Azure data source assumes use of dhclient

This bug was originally filed in Launchpad as [LP: #1936823](https://bugs.launchpad.net/cloud-init/+bug/1936823)

Launchpad details

affected_projects = []

assignee = None

assignee_name = None

date_closed = None

date_created = 2021-07-19T11:57:08.529823+00:00

date_fix_committed = None

date_fix_released = None

id = 1936823

importance = medium

is_complete = False

lp_url = https://bugs.launchpad.net/cloud-init/+bug/1936823

milestone = None

owner = rjschwei

owner_name = Robert Schweikert

private = False

status = triaged

submitter = rjschwei

submitter_name = Robert Schweikert

tags = []

duplicates = []

_Launchpad user **Robert Schweikert(rjschwei)** wrote on 2021-07-19T11:57:08.529823+00:00_

The Azure data source assumes that all Linux distros use dhclient. Location of a lease file is hard coded to

"""
LEASE_FILE = '/var/lib/dhcp/dhclient.eth0.leases'
"""

and if the file is not found the data source reports errors:

"""
Failed to read /var/lib/dhcp/dhclient.eth0.leases: [Errno 2] No such file or directory: '/var/lib/dhcp/dhclient.eth0.leases'
"""

Further, during the cloud-init local stage cloud-init establishes a temporary dhclient connect but the lease file is written to a temporray location such as:

"""
/var/tmp/cloud-init/cloud-init-dhcp-sbhredt8/dhcp.leases
"""

The Azure data source should check if the network is up rather than depending on specific markers in the file system left by specific implementations for dhcp connections. The kernel sysfs provides more reliable methods to detect network connection precense.