cloud-init and UserData service documentation cleanup

[onitake]

The cloud-init documentation in the CloudStack manual has always been a bit outdated and was missing a few crucial bits, such as the data-server. well-known host name, which is supported by cloud-init since version 19.4.

This PR is almost a full rewrite to make it clearer and easier to use.

One open question: I updated the links to the API docs to 4.14. Is there a generic link that always points to the latest version?

[onitake]

One more thing: Simply base64-ing the cloud-config and passing it to cloudmonkey is not enough. It needs to be a proper multi-part MIME message, such as this one:

Content-Type: multipart/mixed; boundary="//"
MIME-Version: 1.0

--//
Content-Type: text/cloud-config; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="cloud-config.txt"

#cloud-config
write_files:
- path: /testfile    
  content: hello world

I think I'm also going to add this to the example.

[andrijapanicsb]

@onitake you should use relative links, please see some other examples here in the doc.

One interesting thing, unless I was seriously drunk, I recall I was adding a simple one-line cleartext text as userdata while testing some things a few months ago (i.e. not base64 encoded)...

[andrijapanicsb]

requesting docbuild

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[onitake]

@andrijapanicsb I tried plaintext as well, but it wouldn't work with cmk. And without the MIME headers, cloud-init would refuse to decode the file. Apparently, you can put multiple files into this field, that's why MIME headers are needed.

As for relative links: That works with the API docs as well?

[andrijapanicsb]

I'll be honest and say that I have no idea about those specific links - please try to find some existing examples - or link to /latest/ - that might be a safe bet.

[yadvr]

@onitake can you address merge conflict, and update as necessary? Thanks

[DaanHoogland]

@onitake can you address the conflict and the comments?

[yadvr]

Ping @onitake

[onitake]

Sorry for the delay, I'll look into this until tomorrow.

[yadvr]

Thanks @onitake

[onitake]

I adapted the DHCP lease path PR, but haven't found any example on how to create apidoc links in the repository.

However, I found plenty of links that point to https://cloudstack.apache.org/docs/api/ - and that page produces a 404. There is also no https://cloudstack.apache.org/docs/api/latest/ . In other places, https://cloudstack.apache.org/api.html is used, which works and displays a list of API versions.

@rhtyd Maybe we should ensure that https://cloudstack.apache.org/docs/api/apidocs-latest/ (or similar) works, and that https://cloudstack.apache.org/docs/api/ redirects to https://cloudstack.apache.org/api.html or that all the links are fixed?

[yadvr]

@onitake you can give specific version for example http://cloudstack.apache.org/api/ or http://cloudstack.apache.org/api/apidocs-4.14

requesting docbuild

[yadvr]

requesting docbuild

[ACSGitBot]

Your request had been received, i'll go and build the documentation and check the output log for errors.

This shouldn't take long.

[ACSGitBot]

Build finished. You can review it at: https://acs-www.shapeblue.com/docs/WIP-PROOFING/pr132//

Build Log Output:

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[weizhouapache]

checked https://acs-www.shapeblue.com/docs/WIP-PROOFING/pr132//adminguide/virtual_machines/user-data.html?highlight=userdata
looks good.
thanks @onitake

[onitake]

@onitake you can give specific version for example http://cloudstack.apache.org/api/ or http://cloudstack.apache.org/api/apidocs-4.14

Yes, this I know.
@andrijapanicsb requested that I use a more generic URL (such as "latest/"), and I agree that this would be better. But with the way the API docs are set up, there doesn't seem to be a way to refer to the latest version.

I will also prepare a PR to replace https://cloudstack.apache.org/docs/api/ with https://cloudstack.apache.org/api.html - the former link doesn't work.