Kubernetes

Kubernetes is tool for orchestrating microservice applications. It's used heavily @FlowUp, therefore, it's useful to have general knowledge of Kubernetes.

Resources

• Interactive Tutorial
• Official Docs

Kubernetes has a great amount of the resources to learn so here is an outline that can be followed provided:

• Introduction

  • Kubernetes Objects
  • Names
  • Namespaces
  • Labels and Selectors
  • Annotations

• Pod as a basic building block

• Services (service discovery)

  • How services work
  • Type of services

• Workloads

  • ReplicaSet
  • Deployment

• Configuration

  • Configmaps
  • Secrets

• Storage

  • Volumes
  • Persistent Volumes

• Workloads (Advanced)

  • StatefulSet
  • DaemonSet

• One-shot workloads

  • Jobs
  • CronJobs

• Advanced techniques

  • RBAC
  • Node Affinity/Anti-affinity - setting Pods' rules for scheduling (selecting node with specific label, make node with label preferred/unpreferred)
  • Pod Affinity/Anti-affinity - setting Pods' rules for scheduling (selecting node where another Pod with specific label runs, ...)

• Ingress (Nice to know, as we don't use Ingress anymore; networking is now managed by Istio)

Best practices

Creating Kubernetes configurations

It's common to use Helm Charts to create and pack Kubernetes configurations. Versatile configurations reusable in every environment can be created by leveraging advantages of the Helm.

Labels

By default, we use labels provided by Helm. These should be extended in Deployment resources with label type which has value app for services and infra for infrastructure components (such as db).

Then, you can restart whole application by running:

kubectl delete pods -l type=app