Understanding odo

odo is a CLI tool for creating applications on OKD and Kubernetes. With odo, you can write, build, and debug applications on a cluster without the need to administer the cluster itself. Creating deployment configurations, build configurations, service routes and other OKD or Kubernetes elements are all automated by odo.

Existing tools such as oc are operations-focused and require a deep understanding of Kubernetes and OKD concepts. odo abstracts away complex Kubernetes and OKD concepts allowing developers to focus on what is most important to them: code.

Key features

odo is designed to be simple and concise with the following key features:

  • Simple syntax and design centered around concepts familiar to developers, such as projects, applications, and components.

  • Completely client based. No additional server other than OKD is required for deployment.

  • Official support for Node.js and Java components.

  • Partial compatibility with languages and frameworks such as Ruby, Perl, PHP, and Python.

  • Detects changes to local code and deploys it to the cluster automatically, giving instant feedback to validate changes in real time.

  • Lists all the available components and services from the cluster.

Core concepts

Project

A project is your source code, tests, and libraries organized in a separate single unit.

Application

An application is a program designed for end users. An application consists of multiple microservices or components that work individually to build the entire application. Examples of applications: a video game, a media player, a web browser.

Component

A component is a set of Kubernetes resources which host code or data. Each component can be run and deployed separately. Examples of components: Node.js, Perl, PHP, Python, Ruby.

Service

A service is software that your component links to or depends on. Examples of services: MariaDB, Jenkins, MySQL. In odo, services are provisioned from the OpenShift Service Catalog and must be enabled within your cluster.

Officially supported languages and corresponding container images

Table 1. Supported languages, container images, package managers, and platforms
LanguageContainer imagePackage managerPlatform

Node.js

rhscl/nodejs-10-rhel7

NPM

amd64, s390x, ppc64le

rhscl/nodejs-12-rhel7

NPM

amd64, s390x, ppc64le

Java

redhat-openjdk-18/openjdk18-openshift

Maven, Gradle

amd64, s390x, ppc64le

openjdk/openjdk-11-rhel8

Maven, Gradle

amd64, s390x, ppc64le

openjdk/openjdk-11-rhel7

Maven, Gradle

amd64, s390x, ppc64le

Listing available container images

The list of available container images is sourced from the cluster’s internal container registry and external registries associated with the cluster.

To list the available components and associated container images for your cluster:

  1. Log in to the cluster with odo:

    1. $ odo login -u developer -p developer

  2. List the available odo supported and unsupported components and corresponding container images:

    1. $ odo catalog list components

    Example output

    1. Odo Devfile Components:
    2. NAME                 DESCRIPTION                            REGISTRY
    3. java-maven           Upstream Maven and OpenJDK 11          DefaultDevfileRegistry
    4. java-openliberty     Open Liberty microservice in Java      DefaultDevfileRegistry
    5. java-quarkus         Upstream Quarkus with Java+GraalVM     DefaultDevfileRegistry
    6. java-springboot      Spring Boot® using Java                DefaultDevfileRegistry
    7. nodejs               Stack with NodeJS 12                   DefaultDevfileRegistry
    9. Odo OpenShift Components:
    10. NAME        PROJECT       TAGS                                                                           SUPPORTED
    11. java        openshift     11,8,latest                                                                    YES
    12. dotnet      openshift     2.1,3.1,latest                                                                 NO
    13. golang      openshift     1.13.4-ubi7,1.13.4-ubi8,latest                                                 NO
    14. httpd       openshift     2.4-el7,2.4-el8,latest                                                         NO
    15. nginx       openshift     1.14-el7,1.14-el8,1.16-el7,1.16-el8,latest                                     NO
    16. nodejs      openshift     10-ubi7,10-ubi8,12-ubi7,12-ubi8,latest                                         NO
    17. perl        openshift     5.26-el7,5.26-ubi8,5.30-el7,latest                                             NO
    18. php         openshift     7.2-ubi7,7.2-ubi8,7.3-ubi7,7.3-ubi8,latest                                     NO
    19. python      openshift     2.7-ubi7,2.7-ubi8,3.6-ubi7,3.6-ubi8,3.8-ubi7,3.8-ubi8,latest                   NO
    20. ruby        openshift     2.5-ubi7,2.5-ubi8,2.6-ubi7,2.6-ubi8,2.7-ubi7,latest                            NO
    21. wildfly     openshift     10.0,10.1,11.0,12.0,13.0,14.0,15.0,16.0,17.0,18.0,19.0,20.0,8.1,9.0,latest     NO

    The TAGS column represents the available image versions, for example, 10 represents the rhoar-nodejs/nodejs-10 container image. To learn more about CLI commands, go to odo CLI reference.