The process for adding a new OES 2 Linux cluster node to an existing OES 1 Linux cluster is the same as for adding an OES 1 cluster node to an OES 1 Linux cluster and adding a new OES 2 cluster node to an existing OES 2 cluster. See Section 5.4, Installing Novell Cluster Services.
However, you should be aware of the rules that apply to mixed OES 1 and OES 2 clusters. See Section 7.2, Requirements and Guidelines for Upgrading Clusters from OES 1 Linux and OES 2 Linux.