[ClusterLabs] Coming in 1.1.14: Fencing topology based on node attribute

[Digimer]

On 08/09/15 11:23 AM, Ken Gaillot wrote:
> Pacemaker's upstream master branch has a new feature that will be part
> of the eventual 1.1.14 release.
> 
> Fencing topology is used when a node requires multiple fencing devices
> (in combination or as fallbacks). Currently, topologies must be
> specified by node name (or a regular expression matching node names).
> 
> The new feature allows topologies to specified by node attribute.
> 
> For example, imagine a data center where all devices in rack #1 use
> fence devices apc01 and apc02, while all devices in rack #2 use fence
> devices apc03 and apc04.
> 
> Previously, if node1 was in rack #1, you'd have to register a fencing
> topology by its name, which at the XML level would look like:
> 
>    <fencing-topology>
>       <fencing-level id="node1-1" index="1" target="node1"
>           devices="apc01,apc02"/>
>    </fencing-topology>
> 
> 
> With the new feature, you could instead register a topology for all
> hosts that have a node attribute "rack" whose value is "1":
> 
>    <fencing-topology>
>       <fencing-level id="rack-1-1" index="1" target="rack=1"
>           devices="apc01,apc02"/>
>    </fencing-topology>
> 
> 
> You would assign that attribute to all nodes in that rack, e.g.:
> 
>    crm_attribute --type nodes --node node1 --name rack --update 1
> 
> 
> If a server is moved to a different rack, simply update the value of its
> attribute and it will use that rack's fencing configuration. Or if a
> rack gets a new fencing device, you only have to update the fencing
> configuration once rather than for every node in the rack.
> 
> The syntax accepts either '=' or ':' as the separator for the name/value
> pair, so target="rack:1" would work in the XML as well.

Holy crap that is awesome! :D

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Digimer
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