A Comprehensive Guide to Cloud Foundry Services and App Development

Cloud Foundry is an open-source platform-as-a-service (PaaS) that allows developers to build, deploy, and manage applications in the cloud. It provides a flexible and scalable environment for app development.

With Cloud Foundry, developers can use a variety of programming languages, including Java, Python, and Node.js, to build applications. This flexibility is a major advantage of using Cloud Foundry.

One of the key benefits of Cloud Foundry is its ability to automatically scale applications up or down based on demand. This means that developers don't have to worry about provisioning or managing servers, allowing them to focus on writing code.

Cloud Foundry also provides a robust set of services, including database, messaging, and logging, that can be easily integrated into applications.

Cloud Foundry services are a key feature of the platform, allowing applications to access external resources on-demand. This is made possible through the Open Service Broker API, which was launched in December 2016.

External dependencies like databases, messaging systems, and file systems are considered services in Cloud Foundry. Administrators can create a marketplace of these services, which users can provision as needed.

The credentials for these services are stored in environment variables, which are set when an application is pushed to Cloud Foundry. This makes it easy to manage and secure access to external resources.

Cloud Foundry services are integrated with TAS for VMs using a documented API called the Service Broker API, which is versioned independently of the Cloud Controller API.

The component of the service that uses the Service Broker API is called the service broker, previously known as a service gateway, but the term "broker" is now used in conversation and documentation.

Service brokers advertise a catalog of service offerings and service plans, which can vary between services.

To interact with a service, the service broker interprets calls for provision, bind, unbind, and deprovision, each with its own specific function.

A service instance is reserved resource on a service, and its representation can vary by service, such as a single database or a dedicated cluster.

Cloud Foundry allows administrators to create a marketplace of services, from which users can provision these services on-demand.

External dependencies such as databases, messaging systems, file systems and so on are considered services in a platform.

The Open Service Broker API, launched in December 2016, enables applications to access external resources.

This process puts the credentials in an environment variable, making it easy for applications to connect to these services.

Cloud Foundry users can specify the services their applications need when pushing them to the platform, streamlining the deployment process.

By integrating services with Cloud Foundry using APIs, administrators can make them available in the Marketplace for users to provision.

Building an app on Cloud Foundry is a straightforward process that starts by opening the CLI and initiating the buildpack framework. This framework provides the necessary APIs, libraries, and tools to compile and launch the app.

The buildpack lifecycle supports a wide range of languages and frameworks, including Java, Ruby, JavaScript, and Python, among others. Here are some specific examples of languages and frameworks that can be deployed using the buildpack lifecycle:

Managing apps on Cloud Foundry is also a breeze, with features like Garden for managing container apps and orchestration tools like Kubernetes for creating container contents.

Cloud Foundry provides a buildpack framework that structures the app development process, securing APIs, libraries, automation tools, and runtime tools. This framework enables developers to compile and launch their apps efficiently.

To build an app, you'll need to open the CLI for Cloud Foundry, which initiates the process. You can then use the buildpack lifecycle to deploy languages and frameworks such as Java, Ruby, and JavaScript.

Cloud Foundry supports innovation in containers through collaboration with other projects and standards like Open Container Initiative (OCI) and Container Network Interface (CNI). You can deploy applications packaged as Docker images using the Docker lifecycle.

To create a service instance, use the command `cf create-service SERVICE PLAN SERVICE_INSTANCE`. This command allows you to choose the service, plan, and instance name. Service plans offer varying levels of resources or features for the same service.

Here are some common service instance management tasks:

Managing service instances is an essential part of app development and management in Cloud Foundry. By using the CLI, you can easily manage your service instances and ensure your app runs smoothly.

When selecting an App Type, you have the option to choose Cloud Foundry App Instance Type. This type allows you to add Deployments in Provisioning > Code > Deployments.

To create a Cloud Foundry App Instance Type, navigate to Provisioning > Instances and select the Cloud Foundry App Instance Type. From there, you can select NEXT to proceed with the configuration.

A minimal set of options is required to create a Cloud Foundry App Instance Type. These include selecting a Group and PCF Cloud, adding an Instance Name, and selecting a Plan and available options for the Plan.

Here are the minimal options you'll need to select:

Once you've selected these options, you can proceed to the Deployments section, where you'll need to select a Deployment and Version to be deployed. This can be a git repo or a file added in Provisioning > Code > Deployments.

