Add multi-node support

[vishh]

To provide a complete kubernetes experience, user might want to play & experience with features like scheduling and daemon set, etc. If minikube can emulate multiple kubernetes nodes, users can then use most of the kubernetes features.

This is probably not necessary in the first few versions of minikube. Once the single node setup is stable, we can look at emulating multiple nodes.

Up votes from users on this issue can be used as a signal to start working on this feature.

[ernestoalejo]

Other use case: This would allow to reproduce & play locally with failover scenarios (health checking configuration, scheduling in new machines, etc.) with high availability apps when a node fails or machine resources get exhausted. VM can be stopped manually to test for example.

[pgray]

This would be awesome as a feature in minikube, but for anyone looking for something passable in the meantime, this might help.

Is the scope of a feature like this large because minikube supports 5 virtualization types? I see the priority of P3 but I'm not sure if that means it's already being worked on or that there's enough work to do on other stuff that it's not worth trying to do yet.

[marun]

I don't think it's large. It could be as simple as running nodes running docker-in-docker as pods on the master node.

[marun]

It would be nice if minikube could be updated to use kubeadm to make adding new nodes easier. Any plans for that?

[aaron-prindle]

This might be something to look into regarding this:
https://github.com/marun/nkube

[fabiand]

/me also thought about the kubeadm style of adding additional nodes

[fabiand]

Using kubeadm would also help to align with other K8s setups which eases debugging.

[jellonek]

https://github.com/Mirantis/kubeadm-dind-cluster solves this case. It also solves other cases for multi node setup needed during development process, listed in https://github.com/ivan4th/kubeadm/blob/27edb59ba62124b6c2a7de3c75d866068d3ea9ca/docs/proposals/local-cluster.md
Also it does not require any VM during the process.

There is also a demo of virtlet based on it, which shows how in simple steps you can start multi node setup, patch one node with injected image for daemonset for CRI runtime, and then start example pod on it.
All this you can read in https://github.com/Mirantis/virtlet/blob/master/deploy/demo.sh

[MichielDeMey]

@pgray I've used that setup for a long time but it looks like they won't support K8s 1.6+ 😞
coreos/coreos-kubernetes#881

[nukepuppy]

definitely thing it should be a target to use minikube for that.. like minikube start nodes=3 etc etc... i dunno haven't looked at backend but it will fill a tremendous gap right now for developing from desktop to production in the same fashion which will pay for itself in adoption faster than other things.

[ccampo]

I am using Mac and I can already bring up a second Minikube with "minikube start --profile=second". (using VirtualBox) So all I am missing is a way to connect the two so that the default minkube can now also deploy to the second (virtual)node.

[MichielDeMey]

@ccampo I believe that spins up a second cluster, not a second node?