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Understanding odo

Red Hat OpenShift Developer CLI (odo) is a tool for creating applications on OKD and Kubernetes. With odo, you can develop, test, debug, and deploy microservices-based applications on a Kubernetes cluster without having a deep understanding of the platform.

odo follows a create and push workflow. As a user, when you create, the information (or manifest) is stored in a configuration file. When you push, the corresponding resources are created on the Kubernetes cluster. All of this configuration is stored in the Kubernetes API for seamless accessibility and functionality.

odo uses service and link commands to link components and services together. odo achieves this by creating and deploying services based on Kubernetes Operators in the cluster. Services can be created using any of the Operators available on the Operator Hub. After linking a service, odo injects the service configuration into the component. Your application can then use this configuration to communicate with the Operator-backed service.

odo key features

odo is designed to be a developer-friendly interface to Kubernetes, with the ability to:

  • Quickly deploy applications on a Kubernetes cluster by creating a new manifest or using an existing one

  • Use commands to easily create and update the manifest, without the need to understand and maintain Kubernetes configuration files

  • Provide secure access to applications running on a Kubernetes cluster

  • Add and remove additional storage for applications on a Kubernetes cluster

  • Create Operator-backed services and link your application to them

  • Create a link between multiple microservices that are deployed as odo components

  • Remotely debug applications you deployed using odo in your IDE

  • Easily test applications deployed on Kubernetes using odo

odo core concepts

odo abstracts Kubernetes concepts into terminology that is familiar to developers:

Application

A typical application, developed with a cloud-native approach, that is used to perform a particular task.

Examples of applications include online video streaming, online shopping, and hotel reservation systems.

Component

A set of Kubernetes resources that can run and be deployed separately. A cloud-native application is a collection of small, independent, loosely coupled components.

Examples of components include an API back-end, a web interface, and a payment back-end.

Project

A single unit containing your source code, tests, and libraries.

Context

A directory that contains the source code, tests, libraries, and odo config files for a single component.

URL

A mechanism to expose a component for access from outside the cluster.

Storage

Persistent storage in the cluster. It persists the data across restarts and component rebuilds.

Service

An external application that provides additional functionality to a component.

Examples of services include PostgreSQL, MySQL, Redis, and RabbitMQ.

In odo, services are provisioned from the OpenShift Service Catalog and must be enabled within your cluster.

devfile

An open standard for defining containerized development environments that enables developer tools to simplify and accelerate workflows. For more information, see the documentation at https://devfile.io.

You can connect to publicly available devfile registries, or you can install a Secure Registry.

Listing components in odo

odo uses the portable devfile format to describe components and their related URLs, storage, and services. odo can connect to various devfile registries to download devfiles for different languages and frameworks. See the documentation for the odo registry command for more information on how to manage the registries used by odo to retrieve devfile information.

You can list all the devfiles available of the different registries with the odo catalog list components command.

Procedure

  1. Log in to the cluster with odo:

    $ odo login -u developer -p developer

  2. List the available odo components:

    $ odo catalog list components
    Example output
    Odo Devfile Components:
NAME                             DESCRIPTION                                                         REGISTRY
dotnet50                         Stack with .NET 5.0                                                 DefaultDevfileRegistry
dotnet60                         Stack with .NET 6.0                                                 DefaultDevfileRegistry
dotnetcore31                     Stack with .NET Core 3.1                                            DefaultDevfileRegistry
go                               Stack with the latest Go version                                    DefaultDevfileRegistry
java-maven                       Upstream Maven and OpenJDK 11                                       DefaultDevfileRegistry
java-openliberty                 Java application Maven-built stack using the Open Liberty ru...     DefaultDevfileRegistry
java-openliberty-gradle          Java application Gradle-built stack using the Open Liberty r...     DefaultDevfileRegistry
java-quarkus                     Quarkus with Java                                                   DefaultDevfileRegistry
java-springboot                  Spring Boot® using Java                                             DefaultDevfileRegistry
java-vertx                       Upstream Vert.x using Java                                          DefaultDevfileRegistry
java-websphereliberty            Java application Maven-built stack using the WebSphere Liber...     DefaultDevfileRegistry
java-websphereliberty-gradle     Java application Gradle-built stack using the WebSphere Libe...     DefaultDevfileRegistry
java-wildfly                     Upstream WildFly                                                    DefaultDevfileRegistry
java-wildfly-bootable-jar        Java stack with WildFly in bootable Jar mode, OpenJDK 11 and...     DefaultDevfileRegistry
nodejs                           Stack with Node.js 14                                               DefaultDevfileRegistry
nodejs-angular                   Stack with Angular 12                                               DefaultDevfileRegistry
nodejs-nextjs                    Stack with Next.js 11                                               DefaultDevfileRegistry
nodejs-nuxtjs                    Stack with Nuxt.js 2                                                DefaultDevfileRegistry
nodejs-react                     Stack with React 17                                                 DefaultDevfileRegistry
nodejs-svelte                    Stack with Svelte 3                                                 DefaultDevfileRegistry
nodejs-vue                       Stack with Vue 3                                                    DefaultDevfileRegistry
php-laravel                      Stack with Laravel 8                                                DefaultDevfileRegistry
python                           Python Stack with Python 3.7                                        DefaultDevfileRegistry
python-django                    Python3.7 with Django                                               DefaultDevfileRegistry

Telemetry in odo

odo collects information about how it is being used, including metrics on the operating system, RAM, CPU, number of cores, odo version, errors, success/failures, and how long odo commands take to complete.

You can modify your telemetry consent by using the odo preference command:

  • odo preference set ConsentTelemetry true consents to telemetry.

  • odo preference unset ConsentTelemetry disables telemetry.

  • odo preference view shows the current preferences.