To allow an app to communicate with a service external to TAS for VMs, you need to configure the service to accept connections from your app based on its outbound IP address.

You have two options to add the app's IP address to your allow list in the external service configuration.

Add the entire IP address range for the Diego Cell where the app is deployed to your allow list.

Or, derive the app IP address from its DNS name using a command-line tool such as dig, host, or nslookup.

In this case, add the IP address or range of the app instance to your allow list in the external service configuration.

Building an app on Cloud Foundry starts with launching the designated cloud service and opening the CLI, which initiates the process for building an app.

A buildpack framework provides a structure for compiling and launching the app, securing necessary APIs, libraries, and automation tools.

The application development process generates containers into which the app is deployed, with Garden being the runtime tool for managing container apps in Cloud Foundry.

To manage service instances, you can use the CLI to list marketplace services, create service instances, list service instances, rename a service instance, update a service instance, or delete a service instance.

Here are the key tasks for managing service instances:

Components play a crucial role in app configuration and management.

The configuration file is typically stored in a central location, such as a repository or a cloud storage service.

This file contains all the necessary settings and configurations for the app to function properly.

A configuration management tool can help automate the process of updating and rolling back configurations.

These tools can also provide features like version control and auditing, which can be extremely useful in large-scale deployments.

CLI Management is a powerful tool for managing your app's configuration and services. You can use it to list, create, and manage service instances.

To list marketplace services, simply use the CLI to navigate to the services menu. You can also use the CLI to create new service instances, which is a great way to set up new services for your app.

Here are some key CLI commands for managing service instances:

Renaming a service instance is a straightforward process, but keep in mind that it may break your app's use of the service instance if it depends on the instance name for discovering credentials.

Deleting a service instance is a more serious action, as it will deprovision the service instance and delete all associated data. Make sure you're sure before taking this step!

Database schema migration is a crucial process for any app that relies on a relational database. You must apply schema changes periodically to keep your app running smoothly.

To perform database schema migrations on TAS for VMs-managed services, you need to run a database migration task using the cf CLI tool. This requires installing cf CLI v6.23.0 or later.

The cf CLI tool allows you to run tasks without starting the app. You can push the app with cf push -i 0 and then run the task, which is useful for running database schema migrations.

To run a database schema migration as a task on the app, use the following command: $ cf run-task APP-NAME --command "bin/rails db:migrate" --name TASK-NAME. This command submits the task and runs it successfully.

Here's a step-by-step guide to running a database schema migration:

Arbitrary parameters allow you to pass additional configuration parameters with the provision request.

Some services support this feature, and you can pass these parameters in a valid JSON object. This object can be provided either in-line or in a file.

To use arbitrary parameters, you'll need cf CLI v6.12.1 or later. This ensures you have the necessary tools to pass these parameters correctly.

For a list of supported configuration parameters, you should check the documentation for the particular service offering. This will give you the specific details you need to configure your app correctly.

You can pass these parameters in a file, which can be useful for complex configurations. This way, you can keep your configuration organized and easy to manage.

Updating your app's configuration can be a bit tricky, but it's a crucial part of keeping your app running smoothly.

To update your service plan, you'll need cf CLI v6.7+ and cf-release v192+. This will allow you to effectively upgrade and downgrade your service instance to other service plans.

However, not all services will support this feature, so be sure to check the documentation for the particular service offering to see if it's supported. Some services might support updating between some plans but not others, so you might see a meaningful error if the plan update is not supported.

If a service does support updating, you might be able to pass in additional configuration parameters with the update request. These parameters are usually passed in a valid JSON object containing service-specific configuration parameters.

Binding Apps is a crucial part of making your apps work with other services in your environment. Service instance credentials can be delivered to apps running on TAS for VMs in an environment variable.

You can deliver service credentials to an app in a few different ways, but the most common method is through an environment variable. This is a simple way to give your app the credentials it needs to access other services.

For example, you can use the Delivering Service Credentials to an App method to give your app the credentials it needs to access a Marketplace service. This can be especially helpful if you're working with user-provided service instances.

If you're looking for more information on how to deliver service credentials to an app, be sure to check out the Delivering Service Credentials to an App section for more details.

Service keys are a type of credentials that can be managed manually. They're useful for connecting to a service instance from a local client, an app in another space, or even outside of TAS for VMs.

Not all services support service keys, so you'll need to check if the service you're using allows it.

Credentials managed manually through service keys can be used by clients other than the app in the same space.