Kubernetes - Tools

Last Updated: 2023-03-24

Tools

• kubectl
• kubeadm: 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. Used by other tools like minikube, kind, etc.
  • kubeadm init to bootstrap a Kubernetes control-plane node
  • kubeadm join to bootstrap a Kubernetes worker node and join it to the cluster
  • kubeadm upgrade to upgrade a Kubernetes cluster to a newer version; Perform the upgrade of etcd by default.
• kops
• kube-ps1: change bash prompt export '$(kube-ps1)'$PS1
• kubens: work with namespaces
• k9s: https://k9scli.io/
• krew: a plugin manager, Extend kubectl with plugins.
• The KUbernetes Test TooL (kuttl): https://kuttl.dev/

Provision Tools

• Metal3: to provision bare metal hosts. Metals -> OpenStack Ironic -> PXE
  • The Metal3 baremetal operator watches for BareMetalHost (CRD) objects
  • PXE (Preboot Execution Environment) boot: to install a fresh OS on new or malfunctioning computers. On the client side it requires only a PXE-capable network interface controller (NIC), for operating system booting, installation and deployment in data centers.

Lightweight versions

For local testing or environment with limited resources.

• k3s: not a full k8s, a stripped down / recompiled version; for edge and IoT.
• minikube: run a local k8s cluster.
• kind (Kubernetes in Docker): primarily designed for testing Kubernetes itself; kind uses Weave for CNI.

minikube vs kind vs k3s

• minikube: a node is a VM. spawning a VM that is essentially a single node K8s cluster.
• kind: a node is a docker container. Cluster into Docker containers, faster startup speed compared to spawning VM. Can load local images directly into the cluster instead of setting up a registry.
• k3s: running natively on the host. is a minified version of Kubernetes developed by Rancher Labs. By removing dispensable features (legacy, alpha, non-default, in-tree plugins) and using lightweight components (e.g. sqlite3 instead of etcd3)

kind

> docker exec -it kind-control-plane bash
[email protected]:/# ps auxf

you will see

• kube-apiserver, kube-scheduler, etc
• kind uses containerd as a CRI implementation to deal with Pods (and hence - containers).
• There is no docker command or dockerd inside this container to list the images

lists all the images

$ crictl images

crictl to any CRI runtime is what docker command-line tool to the dockerd daemon.

kind uses podman