Explanation

XWiki does not start. The browser shows an initialization failure, Could not initialize main XWiki instance, and the logs carry the reason:

Could not create a DBCP pool. There is an error in the Hibernate configuration file, please review it.

Cause

XWiki could not open a connection to the MySQL server at all, so its connection pool was never created. Despite what the message says, the Hibernate configuration file is frequently correct: the pool reports itself as misconfigured as soon as its very first connection attempt fails, whatever the reason for that failure.

The usual reason is a MySQL server that is not listening where XWiki is looking. Either the server accepts no network connection at all, because skip-networking is enabled, or it is bound to a single interface through bind-address that does not include the address XWiki connects to.

Solution

1. From the machine running XWiki, check whether the server answers at all. This is the same connection XWiki makes, without Hibernate in the way:

   mysql -h <host> -u xwiki -p

   If this fails too, the fault is on the MySQL side and no amount of editing XWiki's configuration will fix it.

2. Open the MySQL server's configuration file and remove or comment out skip-networking, which stops the server from accepting any network connection.
3. In the same file, set bind-address to an address the XWiki host can reach. A server left on 127.0.0.1 accepts connections from its own machine only, which is the usual surprise when XWiki runs on another host or in a container.
4. Restart the MySQL server, then restart XWiki. The pool is created and the wiki is served.

Related

• Configure MySQL.
• "Unknown database" MySQL Error.