I wanna ask something cause I looked for it and couldn't find a clear answer about it anywhere.
Can kubelet be used in windows 10?
Because all I found is usage of kubelet in linux operating systems only.
Also what became my theory is that kubectl is the kubelet version of windows operating system maybe?
I'm really confused about it and couldn't find any clear answer about kubelet in windows and about a comparison between kubelet and kubectl.
I'll be really grateful if someone could explain that to me.
Can kubelet be used in windows 10
Kubelet is one of Node Components and it is part of Kubernetes infrastructure. It is required to proper working of Kubernetes, so it is used in linux/unix, windows and mac.
Also what became my theory is that kubectl is the kubelet version of
windows operating system maybe?
kubelet is an agent that runs on each node in the cluster. It makes sure that containers are running in a pod.
kubectl is a command line interface for running commands against Kubernetes clusters. More information ca be found in documentation.
Please visit Kubernetes Components to get familiar with others Kubernetes components. Here you can find more information about kubelet and here about K8s infrastructure.
I'm really confused about it and couldn't find any clear answer about
kubelet in windows and about a comparison between kubelet and kubectl.
Those both cannot be compared. One is component of infrastructure, second is command line to execute K8s commands.
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To run Kubernetes on Linux/Windows/MacOS you have to have container manager like docker. For Linux there is special package to download, for Windows is Docker for Windows. (Latest versions of Kuberetes also supports Windows Containers, but its different topic.)
To run Kubernetes on Windows, you have to use Minikube. It allows to run a single-node Kubernetes cluster inside a Virtual Machine.
You can find how to configure Kubernetes on Windows in this tutorial.
Hope it help to understand.
You can add windows node to the Kubernetes cluster following the instructions from the official documentation page. As it mentioned in the documentation, you can get all required components using the links from the Kubernetes CHANGELOG-1.15.md page:
Client binaries (kubectl.exe)
Server binaries (no Windows binaries, because windows cannot be master node at this moment)
Node binaries (kube-proxy.exe, kubeadm.exe, kubectl.exe, kubelet.exe)
If you need other version of binaries please find CHANGELOG for specific version on Kubernetes Releases page.
You need to have Docker engine installed on your Windows machine. Here is the manual how to do it for Windows 10.
Related
I know Kind needs Docker, and Minikube needs Virtual Box - but for learning Kubernetes features are they the same?
Thank you.
In terms of learning Kubernetes features, they are the same. You will get the same Kubernetes and Kubernetes resources in both: Pod, Deployments, ConfigMaps, StatefulSets, Secrets, etc. assuming they both have the same Kubernetes version.
Under the hood they very similar too with some implementation differences.
Minikube
Runs K8s in VM (1.7.0 vesion now supports running minikube on Docker)
Support multiple Hypervisors (VirtualBox, Hyperkit, parallels, etc)
You need to ssh to VM to run docker. (minikube ssh)
On the positive side, if you are using VMs, you get the VM isolation which is 'more secure' per se.
Update: It does support running in docker with --driver=docker
Kind
Runs Docker in a VM (Part of the docker desktop installation for Mac, or Windows)
Runs Kubernetes in that "Docker" VM
Supports Hyperkit (Mac) or Hyper-V (Windows) hypervisors.
Has the convenience that you can run the docker client from your Mac or Windows.
You can actually run it in Linux with no need to use a VM (It's a docker native installation on Linux)
It runs all K8s components in a single container.
I am very new to Kubernetes and trying to understand the difference between crio vs dockershim.
I was reading the manual on how to install kubernetes and I see that crio is recommended as a step (see link) Container runtimes/cri-o.
Yet I got more confused when I first tried to launch the pilot and I saw that by default kubernetes is using another cri tool (dockershim) as a default cri tool see link crictl/General usage.
My question is does it worth going through the installation procedure of CRI-O? I have found bugs that on the latest available release for centos7 (1.15.1-2.el7).
I also tested crio-v1.18.0 and the bugs seem to be fixed but on this case it seems that CRI-O can connect to port 10248 when using private repo to pull the pilot images.
Can someone share some light on this? Does it worth it to try to fix those bugs or I am spending too much time on this?
Kubelet (node daemon of Kubernetes) communicates with the container runtime running on the node via Container Runtime Interface. dockershim, as well as crio implement CRI, and act as a connectors between runtime and kubelet, but they refer to different container runtimes.
dockershim is a connector between kubelet and docker
crio is a connector between kubelet and runtime compliant with OCI spec (for example: runc)
There are so many ways of setting up container runtimes. Various kubernetes distributions uses various container runtimes as their defaults (for example, Google Kubernetes Engine installed containerD runtime with containerD-shim when I tried it last time)
I'd say that if you want to start playing with kubernetes and want to have it stable, you should start with docker first (use dockershim as a CRI connector). It's most commonly tested way of using K8S.
I am new to Kubernetes and, trying to setup the master and 2 node architecture using oracle Virtualbox.
OS: Ubuntu 16.04.6 LTS
Docker: 17.03.2-ce
Kubernetes
Client Version: v1.17.4
Server Version: v1.17.4
When I run the join command on the worker node, "kube-controller-manager" and "api-server manager" get disappeared and worker nodes are not getting joined (though join command executed successfully)
I have set the Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=cgroupfs" but still same error.
Please see below snapshot.
Thanks.
The link you have provided is no longer available. While learning and trying out Kubernetes for the first time I highly recommend using the official docs.
There you will find a detailed guide regarding Creating a single control-plane cluster with kubeadm. Note that:
To follow this guide, you need:
One or more machines running a deb/rpm-compatible Linux OS; for example: Ubuntu or CentOS.
2 GiB or more of RAM per machine–any less leaves little room for your apps.
At least 2 CPUs on the machine that you use as a control-plane node.
Full network connectivity among all machines in the cluster. You can use either a public or a private network.
You also need to use a version of kubeadm that can deploy the version
of Kubernetes that you want to use in your new cluster.
Kubernetes’ version and version skew support policy applies to kubeadm
as well as to Kubernetes overall. Check that policy to learn about
what versions of Kubernetes and kubeadm are supported. This page is
written for Kubernetes v1.18.
The kubeadm tool’s overall feature state is General Availability (GA).
Some sub-features are still under active development. The
implementation of creating the cluster may change slightly as the tool
evolves, but the overall implementation should be pretty stable.
If you encounter any issues, first try the troubleshooting steps.
Please let me know if that helped.
I have MiniKube running on my Windows 10 machine. I would like to add an additional node to the cluster.
I have a Centos VM running on a different host that has k8s installed. How to I get the kubectrl join command to run on the VM from the master node running on my Windows machine?
Do I need to install an overlay network on the MiniKube VM? Or is one already installed?
Minikube is officially single-node at the moment. There's a discussion about this limitation at https://github.com/kubernetes/minikube/issues/94 But it seems people have found ways to do it with VirtualBox and there are other ways to run a multi-node cluster locally. Otherwise I'd suggest creating a cluster with one of the cloud providers (e.g. GKE).
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.