[Linux-ha-dev] Cluster management thoughts
lists at beekhof.net
Mon Dec 20 03:40:24 MST 2004
After a productive IRC chat with sunjd, I'd like to clarify my position
on the management tool...
First up, I am not against having a daemon. On the contrary, I think
they are likely to be a necessity. What I /am/ advocating however is
that we first start with a higher level unification API/library that
spans the CCM, CIB, HA, and whatever else is required.
By way of example, where the CIB API allows us to find out the status
of all nodes in the cluster, the higher level API would process the
CIB's result to tell you the active resources on a specific node. Or
where the CIB API allows you to update the CIB, the higher level would
create a resource and add it to CIB.
My rationale here is that if we start with an API, then the number and
types of admin clients are endless while still limiting the duplication
of common functionality. The same API that we use to build a SNMP
notification daemon could also be used to build a daemon that web
clients can connect to, or a local GUI application, or a GUI
application that talks to a daemon, or, or... do people see where I'm
going with this?
By going straight to the daemon I feel we are make life harder for
ourselves... the type of daemon you need/want for a web based client
isnt the same as for a desktop GUI application nor the same for a SNMP
The second thought is to think about migrating some of the
configuration from ha.cf into the CIB.
Obviously there is the possibility for a chicken and egg situation here
so not everything is appropriate to be moved, but everything that does
is one less thing to get wrong.
Changing an option (such as the log level or whether sub-system X
enables apphbd support) is then simply a matter of updating the CIB
which pushes the change to all nodes.
"No means no, and no means yes, and everything in between and all the
rest" - TISM
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