A multi-master replication cluster requires its single node to be
started as a reference point before all the other nodes join it and form
a cluster. This is called cluster bootstrapping which introduces a
primary component before others see that as a reference
point to sync up the data from. The restart of a single node or
reconnecting from a node after a shutdown can be done as usual.
After the whole cluster shutdown the server that was stopped last
should be started first with --new-cluster command line
option (or run manticore_new_cluster to start it via
systemd). To make sure that the server is able to start as a reference
point the grastate.dat file located at the cluster path
should be updated with the value of 1 for
safe_to_bootstrap option. I.e., both conditions,
--new-cluster and safe_to_bootstrap=1, must be
satisfied. An attempt to start any other node without these options set
will trigger an error. To override this protection and start cluster
from another server forcibly --new-cluster-force command
line option may be used. You can alternatively run
manticore_new_cluster --force to use systemd for that.
In case of a hard crash or an unclean shutdown of all the servers in
the cluster you need to identify the most advanced node that has the
largest seqno in the grastate.dat file located
at the cluster path
and start that server with the command line key
--new-cluster-force.