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Chapter 3. Creating applications

3.1. Creating applications using the Developer perspective

The Developer perspective in the web console provides you the following options from the +Add view to create applications and associated services and deploy them on OpenShift Container Platform:

  • Getting started resources: Use these resources to help you get started with Developer Console. You can choose to hide the header using the Options menu kebab .

    • Creating applications using samples: Use existing code samples to get started with creating applications on the OpenShift Container Platform.
    • Build with guided documentation: Follow the guided documentation to build applications and familiarize yourself with key concepts and terminologies.
    • Explore new developer features: Explore the new features and resources within the Developer perspective.

  • Developer catalog: Explore the Developer Catalog to select the required applications, services, or source to image builders, and then add it to your project.

    • All Services: Browse the catalog to discover services across OpenShift Container Platform.
    • Database: Select the required database service and add it to your application.
    • Operator Backed: Select and deploy the required Operator-managed service.
    • Helm chart: Select the required Helm chart to simplify deployment of applications and services.
    • Devfile: Select a devfile from the Devfile registry to declaratively define a development environment.

    • Event Source: Select an event source to register interest in a class of events from a particular system.

      Note

      The Managed services option is also available if the RHOAS Operator is installed.

  • Git repository: Import an existing codebase, Devfile, or Dockerfile from your Git repository using the From Git, From Devfile, or From Dockerfile options respectively, to build and deploy an application on OpenShift Container Platform.
  • Container images: Use existing images from an image stream or registry to deploy it on to the OpenShift Container Platform.
  • Pipelines: Use Tekton pipeline to create CI/CD pipelines for your software delivery process on the OpenShift Container Platform.

  • Serverless: Explore the Serverless options to create, build, and deploy stateless and serverless applications on the OpenShift Container Platform.

    • Channel: Create a Knative channel to create an event forwarding and persistence layer with in-memory and reliable implementations.
  • Samples: Explore the available sample applications to create, build, and deploy an application quickly.
  • Quick Starts: Explore the quick start options to create, import, and run applications with step-by-step instructions and tasks.

  • From Local Machine: Explore the From Local Machine tile to import or upload files on your local machine for building and deploying applications easily.

    • Import YAML: Upload a YAML file to create and define resources for building and deploying applications.
    • Upload JAR file: Upload a JAR file to build and deploy Java applications.

Note that certain options, such as Pipelines, Event Source, and Import Virtual Machines, are displayed only when the OpenShift Pipelines Operator, OpenShift Serverless Operator, and OpenShift Virtualization Operator are installed, respectively.

3.1.1. Prerequisites

To create applications using the Developer perspective ensure that:

To create serverless applications, in addition to the preceding prerequisites, ensure that:

3.1.2. Creating Sample applications

You can use the sample applications in the +Add flow of the Developer perspective to create, build, and deploy applications quickly.

Prerequisites

  • You have logged in to the OpenShift Container Platform web console and are in the Developer perspective.

Procedure

  1. In the +Add view, click on the Samples tile to see the Samples page.
  2. On the Samples page, select one of the available sample applications to see the Create Sample Application form.

  3. In the Create Sample Application Form:

    • In the Name field, the deployment name is displayed by default. You can modify this name as required.
    • In the Builder Image Version, a builder image is selected by default. You can modify this image version by using the Builder Image Version drop-down list.
    • A sample Git repository URL is added by default.
  4. Click Create to create the sample application. The build status of the sample application is displayed on the Topology view. After the sample application is created, you can see the deployment added to the application.

3.1.3. Creating applications using Quick Starts

The Quick Starts page shows you how to create, import, and run applications on OpenShift Container Platform, with step-by-step instructions and tasks.

Prerequisites

  • You have logged in to the OpenShift Container Platform web console and are in the Developer perspective.

Procedure

  1. In the +Add view, click the View all quick starts link to view the Quick Starts page.
  2. In the Quick Starts page, click the tile for the quick start that you want to use.
  3. Click Start to begin the quick start.

3.1.4. Importing a codebase from Git to create an application

You can use the Developer perspective to create, build, and deploy an application on OpenShift Container Platform using an existing codebase in GitHub.

The following procedure walks you through the From Git option in the Developer perspective to create an application.

Procedure

  1. In the +Add view, click From Git in the Git Repository tile to see the Import from git form.
  2. In the Git section, enter the Git repository URL for the codebase you want to use to create an application. For example, enter the URL of this sample Node.js application https://github.com/sclorg/nodejs-ex. The URL is then validated.

  3. Optional: You can click Show Advanced Git Options to add details such as:

    • Git Reference to point to code in a specific branch, tag, or commit to be used to build the application.
    • Context Dir to specify the subdirectory for the application source code you want to use to build the application.
    • Source Secret to create a Secret Name with credentials for pulling your source code from a private repository.

  4. Optional: You can import a devfile, a Dockerfile, or a builder image through your Git repository to further customize your deployment.

