I add the search peers by using the CLI commands in a script. When I check the Distributed Management Console UI, I see that the status for all of them is "Authentication failed". The credentials provided are correct. If I delete them and re-add them manually (I just copy the exact servername:port) they are instantly "Up". What extra step am I missing in my script to have them up instantly?
This problem has been solved once I edited the distsearch.conf with distributed search groups with other names ([distributedSearch:dmcgroupindexer] instead of [distributedSearch:indexer]). After that all the instances were Up again.