[DEV] support configurable cloud-init kernel parameters

[rainest]

Short Description

BSS provides a means to set cloud-init kernel parameters in machine boot configuration.

Definition of Done

1. BSS exposes a new API endpoint or new API endpoint field for per-machine cloud-init parameters.
2. (Optional) BSS exposes a new API endpoint to set default cloud-init parameters.
3. Absent explicit cloud-init configuration, BSS appends the same cloud-init parameters as it does in 1.32.
4. (Optional) Unit tests verify that cloud-init configuration propagates to generated boot scripts.

Additional context

BSS currently adds a standard cloud-init data source kernel parameter. This parameter indicates that a nocloud server is available at a configurable address.

In traditional CSM, this is used for some types of non-compute nodes. Compute nodes do not run cloud-init, but BSS does still include the parameter regardless.

Custom configuration allows using a different data source (in my case, I have a VM testing platform that wants to mount a configuration disk), provide additional settings, or strip cloud-init parameters altogether.

I don't currently see any test for the buildBootScript() function that insert the cloud-init parameters (and all other parameters) or its BootScriptGet() parent. Testing this would need a new unit test.

[rainest]

From initial work, maybe I'm missing something: buildBootScript() at least gives preference to user-supplied parameters. It adds generated parameters, (such as ds=whatever for CloudInit) are inserted via checkParam(), which is a no-op if a param with that key already exists.

#69 adds a test confirming that a ds=something in the generic param string persists to the final script and that no duplicate key shows up from the generated source.

IIRC I was not able to get my own ds param in via the API, so I suspect something further up is eating that before invoking buildBootScript(). I need to check further up the chain.

[rainest]

Alright, no, I'm wrong and missed something earlier or configured my other test host incorrectly. API-level config for param keys does take precedence over any default generated value, and nothing further needs to be done here.

When params includes no ds key, BSS inserts one into the script:

Original state

[root@rst-coredhcp ~]# ./ochami -C default bss boot script get --mac bc:24:11:40:03:a3 --arch i386
#!ipxe
kernel --name kernel http://192.168.8.12/images/alma/vmlinuz initrd=initrd root=live:http://192.168.8.12/images/alma/alma.sqsh xname=x1000c0s0b0n0 nid=16400384 ds=nocloud-net;s=localhost/ || goto boot_retry
initrd --name initrd http://192.168.8.12/images/alma/initramfs || goto boot_retry
boot || goto boot_retry
:boot_retry
sleep 30
chain http://192.168.8.66:27778/boot/v1/bootscript?mac=bc:24:11:40:03:a3&retry=1


[root@rst-coredhcp ~]# ./ochami -C default bss boot params get --mac bc:24:11:40:03:a3 | jq
[
  {
    "cloud-init": {
      "meta-data": null,
      "phone-home": {
        "fqdn": "",
        "hostname": "",
        "instance_id": "",
        "pub_key_dsa": "",
        "pub_key_ecdsa": "",
        "pub_key_rsa": ""
      },
      "user-data": null
    },
    "initrd": "http://192.168.8.12/images/alma/initramfs",
    "kernel": "http://192.168.8.12/images/alma/vmlinuz",
    "macs": [
      "bc:24:11:40:03:a3"
    ],
    "params": "root=live:http://192.168.8.12/images/alma/alma.sqsh"
  }
]

When params does include a ds key, that value takes precedence over the generated one.

Updated state

[root@rst-coredhcp ~]# ./ochami -C default bss boot params set --mac bc:24:11:40:03:a3 --params="root=live:http://192.168.8.12/images/alma/alma.sqsh ds=nocloud-net;s=localhost/foo"
[root@rst-coredhcp ~]# ./ochami -C default bss boot params get --mac bc:24:11:40:03:a3 | jq
[
  {
    "cloud-init": {
      "meta-data": null,
      "phone-home": {
        "fqdn": "",
        "hostname": "",
        "instance_id": "",
        "pub_key_dsa": "",
        "pub_key_ecdsa": "",
        "pub_key_rsa": ""
      },
      "user-data": null
    },
    "initrd": "http://192.168.8.12/images/alma/initramfs",
    "kernel": "http://192.168.8.12/images/alma/vmlinuz",
    "macs": [
      "bc:24:11:40:03:a3"
    ],
    "params": "root=live:http://192.168.8.12/images/alma/alma.sqsh ds=nocloud-net;s=localhost/foo"
  }
]
[root@rst-coredhcp ~]# ./ochami -C default bss boot script get --mac bc:24:11:40:03:a3 --arch i386
#!ipxe
kernel --name kernel http://192.168.8.12/images/alma/vmlinuz initrd=initrd root=live:http://192.168.8.12/images/alma/alma.sqsh ds=nocloud-net;s=localhost/foo xname=x1000c0s0b0n0 nid=16400384 || goto boot_retry
initrd --name initrd http://192.168.8.12/images/alma/initramfs || goto boot_retry
boot || goto boot_retry
:boot_retry
sleep 30
chain http://192.168.8.66:27778/boot/v1/bootscript?mac=bc:24:11:40:03:a3&retry=1

---

Extra call path/type notes

buildBootScript() is currently called from unknownBootScript() (via BootScriptGet()) and from BootScriptGet().

func buildBootScript(bd BootData, sp scriptParams, chain, role, subRole, descr string) (string, error)

type BootData struct {
	Params        string
	Kernel        ImageData
	Initrd        ImageData
	CloudInit     bssTypes.CloudInit
	ReferralToken string
}

type ImageData struct {
	Path   string `json:"path"`             // URL or path to the image
	Params string `json:"params,omitempty"` // boot parameters associated with this image
}

type CloudInit struct {
	MetaData  CloudDataType `json:"meta-data"`
	UserData  CloudDataType `json:"user-data"`
	PhoneHome PhoneHome     `json:"phone-home,omitempty"`
}

type scriptParams struct {
        xname         string
        nid           string
        referralToken string
}