* add "DBSERVER" as an alias for "PRIMARY"
This allows specifying the value "DBSERVER" for `--cluster.my-role`.
"DBSERVER" is only treated as an alias for "PRIMARY", because several
other parts of the code and APIs use the string "PRIMARY".
Changing these from "PRIMARY" to "DBSERVER" would make the change
downwards-incompatible, which we do not want.
The downside of this alias-only solution is that even when specifying
a role value of "DBSERVER", the server will still report its role as
"PRIMARY", which may be a bit confusing. The server will also generate
its id as "PRMR-XXXX" as before:
2018-08-03T15:23:09Z [9584] INFO {cluster} Starting up with role PRIMARY
2018-08-03T15:23:09Z [9584] INFO {cluster} Cluster feature is turned on. Agency version: {"server":"arango","version":"3.4.devel","license":"enterprise"}, Agency endpoints: http+tcp://[::]:4001, server id: 'PRMR-f655b728-4cea-44ac-88e9-8b34baa80958', internal address: tcp://[::1]:8629, role: PRIMARY
* adjusted documentation to use "DBSERVER" instead of "PRIMARY"
* api doc
- secondary role not used anymore. stated.
- primary database is not clear. replaced with dbserver
- brief referenced only dbserver and coordinator - better to provide wider description, in line with what is described below, as other roles can be returned
* typo
* typo
* added starting from 3.4
* additional warning
* cited in the release note
Markus Pfeiffer
Jan
Andreas Streichardt
Max Neunhoeffer