Add global visibility to pool definition

[jlrigau]

When using Jenkins in a cluster, it is useful to have visibility global to all the nodes in the cluster and not only per node.

This PR allows to indicate visibility scope on port allocator configuration by adding a "Global Visibility" checkbox.

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[andresrc]

Hello,

My main concern with this PR is that we are "allocating" ports on nodes w/o checking its availability anywhere. I may have misunderstood the use case, or maybe it not in the scope of this plugin.

Please open a JIRA issue and/or a mailing list thread to elaborate.

Thanks.

[jlrigau]

@andresrc the goal of this PR is similar to #5 (comment)

[andresrc]

Thanks @jlrigau . My concern then is that this use case is somewhat out of the scope of this plugin and may be confusing for some users. A "global" scope, could also imply that I want to reserve a port or port range in every node in the system.

This "external cluster configuration" including ports and other possible configurations that may be needed may be worth its own plugin.

[jlrigau]

Hi @andresrc,

I understand your point of view concerning the scope of this plugin but today the port-allocator plugin already satisfies two goals:

• Reserving a specific port or port range
• Managing a pool definition.

The global scope is only related to the pool definition feature and for me it is very important to manage cluster-specific behaviour within each plugin instead of having to develop a new plugin.

Configuring Jenkins with a cluster through a cloud manager is becoming a common usage today and adapting plugins according to this usage seems to be the right strategy.

[andresrc]

Let's move this forward. Would be possible to have a different name that makes much more clear that no Jenkins node is involved?

Besides, the name of the port manager should use the same notation (now it's a "Global Pool" but a ClusterPortManager) and the help include a more detailed description of the implications of using the field.

Thanks