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- Have the IdP servlet running on multiple cluster nodes. How to do this is described in the howto configure the IdP for Clustering.
- Have the attribute resolver configured to use multiple LDAP/AD servers. How this can be done is described in the LDAP Resolver description.
- Also protect the authentication system to make use of clustering. Have a look at the username/password authentication description.
When it comes to using LDAP (most common case) for attribute resolution and authentication, you may also have a look at the LDAP configuration hints.