launchk8

About

• Learning Kubernetes from the true kubernetes course
• Custom examples demonstrating the learnings
  • Fork Bomb Horizontal Scaling
  • Queued Parallel Jobs by creating and deleting a bunch of folders
• A project to run GitHub Actions, build Docker images and deploy images into pods
• Two GitHub builds, one for a MUD game, the other for a TUI app
• Kubernetes deployment for the the MUD game
• Everything is in workbook.sh and runbook.sh for learnings and reproducibility

Highlights

^ Docker in docker (dind) building an image. Then deploying image to a repository in the cluster.

^ Playing my friends mud game, deployed infra & container. Accessed from pod with open ports.

Approach

• Workbooks - workbooks.sh show the journey I took to make the product. Including, some of the mistakes I made along the way.
• Runbooks - runbook.sh are the simplified set of commands to recreate the project from scratch. The commands are to be run individually and not in a batch.

Learnings

Workbook Includes lecture notes and commands to run examples

• Pods
  • Names, Labels, Querying with labels
  • Namespaces, creating with namespaces
• Controllers
  • ReplicaSet
    • Scaling up, Naked pods
  • Deployment
    • Rollouts, Diagnostics & Revisions
  • Daemon Set
• Services
  • Service
    • Expose, Service Discovery, NodePort
  • LoadBalancer
    • No selector, Session affinity
• Additional Kubectl commands
  • patch, apply, attach, copy, port-forward, top
• Liveness Probes
  • Handlers, Probe types
  • Lifecycle
    • PostStart, PreStop
    • handlers
• Volumes
  • Empty Dir
    • types, hostPath, dynamic volumes
  • Persistent Volumes
    • lifecycle, access modes, storage classes
  • Persistent Volume Claim
  • Pod Claim
  • Local Storage
• Jobs
  • Fixed
    • parallel / nonparallel
    • fixed completions
    • restart policies
  • Queued
    • termination, scaling
  • CronJobs
    • schedule, handle overruns
• Stateful Pods
  • DNS, ClusterIP, Rescheduling Order, number names
• Secrets
  • Assigned Secret
  • files, certificates or generic values
  • access by volume, env vars
  • Config Maps
• Ingress
  • for http, tls termination, name-based virtual hosting
• NetworkPolicy
  • egress, ingress, rules w/ ip tables
• Security Context
  • read only root, kernel capabilities, runAsUser
• Resource Limits
  • unit types, upper/lower bounds, node requests
  • quality of service types
  • limits & requests
  • pod eviction
• Horizontal AutoScaling
  • object, metrics, controllers, custom metrics
• Affinity
  • Pod
  • Node
  • node, pod & and anti
  • weight, topology
• Taints & Tolerances
  • types of effects
  • add labels to nodes

DevOps Project

A mini project which creates a GitHub build isolated inside of Kubernetes.

Architecture

• Docker in Docker
  • builds docker images
  • publishes them to the repo
• GitHub agent
  • runs workflow commands triggered by GitHub
  • can trigger builds on docker
  • can make deployments to the node
• Registry
  • Stores the built images
  • Accessible by the node to deploy

TODO

• Improve resource allocation
• Add liveliness
• Central logging would be good