[mythtv-users] Help troubleshooting why remote frontends not able to connect after upgrade

[Michael T. Dean]

On 04/26/2008 04:03 PM, Paul D. Cnudde wrote:
> I configured my master backend server with the IP address of the machine 
> it runs on, 192.168.1.3, this worked before.  For the sake of argument I 
> set it back to 127.0.0.1, but still I get no joy. In fact the frontend 
> setup program doesn't even detect the Backend sever if I do that, and 
> doesn't prompt me for a PIN.  I set it back to 192.168.1.3.
>   

Good.  It shouldn't be 127.0.0.1.

> Below is an excerpt from the front end logs:
>
> 2008-04-26 15:36:15.638 Using runtime prefix = /usr, libdir = /usr/lib
> 2008-04-26 15:36:16.274 DPMS is active.
> 2008-04-26 15:36:16.295 Empty LocalHostName.
> 2008-04-26 15:36:16.295 Using localhost value of poobah
> 2008-04-26 15:36:16.297 Testing network connectivity to 192.168.1.3
> 2008-04-26 15:36:16.439 New DB connection, total: 1
> 2008-04-26 15:36:16.464 Connected to database 'mythconverg' at host: 
> 192.168.1.3
>
> I'm not sure why its even concerned with localhost or LocalHostName.

LocalHostName is irrelevant.  It's a custom identifier for frontend 
preferences, and it can be anything.  The default is to fall back to 
the, er, local host name, which is quite appropriate for nearly all 
setups.  :)

> As you can see no problem connecting to the db
> anyway a bit later on:
>
> 2008-04-26 15:36:24.761 Connecting to backend server: localhost:6543 
> (try 1 of 5)

Myth only uses a value of localhost at that point when a) MasterServerIP 
is set to localhost or b) MasterServerIP is not specified in the 
database.  MasterServerIP is the setting that I mentioned previously:

IP address
The IP address of the master backend server. All frontend and non-master
backend machines will connect to this server. If you only have one
backend, this should be the same IP address as above.

Below, I will call this setting "MasterServerIP".  Note, however, that 
setting differs from:

IP address
Enter the IP address of this machine.  Use an externally accessible 
address (ie, not 127.0.0.1) if you are going to be running a frontend on 
a different machine than this one.

which I will call "BackendServerIP".

For your config, you must set MasterServerIP to 192.168.1.3 and 
BackendServerIP to 192.168.1.3 on the master backend (only).  On all 
other systems, if you have a backend, you should specify the same value 
for MasterServerIP (192.168.1.3), but change the value of 
BackendServerIP to the IP address of that machine's NIC.  If you don't 
run tmythbackend or mythjobqueue on that system, you don't need to 
specify a BackendServerIP (i.e. can leave it at the default, 
127.0.0.1).  It doesn't hurt, however, if you do specify the proper IP 
address for BackendServerIP even if the machine is a frontend-only machine.

So, assuming you have set everything correctly, it would appear that 
Myth is picking up an incorrect (or no) value for the MasterServerIP on 
the remote systems.  This could be because your systems are hitting 
different databases or ...

To check your database, you can use:

SELECT * FROM settings WHERE value LIKE '%ServerIP';

However, I /strongly/ recommend, if you do find the issue using the 
above query, you fix it through the GUI rather than directly in the 
database.  Doing so has a couple of advantages--you get any 
application-level checking provided by Myth, you don't accidentally 
forget/mess up the WHERE clause (and break your system), and--most 
importantly--you learn how to properly use the GUI that's provided for 
configuration (i.e. you learn what you did wrong the first time).

Mike