Summary

After configurating Kerberos authentication to a SQL Server database, Bitbucket stops responding after a while and the application freezes.

Upgrading previous versions of Stash (that were running with Kerberos) to Bitbucket Server will cause this issue as well.

The reason why is that from Stash to Bitbucket, the software that handles the database pool has changed from BoneCP to HikariCP:

• Stash config properties

  These properties control the database pool. The pool implementation used is BoneCP. Documentation for these settings can be found at: http://jolbox.com/configuration.html

• Bitbucket Server config properties

  These properties control the database pool. The pool implementation used is HikariCP. Documentation for these settings can be found at: https://github.com/brettwooldridge/HikariCP/wiki/Configuration
  To get a feel for how these settings really work in practice, the most relevant classes in HikariCP are:
  com.zaxxer.hikari.HikariConfig Holds the configuration for the database pool and has documentation for the available settings.
  com.zaxxer.hikari.pool.HikariPool Provides the database pool and manages connections.
  com.zaxxer.hikari.util.ConnectionBag Holds references to open connections, whether in-use or idle.

Required fix:
We need to apply a fix in BBS that makes sure when HikariCP goes to open a connection it uses the webapp's ClassLoader, not the ClassLoader of whatever thread it's acquiring a connection on.

Environment

Only mixed-mode authentication is supported on Linux.

Integrated or Kerberos authentication to SQL Server is only supported on a Windows server.

The com.sun packages are not available to plugins, which results in the module not being available to ActiveObjects and causing the error above. On Windows, the Sun packages are not required as the DLL's in the JDBC driver provide everything needed.

Steps to Reproduce

Configure your environment with Kerberos as described on:

• Connecting Bitbucket Server to SQL Server

Expected Results

Application should work normally.

Actual Results

The following error can be seeing in the atlassian-bitbucket.log:

Caused by: javax.security.auth.login.LoginException: unable to find LoginModule class: com.sun.security.auth.module.Krb5LoginModule not found from bundle [com.atlassian.bitbucket.server.bitbucket-notification]

Or

Caused by: java.sql.SQLRecoverableException: IO Error: JNDI Package failure javax.naming.NoInitialContextException: Cannot instantiate class: com.sun.jndi.ldap.LdapCtxFactory [Root exception is java.lang.ClassNotFoundException: com.sun.jndi.ldap.LdapCtxFactory not found from bundle [com.atlassian.bitbucket.server.bitbucket-notification]]

Workaround

1- Add a property to <BITBUCKET_HOME>/shared/bitbucket.properties

Modify bitbucket.properties to add the following line:

db.pool.size.idle=${db.pool.size.max}

This will force the pool to open all of the possible connections immediately, which should prevent the unable to find LoginModule class error from happening in plugins.

2- Use mixed mode

If you'd like to stay on Linux, the solution is to allow mixed-mode authentication on the SQL Server and specify a username and password to connect to the database.

Alternatively, a migration to Windows will allow you to use the native DLL's.