Wednesday, 24 June 2015

Seamless User Profile Migration from MySQL to OpenDJ

Following on from my previous post on OpenDJ password schemes, a common requirement is often to migrate users into the OpenDJ profile store from an existing database. There are numerous ways to do this, such as LDIF file imports or using OpenIDM reconciliation and livesync. However, both methods only really do a like for like comparison – no data cleansing takes place - unless you start to configure some logic processing in there.

This might be fine, but if your existing repositories contain millions of entries, some of which you don't know are live, a quick way to migrate across only active users, is to use OpenAM, with it's Dynamic Profile creation feature.

The above describes the process at a high level. Basically there are 3 authentication modules in a chain, using the flexibility of sufficient and optional modules

In this flow, there are basically 3 states.

User in MySQL User in OpenDJ Authentication Works Against Password Captured
1st Run Yes No MySQL No
2nd Run Yes Yes MySQL Yes
3rd Run Yes Yes OpenDJ/MySQL No

On the first run through, authentication fails against OpenDJ, as the user only exists in MySQL.  The chain then flows down to the JDBC module to authenticate the user.  The scripted module doesn't have an impact yet, as the user is only created in OpenDJ once the authentication chain has completed.  

With regards to the JDBC module, depending on how the password has been stored in the SQL database, it's quite likely you will need to write a password syntax transformation class, to alter the submitted clear text password, into an algorithm that the database is using to store the password.  This is pretty simple and documented process, with an example I wrote for SHA1 hashing available here.

On the second run through, the same thing happens, except this time the scripted module has something to update in the DJ repository - the user was created at the end of the 1st run through remember. The script simply does an idRepository.setAttribute against the newly created DJ user, to update the userPassword attribute with the password value from the sharedState.password.  The script I used is available here.

If all things are working as expected... the 3rd run through is somewhat different.  Not only does the user now exist in the DJ store, but that store also contains the existing user password from MySQL. 

So, whilst the user logs in using the same credentials as if nothing has happened, the authentication chain will authenticate successfully against OpenDJ and then exit the chain.

The main benefit of this approach, is that the end user has not been impacted - they log in with the same credentials as they did when using the MySQL repository.  No impact to their journey and no dreaded password reset use case.  Secondly, only the users that have successfully logged in are created in the new DJ store.  The bi-product of this process, is that a data cleansing aspect as has taken place.  Any users captured in the MySQL database that no longer use the service will no be migrated.

Another benefit of the migration is following my blog on password storage in OpenDJ, you can also seamlessly upgrade the hashing algorithm too.

NB - To allow the flow down of the shared state username and password down between the initial LDAP module and the secondary JDBC module, edit the module options setting within the authentication chain to conain iplanet-am-auth-shared-state-enabled=true.

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