Steps to reproduce/verify on Bionic:
===
Similarly to steps described for Xenial.
Skipping the identical steps.
$ lxc launch ubuntu:bionic lp1863232b
$ lxc exec lp1863232b -- su - ubuntu
One connection/Two requests (added timestamps to check timeout values)
---
$ (cat http-request; sleep 1; cat http-request; sleep 9) | telnet 127.0.0.1 80 2>&1 | while read line; do echo "$(date +'%T') == $line"; done
00:03:46 == Trying 127.0.0.1...
00:03:46 == Connected to 127.0.0.1.
00:03:46 == Escape character is '^]'.
00:03:46 == HTTP/1.1 200 OK
00:03:46 == Date: Tue, 18 Feb 2020 00:03:46 GMT
00:03:46 == Server: Apache/2.4.29 (Ubuntu)
00:03:46 == Content-Length: 13
00:03:46 == Vary: Accept-Encoding
00:03:46 == Keep-Alive: timeout=15, max=100
00:03:46 == Connection: Keep-Alive
00:03:46 == Content-Type: text/plain
00:03:46 ==
00:03:46 == Hello World!
00:03:47 == HTTP/1.1 200 OK
00:03:47 == Date: Tue, 18 Feb 2020 00:03:47 GMT
00:03:47 == Server: Apache/2.4.29 (Ubuntu)
00:03:47 == Content-Length: 13
00:03:47 == Vary: Accept-Encoding
00:03:47 == Keep-Alive: timeout=15, max=99
00:03:47 == Connection: Keep-Alive
00:03:47 == Content-Type: text/plain
00:03:47 ==
00:03:47 == Hello World!
00:03:56 == Connection closed by foreign host.
Reproduce the problem by placing
'sudo systemctl reload apache2'
between the two HTTP requests
(second request hits Error 503,
depending on apache2 MPM module.
mpm_event just closes connection,
mpm_worker/mpm_prefork hit 503)
---
$ lsb_release -cs
bionic
$ dpkg -s libapache2-mod-wsgi | grep ^Version
Version: 4.5.17-1
$ sudo a2dismod mpm_event
$ sudo a2enmod mpm_worker
$ sudo systemctl restart apache2
For reference on socket filename:
$ sudo systemctl restart apache2
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.4982.0.1.sock
$ (cat http-request; sleep 1; sudo systemctl reload apache2; sleep 5; cat http-request; sleep 9) | telnet 127.0.0.1 80 2>&1 | while read line; do echo "$(date +'%T') == $line"; done
14:46:04 == Trying 127.0.0.1...
14:46:04 == Connected to 127.0.0.1.
14:46:04 == Escape character is '^]'.
14:46:04 == HTTP/1.1 200 OK
14:46:04 == Date: Tue, 18 Feb 2020 14:46:04 GMT
14:46:04 == Server: Apache/2.4.29 (Ubuntu)
14:46:04 == Content-Length: 13
14:46:04 == Vary: Accept-Encoding
14:46:04 == Keep-Alive: timeout=15, max=100
14:46:04 == Connection: Keep-Alive
14:46:04 == Content-Type: text/plain
14:46:04 ==
14:46:04 == Hello World!
14:46:10 == HTTP/1.1 503 Service Unavailable
14:46:10 == Date: Tue, 18 Feb 2020 14:46:10 GMT
14:46:10 == Server: Apache/2.4.29 (Ubuntu)
14:46:10 == Content-Length: 374
14:46:10 == Connection: close
14:46:10 == Content-Type: text/html; charset=iso-8859-1
14:46:10 ==
14:46:10 ==
14:46:10 ==
14:46:10 == 503 Service Unavailable
14:46:10 ==
14:46:10 == Service Unavailable
14:46:10 == The server is temporarily unable to service your
14:46:10 == request due to maintenance downtime or capacity
14:46:10 == problems. Please try again later.
14:46:10 ==
14:46:10 == Apache/2.4.29 (Ubuntu) Server at 127.0.0.1 Port 80
14:46:11 ==
14:46:11 == Connection closed by foreign host.
$ sudo tail /var/log/apache2/error.log
...
[Tue Feb 18 14:46:05.923939 2020] [mpm_worker:notice] [pid 4982:tid 139825593654208] AH00297: SIGUSR1 received. Doing graceful restart
[Tue Feb 18 14:46:05.981362 2020] [mpm_worker:notice] [pid 4982:tid 139825593654208] AH00292: Apache/2.4.29 (Ubuntu) mod_wsgi/4.5.17 Python/2.7 configured -- resuming normal operations
[Tue Feb 18 14:46:05.981409 2020] [core:notice] [pid 4982:tid 139825593654208] AH00094: Command line: '/usr/sbin/apache2'
[Tue Feb 18 14:46:10.941713 2020] [wsgi:error] [pid 4986:tid 139825361426176] (2)No such file or directory: [client 127.0.0.1:37514] mod_wsgi (pid=4986): Unable to connect to WSGI daemon process '127.0.0.1' on '/var/run/apache2/wsgi.4982.0.1.sock' as user with uid=33.
