[mythtv-users] Problems connecting a remote frontend after upgrading to Debian Bullseye

[Stephen Worthington]

On Mon, 3 Jan 2022 23:26:19 +0100, you wrote:

>Hello,
>
>I have a combined BE/FE and a FE and both computers were running Debian
>Buster. This weekend I upgraded the combined BE/FE to Debian Bullseye
>and after that I can no longer start the FE on the other computer since
>it can not connect to the database.
>
>I have not seen any obvious changes but the MariaDB has been updated
>from 10.3.31 to 10.5.12. Do anyone know if there have been any changes
>related to remote database access between these versions?
>
>Or do anyone have any suggestions on how to debug this?
>
>Best regards,
>Peter Carlsson

The fist thing to check is to see what port that MySQL/MariaDB is
listening on on the BE:

sudo netstat -anp | grep mysql | grep -i listen

This is what I get:

tcp6       0      0 :::3306                 :::* LISTEN
2894/mysqld
unix  2      [ ACC ]     STREAM     LISTENING     50439    2894/mysqld
/var/run/mysqld/mysqld.sock

You should see something like that if you have IPv6 enabled.  If not,
you should see a "tcp" line instead of a "tcp6" line and
"0.0.0.0:3306" instead of ":::3306".

If you do not see a ":::3306" or "0.0.0.0:3306" line, then it is
likely that your "bind-address" setting in your /etc/mysql/ config
files has been changed.  Either the old one has been overwritten
because it was in a file that the package updated, or it was in the
wrong file and the package has moved or introduced a new
"bind-address" line in a config file that is read after your
"bind-address" line and overrides it.

To find out, do this:

sudo su
cd /etc/mysql
grep -ir "bind-address" *

This is what I get:

my.cnf.migrated:#bind-address           = 127.0.0.1
conf.d/mythtv.cnf:#bind-address=::
conf.d/mythtv.cnf.dpkg-old:#bind-address=0.0.0.0
conf.d/mythtv-tweaks-jsw.cnf:bind-address=::
my.cnf.original:bind-address            = 127.0.0.1
mariadb.conf.d/50-server.cnf:bind-address            = 127.0.0.1
mysql.conf.d/mysqld.cnf:#bind-address           = 127.0.0.1

Only .cnf files matter, so the my.cnf.original, my.cnf.migrated and
mythtv.cnf.dpkg-old files are not read by MySQL/MariaDB and can be
ignored.  So I have two "bind-address" settings that matter as the
rest are commented out.  One is in 50-server.cnf for "127.0.0.1" and
one in mythtv-tweaks-jsw.cnf for "::".  Since the
conf.d/mythtv-tweaks-jsw.cnf file is read after the
mariadb.conf.d/50-server.cnf file, the one that matters is set to
"::", which means "any IPv4 or IPv6 address".  The
conf.d/mythtv-tweaks-jsw.cnf file is one I created, and it is named so
that it is the last file read from the conf.d directory, after the
mythtv.cnf file that gets installed by the MythTV packages on my
Ubuntu system.