Re: More containers?

[Nick Couchman]

On Sat, Jun 16, 2018 at 10:23 AM Joachim Lindenberg 
wrote:

> Hell Nick, all,
>
> I finally found some time to invest into experimenting with docker,
> docker-compose, and guacamole. Good news is, I can run guacamole dockerized
> now, even with docker-compose.
>
> Now the challenges:
>
> ·   as I am running an extension I wanted to make this available in a
> separate (data) container in order not to change your existing ones but
> expose a data volume with the extensions directory. This appears to be
> difficult and also depending on the version of compose (and file). Actually
> I gave up on that one for now, but any suggestions or examples welcome.
>
This is not difficult, this is impossible.  The extensions *must* be in the
same container as the main Tomcat instance that runs Guacamole.  These
extensions are loaded by the Guacamole Client as it is deployed by Tomcat,
so it is really not possible to run extensions in separate containers.  It
doesn't matter if you're sharing the GUACAMOLE_HOME directory or the Tomcat
WebApps directory or the entire filesystem between two containers, you
cannot run an extension in a separate container from the main Guacamole
Client (guacamole.war file).

- Nick

Re: More containers?

[Nick Couchman]

On Sat, Jun 16, 2018 at 6:11 PM Mike Jumper 
wrote:

> On Sat, Jun 16, 2018 at 7:22 AM, Joachim Lindenberg <
> joac...@lindenberg.one> wrote:
>
>> ...
>>
>> (I am aware of that ADD is kind of deprecated). What I don´t understand
>> is why I use /ext/ and in fact the files end up in /root/.guacamole/.
>>
>
> Copying the provided template GUACAMOLE_HOME into place is part of the
> Docker image's startup process:
>
>
> https://github.com/apache/guacamole-client/blob/984ab48ce8dbbb5b9949ce1f5e5f774168b4830b/guacamole-docker/bin/start.sh#L340-L352
>
> The Docker image (somewhat confusingly) uses its own GUACAMOLE_HOME
> variable to define the location that should serve as the basis for the
> webapp's GUACAMOLE_HOME. As the GUACAMOLE_HOME environment variable has
> special meaning to the web application, it is explicitly forced back to
> ~/.guacamole/ with your custom value stored in GUACAMOLE_HOME_TEMPLATE:
>
>
> https://github.com/apache/guacamole-client/blob/984ab48ce8dbbb5b9949ce1f5e5f774168b4830b/guacamole-docker/bin/start.sh#L31-L33
>
> To some extent this also clarifies how to include multiple extensions:
>> just add all of them. However it is not really a modular approach then.
>>
>
> How is separating things into distinct extensions not modular?
>

I don't think the point was that extensions are not modular, I believe it
was that adding all possible extensions to the container defeats the
modular nature of extensions, and I agree.  The solution to trying to
figure out how to get multiple extensions into the Docker image should not
be to just dump them all in.


>
> ·   what I dislike about the docker file above is, that I have to
>> include the configuration with the code and force a rebuild on every
>> configuration change. Imho being able to separate code and data is one of
>> the key aspects in using containers.
>>
>
> I believe this is as aspect of the approach the unmodified Docker image
> already takes. With the exception of third-party customizations (which
> naturally can't be part of the mainline Docker image), the container is
> self-contained and driven by configuration provided through environment
> variables.
>
> You will need to dynamically generate your guacamole.properties during
> container startup (like the existing start.sh does) if you wish to avoid
> rebuilding the image.
>
> Maybe I am just unaware of a better approach, but what comes to my mind is
>> that it would be great to have distinct environment variables pointing to
>> extensions directory vs guacamole configuration. For compatibility reasons
>> the extensions directory variable can still default to the existing
>> definition.
>>
>
> I disagree here.
>
> Though the Docker image layers its own semantics on top of GUACAMOLE_HOME
> (let's set those aside for the moment as they are not a part of the
> webapp), the point of the main GUACAMOLE_HOME directory with respect to
> Guacamole configuration is to be able to rely upon convention. Once the
> location of GUACAMOLE_HOME is defined, the locations of all
> Guacamole-specific configuration files, all extensions, etc. are known and
> rigorous.
>
>
It's also worth noting that one of the changes to the current code that
will be released in version 1.0.0 is the ability to define any of the
guacamole.properties options using environment variables.  This was
introduced in GUACAMOLE-464, and should add some flexibility to the process
of configuring Guacamole in a container environment by allowing those
options to be configured entirely in the environment without writing the
guacamole.properties file, if you choose to do it that way.

-Nick

Re: More containers?

