migration of appliances to VM + upgrade

[nkeuparl]

Hi there, i am planning to migrate PAN/SAN and 2 PSN running ISE 2.4 on old 3315 appliances to PAN/SAN 2PSN 2MNT running ISE 3.2 on virtual machines

is there a guide/ or many / that i could rely on ? ( migrate appliance to vm / maybe running vm+on prem at same time if possible / implementing MNT / migration path from 2.4 to 3.2 )

is it possible to integrate the new vm components in the old infra and disengage the appliances slowly then? 

is it possible to run at the same time diffrent versions ?

how does it work for the certificates and for the licenses ? 

any recommendations?

Thank you!

[marce1000]

    - In my opinion this will be difficult because of the huge leap in versions  ; what I would do is start building the ISE VM based environment manually from scratch (including entering the policies and final testing). 
     Lots of trouble could be avoided   and or 'sudden showstoppers' on the way.  And you have 'free time' for testing
     on the new environment without hurting business (e.g.)
    What I  used to do is  simply switch radius servers  on the NAD's when a new ISE deployment was ready for use.

 M.