thanks for the resposne.  i've also seen some solutions like OpenAM and Shibolleth and Gluu, but not sure which ones will be better with odoo and the overall project

I vote for CAS in Java. I used and it's pretty much feature complete and based on Spring WebFlow and Spring Framework and good practices and standards so it will bring you a lot of extension points for anything.

Here are the links:

https://wiki.jasig.org/display/CAS/Home

https://www.apereo.org/projects/cas

https://github.com/apereo/cas

You could find others solutions but trust me, that one have years of experience and in the days were I used (around 8 years ago, 8 years more mature) the community support was the best. I even think that there was one person that get paid to bring support to the community answers and problems of the new users among other things of course. I highly recommended and also there are clients to a lot of frameworks and programming languages to get integrated.