While getting familiar with kubernetes I do see tons of tools that should helps me to install kubernetes anywhere, but I don't understand exactly what it does inside, and as a result don't understand how to trouble shoot issues.
Can someone provide me a link with tutorial how to install kubernetes without any tools.
There are two good guides on setting up Kubernetes manually:
Kelsey Hightower's Kubernetes the hard way
Kubernetes guide on getting started from scratch
Kelsey's guide assumes you are using GCP or AWS as the infrstructure, while the Kubernetes guide is a bit more agnostic.
I wouldn't recommend running either of these in production unless you really know what you're doing. However, they are great for learning what is going on under the hood. Even if you just read the guides and don't use them to setup any infrastructure you should gain a better understanding of the pieces that make up a Kubernetes cluster. You can then use one of the helpful setup tools to create your cluster, but now you will understand what it is actually doing and can debug when things go wrong.
For simplicity, you can view k8s as three components
etcd
k8s master, which includes kube-apiserver, controller, scheduler
node, which contains kubelet
You can install etcd and k8s master together in one machine. The procedures are
Install etcd. Download etcd package and run it, which is quite
simple. Remember the port of etcd service, e.g. 2379,4001, or any you
set.
Git clone the kubernetes project from github. Find the executable binary file, e.g. for k8s version 1.3, you can find kube-apiserver, kube-controller-manager and kube-scheduler in src/k8s.io/kubernetes/_output/local/bin/linux/amd64 folder
Then run kube-apiserver, specify the etcd ip and port (e.g. --etcd_servers=http://127.0.0.1:4001)
Run scheduler and controller, specifying the apiserver ip and port(e.g. --master=127.0.0.1:8080). There is no oreder between scheduler and controller
Master is running so far. Make sure these processes run without errors. If etcd exits, apiserver would exit. If apiserver exits, scheduler and controller would exit.
On another machine(virtual preferred, network connected), run kubelet. Kubelet could also be found in previous folder(src/k8s.io/kubernetes/_output/local/bin/linux/amd64), specify apiserver ip and port(e.g. --api-servers=http://10.10.10.19:8080). You may install docker or something else on node, which to prove that you could create a container.
Related
I'm looking for a way to create a live Kubernetes cluster without too much hassle.
I've got a nice HP server, which could run a few VM's with kubernetes on top. The reason for VM's is to isolate this from the host machine. Ideally, the VMs should only run containerd and kubelet and are essentially disposable for node-upgrades.
However, I get lost in what tooling would provide this. minikube? microk8s? k3s? rancher? charmed kubernetes? some existing qemu image? some existing vagrant config? The more managed it is, the better. So far I liked minikube, but it doesn't have "start on reboot" for example, nor the flexibility for node upgrades.
I have tried a lot of tools to train for the CKAD certification. For my usage, the better option for a local cluster was k3s and multipass (for online clusters, I have used Civo). Both are very fast to proceed their respective tasks, so it allows me to create clusters at will and dispose them to be able to work on clean environments.
multipass to create VM quickly
k3s which is nothing else than a lightweight kubernetes
You can find easily some tutorials to automate the creation of clusters for example:
https://betterprogramming.pub/local-k3s-cluster-made-easy-with-multipass-108bf6ce577c
https://medium.com/#yankee.exe/setting-up-multi-node-kubernetes-cluster-with-k3s-and-multipass-d4efed47fed5
https://github.com/superseb/multipass-k3s
I've found a partial answer Difference between Minikube, Kubernetes, Docker Compose, Docker Swarm, etc here, but I still do not completely get it:
In my understanding, kubernetes is a container-orchestration system. However, Minikube looks very similar to me.
Can somebody explain me when you would use minikube versus when you would use minikube, and why?
I think your question should have been "Can somebody explain me when you would use minikube versus when you would use Kubernetes, and why?"
Minikube is a small and easy Kubernetes setup for your Work-PC. You can install and configure a Kubernetes cluster very easily with it. However, for a production environment it is not the best choice. Minikube normally starts a virtual machine on your PC witch will affects the performance of your cluster other than Kubernetes which will run directly with your kernel if you use linux. Furthermore, like Butuzov already answered, it is only one node, not a "real" cluster.
