Server 20.04 verses 16.04: python-gnuplot

[Doug Smythies]

Hi All,

For several years now, my main test server has been 16.04,
as is my main gateway router / firewall / web server.
I missed 18.04 because I was not ready to convert to netplan.
I attempt to contribute to the kernel power management group.
Because it has become a challenge to run the leading edge
Kernel on a 16.04 server, and to try to help with the
serverguide, I am attempting to get some 20.04 servers running.

For the upstream kernel work, one very handy tool is the
python-gnuplot package. (For example from the kernel tree:
linux/tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py
which I use a lot, needs that package.)

It has all worked fine for years on my 16.04 test server,
and actually still does, even though that server was upgraded
to 20.04, via 18.04.

I have been unable to get it working on a new 20.04 installation.
If I attempt to install "python-gnuplot" I get:

> Package python-gnuplot is not available, but is referred to by another package.
> This may mean that the package is missing, has been obsoleted, or
> is only available from another source
> However, the following packages replace it:
>  python3-gnuplot
>
> E: Package 'python-gnuplot' has no installation candidate

If I try to install "python3-gnuplot", it wants to convert
my server installation into a full blown desktop. I do not
want that. Even if I do allow it (i.e. I did already, by mistake),
the script still doesn't work:

doug at s18:~/freq-scalers/trace$ sudo ./intel_pstate_tracer.py --interval 300 --name t01 --memory 800000
Traceback (most recent call last):
  File "./intel_pstate_tracer.py", line 35, in <module>
    import Gnuplot
ImportError: No module named Gnuplot
doug at s18:~/freq-scalers/trace$

Any suggestions how I can get this stuff to work on a
20.04 server?

... Doug