Hi,
The code for referencing resource templates in resource sets has been
done and merged upstream for some time. The following link is the
complete documentation of "Resource templates" including the new feature:
https://github.com/gao-yan/pacemaker/commit/18a85d341ee6213004b1ad95a7f9e16c4c336a4c
Also attached the crm shell syntax version.
( Tanja Roth <tar...@suse.de> helped revise the documentation.)
If you find any problems, feel free to let me know. Thanks!
BTW, there's a "migration-limit" cluster option wasn't documented
before. Xen/KVM live migrations are automatically triggered by the
cluster. However, it can happen that so many VMs are scheduled to
migrate to (or from) a node that the node's network interconnect is
overloaded. "migration-limit"is the way to serialize these operations.
Document it now:
https://github.com/gao-yan/pacemaker/commit/0a44e234df1c1a52515b1fbd310cc532536804f4
Regards,
Gao,Yan
--
Gao,Yan <y...@suse.com>
Software Engineer
China Server Team, SUSE.
Resource Templates
==================
Dejan_Muhamedagic_dejan@suse.de_,_Tanja_Roth_taroth@suse.de_,_Thomas_Schraitle_toms@suse.de_,_yan_gao_y...@suse.com
V1.0, February 2012
== Abstract ==
If you want to create lots of resources with similar configurations, defining a
resource template simplifies the task. Once defined, it can be referenced in
primitives or in certain types of constraints.
== Configuring Resources with Templates ==
The primitives referencing the template will inherit all meta
attributes, instance attributes, utilization attributes and operations defined
in the template. And you can define specific attributes and operations for any
of the primitives. If any of these are defined in both the template and the
primitive, the values defined in the primitive will take precedence over the
ones defined in the template.
Hence, resource templates help to reduce the amount of configuration work.
If any changes are needed, they can be done to the template definition and
will take effect globally in all resource definitions referencing that
template.
Resource templates have a similar syntax like primitives. For example:
[source,Bash]
----
rsc_template vm-template ocf:heartbeat:Xen \
meta allow-migrate="true" \
utilization memory="512" \
op monitor interval="15s" timeout="60s" \
op start interval="0" timeout="60s
----
Once you defined the new resource template, you can use it in primitives:
[source,Bash]
----
primitive vm1 @vm-template \
params name="vm1" xmfile="/etc/xen/shared-vm/vm1"
----
The new primitive `vm1` is going to inherit everything from the `vm-template`.
For
example, the equivalent of the above two would be:
[source,Bash]
----
primitive vm1 ocf:heartbeat:Xen \
meta allow-migrate="true" \
utilization memory="512" \
op monitor interval="15s" timeout="60s" \
op start interval="0" timeout="60s \
params name="vm1" xmfile="/etc/xen/shared-vm/vm1"
----
If you want to overwrite some attributes or operations, add them to the
particular primitive's definition.
For instance, the following new primitive `vm2` has special
attribute values. Its `monitor` operation has a longer `timeout` and
`interval`, and
the primitive has an additional `stop` operation.
[source,Bash]
----
primitive vm2 @vm-template \
meta allow-migrate="false" \
utilization memory="1024" \
params name="vm2" xmfile="/etc/xen/shared-vm/vm2" \
op monitor interval="30s" timeout="120s" \
op stop interval="0" timeout="60s"
----
The following command shows the resulting definition of a resource in XML:
[source,Bash]
----
# crm_resource --query-xml --resource vm2
----
The following command shows its raw definition in cib:
[source,Bash]
----
# crm_resource --query-xml-raw --resource vm2
----
== Referencing Templates in Constraints ==
A resource template can be referenced in the following types of constraints:
- `order` constraints
- `colocation` constraints,
- `rsc_ticket` constraints (for multi-site clusters).
Resource templates referenced in constraints stand for all primitives which are
derived from that template. This means, the constraint applies to all primitive
resources referencing the resource template. Referencing resource templates in
constraints is an alternative to resource sets and can simplify the cluster
configuration considerably.
For example:
[source,Bash]
----
colocation vm-template-colo-base-rsc inf: vm-template base-rsc
----
is the equivalent of the following constraint configuration:
[source,Bash]
----
colocation vm-colo-base-rsc inf: ( vm1 vm2 ) base-rsc
----
[NOTE]
======
In a colocation constraint, only one template may be referenced, and the
other reference must be a regular resource.
======
Resource templates can also be referenced in resource sets.
For example:
[source,Bash]
----
order order1 inf: base-rsc vm-template top-rsc
----
is the equivalent of the following constraint configuration:
[source,Bash]
----
order order1 inf: base-rsc vm1 vm2 top-rsc
----
If the resources referencing the template can run in parallel:
[source,Bash]
----
order order2 inf: base-rsc ( vm-template ) top-rsc
----
is the equivalent of the following constraint configuration:
[source,Bash]
----
order order2 inf: base-rsc ( vm1 vm2 ) top-rsc
----
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