The only scenario I can think of is NOT restarting postgres after the package update. This could happen when postgres process is managed outside of init(systemd) such as pacemaker, etc. for HA purposes.
$ sudo lsof / | grep plpgsql.so postgres 21822 postgres DEL REG 252,1 1295136 /usr/lib/postgresql/12/lib/plpgsql.so postgres 21948 postgres DEL REG 252,1 1295136 /usr/lib/postgresql/12/lib/plpgsql.so For a single node scenario with systemd, postgres can be restarted in the postinst of the postgres-common package so there should be no orphaned library in memory. So this might not be related to MAAS snap or postgres packages, but to a simple fact that postgres needs to be restarted after a package update (especially when it's managed by something like pacemaker than systemd itself). [steps to reproduce on a fresh machine/VM] $ sudo apt update && sudo apt upgrade -y $ cat <<EOF | sudo tee /etc/apt/preferences.d/pin-to-release Package: * Pin: release a=*-updates Pin-Priority: 400 Package: * Pin: release a=*-security Pin-Priority: 400 EOF Then, set up MAAS with "Initialise MAAS for a production configuration" using postgres deb packages. https://maas.io/docs/snap/2.9/ui/maas-installation Switch to pg_ctl simulating pacemaker scenario. $ sudo systemctl stop postgresql.service $ sudo systemctl disable postgresql.service $ sudo -u postgres touch /var/lib/postgresql/12/main/postgresql.conf $ sudo cat /etc/postgresql/12/main/pg_hba.conf | sudo -u postgres tee /var/lib/postgresql/12/main/pg_hba.conf $ sudo -u postgres /usr/lib/postgresql/12/bin/pg_ctl start -D /var/lib/postgresql/12/main/ Unpinning and upgrade: $ sudo rm /etc/apt/preferences.d/pin-to-release $ sudo apt upgrade Then, I see "DEL" status in lsof and the actual errors. $ sudo lsof / | grep plpgsql.so postgres 21822 postgres DEL REG 252,1 1295136 /usr/lib/postgresql/12/lib/plpgsql.so postgres 21948 postgres DEL REG 252,1 1295136 /usr/lib/postgresql/12/lib/plpgsql.so $ sudo service snap.maas.supervisor restart 2021-08-16 11:47:02.241 GMT [24009] ERROR: could not load library "/usr/lib/postgresql/12/lib/plpgsql.so": /usr/lib/postgresql/12/lib/plpgsql.so: undefined symbol: EnsurePortalSnapshotExists 2021-08-16 11:47:02.241 GMT [24009] STATEMENT: UPDATE "maasserver_node" SET "managing_process_id" = NULL WHERE "maasserver_node"."id" IN (1) 2021-08-16 11:47:02.245 GMT [24007] ERROR: could not load library "/usr/lib/postgresql/12/lib/plpgsql.so": /usr/lib/postgresql/12/lib/plpgsql.so: undefined symbol: After restarting postgresql explicitly, the error has gone: $ sudo -u postgres /usr/lib/postgresql/12/bin/pg_ctl restart -D /var/lib/postgresql/12/main/ ### ^^^ this should be done through crm or equivalent instead of invoking pg_ctl directly for production. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1939898 Title: Unnatended postgresql-12 upgrade caused MAAS internal error To manage notifications about this bug go to: https://bugs.launchpad.net/maas/+bug/1939898/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
