application - Kubernetes Helm Chart for Stateless, Namespace-Scoped Applications

Overview of the Application Project

The Application project is designed as a generic Helm chart meant to facilitate the deployment of applications that are stateless. It focuses on applications that require namespace-scoped resources only, meaning it does not utilize Cluster Role Bindings. This project is suitable for applications that don't need privileged containers, don't call the underlying Kubernetes API, or use the etcd database by defining custom resources. The applications can run as deployment, job, or cronjob.

Features

Stateless Application Focus: The Helm chart is tailored for stateless applications. This implies simplicity in deployment and management since there is no need for persistent state management.
Namespace Scoped Resources: The project ensures that only namespace-defined resources are created, keeping things simple and secure by avoiding cluster-wide permissions.
Security Considerations: It avoids the need for privileged containers, making it more secure and robust against security threats.
Flexible Deployment Options: Applications using this chart can run as different types of Kubernetes workloads including deployment, job, or cronjob, offering flexibility in scheduling and resource utilization.

Installation and Management

Installing the Chart

To install this chart, you would use the Helm package manager with the following commands:

helm repo add stakater https://stakater.github.io/stakater-charts
helm repo update
helm install my-application stakater/application --namespace test

This set of commands adds the necessary Helm repository, updates it, and then installs the chart into the test namespace with a release name my-application.

Uninstalling the Chart

When the application needs to be removed, it can be easily uninstalled with:

helm delete --namespace test my-application

This command removes all the associated resources from the specified namespace.

Configuration Parameters

The Application project is configurable through a wide array of parameters, each with defaults that enable quick and flexible setups:

Namespace Assignments: Use namespaceOverride to specify or override the namespace for resources.
Deployment Options: Choose deployment strategies, set annotations, manage containers, and control resource allocation.
Service Management: Configure services to define exposure and accessibility with options like type, ports, and annotations.
Persistence: Includes options for volume persistence, managing storage classes, and templates for persistence.
Ingress and Routes: Complex networking setups can be configured through ingress and openshift routes for managing data flow.

Special Features and Add-ons

Networking and Security: Detailed configurations for network setups including service, ingress, and route configuration.
RBAC (Role-Based Access Control): Enhance security with RBAC options to define specific roles and permissions.
Monitoring and Autoscaling: Includes support for service monitors and autoscalers to ensure high availability and efficient resource usage.
Certificates and Secrets Management: Options are available for certificate management and secret storing using tools like cert-manager and SealedSecrets.

Advanced Features

This Helm chart also supports advanced features such as:

Addon Services: Beyond core configuration, the project includes parameters for integrating with services like ForecastleApp and OpenShift OAuth Proxy for additional functionalities.
Custom Application Monitoring: Use endpoint monitors and service monitors for deep integration with Prometheus or similar monitoring solutions.

Conclusion

The Application project offers a versatile tool for deploying stateless applications in a Kubernetes environment. Its focus on namespace-scoped resources, security, and flexibility in deployment types makes it an ideal solution for a variety of use cases. With highly configurable parameters and additional features for monitoring, networking, and persistence, it aims to simplify Kubernetes application management while keeping robust security standards.