What is hyperkube?

Question

I am trying to setup kubernetes in aws and following the guides at https://github.com/kubernetes/kubernetes/blob/master/docs/getting-started-guides/docker-multinode

I couldn't understand what is meant by hyperkube. Can someone please explain to me what it is and how does it work?

And another question I have is while running the command

sudo docker run \     --volume=/:/rootfs:ro \     --volume=/sys:/sys:ro \     --volume=/dev:/dev \     --volume=/var/lib/docker/:/var/lib/docker:rw \     --volume=/var/lib/kubelet/:/var/lib/kubelet:rw \     --volume=/var/run:/var/run:rw \     --net=host \     --privileged=true \     --pid=host \     -d \     gcr.io/google_containers/hyperkube:v${K8S_VERSION} \     /hyperkube kubelet \       --api-servers=http://localhost:8080 \       --v=2 --address=0.0.0.0 --enable-server \       --hostname-override=127.0.0.1 \       --config=/etc/kubernetes/manifests-multi \       --cluster-dns=10.0.0.10 \       --cluster-domain=cluster.local 

it is starting the one pod by default. From the command documentation, it looks like it is getting the pod manifest from the --config=/etc/kubernetes/manifests-multi attribute. But this directory is not present in my host. can somebody please tell me from where it is getting this pod manifest?

Answer 1

Kubernetes is a set of daemons/binaries:

• kube-apiserver (AKA the master),
• kubelet (start/stop containers, sync conf.),
• kube-scheduler (resources manager)
• kube-controller-manager (monitor RC, and maintain the desired state)
• kube-proxy (expose services on each node)
• kubectl (CLI)

The hyperkube binary is an all in one binary (in a way similar to busybox), combining all the previously separate binaries.

The following command:

hyperkube kubelet \   --api-servers=http://localhost:8080 \   --v=2 \   --address=0.0.0.0 \   --enable-server \   --hostname-override=127.0.0.1 \   --config=/etc/kubernetes/manifests-multi \   --cluster-dns=10.0.0.10 \   --cluster-domain=cluster.local 

runs the daemon kubelet.