1.1 K8s Vs ECS
Kubernetes is a portable, extensible, open-source platform for managing containerized workloads and services. It is first and foremost a REST API
- Features: (non-exhaustive)
- 🔹 Service discovery and load balancing
- 🔹 Storage orchestration
- 🔹 Automated rollouts and rollbacks
- 🔹 Self-healing
- 🔹 Secret and configuration management
kubectlas a way to interact with the cluster
ECS is a fully managed container orchestration service
- 🔸 Integrated with AWS services
- 🔸 Easy to pick up / Entry level to container world
- 🔸 Ease of use from GUI + Serveless experience with Fargate
aws-clias a way to interact with the cluster
1.2 Main concepts - Terminology
- Terminology used in ECS and K8s world
|Service & Task definition
2.1 Basic Navigation
- 🚀 Setup for Kubernetes
|Tool / Cli
|kubectl (EKS vendored)
|Main Kubernetes Cli used to interact with the cluster
|kubens / kubectx
|(Nice to have) Make it easy to switch clusters or switch between namespaces
|K9s is a terminal based UI to interact with Kubernetes
- Grab EKS configuration
- Switch to
- Switch to the namespace
2.1.2 Navigate Clusters / Deployments / Pods / Specs
- These are a really good resource, no need to bake one more 😃
3.1 Deep Dive - Helm
Helmis a package manager for kubernetes – Helm is your new ecs-cli…
A chart is a collection of files that describe a related set of Kubernetes resources.
A chart is made of Go templates
A single chart might be used to deploy something simple, like a memcached pod, or something complex, like a full web app stack with HTTP servers, databases, caches, and so on.
- Layout of a chart:
Helm charts can be fetched from open source git repositories, here are a few examples:
hydratesa Chart using values contained in
values.yaml. Overrides can be defined allowing you to change the default behavior of the chart.
3.2 Deep Dive - Helmfile
Helmfileis a wrapper on top of helm – Helmfile is what Terragrunt is to Terraform…
Helmis a great tool for templating and sharing K8s manifests… However it can become quite cumbersome to install larger multi-tier applications or groups of applications across multiple Kubernetes clusters.
Give each Helm chart its own
helmfile.yamland include them recursively in a centralized
Separate out environment specific values from general values. Often you’ll find while a Helm chart can take 50 different values, only a few actually differ between your environments.
As well as providing a set of values, either Environment specific or otherwise, you can also read Environment Variables, Execute scripts and read their output (Fetch a secret from AWS SSM)
Store remote state in git/s3/fileshare/etc in much the same way as Terraform does.
- Sample content of an
GitOps is a way to do Kubernetes cluster management and application delivery. It works by using Git as a single source of truth for declarative infrastructure and applications.
With GitOps, the use of software agents can alert on any divergence between Git with what’s running in a cluster, and if there’s a difference, Kubernetes reconcilers automatically update or rollback the cluster depending on the case. With Git at the center of your delivery pipelines, developers use familiar tools to make pull requests to accelerate and simplify both application deployments and operations tasks to Kubernetes.
Read more about GitOps on Weaveworks blogpost
#1 THE ENTIRE SYSTEM DESCRIBED DECLARATIVELY
#2 THE CANONICAL DESIRED SYSTEM STATE VERSIONED IN GIT
#3 APPROVED CHANGES THAT CAN BE AUTOMATICALLY APPLIED TO THE SYSTEM
#4 SOFTWARE AGENTS TO ENSURE CORRECTNESS AND ALERT ON DIVERGENCE.