xenial: cherry pick 4f62ae8

[OddBloke]

No description provided.

[OddBloke]

I've confirmed this works using my test from #761.

[blackboxsw]

LGTM:

1. minor authorship diff

diff --git a/debian/changelog b/debian/changelog
index c6114ae7..2d8de46a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -3,7 +3,7 @@ cloud-init (20.4-0ubuntu1~16.04.2) xenial; urgency=medium
   * cherry-pick 4f62ae8d: Fix regression with handling of IMDS ssh keys
     (#760) (LP: #1910835)
 
- -- Daniel Watkins <oddbloke@ubuntu.com>  Mon, 11 Jan 2021 17:41:09 -0500
+ -- Chad Smith <chad.smith@canonical.com>  Mon, 11 Jan 2021 15:26:17 -0700
 
 cloud-init (20.4-0ubuntu1~16.04.1) xenial; urgency=medium
 

2. build-package succeeds
3. sbuilt-id succeeds
4. quilt push -a applies the right functional diff and quilt pop -a removes cleanly

diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index 04ff2131..d7f318c7 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -266,7 +266,7 @@ BUILTIN_DS_CONFIG = {
     },
     'disk_aliases': {'ephemeral0': RESOURCE_DISK_PATH},
     'dhclient_lease_file': LEASE_FILE,
-    'apply_network_config': True,  # Use IMDS published network configuration
+    'apply_network_config': False,  # Use fallback network config not IMDS
 }
 # RELEASE_BLOCKER: Xenial and earlier apply_network_config default is False
 
@@ -651,6 +651,10 @@ class DataSourceAzure(sources.DataSource):
         LOG.debug('Retrieving public SSH keys')
         ssh_keys = []
         try:
+            raise KeyError(
+                "Not using public SSH keys from IMDS"
+            )
+            # pylint:disable=unreachable
             ssh_keys = [
                 public_key['keyData']
                 for public_key
@@ -1271,6 +1275,10 @@ class DataSourceAzure(sources.DataSource):
 
             pubkey_info = None
             try:
+                raise KeyError(
+                    "Not using public SSH keys from IMDS"
+                )
+                # pylint:disable=unreachable
                 public_keys = self.metadata['imds']['compute']['publicKeys']
                 LOG.debug(
                     'Successfully retrieved %s key(s) from IMDS',