DevOps/Kubernetes

Kubernetes (commonly stylized as K8s[3]) is an open-source Container-Orchestration system for automating deployment, autoscaling (based on CPU, memory or custom metrics) and management of containerized applications.[4] It works with a range of container tools, including Docker.

Kubernetes objects, concepts or subsystems:

• Containers, Pods, Volumes
• Persistent Volumes subsystem provides an API for users and administrators that abstracts details of how storage is provided from how it is consumed
• namespaces

Installation

See: Installation and Kubernetes changelog.

Microk8s

MicroK8s single node Kubernetes solution available since December 2018

• Installation:
  • snap install microk8s
  • snap install microk8s --classic

minikube

brew cask install minikube

Kubernetes Log files

Master

• /var/log/kube-apiserver.log - API Server, responsible for serving the API
• /var/log/kube-scheduler.log - Scheduler, responsible for making scheduling decisions
• /var/log/kube-controller-manager.log - Controller that manages replication controllers
• etcd

Worker Nodes

• /var/log/kubelet.log - Kubelet, responsible for running containers on the node
• /var/log/kube-proxy.log - Kube Proxy, responsible for service load balancing

Kubernetes Ports

• Kubernetes API: TCP 6443

See also OpenShift port requeriments: https://docs.openshift.com/container-platform/4.2/installing/installing_bare_metal/installing-bare-metal.html

Activities

• Read Kubernetes changelog: https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG.md
• Read the History of Kubernetes: https://blog.risingstack.com/the-history-of-kubernetes/
• Read wikitech documentation: https://wikitech.wikimedia.org/wiki/Portal:Toolforge/Admin/Kubernetes
• Read Kubernetes Storage documentation: https://kubernetes.io/docs/concepts/storage/ and types of Volumes supported.

Kubernetes Cloud Service Providers

Kubernetes is offered as a service on multiple public clouds, including Amazon Web Services (EKS) (since June 2018 in the US East (N. Virginia) and US West (Oregon) Regions), Microsoft Azure (AKS) since october 2017, DigitalOcean (since May 2018), Google Kubernetes Engine (GKE) in Google Cloud Platform (at least since November 2014), IBM Cloud , Alibaba Cloud , Mail.Ru Cloud Solutions (since May 2018). For a more comprehensive list you can check https://kubernetes.io/docs/setup/pick-right-solution/#hosted-solutions. Most of them if not all requires a valid credit card.

Kubernetes Timeline

• 12/2018 Microk8s released

See also

• microk8s (runs a single-node Kubernetes cluster inside a VM on your laptop, also distributed like snap by Canonical)
• minikube brew cask install minikube
• etcd distributed key/value store used by Kubernetes
• Pod (aggrupation of containers)
• Peloton, a unified resource scheduler developed by Uber
• Nomad container orchestration tool developed by HashiCorp
• Helm package manager for Kubernetes
• Certified Kubernetes Administrator
• Openshift Kubernetes based platform
• Mesos
• Anthos and GCP
• KOPS Kubernetes Operations https://github.com/kubernetes/kops

External Links

• Kubernetes on Reddit