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Setting up a Load-Balanced Server

To scale a deployment to a larger number of users and to increase the availability, Oxygen XML Web Author can be deployed on a set of load-balanced servers. This topic describes the required setup for such a scenario.

Restriction: The concurrent editing feature does not work if Oxygen XML Web Author is deployed on multiple servers behind a load balancer.

Configure Session Stickiness

Every Oxygen XML Web Author server keeps the state of the edited documents in memory for performance reasons. This implies that every user should connect to the same back-end server for the duration of an editing session. To achieve this result in a load-balanced setting, you should enable session stickiness.

If your reverse proxy just allows basic routing based on a cookie, you might consider creating a plugin for each Web Author server that implements a com.oxygenxml.ServletFilterExtension extension that sets a particular cookie (e.g. a cookie with a name like "wa-server-route" and with values like "wa1", "wa2", etc.) for every request that reaches each Web Author server. In addition, you have to define the routing rules in your reverse proxy that routes each request based on the cookie set by that plugin. A generic sample plugin that defines a ServletFilterExtension can be found here.

Note:

By default, Web Author uses the JSESSIONID cookie to track the active sessions. Some load-balancers implement session stickiness by modifying the JSESSIONID session cookie, which might break the Web Author's session tracking mechanism.

In this case, you will need to change the name of the cookie Oxygen XML Web Author uses to track sessions by changing the WEB-INF/shiro.ini configuration file to add:

sessionManager.sessionIdCookie.name = NAME

Configure Server Health Checks

To detect unhealthy servers, Oxygen XML Web Author offers a health check REST API. The endpoint has the following interface:

URL: rest-public/status
Response status code: 200 for a healthy server and 503 for an unhealthy server.
Response body: For an unhealthy server, the response body contains a text description of the problem.

Configure the License Server

All Oxygen XML Web Author servers can use the same pool of floating licenses. To this end, they all need to be configured to use the same license server.

Share Configuration Between All Instances

The configuration (including options, frameworks, and plugins) is stored in the file system in a directory that can be changed using the oxygen.data.dir system property. For all instances to use the same options, oxygen.data.dir should point to the same directory on a shared file system (for example, NFS).

To manage the configuration, you have two options:

Use the Administration Page of one of the instances to change these options and then restart all other instances so that they pick up the new configuration.
Create a custom Web Application Archive (WAR) that contains Oxygen XML Web Author and all the configuration. Every time you want to change the configuration, create a new version of the WAR file and deploy it again. Such a custom WAR can be built using the Web Author Component integration project.