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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