Installing ifupdown on bionic does not install a /etc/network/interfaces that sources /etc/network/interfaces.d/*

[chenxiang wang]

For the ubuntu1804 template VM of Azure, the file /etc/network/interfaces lacks a line:
source /etc/network/interfaces.d/*
So the VM can't get configurations under /etc/network/interfaces.d/
After installing ifupdown on the VM, cloud-init will rewrite file /etc/network/interfaces.d/50-cloud-init.cfg rather than /etc/netplan/50-cloud-init.yaml, but /etc/network/interfaces.d/50-cloud-init.cfg won't take effect.

[Scott Moser (smoser)]

In previous ubuntu, we mostly considered it an image-creation bug if /etc/network/interfaces did not have the 'source' line you have described.

That said, is there a reason you want to have ifupdown on 18.04?

[Scott Moser (smoser)]

Please set back to New after responding.

[chenxiang wang (chenxiangw)]

Yes, we need to install Linux Virtual Delivery Agent (a product of Citrix) on 1804, and ifupdown is a dependency of this product. When we deploy duplicated VMs they can't get ip addresses due to this problem.

[Dan Watkins (oddbloke)]

Hi!

I believe this is an issue with ifupdown, rather than cloud-init. As such, I've added an ifupdown task and marked cloud-init's task as Invalid. If it's determined that we won't fix this in ifupdown, then please move the cloud-init task back to New and we can consider working around this in cloud-init.

In the meantime, you'll have to modify /etc/network/interfaces yourself to perform the sourcing.

Thanks!

Dan

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/3475