no cloud agents: digitalocean

[dustymabe]

In #12 we decided that we'd like to try to not ship cloud agents. This ticket will document investigation and strategy for shipping without a cloud agent on the digitalocean cloud platform.

See also #41 for a discussion of how to ship cloud specific bits using ignition.

[bgilbert]

DigitalOcean doesn't have an agent. On Container Linux, coreos-metadata is responsible for configuring networkd from the initramfs on every boot, since DigitalOcean provides network parameters via a link-local metadata server and didn't originally support DHCP. I'm not sure whether DHCP works now, but I presume the metadata server is still needed for configuring private IPs.

[dustymabe]

I'm not sure whether DHCP works now, but I presume the metadata server is still needed for configuring private IPs.

@ryanpq - do you know?

[ryanpq]

DHCP in DO is only in a very limited release. User-imported images are set to use DHCP since no cloud agent or standard cloud-init can be ensured. DHCP is not in use on any base or application images (or droplets created with them) currently.

[dustymabe]

Thanks @ryanpq 😃 . We have some time before Fedora CoreOS will be shipped so maybe time to improve that there. We'll play around with DHCP as it exists in DO today and see if it works well enough for us.

[bgilbert]

@ryanpq Since a private IP address is assigned to the same NIC as the public one, I assume private IPs will still require querying the metadata service?

[ryanpq]

Yes. We can support providing this information via the metadata service or a configdrive

[dustymabe]

@ryanpq - In other words, you won't get private IP information if you only use DHCP and don't pick it up from other sources. Is that correct?

[ryanpq]

That is correct. DHCP isn't offered at all for standard images. Currently it is a feature only in use by droplets created via custom images (images imported using the new feature). The reason for this is that we cannot be sure that a VM image a user imports will have a compatible cloud-init or similar service available. DHCP on DO is not yet compatible with some services like private IPs and ipv6. For this reason it is not yet used for any droplets created using standard (base OS or one-click) images.

[bgilbert]

It appears that #111 is the only missing piece. Will PR the design doc.

[dustymabe]

thanks @bgilbert

[bgilbert]

It turns out that DO does have an agent for reporting droplet metrics back to DO. I don't think there's any reason for us to ship it.

[bgilbert]

Design doc PR merged in #113.