schema doesn't match gpt partition types for cc_disk_setup

[Ross Vandegrift]

I tried using cc_disk_setup to build a host with a discoverable partition. `cloud-init schema --system` says:

> Cloud config schema errors: disk_setup./dev/disk/by-id/google-home: Additional properties are not allowed (disk_setup./dev/disk/by-id/google-home.layout: [[100, '933AC7E1-2EB4-4F13-B844-0E14E2AEF915']] is not valid under any of the given schemas.

The schema requires partition types to be integers here: https://github.com/canonical/cloud-init/blob/main/cloudinit/config/schemas/schema-cloud-config-v1.json#L1144-L1151

Sample input:
```
disk_setup:
  /dev/disk/by-id/google-home:
    table_type: gpt
    layout:
      - - 100
        - 933AC7E1-2EB4-4F13-B844-0E14E2AEF915 # Linux home
```

[Brett Holman (holmanb)]

I see a couple issues with the sample input:

1. Note that a list nested in another list is also not valid (note the two "-"s before the "100").

2. 933AC7E1-2EB4-4F13-B844-0E14E2AEF915 is not a valid partition type, see here[1] for a list of valid options.

From the docs[2]:

> Partitions can be specified by providing a list to layout, where each entry in the list is either
> a size or a list containing a size and the numerical value for a partition type. The size for
> partitions is specified in percentage of disk space, not in bytes (e.g. a size of 33 would take
> up 1/3 of the disk space). The partition type defaults to ‘83’ (Linux partition), for other types
> of partition, such as Linux swap, the type must be passed as part of a list along with the size.

See the examples[3] page for more info:

[1] https://tldp.org/HOWTO/Partition-Mass-Storage-Definitions-Naming-HOWTO/x190.html
[2] https://cloudinit.readthedocs.io/en/latest/reference/modules.html#disk-setup
[3] https://cloudinit.readthedocs.io/en/latest/reference/examples.html#disk-setup

[Ross Vandegrift (ross-kallisti)]

Hi Brett,

This config is accepted by cloud-init and it works. So if the schema is right, cc_disk_setup.py is buggy. But I don't think that's the case - please reopen.

The modules reference you quoted is actually where I found the idea for that config:
> Partitions can be specified by providing a list to layout, where each entry in the list is either a size or a list containing a size and the numerical value for a partition type.
It says layout list items can themselves be lists, containing a size and type. The docs say type is an integer, but the code in cc_disk_setup.py accepts strings - so I think the doc just needs to be corrected.

933AC7E1-2EB4-4F13-B844-0E14E2AEF915 is a valid GPT partition type, but not a valid DOS type. See [1] and [2]. The tldp doc you referenced is about DOS disk labels.

Thanks,
Ross

[1] - https://en.wikipedia.org/wiki/GUID_Partition_Table
[2] - https://uapi-group.org/specifications/specs/discoverable_partitions_specification/

[Brett Holman (holmanb)]

Thanks for the additional info. I see the problem now.

[Brett Holman (holmanb)]

Fix PR
https://github.com/canonical/cloud-init/pull/1995

[Chad Smith (chad.smith)]

This is believed to be fix released in cloud-init 23.1. If it is still a problem, please re-open this bug.