[mythtv-users] 'service mythbackend start' fails on slave backend

[Nick Morrott]

On 28/09/2007, Andrew Robinson <awrobinson-ml at nc.rr.com> wrote:
> Nick Morrott wrote:
> > On 27/09/2007, Andrew Robinson <awrobinson-ml at nc.rr.com> wrote:
> >> I am trying to setup a slave backend and I have narrowed my problem down
> >> to this. When I start mythbackend from a command line like
> >> '/etc/init.d/mythbackend start', mythbackend starts up and connects to
> >> the database just fine. However, when I use the 'service' command, ie,
> >> 'service mythbackend start', mythbackend fails to connect to the
> >> database on the master backend. Apparently when I use the 'service'
> >> command, I do not get the environment required. I will keep on trying to
> >> track this down. While I do, has anyone else encountered this and
> >> figured out a solution? I am running Fedora 7 on the slave backend.
> >
> > This is very much likely due to a bad $HOME variable. Which version of
> > MythTV are you running, and how many copies of the mysql.txt do you
> > have on your system? (You may have MythTV directories in /, /root and
> > /home/mythtv. You need to ensure all mysql.txt contain the correct
> > information for accessing the database.
> >
>
> The .mythtv in the / directory was the solution. In the mysql.txt file
> there, DBHostName was set to "localhost". I changed it to the name of
> the master backend and 'service mythbackend start' worked. I had looked
> at the .mythtv directories in /home/mythtv and /root. I had not thought
> to look for one in /. Thanks!
>
> I think the $HOME directory also explains how I did get it to work. I
> focused on these three lines in the /etc/init.d/mythbackend script:
>
>    # Does not work on Red Hat, do to to missing audio/video groups.
> #  cd $MYTHTV_HOME && daemon --user mythtv $binary $OPTIONS
>    cd $MYTHTV_HOME && daemon $binary $OPTIONS
>
> Despite the warning about Red Hat, I decided to try the version with
> "--user mythtv". I found the mythbackend program ran and connected to
> the database on the master backend, but it would not write to the log
> files. So I tried substituting "--user root" instead. With that,
> mythbackend ran, connected to the database, and wrote to the logs. I
> wasn't sure if there would be any unintended consequences, but hey, it
> worked. Myth finally acknowledge the tuners on the slave backend.

If you had first run mythbackend as root, the log files will be owned
by root in /var/log/mythtv and so the mythtv would have no write
privileges to the file.

> I think with your reply I understand what was happening. With "--user
> mythtv", I was accessing the mysql.txt in mythtv's home directory.
> Likewise with "--user root", I was accessing the mysql.txt file in
> root's home directory. With no "--user" option, I was accessing the
> mysql.txt file under the / directory. At the time, the DBHostName
> variable in that file was set to "localhost".
>
> Thanks for the help!

No problem. That's why I supplied the patch (it was committed to trunk
a few months ago) to try and fix these issues on Fedora. The SVN
version of the init script contains comments warning about running
mythbackend as non-root on Fedora - issues with realtime scheduling
and access to hardware are the problems to overcome.

-- 
Nick Morrott

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