EC2: Rewrite network config on AWS Classic instances every boot
AWS EC2 instances' network come in 2 basic flavors: Classic and VPC
(Virtual Private Cloud). The former has an interesting behavior of having
its MAC address changed whenever the instance is stopped/restarted. This
behavior is not observed in VPC instances.
In Ubuntu 18.04 (Bionic) the network "management" changed from ENI-style
(etc/network/interfaces) to netplan, and when using netplan we observe
the following block present in /etc/netplan/50-cloud-init.yaml:
match:
macaddress: aa:bb:cc:dd:ee:ff
Jani Ollikainen noticed in Launchpad bug #1802073 that the EC2 Classic
instances were booting without network access in Bionic after stop/restart
procedure, due to their MAC address change behavior. It was narrowed down
to the netplan MAC match block, that kept the old MAC address after
stopping and restarting an instance, since the network configuration
writing happens by default only once in EC2 instances, in the first boot.
This patch changes the network configuration write to every boot in EC2
Classic instances, by checking against the "vpc-id" metadata information
provided only in the VPC instances - if we don't have this metadata value,
cloud-init will rewrite the network configuration file in every boot.
This was tested in an EC2 Classic instance and proved to fix the issue;
unit tests were also added for the new method is_classic_instance().
Reported-by: Jani Ollikainen <email address hidden>
Suggested-by: Ryan Harper <email address hidden>
Co-developed-by: Chad Smith <email address hidden>
Signed-off-by: Guilherme G. Piccoli <email address hidden>
netinfo: Adjust ifconfig output parsing for FreeBSD ipv6 entries
FreeBSD ifconfig output for ipv6 addrs doesn't find scopeid values
when present in the output and the pformat rendering assumes that
an ipv6 address will have a 'scope6' entry in the netdev info
dictionary. This patch finds the scopeid value, which is not
always inside <>, and in some cases v6 addrs don't have a scopeid
value in the output, so when rendering the table, allow scope6 value
to be replaced with the empty value.
netplan: Don't render yaml aliases when dumping netplan
Cloud-init rendered netplan with duplicate aliases if a network config
included "global" nameserver/search values. Netplan uses can read yaml
files which do use aliaes but cloud-init did not render a single yaml
dictionary, instead it combined yaml sections into a single document
which sometimes resulted in duplicate aliases being present.
This branch introduces a yaml SafeDumper class which can set the
'ignore_aliases' attribute. This is not enabled by default but callers
to util.yaml_dumps can pass a boolean to toggle this. The netplan
render uses noalias=True and the resulting yaml output does not contain
any aliases.
opennebula: also exclude epochseconds from changed environment vars
In addition to EPOCHREALTIME there is also an EPOCHSECONDS environment
variable that OpenNebula needs to exclude as it is expected to change.
This commit supplements the other exclusion in commit
d1a2fe7307e9cf2251d1f9a666c12d71d3f522d6.
Without this fix, unittests will intermittently fail if
parse_shell_config is run across a timing boundary where the
EPOCHSECONDS changes mid-test.
