What does kubeadm do exactly?

1
votes

I'm installing a kubernetes cluster on raspberry pis with hypriotOS. During the installation process, I have to only install kubeadm by using

apt-get install kubeadm

Can someone explain to me what kudeam actually does? I already read about bootstrapping in the documentation, but I don't understand exactly. I'm also wondering why I only have to install kubeadm, since it is written in the documentation that:

kubeadm will not install or manage kubelet or kubectl

After the installation I can use kubectl etc. without having installed it explicitly like

apt-get install kubeadm kubectl kubelet kubernetes-cni

2
dockerkuberneteskubeadm

2 Answers

1
votes

kubeadm is a tool that is part of the Kubernetes distribution as of 1.4.0 which helps you to install and set up a Kubernetes cluster.

kubeadm performs the actions necessary to get a minimum viable cluster up and running. By design, it cares only about bootstrapping, not about provisioning machines. Likewise, installing various nice-to-have addons, like the Kubernetes Dashboard, monitoring solutions, and cloud-specific addons, is not in scope.

Instead, we expect higher-level and more tailored tooling to be built on top of kubeadm, and ideally, using kubeadm as the basis of all deployments will make it easier to create conformant clusters

1
votes

As mentioned by @Manuel Domínguez: Kubeadm is a tool to built Kubernetes clusters. It's responsible for cluster bootstrapping. It support also upgrades, downgrades, and managing bootstrap tokens.

First at all Kubeadm runs a series of prechecks to ensure that the machine is ready to run Kubernetes, during bootstraping the cluster kubeadm is downloading and install the cluster control plane components and configure all necessary cluster resources.

f.e.

Control plane components like:

  • kube-apiserver,
  • ube-controller-manager,
  • kube-scheduler,
  • etcd

Runtime components like:

  • kubelet,
  • kube-proxy
  • container runtime

You can find more information about Kubeadm:

Hope this help