packaging/deployment

Resin provides a wide variety of custom packaging and deployment options.

In this scenario, you want to configure a web-app with a specific root-directory and specify the location of the .war file. As usual, when Resin sees any changes in the .war file, it will expand the new data into the root-directory and restart the web-app. This capability, gives sites more flexibility where their directories and archive files should be placed, beyond the standard webapps directory.

The optional archive-path argument of the <web-app> will point to the .war file to be expanded.

<resin xmlns="http://caucho.com/ns/resin">
<cluster id="">
  <host id="">

    <web-app id="/foo" root-directory="/var/www/foo"
             archive-path="/usr/local/stage/foo.war"/>

  </host>
</cluster>
</resin>

The startup-mode is used in a number of places to determine the behaviour of a resource when the server starts.

The startup-mode has three values: "automatic", "lazy", and "manual".

• automatic - starts the resource on server start (default)
• lazy - starts the resource on the first use
• manual - waits for JMX to start the resource

The redeploy-mode is used in a number of places to determine the behaviour of a resource when it is replaced or modified while the server is running.

The redeploy-mode has two values: "automatic", and "manual".

• automatic - restarts the resource when it is modified (web.xml, *.class, *.war, etc).
• manual - waits for JMX to restart the resource when changes occur.

Resin can deploy multiple versions of a web-app simultaneously, simplifying any application upgrades. The old version of the web-app will continue to receive old sessions, while the new version will get the new requests. So any user will see a consistent version as the web site update occurs with no downtime required.

The versioning requires <web-app-deploy>, i.e. it works with the webapps directory. The versioning is numerically-based, allowing dotted notation, to determine the most recent version. A simple deployment process might use foo-101 to upgrade from foo-100. A more complicated one might use foo-10.3.14 to upgrade from foo-10.3.13.

The versioning attribute of the <web-app-deploy> enables versioning:

<resin xmlns="http://caucho.com/ns/resin">
<cluster id="">
<host id="">

  <web-app-deploy path="webapps" versioning="true"/>

</host>
</cluster>
</resin>

It may be possible to deploy a web application to a live server without interruption to service if certain conditions are met.

1. The session objects for your users are being persisted.
2. The usage of session scoped objects between the old version and the new is compatible.
3. The usage of application scoped objects between the old version and the new is compatible.
4. Database schema changes are not required.

Resin allows you to have a backup instance running. The idea is that this backup instance of Resin takes over if your primary Resin instance goes down.

If you are using a load balancer to distribute your load to multiple primary servers, each primary server has a backup server.

You can use this feature to deploy to a live server without interruption of service.

1. shutdown primary server(s) (backup server(s) takes over)
2. deploy new war to primary server(s)
3. start primary server(s). As soon as the primary server starts, the user will be using the new version of the application.
4. deploy new war to backup server(s)

As of Resin 4.0.0, it is now possible to deploy web applications remotely to a shared repository that is distributed across the cluster. This feature allows you to deploy once to any triad server and have the application be updated automatically across the entire cluster. When a new dynamic server joins the cluster, the triad will populate it with these applications as well.

To deploy an application remotely:

1. log into the resin-admin console on any triad server. Make sure you are connecting over SSL, as this feature is not available over a non-encrypted channel.
2. Browse to the "webapp" tab of the resin-admin server and at the bottom of the page, enter the virtual host, URL, and local .war file specifying the web application, then press "Deploy".
3. The application should now be deployed on the server. In a few moments, all the servers in the cluster will have the webapp.

Command line deployment capabilities were introduced in Resin 4.0.14. The set of commands allows deploying, undeploying, listing applications deployed on the server and controlling application lifecycle.

java -jar lib/resin.jar deploy -user admin -password secret /projects/hello-world/hello-world.war
Deployed production/webapp/default/hello-world as hello-world.war to http://127.0.0.1:8080/hmtp

java -jar lib/resin.jar deploy-list -user admin -password secret
                    production/webapp/default/hello-world

java -jar lib/resin.jar deploy-copy -user admin -password secret -source hello-world -target foo
copied production/webapp/default/hello-world to production/webapp/default/foo

java -jar lib/resin.jar undeploy -user admin -password secret undeploy foo
Undeployed foo from http://127.0.0.1:8080/hmtp

java -jar lib/resin.jar start-webapp -user admin -password secret foo
'production/webapp/default/foo' is started

java -jar lib/resin.jar stop-webapp -user admin -password secret foo
'production/webapp/default/foo' is stopped

java -jar lib/resin.jar restart-webapp -user admin -password secret foo
'production/webapp/default/foo' is restarted

With remote deployment, you can use an ant or maven task to deploy a .war file to a running Resin instance. This will require some configuration of the resin.xml to enable deployment. For security reasons, remote deployment and administration is disabled by default, so you will need to enable the features to use them.

• Enable remote administration (the HMTP service).
• Add at least one admin user in AdminAuthenticator.
• Enable the remote deploy service.

The first step is enabling remote administration, so you can manage the server remotely, either with eclipse, or ant, or maven. If disabled, Resin will ignore all remote administration requests. The disabled error message will be something like "Failed to connect to HMTP because HMTP service has not been enabled." In the resin.xml, the <resin:RemoteAdminService> tag enables remote administration:

<resin xmlns="http://caucho.com/ns/resin"
       xmlns:resin="urn:java:com.caucho.resin">
       ...

  <resin:AdminAuthenticator>
     <resin:user name="harry" password="..."/>
  </resin:AdminAuthenticator>

  <cluster id="">

    <resin:RemoteAdminService/>
    <resin:DeployService/>

    ...
  </cluster>
</resin>

The second step is adding at least one administration user, so only authorized administrators can update the server. The <resin:AdminAuthenticator> tag configures administrators. If no administrators are added, Resin will reject any remote administration requests.

The third step is enabling the deploy service itself with the <resin:DeployService> tag. The deploy service is responsible for managing uploads of new applications and distributing them to the servers in the cluster.

When troubleshooting, it's helpful to know that Resin uses BAM/HMTP to connect the deployment client with the deployment server. The <resin:RemoteAdminService> enables BAM/HMTP. If the server is down or the remote admin service isn't enabled, the error messages will complain that the BAM/HMTP connection is not allowed.