[Mike Jumper]

On Sat, Jun 16, 2018 at 7:22 AM, Joachim Lindenberg 
wrote:

> ...
>
> (I am aware of that ADD is kind of deprecated). What I don´t understand is
> why I use /ext/ and in fact the files end up in /root/.guacamole/.
>

Copying the provided template GUACAMOLE_HOME into place is part of the
Docker image's startup process:

https://github.com/apache/guacamole-client/blob/984ab48ce8dbbb5b9949ce1f5e5f774168b4830b/guacamole-docker/bin/start.sh#L340-L352

The Docker image (somewhat confusingly) uses its own GUACAMOLE_HOME
variable to define the location that should serve as the basis for the
webapp's GUACAMOLE_HOME. As the GUACAMOLE_HOME environment variable has
special meaning to the web application, it is explicitly forced back to
~/.guacamole/ with your custom value stored in GUACAMOLE_HOME_TEMPLATE:

https://github.com/apache/guacamole-client/blob/984ab48ce8dbbb5b9949ce1f5e5f774168b4830b/guacamole-docker/bin/start.sh#L31-L33

To some extent this also clarifies how to include multiple extensions: just
> add all of them. However it is not really a modular approach then.
>

How is separating things into distinct extensions not modular?

·   what I dislike about the docker file above is, that I have to
> include the configuration with the code and force a rebuild on every
> configuration change. Imho being able to separate code and data is one of
> the key aspects in using containers.
>

I believe this is as aspect of the approach the unmodified Docker image
already takes. With the exception of third-party customizations (which
naturally can't be part of the mainline Docker image), the container is
self-contained and driven by configuration provided through environment
variables.

You will need to dynamically generate your guacamole.properties during
container startup (like the existing start.sh does) if you wish to avoid
rebuilding the image.

Maybe I am just unaware of a better approach, but what comes to my mind is
> that it would be great to have distinct environment variables pointing to
> extensions directory vs guacamole configuration. For compatibility reasons
> the extensions directory variable can still default to the existing
> definition.
>

I disagree here.

Though the Docker image layers its own semantics on top of GUACAMOLE_HOME
(let's set those aside for the moment as they are not a part of the
webapp), the point of the main GUACAMOLE_HOME directory with respect to
Guacamole configuration is to be able to rely upon convention. Once the
location of GUACAMOLE_HOME is defined, the locations of all
Guacamole-specific configuration files, all extensions, etc. are known and
rigorous.

- Mike

Re: More containers?

[Nick Couchman]

On Wed, May 9, 2018 at 11:57 AM, Joachim Lindenberg 
wrote:

> Hello,
>
> I assume I will have to upgrade guacamole in the near future. Rather than
> updating all dependencies and recompiling, I´d actually favor to use
> docker. Now initially I decided against docker because I didn´t like the
> database…
>

Well, you don't *have* to, but we're resolving a decent number of issues
and adding features along the way, so if you want the bug fixes and
features, you'll need to upgrade.  And, yes, Docker is designed to ease
this process.


> I am also running mailcow-dockerized (and the database drives up memory
> utilization L). mailcow-dockerized uses lots of containers plus a central
> configuration directory (which is filled via git, i.e. my configuration
> changes are locally merged with central ones). I am wondering whether you
> can/want to adopt similar separation and offer separate containers for
> guacd (as already), guacamole, and database (could be a choice of different
> database including lightweights J).
>

Yes, best practices for containers is to run a single workload per
container, so you should run your guacd instance, guacamole-client (Tomcat
+ Guacamole Client + Extensions), and Database in separate instances.


> As you already have an extension concept that wires guacamole and the
> database, I guess it should be possible to expose or copy the relevant
> directories/configuration from one container to the other and have that
> picked up. Ideally one can run not just one extension but multiple using
> distinct containers. Or edit the composition not to load a database.
>

Docker does allow you to make directories available from your host to the
containers, which also means you could share the configuration amongst the
various containers.  If you look at the very last section of the Guacamole
Manual on Docker (http://guacamole.apache.org/doc/gug/guacamole-docker.html)
you'll see an example of using the "-v" flag to forward a directory through
to a container.

However, I'm not sure what you mean by running "multiple extensions using
distinct containers" - this doesn't make sense to me.  All of your
extensions need to be present in the container where Tomcat is running the
Guacamole Client.  You could run a separate instance of the Tomcat client
for each extension, but these will not be magically linked together -
you'll have one container with one extension (JDBC, for example) running,
another container with another one, etc., and different clients that behave
differently.  If you want to use multiple extensions with the Guacamole
Client, you should run all of these extensions in a single container with
the Guacamole Client.

-Nick