[mythtv-users] Linux frontend database connection problems - FIXED
Piers Kittel
mailing at biased.org
Sun Aug 19 13:44:12 UTC 2007
Geoff,
Thanks *so* much for replying - it is much appreciated!
> Have you started at first principles?
Yeah, but I'll do it again.
> Can you cross ping between the machines?
Yes
> Can you ssh from the frontends? Needs /etc/host entries to be
> correct.
Yes
> Can you nsf mount from the frontends? Needs stuff setup and running on
> the backend machine. If nsf works, then you have proved that all the
> required TCPIP is correct.
Assume you mean NFS - yes, as one of the frontend is a diskless
frontend, and accesses its data via NFS which is on the backend.
> Now that leaves mysql access.
> Make sure mysqld is OFF on each frontend and running on the backend.
MySQL is not running on the frontends
> Make sure that the mysql ports are open. Fedora has a little program
> called 'lokkit' which is made for port opening/checking.
MySQL should be working, after all, the OS X frontends doesn't have
any problems. I use a program called nmap, and it reports:
piers at hinata:~$ nmap destiny
Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2007-08-19 13:13
BST
Interesting ports on destiny (192.168.1.2):
Not shown: 1670 closed ports
PORT STATE SERVICE
22/tcp open ssh
53/tcp open domain
80/tcp open http
111/tcp open rpcbind
443/tcp open https
665/tcp open unknown
2049/tcp open nfs
3306/tcp open mysql
6543/tcp open mythtv
6544/tcp open mythtv
Nmap finished: 1 IP address (1 host up) scanned in 0.279 seconds
piers at hinata:~$
As we can see, there's a mysql entry in the list - as well as 2
MythTV ports.
(FYI, Hinata = the diskless frontend, destiny is the backend)
> The backend needs a unique name/IP. Set it in each frontend in
> /etc/hosts. DHCP is a real problem here: use static IP addresses.
The backend and the diskless frontend both use static IP addresses.
> Mythtv-setup on the backend cannot use 127.0.0.1 !!!
Correct - remember the OS X frontends works fine.
> At this point you should be able to ssh into the back from the fronts
> and vice versa. If you set up nfs then you should be able to mount the
> storage partition from the frontends.
Have done...
piers at hinata:~$ df -h
Filesystem Size Used Avail Use% Mounted on
tmpfs 126M 0 126M 0% /lib/init/rw
tmpfs 126M 0 126M 0% /dev/shm
rootfs 9.2G 4.2G 4.6G 48% /
destiny.10sca.intranet:/video
298G 69G 230G 23% /video
piers at hinata:~$
> Create a mysql user for each frontend machine by amending and re-
> running
> the mc.sql script which is in mythtv/database.
> ....(I'm not sure if mysql will work from multiple frontends using the
> same mysql user.)
Can't be a problem with the server, because all OS X frontends works
fine - just not the Linux frontends. Did this anyway, and didn't work.
> At this point, running 'select host,user,password from user;' on the
> mysqld server (backend) machine, as root mysql user should list the
> various frontend machines by name, the mysql users and show the
> hash of
> the password. At this point you should be able to log into the mysql
> server from each frontend and run mysql queries as the frontend's user
> and as the root mysql user. If you cannot do this, myth will not be
> able
> to either.....
I can connect to the mysql database via the frontend using the mysql-
client software:
piers at hinata:~$ mysql -h 192.168.1.2 -u mythtv -p mythconverg
Enter password:
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 73
Server version: 5.0.32-Debian_7etch1-log Debian etch distribution
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> quit
Bye
piers at hinata:~$
It works fine!
> Run 'find' to check for duplicate copies of mysql.txt on each machine.
> Fix the /home/mythtv frontend copy of mysql.txt to refer to the
> correct
> backend IP addess and the frontend mysql user name.
Have deleted every instance of mysql.txt on the frontend, and re-ran
the frontend, and entered the exact same settings I used to log onto
the server above and it doesn't work! I am much more confident the
SQL driver mythtv uses is broken somehow.
2007-08-19 13:39:53.323 Writing settings file /home/piers/.mythtv/
mysql.txt
2007-08-19 13:39:53.338 Unable to connect to database!
2007-08-19 13:39:53.339 No error type from QSqlError? Strange...
QSqlQuery::exec: database not open
QSqlQuery::exec: database not open
2007-08-19 13:39:53.392 DB Error (KickDatabase):
Query was:
SELECT NULL;
No error type from QSqlError? Strange...
2007-08-19 13:39:53.448 Failed to init MythContext, exiting.
Hmm... libqt3-mt-mysql somehow got uninstalled (probably in the dist-
upgrade) - reinstalled it, now mythfrontend works, but very slowly
and video doesn't work, but that's another thread :)
> And remember:
> If at first you don't succeed, sky-diving is nor recommended.
Good advice. :)
Thanks for all your help and for your time! It is much appreciated :)
Regards - Piers
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