We've hit this again on our production MAAS server, see below. We're in a position where we regularly need to check if our regiond processes are hung and restart them. I'd therefore like to ask for a bump in priority here. Any chance for a fix soon on the 2.9 branch? Does MAAS need simplestreams to cut a release before this fix can be picked up?

ubuntu@maas:~$ ps -ef | grep region
root      633597  633491  0 14:07 ?        00:02:28 python3 /snap/maas/11778/sbin/regiond
root      633814  633597  0 14:07 ?        00:33:34 python3 /snap/maas/11778/sbin/regiond
root      633816  633597  0 14:07 ?        00:34:25 python3 /snap/maas/11778/sbin/regiond
root      633817  633597  0 14:07 ?        00:35:24 python3 /snap/maas/11778/sbin/regiond
root      633818  633597  0 14:07 ?        00:34:17 python3 /snap/maas/11778/sbin/regiond
ubuntu    648515  648489  0 18:19 pts/0    00:00:00 grep --color=auto region
ubuntu@maas:~$ sudo strace -p 633597
strace: Process 633597 attached
epoll_wait(3, [], 10, 94)               = 0
epoll_wait(3, [], 10, 0)                = 0
epoll_wait(3, [], 10, 99)               = 0
epoll_wait(3, [], 10, 399)              = 0
epoll_wait(3, [], 10, 0)                = 0
epoll_wait(3, ^Cstrace: Process 633597 detached
 <detached ...>

ubuntu@maas:~$ sudo strace -p 633814
strace: Process 633814 attached
recvfrom(30, ^Cstrace: Process 633814 detached
 <detached ...>

ubuntu@maas:~$ sudo lsof -i -a -p 633814
COMMAND    PID USER   FD   TYPE    DEVICE SIZE/OFF NODE NAME
python3 633814 root   10u  IPv6 696471999      0t0  TCP maas:5240->10.229.192.54:54706 (ESTABLISHED)
python3 633814 root   14u  IPv6 680163730      0t0  TCP *:5251 (LISTEN)
python3 633814 root   15u  IPv4 696151424      0t0  TCP localhost:51510->localhost:postgresql (ESTABLISHED)
python3 633814 root   16u  IPv6 683429160      0t0  TCP maas:5240->1.general.morphis.uk.vpn:38664 (CLOSE_WAIT)
python3 633814 root   17u  IPv4 680183835      0t0  TCP localhost:59674->localhost:postgresql (ESTABLISHED)
python3 633814 root   18u  IPv4 696173835      0t0  TCP localhost:51520->localhost:postgresql (ESTABLISHED)
python3 633814 root   19u  IPv6 680176399      0t0  TCP maas:5251->maas:45382 (CLOSE_WAIT)
python3 633814 root   20u  IPv4 696078469      0t0  TCP localhost:51486->localhost:postgresql (ESTABLISHED)
python3 633814 root   21u  IPv6 680176401      0t0  TCP *:5240 (LISTEN)
python3 633814 root   22u  IPv4 696206297      0t0  TCP localhost:51932->localhost:postgresql (ESTABLISHED)
python3 633814 root   23u  IPv6 680199940      0t0  TCP maas:5240->2.general.dannf.us.vpn:55866 (CLOSE_WAIT)
python3 633814 root   26u  IPv6 680154669      0t0  TCP maas:5240->2.general.dannf.us.vpn:55848 (ESTABLISHED)
python3 633814 root   27u  IPv4 696430193      0t0  TCP localhost:51948->localhost:postgresql (ESTABLISHED)
python3 633814 root   28u  IPv6 680199946      0t0  TCP maas:5240->2.general.dannf.us.vpn:55868 (CLOSE_WAIT)
python3 633814 root   29u  IPv4 696373443      0t0  TCP localhost:51938->localhost:postgresql (ESTABLISHED)
python3 633814 root   30u  IPv4 696457905      0t0  TCP maas:49652->images-maas-io.sawo.canonical.com:http (ESTABLISHED)
python3 633814 root   31u  IPv4 696394600      0t0  TCP localhost:51944->localhost:postgresql (ESTABLISHED)
python3 633814 root   32u  IPv4 696155256      0t0  TCP localhost:51502->localhost:postgresql (ESTABLISHED)
ubuntu@maas:~$