Comment 1 for bug 1021954

An addition to this. It appears that it is trying to connect *only* to /var/lib/mysql/mysql.sock for connections.

I just removed the file (a link to the first instance's socket) and got this error:

120706 15:04:23 innobackupex: Starting mysql with options: --defaults-file='/tmp/instance03.cnf' --password=xxxxxxxx --user='<user>' --unbuffered --120706 15:04:23 innobackupex: Connected to database with mysql child process (pid=23948)
innobackupex: Error: mysql child process has died: ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

This socket is not specified anywhere in the global my.cnf, or the cnf in the --defaults-file directive