Merge ~utlemming/cloud-init:lp-1676908-nic_selection_for_meta_data into cloud-init:master

[Ben Howard]

[Ben Howard (utlemming)]

Re-worked interface selection for IPv4LL address.

[Server Team CI bot (server-team-bot)]

FAILED: Continuous integration, rev:f94ca425014f634ad009543e4e9125b1ec6cf386
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review: Needs Fixing (continuous-integration)

ad4d45f... by Ben Howard on 2017-04-11

DigitalOcean: assign IPv4ll address to lowest indexed interface.

Previously the IPv4LL address for metadata discovery was assigned to the
first interfaces from an alphabetic sort. On DigitalOcean, the metadata
is only accessible from the first interface. This fixes a problem where the
IPv4LL address is bound to the wrong interface with snapshots.

This is part of general improvements to the DigitalOcean Datasource in
bug 1676908.

[Server Team CI bot (server-team-bot)]

FAILED: Continuous integration, rev:da92b43445f07ab02ae673bbfb78c710cde8f297
No commit message was specified in the merge proposal. Click on the following link and set the commit message (if you want a jenkins rebuild you need to trigger it yourself):
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https://jenkins.ubuntu.com/server/job/cloud-init-ci/243/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=metal-amd64/243
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=metal-arm64/243
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=metal-ppc64el/243
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review: Needs Fixing (continuous-integration)

Unmerged commits

ad4d45f... by Ben Howard on 2017-04-11

DigitalOcean: assign IPv4ll address to lowest indexed interface.

Previously the IPv4LL address for metadata discovery was assigned to the
first interfaces from an alphabetic sort. On DigitalOcean, the metadata
is only accessible from the first interface. This fixes a problem where the
IPv4LL address is bound to the wrong interface with snapshots.

This is part of general improvements to the DigitalOcean Datasource in
bug 1676908.

diff --git a/cloudinit/sources/helpers/digitalocean.py b/cloudinit/sources/helpers/digitalocean.py
index 72f7bde..3fbe83c 100644
--- a/cloudinit/sources/helpers/digitalocean.py
+++ b/cloudinit/sources/helpers/digitalocean.py
@@ -23,11 +23,17 @@ def assign_ipv4_link_local(nic=None):
     """
 
     if not nic:
-        for cdev in sorted(cloudnet.get_devicelist()):
+        cindex = -1
+        for cdev in cloudnet.get_devicelist():
             if cloudnet.is_physical(cdev):
-                nic = cdev
-                LOG.debug("assigned nic '%s' for link-local discovery", nic)
-                break
+                ifindex = cloudnet.read_sys_net_int(cdev, 'ifindex')
+                if (cindex == -1 or (
+                    cindex != -1 and ifindex < cindex)):
+                    msg = ("'%s' is a candidate for metadata discovery with "
+                           "an index of %s.")
+                    LOG.debug(msg % (cdev, ifindex))
+                    nic = cdev
+                    cindex = ifindex
 
     if not nic:
         raise RuntimeError("unable to find interfaces to access the"