docs: detail how to mount and use external drivers

[adwk67]

Description

docs: detail how to mount and use external drivers.
fixes #416.

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1. Changes are OpenShift compatible
2. Integration tests passed (for non trivial changes) Tested with integration test in local branch

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1. Code contains useful comments
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4. Documentation added or updated. Follows the style guide.
5. Changelog updated
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[maltesander]

Just minor things, LGTM otherwise.

[adwk67]

@maltesander I have a local integration test for this. What do you think - shall I push that too and just leave it commented out of the test definitions (so it can be activated as necessary)? I wouldn't leave it active as we would either have to upload the mysql driver to Nexus or have an external dependency.

[fhennig]

I wanna look at it more in depth, but already I'd like the fileame to just be database-driver.adoc and also if you could put linebreaks between sentences (so each sentence is on its own line) that would be great!

[maltesander]

@maltesander I have a local integration test for this. What do you think - shall I push that too and just leave it commented out of the test definitions (so it can be activated as necessary)? I wouldn't leave it active as we would either have to upload the mysql driver to Nexus or have an external dependency.

I dont think its in scope here, but having an integration test (could be an existing one) switching to mysql for testing would be nice :)

[fhennig]

Just a few things, thanks for documenting this!

[sbernauer]

Thanks for documenting this!
Would you be willing to also document a small Dockerfile that does something like

FROM <our image>
curl -o /stackable/external-drivers/mysql-connector-j-8.0.31.jar" https://repo1.maven.org/maven2/com/mysql/mysql-connector-j/8.0.31/mysql-connector-j-8.0.31.jar

This should be very easy and help a lot for a lot of customers (that don't have or want ReadWriteMany). IMHO we should also recommend this and only have the PVC part as a last resort but that's just my 2 cents 🙈

[fhennig]

I think it's a good idea to document the alterantives as well, but it wasn't part of the original scope ofthe ticket. But ideally we'd lay out the options for the users, and then they can decide (Do I want to host an image somewhere? Can I use ReadWriteMany? etc)

[sbernauer]

I also volunteer to quickly throw the Dockerfile together, I don't want to put the burden on @adwk67. Shall I do that?

[adwk67]

I've documented it here 64754ea but couldn't get it to work yet. Maybe we can take a look together @sbernauer ?

[adwk67]

ok, got it working now.

[sbernauer]

I was just able to had a look at this and you pushed the solution.
Many thanks for adding the Dockerfile! It builds on my machine and I assume you tested if the image works against mysql.

Requested changes have been implemented.