What are the differences in running Minikube with a VM hypervisor (VirtualBox/HVM) vs none?
I am not asking whether or not Minikube can run without a hypervisor. I know that running on '--vm-driver=none' is possible and it runs on the local machine and requires Docker be installed.
I am asking what is the performance differences. There is not a lot of documentation on how '--vm-driver=none' works. I am wondering would running without the VM affect the functionality of Minikube.
This is how I explain it to myself:
driver!=none mode
In this case minikube provisions a new docker-machine (Docker daemon/Docker host) using any supported providers. For instance:
a) local provider = your Windows/Mac local host: it frequently uses VirtualBox as a hypervisor, and creates inside it a VM based on boot2docker image (configurable). In this case k8s bootstraper (kubeadm) creates all Kubernetes components inside this isolated VM. In this setup you have usually two docker daemons, your local one for development (if you installed it prior), and one running inside minikube VM.
b) cloud hosts - not supported by minikube
driver=none mode
In this mode, your local docker host is re-used.
In case no.1 there will be a performance penalty, because each VM generates some overhead, by running several system processes required by VM itself, in addition to those required by k8s components running inside VM. I think driver-mode=none is similar to "kind" version of k8s boostraper, meant for doing CI/integration tests.
Related
Whenever I try to run the Kubernetes cluster from the master’s machine using the below command, my system hangs and gets very slow and I even cant open explorer, or firefox. I have two VM with network configuration NAT and Host-only adapter.
kubeadm init --apiserver-advertise-address=<ip-address-of-kmaster-vm> --pod-network-cidr=192.168.0.0/16
Any help is highly appreciated
As was discussed in comments, the root cause of the issue was not enough resources available in this VirtualMachine.
In Kubeadm documentation, minimal requirements are:
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.
OP's VM had set RAM to 2GB which casued performance issue using different applications.
When RAM on the VM was set to 4GB, Virtual Machine is working perfectly fine.
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 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).
We are running all our applications in Linux VM's and tried Kubernetes cluster on local Mac using minikube and it looks promising.
Interested in setting up Kubernetes on Linux VM's, but:
Is is possible to setup production ready cluster on Linux VM's?
As shown in kubernetes/kubeadm issue 465, setting up a cluster using VMs can be a challenge.
Using Calico will help, since it provides secure network connectivity for containers and virtual machine workloads.
Use Calico 2.6.
I started learning about Docker. But I keep getting confused often, even though I read it in multiple places.
Docker Host and Docker Container.
Docker Engine is the base Engine that handles the containers.
Docker Containers sit on top of Docker engine. This is created by recipes (text file with shell script). It pulls the image from the hub and you can install your stuff on it.
In a typical application environment, you will create separate containers for each piece of the system, Application Server, Database Server, Web Server, etc. (one container for each).
Docker Swarm is a cluster of containers.
Where does the Docker Host come in? Is this another word for Container or another layer where you can keep multiple containers together?
Sorry may be a basic question.
I googled this, but no use.
The docker host is the base traditional OS server where the OS and processes are running in normal (non-container) mode. So the OS and processes you start by actually powering on and booting a server (or VM) are the docker host. The processes that start within containers via docker commands are your containers.
To make an analogy: the docker host is the playground, the docker containers are the kids playing around in there.
Docker Host is the machine that Docker Engine is installed.
Here's a picture, which I find easier to understand than words. I found it here.
The Host is the machine managing the containers and images, where you actually installed Docker.
Docker host is the machine where you installed the docker engine. the docker container can be compared with a simple process running on that same docker host.
The Host is the underlying OS and it's support for app isolation (ie., process and user isolation via "containers." Docker provides an API that defines a method of application packaging and methods for working for the containers.
Host = container implementation
Docker = app packaging and container management