python3.6 test_ssl fails reliably on systems under load

Bug #1795999 reported by Dimitri John Ledkov
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Auto Package Testing
Incomplete
Undecided
Unassigned
python3.6 (Ubuntu)
New
Undecided
Unassigned

Bug Description

$ autopkgtest-buildvm-ubuntu-cloud --arch i386

put system under load; e.g. pull-lp-source boost1.67; cd boost1.67; DEB_BUILD_OPTIONS=parallel=12 ./debian/rules build should do it, on an 4core/8hypercore system

$ autopkgtest -s --shell --apt-pocket=proposed --apt-upgrade python3.6 --test-name testsuite -- qemu -c 1 -q qemu-system-i386 ./autopkgtest-cosmic-i386.img

test_ssl fails

To rerun test_ssl alone, one can do:
$ python3.6 -W default -bb -E -R -m test -j 1 -w -uall,-network,-urlfetch,-gui test_ssl --verbose

in a racy manner, for many test cases, due to ConnectionRefused from the TestEchoServer

One way to solve this is to reduce the load, cause without load TestEchoServer keeps up just fine.

Symptoms are s.connect failing with ConnectionRefusedError, or for example s.getpeercreds failing with Transport not connected.

I'm not sure it's worth any time fixing this test-server implementation, as clearly it is testing the ssl server/client bits, that work correctly on a normal, not-under-stress systems. And thus the ssl bits are correctly validated.

I will try to create a reproducer which does not involve VMs and stressing host.

meanwhile it would be nice to run python tests on slightly bigger machines, e.g. mark it as big_packages.

description: updated
description: updated
Revision history for this message
Iain Lane (laney) wrote :

It's true that ScalingStack hosts are slower now, but I'm not convinced that running python's tests on a bigger VM is a solution. This to me feels like the tests are buggy and/or racy, and they should probably better be fixed to deal with running in resource-constrained environments - you'd want to know that Python works well there anyway.

Changed in auto-package-testing:
status: New → Incomplete
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