Imagine that you want to test your Kubernetes cluster with Singularity-CRI locally, but don’t want to waste time setting is all up or messing with Minikube.

Sykube comes to the rescue! Inspired by Minikube, it allows you to run Kubernetes cluster locally within Singularity instances with Singularity-CRI baked in. Moreover, unlike Minikube, it is capable of spawning not only one, but arbitrary amount of nodes.

Another nice feature is ephemeral clusters. With this option on, Sykube will create local cluster on tmpfs making sure nothing is left after host reboot.

For more info refer to Sykube repo.



Assuming you already have Singularity 3.1+ installed, do the following:

$ sudo singularity run library://sykube

This with pull the Sykube image and add a binary in /usr/local/bin. To verify your installation you can check usage options with the following command:

$ sykube -h

Running local cluster

Before creating new Sykube cluster make sure you removed any existing. To create new Sykube cluster do the following:

$ sykube init


Make sure you don’t have any restrictions applied to iptables FORWARD target. To check this do the following:

$ sudo iptables -nL

Problems are often caused by Docker daemon since it adds custom iptables rules. That prevents Sykube instance network from being correctly setup.

To disable docker and reboot you should do the following:

$ sudo service docker stop && \
  sudo systemctl disable docker && \

After that Sykube should work correctly. Note this workaround may be redundant soon as there is an open GitHub issue referencing it here.

This may take a few minutes, stay patient.

After that if you already have kubectl installed, you may want to configure it to work with Sykube cluster. To do that run the following:

$ sykube config > ~/.kube/config

If you don’t have kubectl, you can use Sykube, e.g:

$ sykube exec master kubectl <args>

Cleaning up

After testing you may want to remove the cluster. To do that run the following:

$ sykube stop && \
  sykube delete