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Hi all.
We're using UltraMonkey (ldirector and heartbeat) on a pair of hosts.
As they were being added in to replace an older pair, we called them by
some temporary names ('oldhostname-A-new' and 'oldhostname-B-new') as
we eased them in. Now we needed to change their names (to the hosts
they replaced), but since hostnames are used in HA setup, there is a
procedure to get this done with no downtime. Here is what we have just
done, posted just to add to collective knowledge (unless someone has
already posted this or it is a FAQ, in which case I am sorry for the
noise):
Overview: host A needs to become host C and B needs to become host D.
A: Make A (host that will become C) active load balancer: hb_takeover.
B: /etc/init.d/heartbeat stop; vi /etc/ha.d/ha.cf
# add an entry for C and D so 4 hosts are listed
B: /etc/init.d/heartbeat start
B: hb_takeover
A: /etc/init.d/heartbeat stop; vi /etc/ha.d/ha.cf
# add an entry for C and D so 4 hosts are listed
A: /etc/init.d/heartbeat start
A: hostname C
# changes the first host's name, don't forget to update /etc/hostname
to C
A: hb_takeover
B: /etc/init.d/heartbeat stop; vi /etc/ha.d/ha.cf
# remove A and B leaving only C and D
B: hostname D
# changes the second host's name, don't forget to update /etc/hostname
to D
B: /etc/init,.d/heartbeat start
B: hb_takeover
A: /etc/init.d/heartbeat stop; vi /etc/ha.d/ha.cf
# remove A and B leaving only C and D
A: /etc/init.d/heartbeat start
A: hb_takeover
# Leave host A as the active load balancer, if you wish
(BTW, really impressed with the speed of takeover, less than half a
second I think, and no packets dropped with shared connection state via
ipvs_syncbackup and ipvs_syncmaster running on both nodes! Excellent!).
Regards,
James
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