /ACTION=AddNode /INSTANCENAME="<Insert Instance Name>"
/SQLSVCACCOUNT="<SQL account that is used on other nodes>"
/SQLSVCPASSWORD="<password for SQL account>" /AGTSVCACCOUNT="<SQL Server
Agent account that is used on other nodes>", /AGTSVCPASSWORD="<SQL Server
Agent account password>" /INDICATEPROGRESS

More information can be found
here,http://technet.microsoft.com/en-us/l...9.aspx#AddNode.

Best regards,
Charles Wang