[mod_cluster-issues] [JBoss JIRA] (MODCLUSTER-71) Handle multiple versions of the same webapp

[Dominique CLAIRAC (JIRA)]

    [ https://issues.jboss.org/browse/MODCLUSTER-71?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12768692#comment-12768692 ] 

Dominique CLAIRAC commented on MODCLUSTER-71:
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We have the same problem.

On JBoss side, we have two server groups (A and B) with two JBoss Full-HA servers in each group.

On mod_cluster side:
 - Each server of a same server group is declared in an unique "load-balancing-group", so we have 2 LBGroup with 2 nodes in each.
 - Requests are routed to goup A or Group B, depending on the load and session affinity.

During an application update:
 - We disable the Node B to drain sessions to the node A. 
 - We then update the application with the new version on server group B with autoEnableContexts = false (It should be better to have stopped status than disabled when autoEnableContexts is false, because application is still accessible for someone with node JVM_ROOT in an old JSESSION_ID).

Then we would like administrators to test the application before draining requests from A to B (new version activation).

After reflection, I would suggest something like this:

Choice 1:
On JBoss side, possibility that the application is declared as STOPPED rather than DISABLED on deployment
On cluster_manager UI: ability to generate a token associated with a server or LB group, which will be stored in a cookie.
On request with this token, mod_cluster must send the request to the node or the LB group associated to the token, even if the application is marked as STOPPED on it.

Choice 2:
Ability to declare an IP range as the test network in mod_cluster apache configuration (eg: mod_cluster_test_network = 192.168.174.0)
Have a property (eg "test_mode") in the mod_cluster subsystem on jboss side.
If test_mode is true, only requests from the mod_cluster_test_network network can reach the server in question)
Whith this solution, we juste have to change the value of "test_mode" on jboss conf to achieve our goal
                
> Handle multiple versions of the same webapp
> -------------------------------------------
>
>                 Key: MODCLUSTER-71
>                 URL: https://issues.jboss.org/browse/MODCLUSTER-71
>             Project: mod_cluster
>          Issue Type: Feature Request
>            Reporter: Brian Stansberry
>            Assignee: Jean-Frederic Clere
>
> This is a big picture future roadmap kind of thing.
> Assume the AS develops the ability to host two versions of the same webapp concurrently. Imagine a workflow like this:
> 1) Version 1 is running, handling requests
> 2) Version 2 is deployed, is allowed to receive a low workload to validate that it works properly.
> 3) Version 2 is shifted to allow full workload
> 4) Version 1 is put into disabled mode to drain sessions
> 5) Version 1. is undeployed.
> Obviously making this work requires a lot of currently non-existent stuff in the AS.  Point of this JIRA is think about how to deal with it at the mod_cluster level.

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