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Resolved Server Error 502 Bad Gateway on Plesk Panel Website

onycro

onycro

Basic Pleskian
Regards community,

this is my problem:
When trying to reach my plesk panel website (https://domain.com:8443/) plesk returns a website saying "Server Error 502 Bad Gateway Web server received an invalid response while acting as a gateway or proxy server.". So I can't login to my webpage.
Furthermore I have received three E-Mails stating:
/usr/bin/sw-engine: symbol lookup error: /usr/bin/sw-engine: undefined symbol: _ZNK3APS4Meta14ScreenshotInfo4pathB5cxx11Ev


this is what may have caused it:
I was upgrading my ubuntu server with distupgrade.helper.ubt14-ubt16.x64.sh (according to your article see here). Well then everything went wrong and the install could not finish and everything was broken (websites, services and plesk). The server was still up with ssh. So I choose to do the following steps (see source):

apt-get update
apt-get dist-upgrade
apt-get autoremove
apt-get autoclean
update-grub

So this went well and I've had Ubuntu 16 up and running. Then I used my last plesk backup and restored it completely. So all websites came back online but not on port 443. So I enabled apache module ssl. Then everything seemed ok .... until today (even plesk was fine).

this is what I tried to do, to solve my problem:
Checked a help article: Unable to access Plesk: symbol lookup error: /usr/bin/sw-engine: undefined symbol
Which suggested me to check libaps. Which I've did:
Version: 1.0.8-ubuntu14.04.798670.16071418 is installed right now.

Where do I get the 16.04. version? Is this the correct version for my system:
http://autoinstall.plesk.com/PSA_17...s_1.0.8-ubuntu16.04.798670.16061715_amd64.deb

This is my system:
Code: 
cat /usr/local/psa/version
17.5.3 Ubuntu 14.04 1705170317.16

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.3 LTS
Release:        16.04
Codename:       xenial

Can you help me please?

Thank you all a lot!
Regards
 
Hi onycro,

pls. note, that you still didn't finish your upgrade process, as you can see with your result of "cat /usr/local/psa/version". Before you continue, it is recommended to upgrade all your current packages on your server, which you should do with:

Code: 
plesk installer --select-release-current --upgrade-installed-components
Code: 
plesk repair installation -y -v

plesk repair all -y -v
Code: 
aptitude upgrade

Pls. note as well, that on Ubuntu/Debian based systems, "aptitude" is far better instead of "apt-get", as it offers possibilities to choose between ( possible ) installation/deinstallation/upgrade - options, in case that you experience dependencies issues/errors/problems.



onycro said:
Well then everything went wrong and the install could not finish and everything was broken (websites, services and plesk)
Click to expand...
Pls. note, that it is essential that you log your actions over the command line, to be able to investigate issues/errors/problems and to resolve ALL of your existing issues/errors/problems. At the moment, you don't provide enough informations, so that no investigations could be done, which may leave your system and its depending services in an inoperable state.​
 
I tried your first command and it failed, here is the complete log of the stdout on my console.
Pastebin Link
And here is the logfile, which I guess was created while the process:
Gist Link

Then I tried your second command
Code: 
$plesk repair installation -y -v
/usr/bin/sw-engine: symbol lookup error: /usr/bin/sw-engine: undefined symbol: _ZNK3APS4Meta14ScreenshotInfo4pathB5cxx11Ev
exit status 127

Same thing happened for
Code: 
plesk repair all -y -v

aptitude upgrade I didn't use now.

What logfiles may I provide you to achieve better investigations?
I hope my logfile of the plesk distupgrade script (which I've used in the beginning) might be helpful:
Pastebin Link
 
Last edited:
Hi onycro,

onycro said:
aptitude upgrade I didn't use now.
Click to expand...
Could you explain, WHY not?

You saw the error
Code: 
/usr/bin/sw-engine: symbol lookup error: /usr/bin/sw-engine: undefined symbol: _ZNK3APS4Meta14ScreenshotInfo4pathB5cxx11Ev
... and know, that there is an updated/upgraded version for "libaps" and "sw-engine" but don't want to install it with the help of "aptitude"?
Code: 
apt-cache policy libaps
libaps:
  Installed: 1.0.8-ubuntu.16.04.170921.1146
  Candidate: 1.0.8-ubuntu.16.04.170921.1146
  Version table:
 *** 1.0.8-ubuntu.16.04.170921.1146 500
        500 http://ftp.hosteurope.de/mirror/autoinstall.plesk.com/ubuntu/PSA_17.8.6 xenial/all amd64 Packages
        100 /var/lib/dpkg/status
     1.0.8-ubuntu16.04.798670.16061715 500
        500 http://ftp.hosteurope.de/mirror/autoinstall.plesk.com/ubuntu/PSA_17.5.3 xenial/all amd64 Packages
Code: 
apt-cache policy sw-engine
sw-engine:
  Installed: 2.24.1-ubuntu.16.04.170921.1146
  Candidate: 2.24.1-ubuntu.16.04.170921.1146
  Version table:
 *** 2.24.1-ubuntu.16.04.170921.1146 500
        500 http://ftp.hosteurope.de/mirror/autoinstall.plesk.com/ubuntu/PSA_17.8.6 xenial/all amd64 Packages
        100 /var/lib/dpkg/status
     2.22.3-ubuntu1604.201709121114 500
        500 http://ftp.hosteurope.de/mirror/autoinstall.plesk.com/ubuntu/PSA_17.5.3 xenial/all amd64 Packages


