Deploy software on Kubernetes with argoCD

date:

tags: containers kubernetes argoCD

categories: Containers Kubernetes

updated: 2024-02-01

Once you have a kubernetes environment running, a tool like argoCD can help you manage applications that you want to deploy on kubernetes. ArgoCD expects a pattern of using git repositories as the source of truth for defining the state of your applications. You can communicate with the kubernetes API by submitting requests in YAML or JSON format. I am going to be focusing on managing applications with helm charts.

ArgoCD automates the deployment of applications in kubernetes. Application deployments can track updates to git branches, tags, or pinned to a specific version of manifests at a specific commit.

ArgoCD installs to a kubernetes cluster and continuously monitors running applications and compares with the state of the configured git repositories.

Try argoCD

You can try argoCD in any kubernetes environment including dev environments such as minikube. If you are not familiar with kubernetes, check out a previous post about getting started with kubernetes.

Quick install

To install argo, create the specified namespace and apply the latest version of the argoCD deployment manifest.

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

Production install

Outside of a dev environment, you want to manage the state of argoCD application in a declarative manner similar to how argoCD is managing the state of your applications.

ArgoCD will be installed using a helm chart.

You will need access to your own kubernetes cluster and the helm CLI installed on your machine.

Installing helm

Helm is available on package manager for several operating systems. For the latest release, you can also download pre-compiled binaries on the GitHub release page:

https://github.com/helm/helm/releases

Install on macOS

You can install helm using brew on macOS:

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brew install helm

Install on windows

You can install helm on windows using the Chocolatey package manager. If you are not familiar with Chocolatey, check out a previous post

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choco install kubernetes-helm

Install on fedora linux

On Fedora, you can install from the fedora repositories using the dnf package manager:

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sudo dnf install helm

Install argoCD helm chart

Once you have the helm binary installed, add the argoCD helm repository and install the argoCD chart:

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helm repo add argo https://argoproj.github.io/argo-helm

Then:

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helm install my-release argo/argo-cd

You can customize the deployment with a values.yaml file. For example to deploy in a HA configuration:

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redis-ha:
  enabled: true

controller:
  replicas: 1

server:
  autoscaling:
    enabled: true
    minReplicas: 2

repoServer:
  autoscaling:
    enabled: true
    minReplicas: 2

applicationSet:
  replicas: 2

To install with the values file:

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helm install my-release -f values.yaml argo/argo-cd

Deploying a helm application with argocd

Here is an example of how to manage an application deployed using a helm chart with argoCD. You can store this in a git repository and apply it to a cluster with argoCD installed.

argo-example-helm.yaml

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---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: longhorn
  namespace: argocd
spec:
  destination:
    namespace: longhorn-system 
    server: https://kubernetes.default.svc
  project: default
  source:
    chart: longhorn 
    repoURL: https://charts.longhorn.io
    targetRevision: 1.5.1
    helm:
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true

This manifest uses the api added by argoCD to deploy a argo Application object in the argocd namespace. The example above will install an application that will provision Persistent Volume objects using partitions on the kubernetes worker nodes.

Deploy the application to your cluster using kubectl if you do not have this tool, check out a previous post to find out where to get it.

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kubectl apply -f argo-example-helm.yaml

You can see resources deployed in your cluster:

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kubectl get all -n argocd

See argo applications by searching for the custom resource:

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kubectl get applications -n argocd

Once argoCD has completed deploying an application the previous command should show the name of the application along with the sync and health status:

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NAME         SYNC STATUS   HEALTH STATUS
longhorn     Synced        Healthy

Next steps

After you have deployed argoCD, you can access argo using the CLI or the web UI.

There is an initial admin token created to interact with argoCD:

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kubectl get secrets -n argocd

You are looking for argocd-initial-admin-secret.

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kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d; echo

This token can be used with the built-in admin user to access the UI or CLI.

Argo UI

You can access the UI by port forwarding the connecting with kubectl

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kubectl get services -n argocd

You are looking for the service argocd-server.

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kubectl port-forward service/argocd-server -n argocd 4443:443

That will make the argoCD UI available on your localhost port 4443.

Access the UI in the browser via https://localhost:4443 and accept the warning about a self-signed certificate. The proxy will be active until you press CTRL + C to exit the process in your terminal.

Clean up

You can remove argoCD from your kubernetes cluster by removing the argoCD namespace.

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kubectl delete namespace argocd
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