Inconsistencies between juju debug-hooks and "normal" hook environment

Casey Marshall casey.marshall at canonical.com
Wed Oct 21 19:06:07 UTC 2015 

On Wed, Oct 21, 2015 at 1:49 PM, Cory Johns <cory.johns at canonical.com>
wrote:

> Matty,
>
> I do think that a bug should be opened for it, and I will do so.  Is LP
> still the better place to open the bug vs GitHub?
>

Yes, please open the bug in Launchpad.

Thanks,
Casey


>
> On Wed, Oct 21, 2015 at 5:48 AM, Matthew Williams <
> matthew.williams at canonical.com> wrote:
>
>> Hey Folks,
>>
>> Is there some action we should take to deal with this - in which case can
>> we raise an lp bug for it. Or do we think there's no action needed?
>>
>> Matty
>>
>> On Tue, Oct 6, 2015 at 3:55 PM, Matt Bruzek <matthew.bruzek at canonical.com
>> > wrote:
>>
>>> Merlijn,
>>>
>>> Now that I see more of what you are doing I have an alternate suggestion.
>>>
>>> When you are running 'juju init' use the su command to run as the
>>> "ubuntu" user.
>>>
>>> su - ubuntu -c 'juju init'
>>>
>>> Using the su command in this way gives a "login" environment for the
>>> user "ubuntu".  I wrote a charm (named merlijn) to test this and I saw the
>>> error you are reporting:
>>> unit-merlijn2-0[2994]: 2015-10-06 14:35:26 INFO
>>> unit.merlijn2/0.config-changed logger.go:40 + echo /root
>>> unit-merlijn2-0[2994]: 2015-10-06 14:35:26 INFO
>>> unit.merlijn2/0.config-changed logger.go:40 /root
>>> unit-merlijn2-0[2994]: 2015-10-06 14:35:26 INFO
>>> unit.merlijn2/0.config-changed logger.go:40 + juju init
>>> unit-merlijn2-0[2994]: 2015-10-06 14:35:26 INFO
>>> unit.merlijn2/0.config-changed logger.go:40 error: cannot determine juju
>>> home, required environment variables are not set
>>>
>>> What you were trying to do is create a juju environment for the root
>>> user (which is not advised) rather you want to create a juju environment
>>> for the normal (ubuntu) user.
>>>
>>> Using the su command I was able to create a juju configuration file:
>>> 2015-10-06 14:47:10 INFO config-changed + echo /root
>>> 2015-10-06 14:47:10 INFO config-changed /root
>>> 2015-10-06 14:47:10 INFO config-changed + su - ubuntu -c 'juju init'
>>> 2015-10-06 14:47:11 INFO config-changed A boilerplate environment
>>> configuration file has been written to /home/ubuntu/.juju/environments.yaml.
>>>
>>> Likewise if you want to create artifacts for the ubuntu user, use the
>>> "su - ubuntu" command.
>>>
>>> Hope that helps.
>>>
>>>
>>>    - Matt Bruzek <matthew.bruzek at canonical.com>
>>>
>>> On Tue, Oct 6, 2015 at 9:30 AM, Cory Johns <cory.johns at canonical.com>
>>> wrote:
>>>
>>>> Merlijn,
>>>>
>>>> That is an annoying inconsistency.  It's probably related to
>>>> debug-hooks bootstrapping itself via `juju ssh` which logs in as the ubuntu
>>>> user since root ssh is disabled, as well as it being unlikely that the
>>>> actual hook context is a login shell.
>>>>
>>>> I imagine the generate-config error is due to the lack of either $HOME
>>>> or $JUJU_HOME being set.  I would recommend trying explicitly setting
>>>> JUJU_HOME=/home/ubuntu before calling generate-config and see if that works
>>>> around it.
>>>>
>>>> I've also created a bug against juju-core for this:
>>>> https://github.com/juju/juju/issues/3449
>>>>
>>>> On Tue, Oct 6, 2015 at 10:06 AM, Merlijn Sebrechts <
>>>> merlijn.sebrechts at gmail.com> wrote:
>>>>
>>>>>
>>>>> Hi Matt
>>>>>
>>>>>
>>>>> Thank you for your response. It was nice seeing you too!
>>>>>
>>>>> Let me explain my two, maybe related problems a bit more:
>>>>>
>>>>>
>>>>> 1. Home directory is different between debug and non-debug hook
>>>>> context.
>>>>>
>>>>>    - Using the manual provider.
>>>>>    - When deploying a Charm, the install hook is run as the "root"
>>>>>    user.* "echo ~" prints "/root".*
