run-on-kubernetes.md

Compose unikernels to run application on Kubernetes

Section Here Come Unikernels describes how to prepare application to run it locally using OSv unikernels. Similar steps need to be taken when composing them to run on Kubernetes, and luckily there is a script to automate it (replace imageserver pod ID to match your environment):

$ npm install
$ ./virtlet_deploy/compose-and-upload-images.sh image-server-1782580915-zv2w3

Script compose-and-upload-images.sh first composes unikernel for each service and sets appropriate boot command for it. Then it uploads the unikernel to the imageserver. When the script finishes, your Kubernetes cluster is ready to actually boot unikernels, but note two things:

1. image urls are now on image-service.kube-system endpoint instead on S3. Therefore you need to use micro-deployments-local.yaml blueprint instead micro-deployments.yaml to deploy application.
2. while S3 server serves via https the image-server is plain http. At the time of writing this document, one needs to reconfigure Virtlet runtime to use SSL; see Virtlet documentation how to do this.

One may be wondering why are we uploading same unikernel 6 times, only with different boot command. Answer is really simple: because Virtlet does not support setting boot command dynamically (yet).