Demystifying Kubernetes: An introduction for Sysadmins & co.

Federica Teodori

Project Manager

fteodori@suse.com

Miquel Sabaté

Software Engineer

msabate@suse.com

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In the beginning, there was ...

● A developer● An application● Many problems

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/ˌpanəˈsiːə/nouna solution or remedy for all difficulties or diseases.

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Live long and prosper!

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Reality check:

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The “orchestration” problem

● Isn't really anything new ● Not “containers only” problems● Distributed DC. Highly Available applications, load balancers ...● Do we really need to reinvent the wheel yet another time?

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Orchestrate!

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Kubernetes facts:

● Container orchestrator● Open source● Based on rock solid papers● Opinionated solution: has an answer to most questions● Created by Google, now part of the CNCF● Big and active community● Battle-tested with real-world production scenarios

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Concepts: container

● Contains an application and its required environment● Isolated, so load balancing, connectivity, storage, etc. becomes a challenge● The most basic unit from the Kubernetes point of view

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Concepts: pod

● A runnable unit of work● It can be just one container, or multiple related containers● Kubernetes connects pods to the network and the cluster environment.

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Concepts: replication controller

● Manages pods● Makes sure that a specific number of “replicas” are running at the same time

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Concepts: service

● An abstraction that tells to Kubernetes what is your application providing

• This information is also given to all pods and replication controllers.● The IP and port of a service always stays the same

• Managed by Kubernetes

• Integrated service discovery

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Concepts: volume

● A location where containers can access and store data● There are lots of storage backends: local storage, Ceph, etc.

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Concepts: label

● A way to identify anything● Open-ended: the meaning of a label is up to the administrator

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Concepts: namespace

● Grouping mechanism● A degree of isolation for the different parts of your cluster

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Architecture

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Cool, how do I deploy it?

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You simply need to...

● Install certificates on each node.● Install, configure and make sure that the following work together on

multiple nodes:● etcd● All the Kubernetes binaries: kube-proxy, kubelet, kube-controller-manager,

kube-scheduler, kube-apiserver.● flannel● Docker

● That’s a total of 5 extra configuration files for each master, plus 4 for each minion, and another one for etcd.

● Read for quite some hours “Getting started” guides.

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What are we doing?

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SUSE & Kubernetes:

● Main focus: Reduce administration overhead

- SUSE OpenStack Cloud 7 and Magnum

- SUSE Containers as a Service Platform

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Questions ?