Advanced Usage & Known Limitations

Networking

The current state of the networking stack should be considered unstable. Every time you run a new microVM firegopher creates a new tap device and assigns it an unused IP from the range 172.19.0.0/16.

This is somewhat wasteful as this results in creating a lot of dangling network devices and assigned IPs. You are currently responsible for cleaning them up.

There is currently no way of predefining a static IP for a microVM.

Base images

Currently the only officially supported base image is a slightly modified version of Ubuntu 22.04 Minimal for demo purposes.

You can create your own base image to be used with firegopher by following the process outlined by the Firecracker team here and placing the resulting imagename.ext4 file in /srv/firegopher. Afterwards you can use the base image by running firegopher with the flag --baseImage=imagename.

Persistent storage

Currently you can only run firegopher with a single persistent volume that is always mounted to /data.

Right now you are responsible for creating a image file to back that volume and provide it through the dataVolume flag (e.g. --dateVolume=volume.img).

Firegopher should be considered unstable and unfit for production use-cases

In addition to the lacking testing infrastructure this project currently does not implement the basic security and performance considerations needed to run Firecracker in production.

This is due to the fact that it was created as a proof of concept in the context of a university project at CODE UAS Berlin.

Firecracker production host recommendations

Currently firegopher does not implement the production host setup recommendations that the AWS Firecracker team has provided in their git repo.

Memory usage

Firecracker has the habit of eating up as much ram as it can get its hands on without returning it to the system. You can read a Hacker News thread discussing this here.

An option for dealing with this is using a memory baloon device with Firecracker, which firegopher currently does not do.