So you use Kubernetes if you are in a production environment where you need distributed systems and workload as well as redundancy and failure safety.
Hope that helps for your understanding.
Edit: Use cases
Minikube:
Developer or DevOps who trying to execute a complex distributed system locally for testing purposes but with deployment over Helm.
Developer or DevOps who tries to create a deployment with Helm locally.
Kubernetes (standalone):
Execute complex distributed system on production systems.
Execute heavy workload (multiple products, distributed systems) in production
minikube - is one node cluster, with a master that can get loads, with a lot of solved and automated issues. designated to test, learn things from kubernetes ecosystem.
kubernetes itself is orchestrator that can come to you as managed service with a lot of problems (pv or loadbalancers) solved or like a lego, or you will tune here and there... well thing we called production ready.
minikube is ok to learn (not always but in 90% of cases) or experiment with tiny loads.
I was looking into the different ways of installing Kubernetes in https://kubernetes.io/docs/setup/pick-right-solution/ but I'm still not sure which one is the best for me.
I have access to a testbed that can provision CENTOS 7.3 VM's through vagrant. This tesbed is basically a bare-metal environment in which the VM's are started up.
I can configure each host individually so I suppose kubeadm (https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/) would be a good way to go?
Brandon,
While the Kubernetes community supports multiple cluster deployment solutions simultaneously (mainly because there is no single best solution that will satisfy all the needs of everyone), Kubeadm (https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/) - is the right solution that we may suggest for you.
Kubeadm is a community-driven, cross-distribution cluster deployment and LCM tool, that is widely recognized as a standard way to deploy Kubernetes clusters with a wide variety of options.
Also, feel free to check the article (https://medium.com/#lizrice/kubernetes-in-vagrant-with-kubeadm-21979ded6c63) that describes the way of Kubernetes cluster deployment with Kubeadm and Vagrant.
I am trying to install kubernetes on Self-hosted production environment running on Ubuntu 16.04. I am not able to find any helpful guide to setup production grade kubernetes master and connect worked nodes to it.
any help is much appreciated.
you can use the kubespray to self Host production environment.
https://github.com/kubernetes-incubator/kubespray
Depends on what you understand by saying "self-host". The most people think it's about deploying kubernetes in the own environment.
If you want to compare different approaches to deploy k8s in a custom environment, refer to this article which covers a bunch of options suitable for that.
If you are interested in how to set up an HA Kubernetes cluster using kubeadm, refer to this article.
However, in kubernetes, there is a different definition of "self-hosted". It means running kubernetes itself as a workload in kubernetes. If you are interested in a real self-hosted approach (on a custom environment), refer to this article
Hope this helps
You can use typhoon which can be used to provision an HA kubernetes cluster.
Here is a sample configuration which I used to bring up my own home cluster.
A few advantages of typhoon are that you have the option of choosing your choice of a cloud provider for provisioning your infrastructure, which is done using terraform and the fact that it gives you upstream k8s is a big plus too.
Internally, it uses bootkube to bring up the temporary control plane, which would consist of
api-server
controller-manager
scheduler
and then when we have the temporary control plane object, we inject the objects to the API server to have our k8s cluster.
Have a look at this kubecon talk given by CoreOS which explains how this is working.
If used on the production system, k8s related services might be down at sometime. Are there any scripts provided that can monitor and restart the services, or i need to develop my scripts and add them to crontab.
I'm guessing you mean things like the scheduler, apiserver etc. If so, they're already monitored by the kubelet running on that node. Kubelet itself is monitored by a babysitter (your init system- eg upstart, systemd etc). Depending on how your provisioned your cluster, the manifest files for those kube-daemons might be under /etc/kubernetes/manifest, those will have health checks.
Yes..How about dashboard (web ui) and kube-dns .. recently we deployed a new cluster and kube-dns was not working, didn't realize until user reported. Looking for a automated test/utility which can validated all the kubernetes required services running properly after new cluster deployment. Looked into prometheus which helps for continuous monitoring but may not help on new cluster setup validation.