azure: fix regression introduced when persisting ephemeral dhcp lease
In commitish 9073951 azure datasource tried to leverage stale DHCP
information obtained from EphemeralDHCPv4 context manager to report
updated provisioning status to the fabric earlier in the boot process.
Unfortunately the stale ephemeral network configuration had already been
torn down in preparation to bring up IMDS network config so the report
attempt failed on timeout.
This branch introduces obtain_lease and clean_network public methods on
EphemeralDHCPv4 to allow for setup and teardown of ephemeral network
configuration without using a context manager. Azure datasource now uses
this to persist ephemeral network configuration across multiple contexts
during provisioning to avoid multiple DHCP roundtrips.
azure: add udev rules to create cloud-init Gen2 disk name symlinks
Cloud-init delivers udev rules on Azure to create the following symlinks:
- /dev/disk/cloud/azure_root
- /dev/disk/cloud/azure_root-part#
- /dev/disk/cloud/azure_resource
- /dev/disk/cloud/azure_resource-part#
Cloud-init cc_disk_setup expects presence of these dev links in order to
setup the mounted ephemeral disks. Gen1 instances udev rules match based
only a DEVICE_ID attribute that no longer exists on Gen2 instances.
Supplement existing Gen1 rules with matches on specitic SCSI target/lun
path 0:0:0 and 0:0:1 and generate links for azure_root and azure_resource
respectively.
azure: report ready to fabric after reprovision and reduce logging
When reusing a preprovisioned VM, report ready to Azure fabric as soon as
we get the reprovision data and the goal state so that we are not delayed
by the cloud-init stage switch, saving 2-3 seconds. Also reduce logging
when polling IMDS for reprovision data.
instance-data: fallback to instance-data.json if sensitive is absent.
On cloud-init upgrade path from 18.3 to 18.4 cloud-init changed how
instance-data is written. Cloud-init changes instance-data.json from root
read-only to redacted world-readable content, and provided a separate
unredacted instance-data-sensitive.json which is read-only root.
Since instance-data is only rewritten from cache on
reboot, the query and render tools needed fallback to use the 'old'
instance-data.json if the new sensitive file isn't yet present.
This avoids error messages from tools about an absebt
/run/instance-data-sensitive.json file.
