[jboss-as7-dev] Problems with .deploy markers in shared directories

[Brian Stansberry]

Did this kind of deployment dir sharing work on previous AS releases? I 
suppose it might have for .war files since IIRC wars were copied into 
tmp/. For other deployment types I believe doing this would have led to 
file lock problems on Windows.

Anyway, I've opened https://issues.jboss.org/browse/AS7-4383 to look 
into not writing marker files or optionally writing them in data/. Part 
of the purpose of those marker files was a request that we provide in 
the dir itself input to users as to what was happening with the deployment.

Even if AS7-4383 were done I don't think *exploded* deployments would 
work reliably at all if scanners on multiple servers were scanning the 
same dir. There would likely be file lock problems and deleting the 
.deployed file is the intended trigger for undeploy. Deleting the 
deployment itself also triggers undeploy, but it is very dangerous to do 
it that way for an exploded deployment.

More in-line...

On 3/30/12 7:34 AM, Bela Ban wrote:
> I have a big problem with the way AS deploys applications: I have a
> web.war and a cluster of AS 7.1.1 instances.
>
> Each instance has separate work, data, log, tmp etc directories
> (jboss.node.name, jboss.server.data.dir, jboss.server.temp.dir etc).
>
> I have a $HOME/jboss/standalone/deployments dir into which I copied
> web.war, assuming that web.war is an application that can be shared by
> all cluster nodes.... However, the markers screw things up, as they
> actually modify things.
>
> The first node is started and adds a suffix web.war.dodeply -->
> .isdploying --> .deployed.
>
> The second node is started and does the same. (The weird thing is why
> does the 2nd node even deploy web.war anymore, as the marker .deployed
> suggested that the app has already been deployed !)
>

It knows it's not deployed, because it can check the server-side state.

> However, if I start a few nodes concurrently, then this lifecycle is
> screwed, and I end up with some nodes having web.war deployed and others
> not. This apparently gets sorted out, and after some time the marker is
> .deployed again. But this spits out nasty warnings in-between.
>
> Is there a recommended way to share web.war between cluster nodes ?
>

Recommended is to use the CLI to do the deployments. This can be 
scripted easily enough if you know the addresses/ports the servers are 
listening on. (I realize that may be a problem in some situations.)

You can also configure the AS to use a deployment at a specific location:

<deployments>
  <deployment name="demo.war" runtime-name="demo.war">
    <fs-archive path="demo.war" relative-to="user.home"/>
  </deployment>
</deployments>

The value for fs-archive "path" can be absolute if the relative-to 
attribute is not used.

I just filed a JIRA to make it easier to set this up via the CLI:

https://issues.jboss.org/browse/AS7-4385

> IMO, markers should be in the *data* dir for a node, which can easily be
> separated by using -Djboss.server.data.dir=xxx !
>

See above; the request was to provide input to the user as to what went 
on. The user is not meant to look in the data/ dir; it's the AS' private 
playground. Also, the recommended trigger for undeploy is deleting the 
.deployed file.

> What's the recommended way to share applications between nodes ? (I
> tried domain mode, but couldn't get it to work after half a day...)
>
> If this is an RTFM, perhaps I didn't google enough, then let me know !
>


-- 
Brian Stansberry
Principal Software Engineer
JBoss by Red Hat