Firecracker notes

I am increasingly wary of running cargo install or npm install even with trusted dependencies. Never mind, how do you realistically get to a point where you trust all your dependencies these days?

So I decided to use Firecracker, partly because I wanted to learn how to use it. I started with this but decided that I'd rather use a prebuilt kernel to get started more quickly. Moar quicker = moar better.

The getting started guide is pretty good. I ended up using the config file rather than the socket API, so the network setup guide was also important. The last section seems especially useful for not having to set up the interface every time the guest restarts. The socket API probably does make more sense for scripting, so it seems likely that I'll end up back there again.

I also had to resize the ext4 filesystem, which turns out to be really easy! With the vm shut down, I just ran:

e2fsck -f ubuntu-24.04.ext4
resize2fs ubuntu-24.04.ext4 10G

Then I restarted and had much more space to work with.