Failover is possible using Bucardo, although that is not one of its primary goals. For swap syncs, of course, there is very little that needs to be done; just point your application to the other database. For a pushdelta sync on the other hand, making one of the targets into a source involves the following steps:

• Set the old source as ‘inactive’ in the db table.
• Alter the sync so that the new source is the sourcedb.
• Run database function validate_sync() so that triggers and other supporting items get created on the new source.
• If you are in doubt that the targets are up to date, set onetimecopy to 2.
• Restart Bucardo.