[ Docs ] - Charming with Docker

[Charles Butler]

I see your concerns about layering, reactive, et-al. for introductory/new
charmers. I however raise you a value proposition, and will speak to
the point we are generating the 'best practice' method, that we want to
guide charmers down. The common feedback we've received from
authors is "I'm not as concerned with the overhead of learning, I just want
you to tell me the best way to do it." While this represents a small
number from the overall community of people charming, we've delivered on
this asked behavior. We're taking away some maintenance
burdens, and exposing a scaffolded framework to deliver your app
containerized workload.

While its arguably more complex than `curl get.docker.com | sh` - there are
a few things happening here that should concern you already.

- You're not verifying the payload, and blindly executing it via a shell.
This violates charm store policy, and is a black hole into whats happening
without tailing the unit logs.

While the script is a replica of that installation method, (credit is given
in the layer repository readme) it was deemed important to mimic
their recommended install - when you look at the ansible based docker charm
and its divergent history + issue log.

The script has been modified to surface what the unit is doing via the
newer `juju status-set` routines  for clear visibility. And we get the
added benefit of supporting  cent/debian out of the box with this method.
The ownership burden is on  us, the ~charmers that are maintaining
the docker layer.

I appreciate the feedback though Kapil, and thanks for acknowledging the
raise in knowledge to 'get started' - you're right its not as straight
forward as curling a bash script and piping to sudo. But we don't encourage
that anyway :) We feel that you can learn and get productive with this
fairly quickly, with minimal knowledge of whats actually happening layers
below. Just look at what states become exposed and take action.

Give it a spin and let us know if you've changed your opinion at all, and
I'll be happy to talk/work through the concerns.

- Charles




Charles Butler <charles.butler at canonical.com> - Juju Charmer
Come see the future of datacenter orchestration: http://jujucharms.com

On Tue, Sep 15, 2015 at 7:46 AM, Kapil Thangavelu <kapilt at gmail.com> wrote:

> i think participating in the burgeoning docker ecosystem is a worthwhile
> goal by making it easier to write charms that utilize docker. I do have
> some concerns though about the complexity of the layering that's taking
> place in the charm ecosystem. I've found that juju has been fairly hard to
> teach and adapt to real world usage and the layering of frameworks at the
> charm authoring level makes learning and productivity for new users even
> harder to achieve (ie those docs reference, charm helpers, reactive charm
> helpers, docker reactive 'layer', charm composition), all of which are
> fairly advanced concepts to a new user, and frankly is all of that
> nescessary to understand running a shell script
> https://github.com/juju-solutions/layer-docker/blob/master/scripts/install_docker.sh
> which is effectively the jujuized version of (curl get.docker.com | sh)
> .. now say i want to configure an insecure registry or any other docker cli
> param i have to break apart the layer abstraction anyways. It does seem
> like a useful intro to some of the advanced/additional concepts in charm
> authoring ecosystem, but at the same time the burden seems high (ie. kiss
> violation) for how to run a docker container.
>
> cheers,
>
> Kapil
>
>
> On Fri, Sep 11, 2015 at 11:40 AM, Charles Butler <
> charles.butler at canonical.com> wrote:
>
>> If anyone here is interested in delivering Docker App Containers with
>> Juju, mbruzek and I have put together some documents around a hot new
>> process using composer layers and the reactive framework.
>>
>> This is interesting because you the charm author will only be concerned
>> with how to deliver your application layers logic. You don't need to worry
>> about installing docker, or how to scaffold out a full charm boilerplate.
>> This entire process reduces the total cost of ownership of the author to
>> just managing their app layer + container.
>>
>>  https://github.com/juju/docs/pull/672
>>
>> And we've constructed/linked to an example charm using this process.
>> There's probably holes in this document, and welcome feedback directly on
>> the pull request to suss them out.
>>
>> We're fully interested in receiving your feedback about this, as its
>> important that we are properly engaging our users that are interested in
>> delivering their dockerized app with Juju, and that we've given you the
>> proper lessons to do so easily, and made the right decisions in tooling.
>>
>> All the best,
>>
>>
>> Charles Butler <charles.butler at canonical.com> - Juju Charmer
>> Come see the future of datacenter orchestration: http://jujucharms.com
>>
>> --
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>> Juju at lists.ubuntu.com
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>>
>>
>
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