Kubernetes
Kubernetes (commonly stylized as k8s) is an open-source container-orchestration system for automating application deployment, scaling, and management. Developed by Google in Go under the Apache 2.0 license, it was first released on June 7, 2014 reaching 1.0 by July 21, 2015. It works with a range of container tools, including Docker. Many cloud services offer a Kubernetes-based platform or infrastructure as a service (PaaS or IaaS) on which Kubernetes can be deployed as a platform-providing service. Many vendors also provide their own branded Kubernetes distributions.
It has become the standard infrastructure to manage containers in production environments. Docker Swarm would be an alternative but it falls short in features compared with Kubernetes.
These are some of the advantages of using Kubernetes:
- Widely used in production and actively developed.
- Ensure high availability of your services with autohealing and autoscaling.
- Easy, quickly and predictable deployment and promotion of applications.
- Seamless roll out of features.
- Optimize hardware use while guaranteeing resource isolation.
- Easiest way to build multi-cloud and baremetal environments.
Several companies have used Kubernetes to release their own PaaS:
- OpenShift by Red Hat.
- Tectonic by CoreOS.
- Rancher labs by Rancher.
Learn roadmap⚑
K8s is huge, and growing at a pace that most mortals can't stay updated unless you work with it daily.
This is how I learnt, but probably there are better resources now:
- Read containing container chaos kubernetes.
- Test the katacoda lab.
- Install Kubernetes in laptop with minikube.
- Read K8s concepts.
- Then K8s tasks.
- I didn't like the book Getting started with kubernetes
- I'd personally avoid the book Getting started with kubernetes, I didn't like it
¯\(°_o)/¯.
Tools to test⚑
-
Velero: To backup and migrate Kubernetes resources and persistent volumes.
-
Popeye is a utility that scans live Kubernetes cluster and reports potential issues with deployed resources and configurations. It sanitizes your cluster based on what's deployed and not what's sitting on disk. By scanning your cluster, it detects misconfigurations and helps you to ensure that best practices are in place, thus preventing future headaches. It aims at reducing the cognitive overload one faces when operating a Kubernetes cluster in the wild. Furthermore, if your cluster employs a metric-server, it reports potential resources over/under allocations and attempts to warn you should your cluster run out of capacity.
Popeye is a readonly tool, it does not alter any of your Kubernetes resources in any way!
-
Stern allows you to tail multiple pods on Kubernetes and multiple containers within the pod. Each result is color coded for quicker debugging.
The query is a regular expression so the pod name can easily be filtered and you don't need to specify the exact id (for instance omitting the deployment id). If a pod is deleted it gets removed from tail and if a new pod is added it automatically gets tailed.
When a pod contains multiple containers Stern can tail all of them too without having to do this manually for each one. Simply specify the container flag to limit what containers to show. By default all containers are listened to.
-
Fairwinds' Polaris keeps your clusters sailing smoothly. It runs a variety of checks to ensure that Kubernetes pods and controllers are configured using best practices, helping you avoid problems in the future.
-
kube-hunter hunts for security weaknesses in Kubernetes clusters. The tool was developed to increase awareness and visibility for security issues in Kubernetes environments.