[feature-request] Add non-x86 Ubuntu EC2 mirrors in to default cloud-init configuration

[Philip Roche]

With the announcement of EC2s A1 instances we'd (CPC) like to be able to rely on cloud-init to configure archive mirrors for non-x86 architectures.

Currently the AMIs have the mirrors configured using /etc/cloud/cloud.cfg.d/95_mirrors.cfg which points to the in region archive mirrors for non-x86 architectures.

```
# Add archive mirrors for non-x86 architectures
system_info:
   package_mirrors:
     - arches: [i386, amd64]
       failsafe:
         primary: http://archive.ubuntu.com/ubuntu
         security: http://security.ubuntu.com/ubuntu
       search:
         primary:
           - http://%(ec2_region)s.ec2.archive.ubuntu.com/ubuntu/
           - http://%(availability_zone)s.clouds.archive.ubuntu.com/ubuntu/
           - http://%(region)s.clouds.archive.ubuntu.com/ubuntu/
         security: []
     - arches: [armhf, armel, default]
       failsafe:
         primary: http://ports.ubuntu.com/ubuntu-ports
         security: http://ports.ubuntu.com/ubuntu-ports
       search:
         primary:
           - http://%(ec2_region)s.ec2.ports.ubuntu.com/ubuntu-ports/
           - http://%(availability_zone)s.clouds.ports.ubuntu.com/ubuntu-ports/
           - http://%(region)s.clouds.ports.ubuntu.com/ubuntu-ports/
         security: []
```

See http://paste.ubuntu.com/p/QGvGKpKYKb/ for current AMIs that can be used for testing.

So the feature request is that coud-init configure the above mirrors automatically without us having to write /etc/cloud/cloud.cfg.d/95_mirrors.cfg on the image.

Please let me know if you would like me to spin up instances for testing instead or if you need any further info.

[Scott Moser (smoser)]

@Phillip,

We have two possible paths here:
a.) make 'default' use the 'search/primary' list:
 - http://%(ec2_region)s.ec2.ports.ubuntu.com/ubuntu-ports/
 - http://%(availability_zone)s.clouds.ports.ubuntu.com/ubuntu-ports/
 - http://%(region)s.clouds.ports.ubuntu.com/ubuntu-ports/

b.) add a 'arches: [armhf, armel]' that uses the above search list
and leave the 'default' to fall back to ports.ubuntu.com

The choice is based on whether or not the infrastructure at
 *.ec2.archive.ubuntu.com and *.clouds.archive.ubuntu.com
support arches other than armhf and armel..

I suspect that they do support arm64, but do they support others?
 * yes: http://paste.ubuntu.com/p/D6wW4JqJrW/
 * no: http://paste.ubuntu.com/p/hwnmFxJsMv/

Also relevant is the question of whether or not we want to have
user's mirror selection change through an SRU. Even though the
official mirrors may support it, the customer may have put up
a 'ports.ubuntu.com' mirror and even dns-hijacked that, but
their infrastrucutre likely would not support requests to
us-east-1.ec2.ports.ubuntu.com or us-east-1a.clouds.ports.ubuntu.com .

[Scott Moser (smoser)]

I got some feedback from Phillip.

As of today, the commit message in the MP is correct.

We've decided to limit the auto-selection of those
mirrors to arm, where we know a use case. That way new instances
of ppc64el or other arches will not select them. Such a behavior change
could be problematic for a user in a firewalled environment.

The 'default' path will still end up hitting ports.archive.ubuntu.com.

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

This bug is fixed with commit a582a2d2 to cloud-init on branch master.
To view that commit see the following URL:
https://git.launchpad.net/cloud-init/commit/?id=a582a2d2

[Ryan Harper (raharper)]

This bug is believed to be fixed in cloud-init in version 18.5. If this is still a problem for you, please make a comment and set the state back to New

Thank you.

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/3288