Using ConfigMaps and secrets in Kubernetes

A configMap is an API object used to store non-confidential data in key-value pairs. Pods can consume ConfigMaps as environment variables, command-line arguments, or as configuration files in a volume.

Configuring applications on Kubernetes

- Property files packaged with the application.

- Environment variables

- Configuration service

Securing the configuration server with spring security

Refreshing configuration at runtime with Spring Cloud Bus

Managing secrets with spring cloud config

Argo CD is a software agent running in a cluster that automatically pulls the desired state from a source repository and applies it to the cluster whenever the two states diverge. Thats how we implemented continuous deployment.

GitOps is based on four principles according to which a system deployment should be declarative, versioned and immutable, pulled automatically, and continuously reconciled.

The final part of the deployment is the production stage, where the deployment manifests are updated with the newest release version and ultimately deployed.

Deployment can be push-based or pull-based.

GitOps is a set of practices for operating and managing software systems.

The Kustomize approach to configuration customization is based on the concepts of bases and overlays. Overlays are built on top of base manifests and customized via patches.

Defined patches for customizing env variables, Secrets mounted as volumes, CPU and memory resources, ConfigMaps, and Ingress

At the end of the commit stage, a release candidate is delivered to the artifact repository. Next, the acceptance stage deploys the application in a production like environment and runs functional and non-functional tests. If they all succeed, the release candidate is ready for production.

when it comes to continuous delivery, each release candidate should be uniquely identifiable.

Using Git commit hash, we can ensure uniqueness, traceability, and automation. Semantic versioning can be used as the display name communicated to users and customers.

The idea behind continuous delivery is that an application is always in a releasable state.
when the delivery pipeline completes its execution, we will obtain an artifact (a container image) we can use to deploy the application in production.