Resource Instance

A resource instance is the instantiation of a ResourceAgent[1] into a real resource[2], rather than the general ResourceAgentType[3] of the ResourceAgent[1].

For example, IPaddr is the type of a resource agent. But, to instantiate (or create) a particular IPaddr resource, one needs to have the parameters which describe this particular IPaddr object and distinguish it from all other IPaddr resources. For example, one might create an IPaddr object which needs three parameters in order to describe it. They might be

• address
• cidrmask
• broadcast
• interface

The parameters for any ResourceAgent[1] are described by its ResourceAgentMetadata[4].

So, to deal with a resource instance of an IPaddr resource, one needs to give its parameters. An example might be

• address=10.10.10.202
• cidrmask=24
• broadcast=10.10.10.255
• interface=eth0

And, this resource instance would be distinct from the following one:

• address=10.10.10.203
• cidrmask=24
• broadcast=10.10.10.255
• interface=eth0

For more information regarding resource instances, also refer to the OpenClusterFramework[5] ResourceAgent[1] API.

• It is worth noting that this is the best description available, but the LocalResourceManager[6] is not limited to OCF[7] ResourceAgent[1]s.

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This information provided courtesy of the Linux-HA project at http://linux-ha.org/