Cannot watch recording in progress / live TV on remote FE with multihomed backend

[white-haired-uncle]

• Platform:

spartan$ uname -a
Linux spartan 6.12.43+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.43-1 (2025-08-27) x86_64 GNU/Linux
spartan$ head /etc/os-release 
PRETTY_NAME="Devuan GNU/Linux 6 (excalibur/ceres)"

mythbackend$ uname -a           
Linux mythbackend 6.12.38+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.38-1 (2025-07-16) x86_64 GNU/Linux
mythbackend$ head /etc/os-release 
PRETTY_NAME="Devuan GNU/Linux 6 (excalibur/ceres)"

• MythTV version:

spartan$ /usr/local/bin/mythfrontend --version
Please attach all output as a file in bug reports.
MythTV Version : v36-Pre-518-gab57738caf
MythTV Branch : master
Network Protocol : 91
Library API : 36.20250212-1
QT Version : 5.15.15
Options compiled in:
 linux profile use_hidesyms using_alsa using_oss using_pulse using_pulseoutput using_airplay using_backend using_bindings_perl using_bindings_python using_bindings_php using_dvb using_firewire using_firewire_linux using_frontend using_hdhomerun using_iptv using_satip using_vbox using_ceton using_joystick_menu using_libcrypto using_gnutls using_libdns_sd using_libxml2 using_lirc using_mheg using_opengl using_egl using_qtscript using_qtdbus using_sqlite3 using_taglib using_v4l2 using_v4l2prime using_x11 using_system_libexiv2 using_system_libbluray using_system_libudfread using_drm using_bindings_perl using_bindings_python using_bindings_php using_freetype2 using_mythtranscode using_opengl using_egl using_drm using_vaapi using_nvdec using_vdpau using_ffmpeg_threads using_mheg using_libass using_libxml2

mythbackend$ mythbackend --version
Please attach all output as a file in bug reports.
MythTV Version : v36-Pre-515-g60cc32a489
MythTV Branch : master
Network Protocol : 91
Library API : 36.20250212-1
QT Version : 5.15.15
Options compiled in:
 linux profile use_hidesyms using_alsa using_oss using_pulse using_pulseoutput using_airplay using_backend using_bindings_perl using_bindings_python using_bindings_php using_dvb using_firewire using_firewire_linux using_frontend using_hdhomerun using_iptv using_satip using_vbox using_ceton using_joystick_menu using_libcrypto using_gnutls using_libdns_sd using_libxml2 using_lirc using_mheg using_opengl using_egl using_qtscript using_qtdbus using_sqlite3 using_taglib using_v4l2 using_v4l2prime using_x11 using_system_libexiv2 using_system_libbluray using_system_libudfread using_drm using_bindings_perl using_bindings_python using_bindings_php using_freetype2 using_mythtranscode using_opengl using_egl using_drm using_vaapi using_nvdec using_vdpau using_ffmpeg_threads using_mheg using_libass using_libxml2

• Package version:

• Component:

What steps will reproduce the bug?

Try to watch a recording in progress on a REMOTE frontend. It will fail "can't connect to the backend" (it's trying to connect to 127.0.0.1). When the recording completes, you can watch just fine.

How often does it reproduce? Is there a required condition?

I never watch things in progress (this was an accident), but I reproduced it on a different frontend, and with two different recordings.

Here we see the fe starting and talking to the correct be:

2025-09-06T17:48:09.171754-04:00 spartan mythfrontend: mythfrontend[27558]: I SendMessage mythcoreco
ntext.cpp:469 (ConnectCommandSocket) MythCoreContext::ConnectCommandSocket(): Connecting to backend 
server: 172.30.219.113:6543 (try 1 of 1)

And here I try to watch a recording in progress:

2025-09-06T17:48:30.360352-04:00 spartan mythfrontend: mythfrontend[27558]: I CoreContext mythcoreco
ntext.cpp:469 (ConnectCommandSocket) MythCoreContext::ConnectCommandSocket(): Connecting to backend 
server: 127.0.1.1:6543 (try 1 of 1)

mythfrontend.log

[rcrdnalor]

Interesting, the address 127.0.1.1 is used by the local Name Service Resolution stub. Whenever you get this address, something in the Name Service Resolution went wrong.
Please post for both instances (backend and frontend) the output of
host <hostname of the local machine>
host <hostname of the remote machine>
and check if those values are correct.

