Comment 6 for bug 1181236

Currently as it stands, while restoring from backup, one needs to
manually create grastate.dat from xtrabackup_galera_info which is
not nice. This bug is to automatically generate grastate.dat from
xtrabackup_galera_info at apply-log stage.

Now, technically, wsrep-recover recovers the galera co-ordinates.
So why is grastate.dat needed (or the larger point of collecting galera-info from xtrabackup)? https://bugs.launchpad.net/galera/+bug/1112724 seems to be the issue.

""
Submitting a ---wsrep_start_position when the datadir does not have a grastate.dat not work -- it forces a zero state and SSTs instead.
""

So, if I have a backup without (grastate.dat created manually from xtrabackup_galera_info or grastate.dat already present) wsrep-recover may work but its co-ordinates are not taken.

If lp:1112724 is fixed, then I don't think we need any galera
specific stuff from xtrabackup (--galera-info). Also, assuming no DDL is run,
--no-lock can also be used. There will be no need for
xtrabackup_galera_info either.

@Alexey, any plans on lp:1112724? (seems to be only for galera
3.0 though)

So, in interim and for galera 2.x (PXC 5.x), I think generating grastate.dat from xtrabackup_galera_info may be good, and regarding the specification, since this change is non-invasive one, if it changes (and I presume it changes only in 3.x) then we can remove this.