    • If your Git repository contains a devfile, a Dockerfile, or a builder image, it is automatically detected and populated on the respective path fields. If a devfile, a Dockerfile, and a builder image are detected in the same repository, the devfile is selected by default.
    • To edit the file import type and select a different strategy, click Edit import strategy option.
    • If multiple devfiles, Dockerfiles, or builder images are detected, to import a specific devfile, Dockerfile, or a builder image, specify the respective paths relative to the context directory.

  5. After the Git URL is validated, the recommended builder image is selected and marked with a star. If the builder image is not auto-detected, select a builder image. For the https://github.com/sclorg/nodejs-ex Git URL, by default the Node.js builder image is selected.

    1. Optional: Use the Builder Image Version drop-down to specify a version.
    2. Optional: Use the Edit import strategy to select a different strategy.
    3. Optional: For the Node.js builder image, use the Run command field to override the command to run the application.

  6. In the General section:

    1. In the Application field, enter a unique name for the application grouping, for example, myapp. Ensure that the application name is unique in a namespace.

    2. The Name field to identify the resources created for this application is automatically populated based on the Git repository URL if there are no existing applications. If there are existing applications, you can choose to deploy the component within an existing application, create a new application, or keep the component unassigned.

      Note

      The resource name must be unique in a namespace. Modify the resource name if you get an error.

  7. In the Resources section, select:

    • Deployment, to create an application in plain Kubernetes style.
    • Deployment Config, to create an OpenShift Container Platform style application.

    • Serverless Deployment, to create a Knative service.

      Note

      The Serverless Deployment option is displayed in the Import from git form only if the OpenShift Serverless Operator is installed in your cluster. For further details, refer to the OpenShift Serverless documentation.

  8. In the Pipelines section, select Add Pipeline, and then click Show Pipeline Visualization to see the pipeline for the application. A default pipeline is selected, but you can choose the pipeline you want from the list of available pipelines for the application.

  9. Optional: In the Advanced Options section, the Target port and the Create a route to the application is selected by default so that you can access your application using a publicly available URL.

    If your application does not expose its data on the default public port, 80, clear the check box, and set the target port number you want to expose.

  10. Optional: You can use the following advanced options to further customize your application:
Routing

By clicking the Routing link, you can perform the following actions:

  • Customize the hostname for the route.
  • Specify the path the router watches.
  • Select the target port for the traffic from the drop-down list.

  • Secure your route by selecting the Secure Route check box. Select the required TLS termination type and set a policy for insecure traffic from the respective drop-down lists.

    Note

    For serverless applications, the Knative service manages all the routing options above. However, you can customize the target port for traffic, if required. If the target port is not specified, the default port of 8080 is used.

Domain mapping

If you are creating a Serverless Deployment, you can add a custom domain mapping to the Knative service during creation.

  • In the Advanced options section, click Show advanced Routing options.

    • If the domain mapping CR that you want to map to the service already exists, you can select it from the Domain mapping drop-down menu.
    • If you want to create a new domain mapping CR, type the domain name into the box, and select the Create option. For example, if you type in example.com, the Create option is Create "example.com".
Health Checks

Click the Health Checks link to add Readiness, Liveness, and Startup probes to your application. All the probes have prepopulated default data; you can add the probes with the default data or customize it as required.

To customize the health probes:

  • Click Add Readiness Probe, if required, modify the parameters to check if the container is ready to handle requests, and select the check mark to add the probe.
  • Click Add Liveness Probe, if required, modify the parameters to check if a container is still running, and select the check mark to add the probe.

  • Click Add Startup Probe, if required, modify the parameters to check if the application within the container has started, and select the check mark to add the probe.

    For each of the probes, you can specify the request type - HTTP GET, Container Command, or TCP Socket, from the drop-down list. The form changes as per the selected request type. You can then modify the default values for the other parameters, such as the success and failure thresholds for the probe, number of seconds before performing the first probe after the container starts, frequency of the probe, and the timeout value.

Build Configuration and Deployment

Click the Build Configuration and Deployment links to see the respective configuration options. Some options are selected by default; you can customize them further by adding the necessary triggers and environment variables.

For serverless applications, the Deployment option is not displayed as the Knative configuration resource maintains the desired state for your deployment instead of a DeploymentConfig resource.

Scaling

Click the Scaling link to define the number of pods or instances of the application you want to deploy initially.

If you are creating a serverless deployment, you can also configure the following settings:

  • Min Pods determines the lower limit for the number of pods that must be running at any given time for a Knative service. This is also known as the minScale setting.
  • Max Pods determines the upper limit for the number of pods that can be running at any given time for a Knative service. This is also known as the maxScale setting.
  • Concurrency target determines the number of concurrent requests desired for each instance of the application at a given time.
  • Concurrency limit determines the limit for the number of concurrent requests allowed for each instance of the application at a given time.
  • Concurrency utilization determines the percentage of the concurrent requests limit that must be met before Knative scales up additional pods to handle additional traffic.
  • Autoscale window defines the time window over which metrics are averaged to provide input for scaling decisions when the autoscaler is not in panic mode. A service is scaled-to-zero if no requests are received during this window. The default duration for the autoscale window is 60s. This is also known as the stable window.
Resource Limit
Click the Resource Limit link to set the amount of CPU and Memory resources a container is guaranteed or allowed to use when running.
Labels

Click the Labels link to add custom labels to your application.