[white-haired-uncle]

Ah, good catch, I did not notice that 127.0.1.1

mythbackend$ host spartan.localdomain
spartan.localdomain has address 172.30.219.184
mythbackend$ host  172.30.219.184
184.219.30.172.in-addr.arpa domain name pointer spartan.localdomain.

spartan$ host mythbackend
mythbackend.localdomain has address 172.30.219.113
spartan$ host mythbackend.localdomain
mythbackend.localdomain has address 172.30.219.113
spartan$ host 172.30.219.113
113.219.30.172.in-addr.arpa domain name pointer mythbackend.localdomain.

[rcrdnalor]

Well, I am interested in

• on spartan:
  host spartan
• on mythbackend:
  host mythbackend
  Please post the output of the hosts: line in the fie nsswitch.conf by running in a terminal
  grep "hosts" /etc/nsswitch.conf
  for both instances (vbackend and frontend)

[white-haired-uncle]

spartan$ host spartan
spartan.localdomain has address 172.30.219.184
spartan$ grep hosts: /etc/nsswitch.conf 
hosts:          files mdns4_minimal [NOTFOUND=return] dns
spartan$ grep spartan /etc/hosts
127.0.1.1	spartan.localdomain	spartan

mythbackend$ host mythbackend
mythbackend.localdomain has address 172.30.219.113
mythbackend$ grep "hosts" /etc/nsswitch.conf
hosts:          files mdns4_minimal [NOTFOUND=return] dns

Curious, seems nsswitch is ignored?

[rcrdnalor]

Do the files /etc/hosts contain the correct address of the hostname or simply 127.0.1.1 ?
Sorry, I have overlooked your answer :-(

[rcrdnalor]

I f you have set a static IP address by means of:

• /etc/network/interfaces
• NetworkManager GUI (nmcli command {CLI tool for NetworkManager})
• Systemd : The network may be configured in /etc/systemd/network/ directory
• Netplan

then you should use the this address in the file /etc/hosts instead of 127.0.1.1.

See https://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_the_hostname_resolution

If you set-up a static IP via DHCP service based on the MAC address, then everything should be fine on the clients without any further intervention.

I am curious weather the hostname and host columns in the MySQL mythconverg table show the hostname with or without the .localdomain extension

[white-haired-uncle]

On the client side, it's static via dhcp based on MAC:

        host laptop {
                option host-name spartan;
                hardware ethernet 00:e0:4c:68:00:ab;
                fixed-address 172.30.219.184;
        }

mythbackend is /etc/network/interfaces (can't do dhcp on that one, the DNS server is also the VM host and 172.30.219.113 is on a mac-vtap so it can see the HDHR):

auto eth1
iface eth1 inet static
    address 172.30.219.113
    netmask 255.255.255.0
    network 172.30.219.0
    broadcast 172.30.219.255

The other NIC (192.168.124.113, not accessible by spartan) is static via dhcp/dnsmasq:

auto eth0
iface eth0 inet dhcp

I am curious weather the hostname and host columns in the MySQL mythconverg table show the hostname with or without the .localdomain extension

There's no mysql.mythconverg that I can find.

[rcrdnalor]

There's no mysql.mythconverg that I can find.

On the backend:
Grep the password for the MySQL mythconverg access from /etc/mythtv/config.xml
Run in terminal mysql -u mythtv -p mythconverg
Enter (or paste) the password.
Enter show tables;
For each table in recorded, recordedfile run:
select hostname, count(hostname) from recorded;
in that MySQL shell.

For the table in recordedartwork, run:
select host, count(host) from recordedartwork;
in that MySQL shell.