>>>>>    - When the install hook crashes, I connect to the unit using
>>>>>    `debug-hooks` and restart the install hook as you described using  'juju
>>>>>    resolved --retry unit/#'. After a while, tmux shows "[unit/0] 0:bash-
>>>>>    1:install* " at the bottom and cwd is '/var/lib/juju/agents/unit-0/charm'.
>>>>>    As I understand, I am now in the hook context, right? *However,
>>>>>    "echo ~" prints "/home/ubuntu".* Even though the current user is
>>>>>    root.
>>>>>
>>>>>
>>>>>
>>>>> 2. Something causes "juju init" to fail in non-debug hook context and
>>>>> succeeds in debug hook context.
>>>>>
>>>>>
>>>>>    - Using manual provider
>>>>>    - Executing `juju init` or `juju generate-config` in a hook
>>>>>    results in the error message `error: cannot determine juju home,
>>>>>    required environment variables are not set`
>>>>>    - Executing `juju init` or `juju generate-config` in the hook
>>>>>    context using  `debug-hooks` and  'juju resolved --retry unit/#`
>>>>>    succeeds.
>>>>>
>>>>>
>>>>> My current workaround is to generate the initial juju config myself
>>>>> and not use "juju generate-config". However, I'm not sure if this behavior
>>>>> is intentional or a bug.
>>>>>
>>>>>
>>>>> Thanks in advance!
>>>>>
>>>>>
>>>>> 2015-10-06 15:37 GMT+02:00 Matt Bruzek <matthew.bruzek at canonical.com>:
>>>>>
>>>>>> Hell again Merlijn,
>>>>>>
>>>>>> It was nice to see you at the Charmer summit!  This is a very
>>>>>> interesting use of Juju.
>>>>>>
>>>>>> What you are seeing is what we call a "hook context".  Hooks execute
>>>>>> with root authority and have certain environment variables are set. This is
>>>>>> so Juju commands and tools work correctly.  The debug-hooks command puts
>>>>>> you into a "hook context" when you run  'juju resolved --retry unit/#'
>>>>>>
>>>>>> As I wrote all hooks are executed with these environment variables
>>>>>> set.  If you are running the install script manually outside of a hook
>>>>>> context these environment variables would not be set.
>>>>>>
>>>>>> There is more information about the environment variables here:
>>>>>>
>>>>>> https://jujucharms.com/docs/devel/authors-hook-environment
>>>>>>
>>>>>> However, I don't see "JUJU_HOME" listed on this page. Perhaps you
>>>>>> could give me more information on what variable is causing a problem and
>>>>>> perhaps your hooks could set those values in the case where the script runs
>>>>>> manually.
>>>>>>
>>>>>> Cheers!
>>>>>>
>>>>>>    - Matt Bruzek <matthew.bruzek at canonical.com>
>>>>>>
>>>>>> On Tue, Oct 6, 2015 at 5:07 AM, Merlijn Sebrechts <
>>>>>> merlijn.sebrechts at gmail.com> wrote:
>>>>>>
>>>>>>> Hi
>>>>>>>
>>>>>>>
>>>>>>> I'm developing a Charm that installs the Juju client, among other
>>>>>>> things. I'm having some trouble getting this to work. When I use juju
>>>>>>> debug-hooks and manually run the install hook, everything works fine.
>>>>>>> However, when the hook is executed by Juju automatically, I get strange
>>>>>>> errors such as "error: cannot determine juju home, required environment
>>>>>>> variables are not set"
>>>>>>>
>>>>>>> Both the debug-hooks and the normal hook environment execute as
>>>>>>> root. However, a lot of env vars are different, like the home dir.
>>>>>>>
>>>>>>> Debug-hooks:
>>>>>>>     echo ~ : /home/ubuntu
>>>>>>> hook env:
>>>>>>>     echo ~: /root
>>>>>>>
>>>>>>> Is this intentional? This causes a lot of bugs that cannot be
>>>>>>> reproduced by debug-hooks. Is there a way to solve  "error: cannot
>>>>>>> determine juju home, required environment variables are not set"?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Kind regards
>>>>>>> Merlijn Sebrechts
>>>>>>>
>>>>>>> --
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>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
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