DataSourceEc2: use metadata's NIC ordering to determine route-metrics

[OddBloke]

We want to set route-metrics such that NICs are configured with the priority that they are given in the network metadata that we receive from the IMDS. (This switches away from using MAC ordering.)

This also required the following test changes:

• reverse the sort order of the MACs in test data (so that they would trigger the bug being fixed)
• fix up the key names in NIC2_MD (which were under_scored instead of dash-separated)
• use a full interface dict (rather than a minimal one) for TestConvertEc2MetadataNetworkConfig

LP: #1876312

[raharper]

Thanks, this looks good. I'd like another pass to look at some possible issues:

• get_interfaces_by_mac may vary it's output depending on platform, do we need to consistently apply a .lower() or .upper() here?
• in DataSourceEc2 (and likely others) are we dealing with mixed case mac address values?

[OddBloke]

On Fri, May 01, 2020 at 07:55:27AM -0700, Rick Harding wrote: > for mac, nic_name in sorted(macs_to_nics.items()): nic_metadata = macs_metadata.get(mac) if not nic_metadata: continue # Not a physical nic represented in metadata + # device-number is zero-indexed, we want it 1-indexed for the + # multiplication on the following line + nic_idx = int(nic_metadata['device-number']) + 1 is this never empty then? Should it have a default value in case it isn't?

Per https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instancedata-data-categories.html this has been present since 2011, and I don't believe there are any cases where it will be absent.