IdP SSO not working

[Cantor, Scott]

>
>Logging is already set to DEBUG for everything under
>edu.internet2.middleware.shibboleth. I can't see anything logged
>indicating it is inspecting any cookies. What I am seeing is lots of
>lines like this (but with different session ID values):
>
>06:05:12.955 - DEBUG
>[edu.internet2.middleware.shibboleth.idp.session.IdPSessionFilter:160] -
>No session associated with session ID
>NzQxNmVkZTJkMjkwNGUxNmFmNTM1OTVjZGY3ZmI1ZGU2MTZmMjdjODRmYTUwY2RjY2FmMDIyZj
>FmMjkwMDVkOQ== 
>- session must have timed out

I think that means it's getting a cookie that doesn't correspond to a
session in the cache. After the other recent post, I'm led to wonder, how
is this IdP clustered? If it's behind a load balancer, you have to cluster
it or deploy changes and plugins to avoid clustering it. And if you don't,
but have short term stickiness, you get no SSO (and no attribute query
support).

-- Scott