Extending 12-Factor app to 15 Factor

 The 12 Factor app

The 12 Factor app is a methodology to build cloud native applications.

https://12factor.net/

As the name suggests, there are 12 factors.

1. Codebase - Maintain a single source of truth. Single repo for same app.

2. Dependencies - Use dependency managers (PIP for python, Nuget for .NET)

3. Config - Use environment variables, do not commit config files in source control

4. Backend services - DB/Cache/Messaging queue should be external services

5. Build-Release-Run - Build stage compiles code, Release stage combine release artifacts, Run stage executes app

6. Processes - Keep application stateless. Save sessions in db/cache

7. Port Bindings - Self contained app should listen on a port.

8. Concurrency - scale by running multiple instances (horizontal scale instead of vertical scale)

9. Disposability - app should start quickly and shut down gracefully.

10. Dev/Prod Parity - Developers should use similar environments in dev and prod

11. Logs - Write logs to stdout instead of files. Use centralized logging system (ELK)

12. Admin processes - DB migrations or maintenance script as separate tasks.

15 Factor

https://developer.ibm.com/articles/15-factor-applications/

The 12 Factor app was created almost a decade ago and cloud technologies have advanced since their original creation. So 3 additional factors were added.

1. API first - If API is not clearly defined, it can be a nightmare in integration.

2. Telemetry - Real time app monitoring (performance, health, key metrics)

3. Authentication-Authorization - Secure cloud native application endpoints with role based access control (RBAC)

Steaming Cloud Foundry Application Logs to ELK - Architecture

 

Filebeat - is the lightweight log shipper for shipping PCF App logs to Logstash

Logstash - is the data processing pipeline. It collects logs from filebeat,  transform logs and send it to Elasticsearch

Elasticsearch - stores the logs in the data nodes in the form of document

Kibana - is the Visualization & Analytics tool to explore and interact with data stored in the Elasticsearch

Kubectl cheatsheet

Here's the quick-reference guide for essential kubectl commands to manage Kubernetes resources, including pods, deployments, services, logs, and troubleshooting tips. This is ideal for both beginners and experienced users.

https://github.com/nidhisht/kubectl-cheatsheet

Monitoring Cloud Foundry with Grafana and Prometheus - Architecture

Monitoring Cloud Foundry with Grafana and Prometheus involves collecting, storing, and visualizing metrics to enhance observability and manage the Cloud Foundry environment effectively.

1. Install and Configure Prometheus

• Set up Prometheus: Deploy Prometheus in Kubernetes, ensuring it has access to the Cloud Foundry metric endpoints.
• Scrape Cloud Foundry Metrics: Use the CF Exporter, Firehose Exporter or Nozzle Exporter to pull metrics from the Cloud Foundry. 

2. Install and Configure Thanos

• Thanos is an aggregator of multiple Prometheus instances

3. Set up Grafana

• Install Grafana on Kubernetes
• Add Prometheus as a Data Source.
• Create dashboards

Grafana FAQ

What is Grafana?

Grafana is open source visualization and alerting tool. It is widely used for interactive dashboards.

What is Prometheus?

Prometheus is a time-series database

What is Thanos?

Thanos is an aggregator of multiple Prometheus instances

What is pull-based model in Prometheus?

Prometheus collects metrics from defined endpoint. It scrapes data  on a configured interval. Architecturally, its a pull-based model rather than push/insert data.

What are the exporters and examples? 

• Blackbox exporters
• Firehose exporters
• cf exporters

Cloud Foundry FAQ

What is Cloud Foundry?

Cloud Foundry is an open source Platform as a Service (PaaS) for hosting stateless applications or microservices.

What is the ideal workload for Cloud Foundry?

12-factor compliant applications are the ideal workloads for running on Cloud Foundry.

Why are developers preferring Kubernetes over Cloud Foundry?

Downloading and configuring Cloud Foundry requires deep infrastructure knowledge (Bosch) and it also requires dedicated infrastructure resources.

When it comes to Kubernetes, it's much easier to consume. It can be configured on a laptop. It is well documented and has a fast learning curve compared to Cloud Foundry.

What is the advantage of Cloud Foundry?

Cloud Foundry is a proven platform/technology, works at scale and hassle free for developers.

It simplifies application deployment through “cf push”, by allowing developers to focus on writing code rather than worry about underline infrastructure.

What are the disadvantages of Cloud Foundry?

Cloud Foundry is designed for 12-factor compliant applications, which are stateless. 

Large corporations have thousands of legacy stateful applications or monoliths and it can be an obstacle for running on Cloud Foundry. 

Kubernetes allows deployment of legacy stateful applications without modifying them.

What is Korifi?

Korifi is the convergence of Cloud Foundry and Kubernetes.

It brings the best of both worlds - Developer experience of Cloud Foundry and power of Kubernetes. Deployed applications run on the underline Kubernetes platform.

https://www.cloudfoundry.org/technology/korifi/

Orchestration and Chorography in Microservices

 Both Orchestration and Choreography are used for Inter Service Communication (ISC) in microservices.

 Example use case - When an order is completed, an invoice should be generated for the order items.

Orchestration:

• One central service controls entire business transactions
• Its ideal for synchronous Inter Service Communication
• Tightly coupled - All the integration logic exists in a single Orchestration service (Often called as God object)
  
• Easier to Rollback business transaction

 

Solution: OrderOrchestration service  to invoke OrderService.CompleteOrder() first, followed by Invoiceservice.GenerateInvoice(). Here entire integration logic present at the OrderOrchestrationService.

 

Choreography 

• Suited for asynchronous Inter Service Communication
• Loosely coupled
• This is implemented using event based architecture (Example: Apache Kafka/Azure Event Hub). Microservices can be configured as both publisher and subscriber of events.
• Harder to Rollback business transactions

 

Solution - Order Microservice can publish an OrderCompleted event to Event Hub. An Invoice Microservice can be subscribed to this event and can generate invoice based on the subscribed events.