Building a CD Pipeline Using LKE (Part 1): Get Ready

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Slide deck: Cloud Native Continuous Deployment with GitLab, Helm, and Linode Kubernetes Engine: Get Ready (Slide #10)

Get Ready

The goal of this series is to set up a continuous deployment pipeline for a Kubernetes app on a Kubernetes cluster. This introduction will cover what to expect, the prerequisite knowledge, and the software/components that are required.

Navigate the Series

• Main guide: Building a Continuous Deployment Pipeline Using LKE
• Next section: Part 2: Sample Application

Presentation Text

Here’s a copy of the text contained within this section of the presentation. A link to the source file can be found within each slide of the presentation. Some formatting may have been changed.

Get ready!

• We’re going to set up a whole Continuous Deployment pipeline
• … for Kubernetes apps
• … on a Kubernetes cluster
• Ingredients: cert-manager, GitLab, Helm, Linode DNS, LKE, Traefik

Philosophy

• “Do one thing, do it well”
• … But a CD pipeline is a complex system with interconnected parts!
• GitLab is no exception to that rule
• Let’s have a look at its components!

GitLab components

• GitLab dependencies listed in the GitLab official Helm chart
• External dependencies: cert-manager, grafana, minio, nginx-ingress, postgresql, prometheus, redis, registry, shared-secrets (these dependencies correspond to external charts not created by GitLab)
• Internal dependencies: geo-logcursor, gitaly, gitlab-exporter, gitlab-grafana, gitlab-pages, gitlab-shell, kas, mailroom, migrations, operator, praefect, sidekiq, task-runner, webservice (these dependencies correspond to sub-charts embedded in the GitLab chart)

Philosophy

• Use the GitLab chart to deploy everything that is specific to GitLab
• Deploy cluster-wide components separately (cert-manager, ExternalDNS, Ingress Controller…)

What we’re going to do

• Spin up an LKE cluster
• Run a simple test app
• Install a few extras (the cluster-wide components mentioned earlier)
• Set up GitLab
• Push an app with a CD pipeline to GitLab

What you need to know

• If you just want to follow along and watch…
  • container basics (what’s an image, what’s a container…)
  • Kubernetes basics (what are Deployments, Namespaces, Pods, Services)
• If you want to run this on your own Kubernetes cluster…
  • intermediate Kubernetes concepts (annotations, Ingresses)
  • Helm basic concepts (how to install/upgrade releases; how to set “values”)
  • basic Kubernetes troubleshooting commands (view logs, events)
• There will be a lot of explanations and reminders along the way

What you need to have

If you want to run this on your own…

• A Linode account
• A domain name that you will point to Linode DNS (I got cloudnative.party for $5)
• Local tools to control your Kubernetes cluster:
  • kubectl
  • helm
• Patience, as many operations will require us to wait a few minutes!

Do I really need a Linode account?

• Can I use a local cluster, e.g. with Minikube? It will be very difficult to get valid TLS certs with a local cluster. Also, GitLab needs quite a bit of resources.
• Can I use another Kubernetes provider? You certainly can: Kubernetes is a standard platform! But you’ll have to adjust a few things. (I’ll try my best to tell you what as we go along.)

Why do I need a domain name?

• Because accessing gitlab.cloudnative.party is easier than 102.34.55.67
• Because we’ll need TLS certificates (and it’s very easy to obtain certs with Let’s Encrypt when we have a domain)
• We’ll illustrate automatic DNS configuration with ExternalDNS, too! (Kubernetes will automatically create DNS entries in our domain)

Nice-to-haves

Here are a few tools that I like…

• linode-cli to manage Linode resources from the command line
• stern to comfortably view logs of Kubernetes pods
• k9s to manage Kubernetes resources with that retro BBS look and feel 😎
• kube-ps1 to keep track of which Kubernetes cluster and namespace we’re working on
• kubectx to easily switch between clusters, contexts, and namespaces

Warning

• We’re going to spin up cloud resources
• Remember to shut them down when you’re down!
• In the immortal words of Cloud Economist Corey Quinn : You’re charged for what you forget to turn off.