Comment 3 for bug 2012518

That said, in trying to create a clean reproducer, it seems that the issue is just one about logging, not one about actually changing the password. These are the steps I tried:

juju bootstrap lxd lxd --debug
juju add-model test
juju deploy jameinel-ubuntu-lite
juju debug-log -m controller # in one window

juju ssh ubuntu-lite/0
sudo -i
cd /var/log/juju/agents/unit-ubuntu-lite-0
root@juju-6e4447-0:/var/lib/juju/agents/unit-ubuntu-lite-0# grep password agent.conf
apipassword: Auub3/pAtxaQKSRuBrC/nv5T
oldpassword: AvdsckVEF8hj06Yd6ZYlSK/t

root@juju-6e4447-0:/var/lib/juju/agents/unit-ubuntu-lite-0# juju_stop_unit ubuntu-lite/0
ubuntu-lite/0: stopped
root@juju-6e4447-0:/var/lib/juju/agents/unit-ubuntu-lite-0# juju_start_unit ubuntu-lite/0
ubuntu-lite/0: started

In the other window I can see the log lines for:
machine-0: 11:19:09 INFO juju.apiserver.connection agent login: unit-ubuntu-lite-0 for 714a0816-ce6b-4be4-8c7c-e838126e4447
machine-0: 11:19:09 INFO juju.apiserver.common setting password for "unit-ubuntu-lite-0"

However:
root@juju-6e4447-0:/var/lib/juju/agents/unit-ubuntu-lite-0# grep password agent.conf
apipassword: Auub3/pAtxaQKSRuBrC/nv5T
oldpassword: AvdsckVEF8hj06Yd6ZYlSK/t

It didn't actually change the passwords. We should also confirm that inside of Mongo it also has the same password hash for the unit. (I did this multiple times and can see that it continually has the same password as before, but every juju_stop_unit+juju_start_unit triggers the same 'setting password' log entry)

But the fix for this is to fix the log messages to only log when we *actually* change the password for the unit.