kubefed VS cni

The project is similar (in spirit) to kubefed.

What Is KubeFed? KubeFed (Kubernetes Cluster Federation) allows you to use a single Kubernetes cluster to coordinate multiple Kubernetes clusters. It can deploy multiple-cluster applications in different regions and design for disaster recovery. To learn more about KubeFed: https://github.com/kubernetes-sigs/kubefed

There's active work on a standard called kubefed [0] that is being worked on.

> I want a scale-to-zero node-pool in every region, and one kube master api for the world.

Personally, I'd generalize this to: "I want to describe the reliability requirements and configuration for my software and have an automated system solve for where, how many, when, and how to route to it"

I want to have something where I can say "I need to have high availability, lowest latency, and X GB of RAM and Y cores" and have a system automatically schedule me wherever compute is cheapest while also intelligently routing traffic to my servers based on client origins.

[0] - https://github.com/kubernetes-sigs/kubefed

Two of the more common approaches to deploying Kubernetes in hybrid environments are from cloud-to-cloud and cloud to on-prem. Whether this is from using a single control plane like Rancher, Platform9, or Gardener to create multiple clusters that are managed from a single location, or utilizing Kubernetes federation to create a cluster that spans different regions, this model has become a key feature offered by Kubernetes that has helped drive adoption.

This is made possible by the very nature of Kubernetes being a standard portable platform across cloud providers, ability to manage infrastructure as code, ability to setup networking between them whenever needed with the help of multi-cluster service meshes and also due to the ability to orchestrate the deployments using Kubefed and Crossplane.

And the interesting thing about networking in cloud is that it need not be just be limited to the cloud provider within your region but can span across multiple providers across multiple regions as needed and this is where projects like Kubefed, Crossplane definitely does help.

Projects like Kubefed and Crossplane are especially useful here since they help you to manage and orchestrate clusters and the requests you send across different cloud providers even if its going to be across regions.

The CNI is language-agnostic and there are many different plugins available.

Read more about the architecture of CRI-O here. The networking of the pod is set up through CNI, and CRI-O can be used with any CNI plugin.

In generic Kubernetes network policies, there is no action field. The Calico CNI plugin (Kubernetes network plugin that implements the Container Network Interface) provides this functionality, and in particular provides logging even for allowed traffic. And this worked when we tried it in our test clusters and in our own back end.

There is a CNI spec: https://github.com/containernetworking/cni/blob/main/SPEC.md which allows for custom network plugins. Thats how AWS/EKS nodes are able to assign VPC routable IPs to containers running on them.

um, they aren't missing anything (but see below). they are k8s.

so if you want to get the genuine original mainline experience you go to the project's github repo, they have releases, and mention that the detailed changelog has links to the binaries. yeey. (https://github.com/kubernetes/kubernetes/blob/master/CHANGEL... .. the client is the kubectl binary, the server has the control plane components the node binaries have the worker node stuff), you then have the option to set those up according to the documentation (generate TLS certs, specify the IP address range for pods (containers), install dependencies like etcd, and a CNI compatible container network layer provider -- if you have setup overlay networking eg. VXLAN or geneve or something fancy with openvswitch's OVN -- then the reference CNI plugin is probably sufficient)

at the end of this process you'll have the REST API (kube-apiserver) up and running and you can start submitting jobs (that will be persisted into etcd, eventually picked up by the scheduler control loop that calculates what should run where and persists it back to etcd, then a control loop on a particular worker will notice that something new is assigned to it, and it'll do the thing, allocate a pod, call CNI to allocate IP, etc.)

of course if you don't want to do all this by hand you can use a distribution that helps you with setup.

microk8s is a low-memory low-IO k8s distro by Canonical (Ubuntu folks) and they run dqlite (distributed sqlite) instead of etcd (to lower I/O and memory requirements), many people don't like it because it uses snaps

k3s is started by Rancher folks (and mostly still developed by them?),

there's k0s (for bare metal ... I have no idea what that means though), kind (kubernetes in docker), there's also k3d (k3s in docker)

these distributions work by consuming/wrapping the k8s components as go libraries - https://github.com/kubernetes/kubernetes/blob/master/staging...

...

then there's the whole zoo of various k8s plugins/addons/tools for networking (CNI - https://github.com/containernetworking/cni#3rd-party-plugins), storage (CSI - https://kubernetes-csi.github.io/docs/drivers.html), helm for package management, a ton of security-related things that try to spot errors in all this circus ... and so on.

#! /usr/bin/bash # Update apt-get repository and install dependencies apt-get update && apt-get install -y --no-install-recommends dmsetup openssh-client git binutils # Install containerd if it's not present -- prevents breaking docker-ce installations which containerd || apt-get install -y --no-install-recommends containerd # Installing CNI # Current version from https://github.com/containernetworking/cni/releases export CNI_VERSION=v1.0.1 ARCH=$([ "$(uname -m)" = "x86_64" ] && echo amd64 || echo arm64) export ARCH sudo mkdir -p /opt/cni/bin curl -sSL "https://github.com/containernetworking/plugins/releases/download/${CNI_VERSION}/cni-plugins-linux-${ARCH}-${CNI_VERSION}.tgz" | sudo tar -xz -C /opt/cni/bin # Installing Ignite # Get the current version from https://github.com/weaveworks/ignite/releases export VERSION=v0.10.0 GOARCH=$(go env GOARCH 2>/dev/null || echo "amd64") export GOARCH for binary in ignite ignited; do echo "Installing ${binary}..." curl -sfLo ${binary} "https://github.com/weaveworks/ignite/releases/download/${VERSION}/${binary}-${GOARCH}" chmod +x ${binary} sudo mv ${binary} /usr/local/bin done # Check if the installation was successful ignite version

The Container Network Interface (CNI) includes a specification for writing network plugins to configure network interfaces. This allows you to create overlay networks that satisfy Pod-to-Pod communication requirements.

In this lab you will bootstrap three Kubernetes worker nodes. The following components will be installed on each node: runc, container networking plugins, containerd, kubelet, and kube-proxy.

CNI type plugins follow the Container Network Interface spec and are used by the community to create advanced featured plugins. On the other hand, Kubenet utilizes bridge and host-local CNI plugins and has basic features.