[rcrdnalor]

Sorry, wrong queries: please run this in the mysql shell:
select hostname, count(*) as count from settings group by hostname order by count desc;
select hostname, count(*) as count from recorded group by hostname order by count desc;
select host, count(*) as count from recordedartwork group by host order by count desc;

[white-haired-uncle]

(hawkeye was the backend before I moved it to a VM some years back - same `db)

MariaDB [mythconverg]> select hostname, count(*) as count from settings group by hostname order by count desc;
+--------------+-------+
| hostname     | count |
+--------------+-------+
| hawkeye      |   549 |
| wolverine    |   509 |
| localhost    |   325 |
| spartan      |   171 |
| mythbackend  |   166 |
| gopher       |   153 |
| NULL         |   150 |
| hoosier      |   149 |
| backup       |   146 |
| testfrontend |   124 |
+--------------+-------+
10 rows in set (0.401 sec)

MariaDB [mythconverg]> select hostname, count(*) as count from recorded group by hostname order by count desc;
+-------------+-------+
| hostname    | count |
+-------------+-------+
| mythbackend |  8877 |
+-------------+-------+
1 row in set (0.033 sec)

MariaDB [mythconverg]> select host, count(*) as count from recordedartwork group by host order by count desc;
+-------------+-------+
| host        | count |
+-------------+-------+
| hawkeye     |   484 |
| mythbackend |     5 |
+-------------+-------+
2 rows in set (1.845 sec)

[white-haired-uncle]

From the frontend

• I can not watch a recording that is in progress
• I can view the metadata (hit 'i' with recording selected) for a recording that is in progress
• I can delete the recording in progress
• Once the recording completes, I can watch it

So, what is being done that is different between, for example, watching a recording in progress and a completed recording (or anything else I've tried)?

And more specifically, where is the difference (frontend or backend)? In the background I'm working on trying to bisect and see if I can come up with a point when something changed, I know I've watched recordings in progress at some point.

[rcrdnalor]

There is obviously some homework necessary on the videometadata and recordedartwork table. :-)
Since you are the first one who is raising that issue, I would start to consolidate the Name Resolution
before trying to bisect the MythTV code and commits.

This entry looks wrong to me, but I am not an expert:
DNS does not resolve MDNS (or AVAHI) entries per default:

spartan$ grep spartan /etc/hosts
127.0.1.1	spartan.localdomain	spartan

Did you manually added this ? On Ubuntu, I don't get this .localdomain thingy in /etc/hosts.

[white-haired-uncle]

No, I did not add that. I actually just built that machine yesterday, so I'm pretty sure I remember everything I did. Most likely .localdomain was added during the OS install when it asked me for my domain.

I mentioned in the beginning that I'm seeing this with two frontends. The other one is named gopher. gopher boots over the network, so I can boot it into one of several configs.

I built another devuan6 backend in a VM, with v35.0-33-g931474b3a0, and booted gopher into debian13 with v35.0+fixes.20250830.badd4ccc-0ubuntu0 (that's me building a package from source per the wiki instructions). That did not show the issue.

Other than the fact that the FE is debian13 vs devuan6, and those hosts probably aren't in DNS, the config should be about the same as the v36 setups which aren't working. I'll get the BE into DNS, and maybe build myth with a different prefix on spartan, but it looks to me like v35 probably works.

BTW, this is gopher when running debian:

whu@deb13fe$ cat /etc/hosts
127.0.0.1       localhost
127.0.1.1       deb13fe.localdomain     deb13fe

[white-haired-uncle]

Changed the hosts file on mythbackend to 127.0.1.5, and now spartan is trying to connect to THAT.

I suspect what's happening here is frontend is asking for the location of something, probably the backend which hosts the (in-progress) recording, and the master backend is taking the recorded.hostname (or whatever) and resolving it locally, which is just all kinds of wrong. Pass back the host name, let the client do the resolving (like watching completed recordings I suspect?) and all is well.