Wednesday, March 2, 2016

Using the CXF failover feature to authenticate to multiple Apache Syncope instances

A couple of years ago, I described a testcase that showed how an Apache CXF web service endpoint could send a username/password received via WS-Security to Apache Syncope for authentication. In this article, I'll extend that testcase to make use of the CXF failover feature. The failover feature allows the client to use a set of alternative addresses when the primary endpoint address is unavailable. For the purposes of the demo, instead of a single Apache Syncope instance, we will set up two instances which share the same internal storage. When the first/primary instance goes down, the failover feature will automatically switch to use the second instance.

1) Set up the Apache Syncope instances

1.a) Set up a database for Internal Storage

Apache Syncope persists internal storage to a database via Apache OpenJPA. For the purposes of this demo, we will set up MySQL. Install MySQL in $SQL_HOME and create a new user for Apache Syncope. We will create a new user "syncope_user" with password "syncope_pass". Start MySQL and create a new Syncope database:
  • Start: sudo $SQL_HOME/bin/mysqld_safe --user=mysql
  • Log on: $SQL_HOME/bin/mysql -u syncope_user -p
  • Create a Syncope database: create database syncope; 
1.b) Set up containers to host Apache Syncope

We will deploy Syncope to Apache Tomcat. Download Tomcat + extract it twice (calling it first-instance + second-instance). In both instances, edit 'conf/context.xml', and uncomment the the "<Manager pathname="" />" configuration. Also in 'conf/context.xml', add a datasource for internal storage:

<Resource name="jdbc/syncopeDataSource" auth="Container"
    testWhileIdle="true" testOnBorrow="true" testOnReturn="true"
    validationQuery="SELECT 1" validationInterval="30000"
    maxActive="50" minIdle="2" maxWait="10000" initialSize="2"
    removeAbandonedTimeout="20000" removeAbandoned="true"
    logAbandoned="true" suspectTimeout="20000"
    timeBetweenEvictionRunsMillis="5000" minEvictableIdleTimeMillis="5000"
    username="syncope_user" password="syncope_pass"

The next step is to enable a way to deploy applications to Tomcat using the Manager app. Edit 'conf/tomcat-users.xml' in both instances and add the following:

<role rolename="manager-script"/>
<user username="manager" password="s3cret" roles="manager-script"/>

Next, download the JDBC driver jar for MySQL and put it in Tomcat's 'lib' directory in both instances. Edit 'conf/server.xml' of the second instance, and change the port to "9080", and change the other ports to avoid conflict with the first Tomcat instance. Now start both Tomcat instances.

1.c) Install Syncope to the containers

Download and run the Apache Syncope installer. Install it to Tomcat using MySQL as the database. For more info on this, see a previous tutorial. Run this twice to install Syncope in both Apache Tomcat instances.

1.d) Configure the container to share the same database

Next we need to configure both containers to share the same database. Edit 'webapps/syncope/WEB-INF/classes/persistenceContextEMFactory.xml' in the first instance, and change the 'openjpa.RemoteCommitProvider' to:
  • <entry key="openjpa.RemoteCommitProvider" value="tcp(Port=12345, Addresses=;"/>
Similarly, change the value in the second instance to:
  • <entry key="openjpa.RemoteCommitProvider" value="tcp(Port=12346, Addresses=;"/>
This is necessary to ensure data consistency across the two Syncope instances. Please see the Syncope cluster page for more information.

1.e) Add users

In the first Tomcat instance running on port 8080, go to http://localhost:8080/syncope-console, and add two new roles "employee" and "boss". Add two new users, "alice" and "bob" both with password "security". "alice" has both roles, but "bob" is only an "employee". Now logout, and login to the second instance running on port 9080. Check that the newly created users are available.

2) The CXF testcase

The CXF testcase is available in github:
  • cxf-syncope-failover: This project contains a number of tests that show how an Apache CXF service endpoint can use the CXF Failover feature, to authenticate to different Apache Syncope instances.
A CXF client sends a SOAP UsernameToken to a CXF Endpoint. The CXF Endpoint has been configured (see cxf-service.xml) to validate the UsernameToken via the SyncopeUTValidator, which dispatches the username/passwords to Syncope for authentication via Syncope's REST API.

The SyncopeUTValidator is configured to use the CXF failover feature with the address of the primary Syncope instance ("first-instance" above running on 8080). It is also configured with a list of alternative addresses to try if the first instance is down (in this case the "second-instance" running on 9080).

The test makes two invocations. The first should successfully authenticate to
the first Syncope instance. Now the test sleeps for 10 seconds after prompting
you to kill the first Syncope instance. It should successfully failover to the
second Syncope instance on the second invocation.