sources.list - examples: => #9 / #5

Example "How to download Plesk packages and install them manually": => #2


Did you as well read to to run "/opt/psa/bin/distupgrade.helper.ubt14-ubt16_post.x64.sh" AFTER your dist-upgrade, as suggested in your logs?
 
Last edited by a moderator:
Hello UFHH01,

I really appreciate your help and effort. It is not the first time you help me out, so your work is awesome!

My problem is solved I guess. This is what I did:

Code: 
vim /etc/apt/sources.list.d/plesk.list
#add this line:
deb http://ftp.hosteurope.de/mirror/autoinstall.plesk.com/ubuntu/PSA_17.5.3 xenial all

dpkg --purge --force-depends libaps
dpkg --purge --force-depends sw-engine
apt-get clean
apt-get update
aptitude upgrade
plesk installer --select-release-current --upgrade-installed-components
/opt/psa/bin/distupgrade.helper.ubt14-ubt16_post.x64.sh


Result: Plesk is up and websites are up.

I've got many errors during the installation and the distupgrade script.
How can I check my system? Is it a good idea to run

Code: 
plesk repair all -y -v

Thanks again for all your help.
Regards
 
Hello UFHH01,

I executed that command and I've got 1 error:

Code: 
Checking the DNS configuration file

  The NS configuration file '/var/named/run-root/etc/named.conf' is
  absent ............................................................ [ERROR]
    Restoring the DNS configuration file
    '/var/named/run-root/etc/named.conf' ............................ [2017-10-17 10:41:07] ERR [util_exec] proc_close() failed ['/opt/psa/admin/bin/filemng' 'root' 'cp' '-r' '/var/named/run-root/etc/named.conf.default' '/var/named/run-root/etc/named.conf' '--allow-root'] with exit code [1]
Error occured while sending feedback. HTTP code returned: 500
[FAILED]
    - filemng failed: filemng: Error occurred during /bin/cp command.

Restoring DNS server configuration
    Synchronizing DNS zones with the DNS server ..................... [OK]

Error messages: 1; Warnings: 0; Errors resolved: 0

I checked if the files exist and they don't exist:
Code: 
ls /var/named/run-root/etc/named.conf*
ls: Zugriff auf '/var/named/run-root/etc/named.conf*' nicht möglich: Datei oder Verzeichnis nicht gefunden

Where can I get the named.conf or the default of it?

Best regards
onycro
 
Try this one:

# cat /var/named/run-root/etc/named.conf.default
// $Id: named.conf,v 1.1.1.1 2001/10/15 07:44:36 kap Exp $

// -- THE FOLLOWING LINES WERE GENERATED BY PLESK. IF YOU MODIFY THEM, THEY WILL BE OVERWRITTEN WHEN THESE SETTINGS ARE MANAGED IN PLESK UI. --
options {
allow-recursion {
localnets;
};
version "none";
directory "/var";
auth-nxdomain no;
pid-file "/var/run/named/named.pid";
};

key "rndc-key" {
algorithm hmac-md5;
secret "CeMgS23y0oWE20nyv0x40Q==";
};

controls {
inet 127.0.0.1 port 953
allow { 127.0.0.1; } keys { "rndc-key"; };
};

zone "." {
type hint;
file "named.root";
};

zone "0.0.127.IN-ADDR.ARPA" {
type master;
file "localhost.rev";
};
// -- END OF LINES GENERATED BY PLESK. --


// -- PLEASE ADD YOUR CUSTOM DIRECTIVES BELOW THIS LINE. --
// ...
// -- END OF YOUR CUSTOM DIRECTIVES. --


// -- ALL LINES BELOW WERE GENERATED BY PLESK. IF YOU MODIFY THEM, THEY WILL BE OVERWRITTEN WHEN THESE SETTINGS ARE MANAGED IN PLESK UI. --
 
Thanks Igor, for the help. I searched a bit more and this helped me to solve this problem (installing BIND DNS Service):

My Plesk panel > tools & settings > Plesk > Updates and Upgrades > Add component > BIND DNS

Install BIND DNS and then the check is ok.
 
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