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

[Kristoffer Grönlund]

Hi,

Ken Gaillot <kgaillot at redhat.com> writes:

> 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.

Sounds like a really useful feature. :) I have implemented initial
support for this syntax in crmsh, so this will work fine in the next
version of crmsh.

Examples of crmsh syntax below:

> 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>
>

crm cfg fencing-topology node1: apc01,apc02

>
> 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>
>

crm cfg fencing-topology rack=1: apc01,apc02

>
> You would assign that attribute to all nodes in that rack, e.g.:
>
>    crm_attribute --type nodes --node node1 --name rack --update 1
>

crm node attr node1 set rack 1

>
> The syntax accepts either '=' or ':' as the separator for the name/value
> pair, so target="rack:1" would work in the XML as well.

crm cfg fencing-topology rack:1: apc01,apc02

(admittedly perhaps not as clean as using '=', but it works)

Cheers,
Kristoffer

> -- 
> Ken Gaillot <kgaillot at redhat.com>
>
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-- 
// Kristoffer Grönlund
// kgronlund at suse.com