Error whle migrating from R77.30 to R80.4

[Wiktor]

Hey folks
I have followed problem. We have such devices.
Primary_MDS
Secondary_MDS
Primary_MLM
Secondary_MLM

We have tested a lot upgrading pri_mds in lab , done all pre-migration stuff etc. So when finally we moved to real enviroment, there was no problems while migrating pri_mds.
Later we tried to upgrade sec_mlm and sec_mds. But this was was failing after about 2h with followed error:

Error: There is no connectivity with Primary Multi-Domain Management Server.

Todo: Make sure that Primary processes are up and that there is a good connectivity between all the servers.

System databases, logs, and Global domains are upgraded only on the Primary Multi-Domain Server.
The connection is necessary to synchronize the other Multi-Domain Servers and Multi-Domain Log Servers.

If the IP address of the Primary Multi-Domain Management Server was changed, run import again with the '-primaryip' flag.
DONE.


We couldnt understand why its happening, as even on tcpdump being run on both pri_mds and sec_mlm showed that communication is happening at same time when error is happening. Successfull 3way handshake.

Tac proposed to do following, to skip this check during R80 migration script:

touch /var/tmp/do_not_wait_for_primary_upgrade

Although we added it to rc.local, it didn’t survive the upgrade to R80.40 so I had to manually add it again once it booted into R80.40.
Nevertheless, it didnt help us.

Does any of you have any ideas or met such problem?
Keep in mind, we cant go with clean install and import database. TCPDUMP shows, that communication is happening.