bionic still installs 'clean-shutdown' service even though no /sbin/ifdown exists

[John A Meinel]

As part of bootstrap (and maybe elsewhere), juju ends up setting this in cloud-init:
'set -xe',
"install -D -m 644 /dev/null '/etc/systemd/system/juju-clean-shutdown.service'",
"printf '%s\\n' '\n[Unit]\nDescription=Stop all network interfaces on shutdown\nDefaultDependencies=false\nAfter=final.target\n\n[Service]\nType=oneshot\nExecStart=/sbin/ifdown -a -v --force\nStandardOutput=tty\nStandardError=tty\n\n[Install]\nWantedBy=final.target\n' > '/etc/systemd/system/juju-clean-shutdown.service'", "/bin/systemctl enable '/etc/systemd/system/juju-clean-shutdown.service'"

Which means we create a systemd service that looks like:
+ install -D -m 644 /dev/null /etc/systemd/system/juju-clean-shutdown.service
+ printf %s\n
[Unit]
Description=Stop all network interfaces on shutdown
DefaultDependencies=false
After=final.target

[Service]
Type=oneshot
ExecStart=/sbin/ifdown -a -v --force
StandardOutput=tty
StandardError=tty

[Install]
WantedBy=final.target

I think this was an attempt to deal with shutdown and restart issues.

However, "/sbin/ifdown" doesn't exist on Bionic, so we certainly shouldn't be installing a service that wants to be running it.

I don't fully understand "oneshot" type services in systemd. Or exactly why this was created in the first place.

It may be that we can just omit it entirely, or it may be that we should be transitioning to some sort of netplan based "shutdown cleanly".

[Anastasia (anastasia-macmood)]

Marking as Won't Fix for 2.3 series since we are not planning to make any further releases in this series at this stage.

[Canonical Juju QA Bot (juju-qa-bot)]

This bug has not been updated in 2 years, so we're marking it Low importance. If you believe this is incorrect, please update the importance.