Troubleshooting environment upgrades

This section provides strategies and techniques to assist with broken environment upgrades. See Upgrading Juju software for information and instructions pertaining to upgrading your environment.

Case #1 - An agent does not restart (config)

It may occur that an agent does not restart upon upgrade. One thing that may help is the inspection and modification of its agent.conf file. Comparing it with its file before upgrading can be very useful.

Installing a different or modified configuration file will require a restart of the daemon. For example, for machine #2:

juju ssh 2 'ls -lh /etc/init/juju*'

This will return something similar to:

-rw-r--r-- 1 root root 506 Sep  2 00:57 /etc/init/jujud-machine-2.conf
-rw-r--r-- 1 root root 533 Sep  2 00:57 /etc/init/jujud-unit-mysql-0.conf

Therefore, if the agent for machine #2 is not coming up you can connect to the machine:

juju ssh 2

Modify or restore the agent file (/var/lib/juju/agents/machine-2/agent.conf), and while still connected to the machine, restart the agent:

sudo service jujud-machine-2 restart

Case #2 - An agent does not restart (hook)

The restart of an agent, due to invoking upgrade-juju or by manual means (as above) may cause a hook for that particular unit/machine to be called. That can sometimes lead to hook failures. Connect to that unit, see what is wrong, and retry with:

juju resolved --retry

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