Introduction to GitOps: Argo CD & Argo Image Updater

GitOps uses Git as the single source of truth to deliver applications and infrastructure

GitOps Principle

Argo CD resides in K8s cluster, which is k8s controller

• Desired state must expressed declaratively

• Desired state must stored in way to enforcing immutability & versioning

• Software agent (controller= argoCD)automatically pulled desired declarative state from source

• Software agent (controller= argoCD) continuously reconciled actual & desired state

Advantages of GitOps

• security

• versioning

• Auto Upgrade

• Auto Healing from any unwanted changes

• Continuous reconcile

Argo CD Installation methods

• manifest yaml

• helm chart

• operator

ArgoCD Architecture

• Application controller: Reconciling the desired state of applications with the actual state

• Repo server: Interactions with Git repositories, fetching and tracking changes

• API server: Acts as the interface for Argo CD, handling requests from users and other components

• Dex: An identity and access management server used to authenticate and authorize users

• Redis: An in-memory data store used for caching and session management

Argo Image Updater

Argo Image Updater resides in K8s cluster, which is k8s controller

• Scans for new images in CI: It continuously checks for new versions of the container images in registry(GitHub) which is used in applications.

• Updates deployments(manifests) in CD: If there's a new version available, it updates the deployment(manifests).

• Argo CD applies changes: Argo CD then applies these changes to your Kubernetes cluster with help of deployment(manifests) as single source of truth.

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