What is Kubernetes?

In 2017, Docker adoption was up 40%

amongst Datadog's very large customer base

source: "8 Surprising facts About Real Docker Adoption." Datadog, April 2017

The median number of containers running on a single host is aboput 10.

Source: "The 2017 Dockedr Usage Report." Sysdig, April 17, 2017

How do you manage all these containers running on a single host, and across your whole infrastructure?

Orchestrator Features 

* Provision hosts

* Instantiate containers on a host

* Restart failing containers

* Expose containers as services outside the cluster

* Scale the cluster up or down

Kubernetes(K8s)

* Definition: an open-source platform designed to automate deploying, scaling, and operating application containers

* Goal: to foster an ecosystem of components and tools that relieve the burden of running applications in public and private clouds 

Borg was the predecessor to Kubernetes.

Kubernetes is a platform to schedule and run containers on clusters of virtual machines. It runs on bare metal, virtual machines, private datacenter and public cloud.

No golden handcuffs when migrating to the cloud

Kubernetes and Docker

Kubernetes is a container platform

You can use Docker containers to develop and build applicastions, and then use Kubernetes to run these applications on your infrastructure.

Features Kubernetes

"Kubernetes is an open source project that enables software teams of all sizes, from a small startup to a Fortune 100 comapny, to automate deploying, scaling, and managing applications on a group or cluster of server machines..."

"These applications can include everything from internalfacing web applications like a content management system to marquee web properties like Gamil to big data processing."

- Joe Beda

Multi-Host

Container Scheduling

* Done by the kube-scheduler

* Assigns pods to nodes at runtime

* Checks resources, quality of service, policies, and user specifications before scheduling

Scalability and Availability

* K8s master can be deployed in a highly available configuration

* Multi-region deployments available

Scalability (v 1.8)

* Supports 5,000 node clusters

* 150,000 total pods

* Pods can be horizontally scaled via API

Flexibility and Modularization

* Plug-and-play architecture

* Extend architecture when needed

* Add-ons: network dirvers, service3 discovery, container runtime, visualization, and command

Registration

Seamless nodes register themselves with master

Service Discovery

Automatic detection of services and endpoints via DNS or environment variables.

Persistent Storage

* Much requested and important feature when working with containers

* Podc can use persistent volumes to store data

* Data retained across pod restarts and crashes