GitOps Research

Kubernetes Deployments

Pods, Replica Sets, & Deployments in 5 Minutes - Sai Vennam (5 minutes)
Observe
Diff
Act

GitOps vs DevOps

What is GitOps? | GitOps vs DevOps - Sai Vennam (6 Minutes)
Declarative
Version-Controlled
Auto-Reconciled

Flux Overview

Extends K8s with Custom Resources known as Controllers that watch Source Repositories and Auto-Reconcile
Provides GitOps for both Apps and Infra
Has CLI to:
- Bootstrap cluster & repository
- Add Git Sources
- Configure Build and Apply
As K8's custom resource, it's fully declaratively configured using YAML encoded manifests, most of which are generated with the CLI.

Bootstrap a Cluster

Deploys FLux to Cluster
Creates and Configures Infrastructure Github Repo
Commits Flux-System K8s Manifests
Use a CLI to bootstrap a cluster - Geert Baeke - (6 minutes starting at Minute 15)
Get Started with Flux - Tutorial on Fluxcd.io
Bootstrap for Github Organization - Note for how to handle Repos in a Github Org.

brew install fluxcd/tap/flux
flux check --pre
export GITHUB_TOKEN=
export GITHUB_USER=
flux bootstrap github \
  --owner=$GITHUB_USER \
  --repository=my-infra \
  --branch=main \
  --path=app-cluster \
  --personal

Add Source

Generates GitRepository Manifiest that you commit and push to the infrastructure repo created during bootstrap.
Use CLI to add GitRepository - Generates Manifest which you commit

Configure Build and Apply

Generates Kustomization Manifest that you commit and push to the infrastructure repo created during bootstrap.
Use CLI to configure build and apply

Run Migrations with Pre-Deployment Jobs

Kustomization Manifests which are reconciled by Flux can be configured to depend on each other. This makes running pre-deployment jobs like a migration possible.