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.4982.1.1.sock
With the fix/patch for Bionic:
---
$ sudo add-apt-repository ppa:mfo/lp1863232v2
$ sudo apt update
$ sudo apt install -y libapache2-mod-wsgi
$ sudo systemctl restart apache2
$ dpkg -s libapache2-mod-wsgi | grep ^Version
Version: 4.5.17-1ubuntu1
Same behavior by default:
---
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.6043.0.1.sock
$ sudo systemctl reload apache2
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.6043.1.1.sock
$ sudo systemctl reload apache2
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.6043.2.1.sock
Now, manually changing it:
---
$ echo 'WSGISocketRotation Off' | sudo tee -a /etc/apache2/conf-enabled/wsgi.conf
$ sudo systemctl restart apache2
Notice name pattern change as in patch. (u33 = UID 33 = www-data:)
And socket file name remains constant:
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.6403.u33.1.sock
$ sudo systemctl reload apache2
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.6403.u33.1.sock
$ sudo systemctl reload apache2
$ ls -1 /var/run/apache2/wsgi.*.sock
/var/run/apache2/wsgi.6403.u33.1.sock
$ id -un 33
www-data
Check the problem by placing
'sudo systemctl reload apache2'
between the two HTTP requests
(second request hits Error 500 now)
---
The second HTTP request (after reload) no longer hits Error 503,
but now Error 500, and the log file no longer mentions file not
found, but a different message.
The Error 500 is observed in/consistent with Eoan as well, thus
not a missing patch or something -- this is an improvement.
$ (cat http-request; sleep 1; sudo systemctl reload apache2; sleep 5; cat http-request; sleep 9) | telnet 127.0.0.1 80 2>&1 | while read line; do echo "$(date +'%T') == $line"; done
14:49:57 == Trying 127.0.0.1...
14:49:57 == Connected to 127.0.0.1.
14:49:57 == Escape character is '^]'.
14:49:57 == HTTP/1.1 200 OK
14:49:57 == Date: Tue, 18 Feb 2020 14:49:57 GMT
14:49:57 == Server: Apache/2.4.29 (Ubuntu)
14:49:57 == Content-Length: 13
14:49:57 == Vary: Accept-Encoding
14:49:57 == Keep-Alive: timeout=15, max=100
14:49:57 == Connection: Keep-Alive
14:49:57 == Content-Type: text/plain
14:49:57 ==
14:49:57 == Hello World!
14:50:03 == HTTP/1.1 500 Internal Server Error
14:50:03 == Date: Tue, 18 Feb 2020 14:50:03 GMT
14:50:03 == Server: Apache/2.4.29 (Ubuntu)
14:50:03 == Content-Length: 607
14:50:03 == Connection: close
14:50:03 == Content-Type: text/html; charset=iso-8859-1
14:50:03 ==
14:50:03 ==
14:50:03 ==
14:50:03 == 500 Internal Server Error
14:50:03 ==
14:50:03 == Internal Server Error
14:50:03 == The server encountered an internal error or
14:50:03 == misconfiguration and was unable to complete
14:50:03 == your request.
14:50:03 == Please contact the server administrator at
14:50:03 == webmaster@localhost to inform them of the time this error occurred,
14:50:03 == and the actions you performed just before this error.
14:50:03 == More information about this error may be available
14:50:03 == in the server error log.
14:50:03 ==
14:50:03 == Apache/2.4.29 (Ubuntu) Server at 127.0.0.1 Port 80
14:50:03 ==
14:50:03 == Connection closed by foreign host.
$ sudo tail /var/log/apache2/error.log
...
[Tue Feb 18 14:49:58.563491 2020] [mpm_worker:notice] [pid 6403:tid 139801328274368] AH00297: SIGUSR1 received. Doing graceful restart
[Tue Feb 18 14:49:58.619982 2020] [mpm_worker:notice] [pid 6403:tid 139801328274368] AH00292: Apache/2.4.29 (Ubuntu) mod_wsgi/4.5.17 Python/2.7 configured -- resuming normal operations
[Tue Feb 18 14:49:58.620021 2020] [core:notice] [pid 6403:tid 139801328274368] AH00094: Command line: '/usr/sbin/apache2'
[Tue Feb 18 14:50:03.581491 2020] [wsgi:alert] [pid 6735:tid 139801212405504] mod_wsgi (pid=6735): Request origin could not be validated.
[Tue Feb 18 14:50:03.581691 2020] [wsgi:error] [pid 6614:tid 139801220822784] [client 127.0.0.1:37590] Truncated or oversized response headers received from daemon process '127.0.0.1': /var/www/html/hello-world.py