On Mar 22, 2007, at 2:13 AM, Alan Robertson wrote:
Doug Knight wrote:
Hi Andrew,
I had just started reviewing both of thes scripts, and reviewed the
Multistate and clone resource pages on the web site. It looks like
multistate is how I need to handle it, but a couple of questions
first.
1. I noticed that the write-up says the resource must come up on
each of
the servers in "shadow" mode first, then one gets promoted. Does this
imply a "start" on both servers, and the OCF start function
determining
which server is active vs shadow (I'm picturing a check in the OCF
script to determine postgresql standby mode = shadow/crm_master value
low, and postgresql active mode = active/crm_master value high),
then a
promote to the active server?
2. I noticed that the drbd OCF script contains a "notify" function,
where the Stateful OCF script does not. The notify function looks
to be
where the important actions are taken (calling drbd_start_phase_2,
pre/post, etc). Is the notify function necessary, or is it
sufficient in
my case to handle it through the start|stop|promote|demote functions?
Thanks for your help,
Doug
Andrew's out for a while.
The start function starts you up in slave/secondary mode. All
resources
initially start up in "slave" mode.
A set of servers is chosen to run the resources on (it might be one,
two, the whole set, etc. depending on clone_max and clone_node_max and
the usual constraints).
They are started on the selected nodes using "start"
During the start operation, you are given the chance to declare
yourself
ready to become master or not by using the crm_master command line
tool.
I believe that your resource can run that command any time they like -
for example at a monitor operation... But, it is mandatory that they
run it when they first start up.
mandatory in the sense that nothing will get promoted until someone,
somewhere runs it.
but the exact timing is completely up to the user/admin/RA... it is
even possible to run it manually if you have to
After this, heartbeat will try and promote as many of these
resources as
is consistent with its configured properties, and the crm_master
commands that were run.
The notify command tells you when your peers come and go. Do you need
to take actions if you know this?
If so, then you need to implement the notify actions...
--
Alan Robertson <[EMAIL PROTECTED]>
"Openness is the foundation and preservative of friendship... Let me
claim from you at all times your undisguised opinions." - William
Wilberforce
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