Comment 2 for bug 1329809

Single node and Multi node (ubuntu-havana) upgrade works ,
from 18 to build 39 + fix in fabric-utils(https://github.com/Juniper/contrail-fabric-utils/commit/54045822722c6fef6c0e9259b34ad0d2f7981ea0)

Provided the setup is with three cfgm and same three node is database.

If the cfgm and database nodes are different we will face issues with zookeeper, as we moved zookeeper from config node to database node from build 19 and above We have to do rolling restart of zookeeper to migrate the zookeeper database from cfgm nodes to different database node.

I am working on "rolling restart", However in Symantec we manually removed zookeeper from cfgm and provisioned zookeeer in database node, so upgrade in Symanetc should work, I am also trying to bring up a similar setup like Symantec and test upgrade.