openstack: dynamically mount the config-drive

[EmilienM]

When we want to use config-drive in immutable systems, very often the
config-drive is only used at boot and then umounted (e.g. ignition does
this).

Later when we want to fetch Metadata from the config drive, we actually
have to mount it.

In this PR, I'm adding similar code than coreos/ignition where we
dynamically mount the config-drive is the device was found with the
right label (config-2 or CONFIG-2 as documented in OpenStack). If the
device is found, we mount it, fetch the data and umount it.

[github-actions]

Thanks for your PR,
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  Best regards.

[coveralls]

Pull Request Test Coverage Report for Build 10840952209

Details

• 5 of 67 (7.46%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.2%) to 44.862%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/platforms/openstack/openstack.go	5	67	7.46%

Totals
Change from base Build 10734670028:	-0.2%
Covered Lines:	6606
Relevant Lines:	14725

---

💛 - Coveralls

[EmilienM]

It's open for review but I haven't tested it yet.

/hold

[bn222]

/lgtm thanks

[EmilienM]

Just an update on this, the current patch doesn't work yet, I'm reworking it here: openshift/sriov-network-operator#1004 so I can get CI feedback fairly quickly. I'll update this PR as soon as I have satisfying results and ask for reviews here.

[EmilienM]

I got a successful CI run:

2024-09-12T22:31:21.02913626Z	INFO	daemon/writer.go:65	CreateOpenstackDevicesInfo()
2024-09-12T22:31:21.029146361Z	INFO	openstack/openstack.go:118	reading OpenStack meta_data from config-drive
2024-09-12T22:31:21.057448323Z	INFO	openstack/openstack.go:225	found config drive device	{"device": "/dev/sr0"}
2024-09-12T22:31:21.065428364Z	INFO	openstack/openstack.go:229	mounted config drive %s into %s	{"/dev/sr0": "/tmp/sriov-configdrive2821721804"}
2024-09-12T22:31:21.066344839Z	INFO	openstack/openstack.go:118	reading OpenStack network_data from config-drive
2024-09-12T22:31:21.079312593Z	INFO	openstack/openstack.go:234	umounted config drive	{"path": "/tmp/sriov-configdrive2821721804"}

https://gcsweb-ci.apps.ci.l2s4.p1.openshiftapps.com/gcs/test-platform-results/pr-logs/pull/openshift_sriov-network-operator/1004/pull-ci-openshift-sriov-network-operator-master-e2e-openstack-nfv-config-drive/1834316002138001408/artifacts/e2e-openstack-nfv-config-drive/gather-extra/artifacts/pods/openshift-sriov-network-operator_sriov-network-config-daemon-5mhxf_sriov-network-config-daemon.log

[EmilienM]

@SchSeba @zeeke please review :)

[zeeke]

Though these changes add dependencies to blkid and mount commands, they are well perimetered inside the ad-hoc OpenStack logic

Only one other minor comment about logging.

LGTM