Resolved 500 PleskPMMResponseException for Backup & Restore

[sdhh]

Server operating system version

AlmaLinux release 8.8

Plesk version and microupdate number

Plesk Obsidian Web Pro Edition Version 18.0.53 Update #2

Hello,

Backup & Restore page from Plesk is not working any longer for us.
We're getting 500 PleskPMMResponseException while we try to access it.
Upon further investigation I figured out that pmmcli doesn't functioning right :

# /usr/local/psa/admin/bin/pmmcli
Traceback (most recent call last):
File "/usr/local/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py", line 332, in execute
File "/usr/local/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py", line 262, in _wrap_coverage
File "/usr/local/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py", line 294, in _wrap_profiling
File "/usr/local/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py", line 375, in _execute
File "/usr/local/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py", line 433, in execute_entry
File "/usr/local/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py", line 438, in execute_module
File "/usr/lib64/python3.9/runpy.py", line 228, in run_module
return _run_code(code, {}, init_globals, run_name, mod_spec)
File "/usr/lib64/python3.9/runpy.py", line 87, in _run_code
exec(code, run_globals)
File "/usr/local/psa/admin/sbin/pmmcli/pmmcli.py", line 10, in <module>
File "<frozen zipimport>", line 259, in load_module
File "/usr/local/psa/admin/sbin/pmmcli/pmm_api_xml_protocols.py", line 35, in <module>
ModuleNotFoundError: No module named 'lxml'

It seems that plesk is using plesk-py27 packages, so I went ahead and installed a missing
plesk-py27-lxml-4.4.2-0redhat.8.220330.1131.x86_64 package, but yet pmmcli returns the error that module lxml is still missing.

Would appreciate any help of how to have this issue fixed.

Thank you !

 

[Peter Debik]

ModuleNotFoundError: No module named 'lxml'

Probably the python39-lxml is corrupted.

You can try to remove the existing python36-lxml package, e.g.
# rpm -e --nodeps python3-lxml

and then reinstall it
# yum install python3-lxml

 

[sdhh]

Hi Peter, thanks for trying to help !
But it seems that 3.9 is a blocker : switching to 3.6 helped. Borrowed the idea from this guy :

Issue - Problems with backup and new Python version

Hi everybody, I have just installed Plesk on a new server and something that never happened to me before has sprung up. I have installed Plesk on AlmaLinux 8.7 and upgraded Python to version 3.9 from 3.6. I then used alternatives to set the new Python version as the default version accessed when...

talk.plesk.com

 

[Peter Debik]

Did you try to install python3-lxml or did you immediately downgrade to 3.6?

 

[sdhh]

Did you try to install python3-lxml or did you immediately downgrade to 3.6?

I did everything you've asked me to :
1. rpm -e --nodeps python3-lxml
2. yum install python3-lxml

But yet pmmcli didn't want to wake up, clean its mess and start to work
So I went ahead and switched python to 3.6 via alternatives.
And that fixed the problem.

 

[Peter Debik]

Thank you, that is good to know. It was expected that installing the python3-lxml could fix it, regardless of the newer version, because we know of another customer who is using 3.9 without issues. But who knows that the differences in the installations are ...