Crossplane, Argo CD, and Localstack for local testing

In this article, we are going to explore how we can combine three powerful tools: Crossplane, Argo CD, and Localstack, to create a simple, visually tangible, and cost-effective setup for learning and practicing. The aim of this document is not to provide an in-depth exploration of the technologies used here; instead, it focuses on the interaction among them and the synergy they create.

First of all, let's get our setup in place.

✅ A Git repo

There’s not much to say here, just grab an empty repository to play with. We’ll be using it to store all our manifests.

✅ Kubernetes

As Minikube is one of the most extensively used tools for local clusters, let’s use it. If you’re not familiar with the installation process, you can find it here

✅ Argo CD

We will be using Argo CD to manage all other software components from now on, but before that, we need to install it. The documentation is excellent, a vanilla installation is pretty simple and is more than enough for our current project. Just make sure to skip the core version, we need the UI.

kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

✅ Oh, the repo!

We almost forgot to configure our git repo into Argo CD. Assuming you’re utilizing a private repository for your tests, you can follow the instructions in the UI as outlined here. However, for this article, I’ll be using my public repository:

apiVersion: v1
kind: Secret
metadata:
  name: repo-demo
  namespace: argocd
  labels:
    argocd.argoproj.io/secret-type: repository
stringData:
  type: git
  url: https://github.com/leunamnauj/Crossplane-Argocd-and-localstack-for-local-environments.git

Once your repo is defined, you need to set up an Application to manage all the other applications that will be discovered from the repo (App of Apps).

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: appofapps
  namespace: argocd
  finalizers:
    - resources-finalizer.argocd.argoproj.io
  labels:
    name: appofapps
spec:
  project: default
  source:
    repoURL: https://github.com/leunamnauj/Crossplane-Argocd-and-localstack-for-local-environments.git
    targetRevision: HEAD
    path: .

  destination:
    server: https://kubernetes.default.svc
    namespace: argocd
  syncPolicy:
    automated:
      prune: true 
      selfHeal: true 
      allowEmpty: true
    syncOptions:
    - CreateNamespace=true
  revisionHistoryLimit: 10

Well, Crossplane or what?

Now that we have our cluster up and running with Argo CD in place, we can deploy Localstack and Crossplane using Argo CD.

In the public repo, you can find a couple of Applications, which are organized this way for the sake of the article. However, you can group them more simply if you prefer.

• localstack
• crossplane
• crossplane-providers
• test-env

In this section, we’re going to cheat a bit by leveraging Argo CD Sync Phases and Waves to ensure that components are deployed in a convenient sequence, helping us reduce friction.

Localstack and Crossplane

Pretty simple here, we’re just deploying the official helm chart for both tools

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: localstack
  namespace: argocd
  labels:
    name: localstack
  annotations:
    argocd.argoproj.io/hook: Sync
    argocd.argoproj.io/sync-wave: "1"
    argocd.argoproj.io/hook-delete-policy: HookFailed
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  project: default
  source:
    repoURL: https://localstack.github.io/helm-charts
    targetRevision: "0.6.5"
    chart: localstack
  destination:
    server: https://kubernetes.default.svc
    namespace: localstack
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
      allowEmpty: true
    syncOptions:
    - CreateNamespace=true
  revisionHistoryLimit: 10

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: crossplane
  namespace: argocd
  labels:
    name: crossplane
  annotations:
    argocd.argoproj.io/hook: Sync
    argocd.argoproj.io/sync-wave: "1"
    argocd.argoproj.io/hook-delete-policy: HookFailed
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  project: default
  source:
    repoURL: https://charts.crossplane.io/stable 
    targetRevision: "1.14.5"
    chart: crossplane  
  destination:
    server: https://kubernetes.default.svc
    namespace: crossplane-system
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
      allowEmpty: true
    syncOptions:
    - CreateNamespace=true
  revisionHistoryLimit: 10

crossplane-providers

Here’s something a bit different: we’re deploying Crossplane Providers from manifests placed in a specific path. Our focus is on playing with Crossplane and AWS (through Localstack), so for now, we’re only installing the AWS provider. However, you can add anything else you need later on.

Keep in mind that the provider deployment can take a while, depending on your local setup, it will deploy a lot of CRDs.

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: crossplane-providers
  namespace: argocd
  labels:
    name: crossplane
  annotations:
    argocd.argoproj.io/hook: Sync
    argocd.argoproj.io/sync-wave: "2"
    argocd.argoproj.io/hook-delete-policy: HookFailed
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  project: default
  source:
    repoURL: git@github.com:leunamnauj/Crossplane-Argocd-and-localstack-for-local-environments.git
    targetRevision: HEAD
    path: crossplane-providers
  destination:
    server: https://kubernetes.default.svc
    namespace: crossplane-system
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
      allowEmpty: true
    syncOptions:
    - CreateNamespace=true
  revisionHistoryLimit: 10

ℹ️ Note that Crossplane Providers are installed in a second stage after getting crossplane Application up and running.

The glue

By now, we have Localstack, Crossplane, and its AWS provider running. The next step is to stitch both together, providing us with the experience of interacting directly with AWS.

We have this simple secret that contains a dummy set of credentials

apiVersion: v1
kind: Secret
metadata:
  name: localstack-aws-secret
  namespace: crossplane-system
  annotations:
    argocd.argoproj.io/hook: Sync
    argocd.argoproj.io/sync-wave: "3"
    argocd.argoproj.io/hook-delete-policy: HookFailed
type: Opaque
data:
  creds: W2RlZmF1bHRdCmF3c19hY2Nlc3Nfa2V5X2lkID0gdGVzdAphd3Nfc2VjcmV0X2FjY2Vzc19rZXkgPSB0ZXN0Cg==

And a ProviderConfig

apiVersion: aws.upbound.io/v1beta1
kind: ProviderConfig
metadata:
  name: localstack
  annotations:
    argocd.argoproj.io/hook: Sync
    argocd.argoproj.io/sync-wave: "3"
    argocd.argoproj.io/hook-delete-policy: HookFailed
spec:
  credentials:
    source: Secret
    secretRef:
      name: localstack-aws-secret
      namespace: crossplane-system
      key: creds
  endpoint:
    hostnameImmutable: true
    url:
      type: Static
      static: http://localstack.localstack.svc.cluster.local:4566

As you can see here, it grabs credentials from the previously defined Secret, and in the endpoint section, it points to our Localstack service.

Getting everything in motion!

The last moving part here is our “hello world”, managed by the Application called test-env.
Similar to crossplane-providers, this Application will be searching for Crossplane manifests in a specific path, in this case, /test-env

Here, you’ll find a very simple AWS setup: a VPC, three subnets, a security group, and an EC2 instance.

Now it is time to sync up test-env Application

✨ At this point, everything comes together, and we can see the true potential of this setup. ✨

We can use the Argo CD UI to more easily visualize all the resources deployed by Crossplane. With version control in place, we have the flexibility to roll back changes if needed, along with all the cool features of GitOps.

Conclusion

In summary, our journey through Crossplane, Argo CD, and Localstack showcases a seamless, cost-effective local setup for experimenting with Crossplane and AWS. By leveraging the Argo CD UI and embracing GitOps practices, we highlight the powerful synergy of these tools.