Update user-data.rst

[NPdocker]

Update syntax for cloud-init

[yadvr]

LGTM, we need one more review, can you check @weizhouapache @onitake thnx

[onitake]

Hi @NPdocker - can you clarify why this PR is necessary?
Was there a configuration format change in cloud-init?

[yadvr]

With the other PR merged, do we need this - can you check and advise @onitake @NPdocker @weizhouapache ?

[weizhouapache]

@rhtyd
I have same question as @onitake .
we use the old config in vms, it works fine.

      datasource:
        CloudStack: {}
        None: {}
      datasource_list:
        - CloudStack

[onitake]

I think the reason for the previous stanza was that older cloud-init versions did not propagate anything without explicitly mentioning CloudStack both in datasource and datasource_list. This might have changed, or the missing None in datasource_list prevented it from working.

@Doni7722 Could you verify if datasource_list: [ CloudStack, None ] without datasource works for us? Thanks!

[Doni7722]

@onitake I'll test that today and let you know the results.

[Doni7722]

@onitake I did verify and can confirm that it works fine with datasource_list: [ CloudStack, None ] without datasource