[mythtv-users] Ver 31 frontend cannot connect to the database

[Bill Meek]

On 11/23/20 12:07 AM, Mike Carron wrote:
> 
> On 11/22/20 8:38 PM, Bill Meek wrote:
>> On 11/22/20 10:27 PM, Mike Carron wrote:
>>> On 11/22/20 7:14 PM, Bill Meek wrote:
>>>>> On 11/22/20 5:20 PM, Bill Meek wrote:
>>>>>> On 11/22/20 6:23 PM, Mike Carron wrote:
>>>>>>> My backend host recently failed badly enough that I was not able to
>>>>>>> salvage anything so I replaced the hardware and installed a new Ubuntu
>>>>>>> 20.04 and a new v31 mythtv-backend-master with xmltv.
>>>>>>>
>>>>>>> I then upgraded a remote frontend (Ubuntu 18.04) from MythTV 30 to 31
>>>>>>> but that frontend will not connect to the database.
>>>>>>>
>>>>>>> I've checked and rechecked the frontend setup screen and everything is
>>>>>>> correct. The config.xml files for both look like they should work. I've
>>>>>>> tried the backend config with </host> = localhost and = 192.168.0.222
>>>>>>> (the backend machine IP). The frontend config host is 192.168.0.222.
>>>>>>>
>>>>>>> I know the ip addresses are good. I can load 192.168.0.222:6544 into the
>>>>>>> address line of the Firefox on the frontend machine and it finds the
>>>>>>> database immediately.
>>>>>>>
>>>>>>> I'm no doubt missing something obvious but I can't find it. It seems
>>>>>>> like I have worn out 2 search engines trying.
>>>>>>>
>>>>>>> Suggestions?
>>>>>>>
>>>>>>> mike
>>>>>> On the backend's config.xml, always use localhost (or 127.0.0.1 if localhost
>>>>>> can't be resolved). That causes a socket to be used.
>>>>>>
>>>>>> See if mysql is running on the backend: systemctl status mysql mysqld mariadb
>>>>>> Probably is if the backend is running OK.
>>>>>>
>>>>>> One of the above ^^^ should be running. All three will work if
>>>>>> using mariadb and the Alias= lines in the service are setup.
>>>>>>
>>>>>> On the frontend, the following three must work: ping 192.168.0.222,
>>>>>> nmap --reason -p 3306 192.168.0.222 (expect a syn-ack) and then:
>>>>>>
>>>>>>      mysql --host=192.168.0.222 --user=mythtv --password=<from config.xml> mythconverg
>>>> On 11/22/20 8:50 PM, Mike Carron wrote:
>>>>> backend's config.xml uses localhost.
>>>>>
>>>>> status for mysql, mysqld and mariadb: active (running)
>>>>>
>>>>> ping 192.168.0.222 works
>>>>>
>>>>> nmap --reason -p 3306 192.168.0.222 produces:
>>>>>
>>>>> PORT     STATE  SERVICE REASON
>>>>> 3306/tcp closed mysql   reset ttl 64
>>>>> MAC Address: A8:5E:45:E3:5A:9F (Unknown)
>>>>>
>>>>> mysql --host=192.168.0.222 --user=mythtv --password=<from config.xml>
>>>>> mythconverg produces:
>>>>>
>>>>> ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.0.222' (111)
>>>>>
>>>>> This looks like the problem but I have no idea how to fix it.
>>>> See the answer from Ramesh.
>>>>
>>>> grep --recursive bind.address /etc/mysql
>>>>
>>>> My choice, which allows connections from any host
>>>> including IPv6:
>>>>
>>>> $ cat /etc/mysql/mariadb.conf.d/mythtv.cnf
>>>> [mysqld]
>>>> bind_address=::
>>>>
>>>> Restart mysql for it to take affect.
>>>>
>>> On my backend /etc/mysql/mariadb.conf.d contains: 50-client.cnf
>>> 50-mysql-clients.cnf  50-mysqld_safe.cnf  50-server.cnf.
>>>
>>> mythtv.cnf is in /etc/mysql/conf.d/,  the contents are:
>>>
>>> [mysqld]
>>> bind-address=::
>>> max_connections=100
>>>
>>> I restarted mysql. Nothing changed.
>> Need to be careful here. Try this:  tail -5 /etc/mysql/my.cnf
>>
>> That tells you the order that the sub-directories are included in.
>>
>> Any instance of bind_address AFTER the one you set will override it.
>>
>> Do the grep above to see if there are any other bind-addresses. Don't
>> change them, just be sure mythtv.cnf is read alphabetically after
>> everything else.
>>
>> Also, "Nothing changed" isn't clear enough. Did the nmap and mysql
>> commands fail exactly the same way. You could have moved on from
>> a connect failure to a password problem (for example).
>>
> Both nmap and mysql commands fail in the frontend. Both work in the
> backend. Here is the result of nmap:
> 
> root at MythTVMBE:/# nmap --reason -p 3306 192.168.0.222
> Starting Nmap 7.80 ( https://nmap.org ) at 2020-11-22 21:57 PST
> Nmap scan report for MythTVMBE (192.168.0.222)
> Host is up, received localhost-response (0.000064s latency).
> 
> PORT     STATE  SERVICE REASON
> 3306/tcp closed mysql   reset ttl 64
> 
> Nmap done: 1 IP address (1 host up) scanned in 0.16 seconds
> 
> If I'm reading this correctly my problem is that port 3306 is closed.
> Port 3306 is what the frontend is trying to talk to. How do I open it?
> I'm not a mysql expert and I'm way too old to become one.

Unfortunately, the bind-address solution is my best shot or at least my 1st.

Lets see the command and output from this: grep --recursive bind.address /etc/mysql

Then the command and output from this: tail -5 /etc/mysql/my.cnf

-- 
Bill