Buildkit doesn't work on DigitalOcean Kube cluster

[kklin]

What happened?

❯ blimp up
Booting cloud sandbox
[Error] Get help at https://kelda.io/blimp/docs/help/
Message: Failed to create development sandbox
Error: rpc error: code = Unavailable desc = transport is closing

The buildkit pod is unhealthy, with the following logs:

time="2020-12-21T04:38:58Z" level=warning msg="/proc/sys/kernel/unprivileged_userns_clone needs to be set to 1."
[rootlesskit:parent] error: failed to start the child: fork/exec /proc/self/exe: operation not permitted

What were you expecting to happen?

Buildkit should successfully start, and the development sandbox should be deployed.

There's some additional UX issues here as well:

• The error message should be better.
• The compose file doesn't even require building images. So even if buildkit isn't working, we should let the development sandbox be created.

Reproduction steps

Additional context

Switching to non-rootless images for buildkit may fix the issue on DO.

Reported by Ian Walter in Slack (https://kelda.slack.com/archives/C4LF0KL4D/p1608525499118200)