argocd-poc

Proof of concept Argo CD project

Contents

CD Considerations

Desired Solution Characteristics

• CD tool can be configured entirely from code (declarative configuration).
• CD tool can be deployed in a distributed fashion (e.g. one instance of the tool per Kubernetes cluster)

Why Git Ops

• Git history doubles as audit trail (though you should still implement true auditing of Kubernetes configuration changes)
• Changing the Kubernetes cluster state from within the cluster is safer than granting outside agents permission to change cluster state.

Why Argo CD

Of all the Git-Ops-flavored Kubernetes deployment tools I found in the Continuous Delivery section of the CNCF Landscape, Argo seems to be the the most suitable for building a continuous delivery platform on top of Kubernetes.

• Declarative configuration reduces management overhead at scale.

  Unlike Spinnaker and Jenkins, Argo CD can be configured exclusively using declarative configurations (no clicking & typing required)

• Strong application definition model supports logical grouping of services.

  The unit-of-work is the Application, each of which belongs to a Project, optionally with other Applications.

• Free, self-hosted in Kubernetes

Other tools evaluated

Weave

TODO

Jenkins X

TODO

Spinnaker

TODO

Go CD

• Does not seem suitable for distributed deployments (e.g. one go-cd instance per cluster), instead seems more suited for single "master" instance that deploys to all clusters.
• Declarative pipelines are supported, but written in XML and

Getting Started

Prerequisites

1. Running Kubernetes locally (e.g. with Minikube).

2. Authenticated in kubectl with local cluster:

   $ kubectl config get-clusters
   > NAME
       <cluster-name>

3. An argocd namespace exists in the cluster:

   $ kubectl get namespaces | grep argocd
   > argocd        Active    1d

4. Argo CD is running in the argocd namespace:

   $ kubectl get deployments -n argocd
   NAME                            DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
   argocd-application-controller   1         1         1            1           18d
   argocd-repo-server              1         1         1            1           18d
   argocd-server                   1         1         1            1           18d
   dex-server                      1         1         1            1           18d

Steps for local setup

1. Set the context to the argocd namespace:

   kubectl config set-context $(kubectl config current-context) --namespace=argocd

2. Create the Argo CD custom resources (Projects, Apps) and Project Namespaces defined in main.yaml

   kubectl apply -f main.yaml

https://kustomize.io/