  1. Click Create to create the application and a success notification is displayed. You can see the build status of the application in the Topology view.

3.1.5. Deploying a Java application by uploading a JAR file

You can use the web console Developer perspective to upload a JAR file by using the following options:

  • Navigate to the +Add view of the Developer perspective, and click Upload JAR file in the From Local Machine tile. Browse and select your JAR file, or drag a JAR file to deploy your application.
  • Navigate to the Topology view and use the Upload JAR file option, or drag a JAR file to deploy your application.
  • Use the in-context menu in the Topology view, and then use the Upload JAR file option to upload your JAR file to deploy your application.

Prerequisites

  • The Cluster Samples Operator must be installed by a cluster administrator.
  • You have access to the OpenShift Container Platform web console and are in the Developer perspective.

Procedure

  1. In the Topology view, right-click anywhere to view the Add to Project menu.
  2. Hover over the Add to Project menu to see the menu options, and then select the Upload JAR file option to see the Upload JAR file form. Alternatively, you can drag the JAR file into the Topology view.
  3. In the JAR file field, browse for the required JAR file on your local machine and upload it. Alternatively, you can drag the JAR file on to the field. A toast alert is displayed at the top right if an incompatible file type is dragged into the Topology view. A field error is displayed if an incompatible file type is dropped on the field in the upload form.
  4. The runtime icon and builder image are selected by default. If a builder image is not auto-detected, select a builder image. If required, you can change the version using the Builder Image Version drop-down list.
  5. Optional: In the Application Name field, enter a unique name for your application to use for resource labelling.
  6. In the Name field, enter a unique component name to name the associated resources.
  7. In the Resources field, choose the resource type for your application.
  8. In the Advanced options menu, click Create a Route to the Application to configure a public URL for your deployed application.
  9. Click Create to deploy the application. A toast notification is shown to notify you that the JAR file is being uploaded. The toast notification also includes a link to view the build logs.
Note

If you attempt to close the browser tab while the build is running, a web alert is displayed.

After the JAR file is uploaded and the application is deployed, you can view the application in the Topology view.

3.1.6. Using the Devfile registry to access devfiles

You can use the devfiles in the +Add flow of the Developer perspective to create an application. The +Add flow provides a complete integration with the devfile community registry. A devfile is a portable YAML file that describes your development environment without needing to configure it from scratch. Using the Devfile registry, you can use a pre-configured devfile to create an application.

Procedure

  1. Navigate to Developer Perspective +Add Developer Catalog All Services. A list of all the available services in the Developer Catalog is displayed.
  2. Under All Services, select Devfiles to browse for devfiles that support a particular language or framework. Alternatively, you can use the keyword filter to search for a particular devfile using their name, tag, or description.
  3. Click the devfile you want to use to create an application. The devfile tile displays the details of the devfile, including the name, description, provider, and the documentation of the devfile.
  4. Click Create to create an application and view the application in the Topology view.

3.1.7. Using the Developer Catalog to add services or components to your application

You use the Developer Catalog to deploy applications and services based on Operator backed services such as Databases, Builder Images, and Helm Charts. The Developer Catalog contains a collection of application components, services, event sources, or source-to-image builders that you can add to your project. Cluster administrators can customize the content made available in the catalog.

Procedure

  1. In the Developer perspective, navigate to the +Add view and from the Developer Catalog tile, click All Services to view all the available services in the Developer Catalog.
  2. Under All Services, select the kind of service or the component you need to add to your project. For this example, select Databases to list all the database services and then click MariaDB to see the details for the service.

  3. Click Instantiate Template to see an automatically populated template with details for the MariaDB service, and then click Create to create and view the MariaDB service in the Topology view.

    Figure 3.1. MariaDB in Topology

    odc devcatalog toplogy

3.1.8. Additional resources

3.2. Creating applications from installed Operators

Operators are a method of packaging, deploying, and managing a Kubernetes application. You can create applications on OpenShift Container Platform using Operators that have been installed by a cluster administrator.

This guide walks developers through an example of creating applications from an installed Operator using the OpenShift Container Platform web console.

Additional resources

  • See the Operators guide for more on how Operators work and how the Operator Lifecycle Manager is integrated in OpenShift Container Platform.

3.2.1. Creating an etcd cluster using an Operator

This procedure walks through creating a new etcd cluster using the etcd Operator, managed by Operator Lifecycle Manager (OLM).

Prerequisites

  • Access to an OpenShift Container Platform 4.10 cluster.
  • The etcd Operator already installed cluster-wide by an administrator.

Procedure

  1. Create a new project in the OpenShift Container Platform web console for this procedure. This example uses a project called my-etcd.

  2. Navigate to the Operators Installed Operators page. The Operators that have been installed to the cluster by the cluster administrator and are available for use are shown here as a list of cluster service versions (CSVs). CSVs are used to launch and manage the software provided by the Operator.

    Tip

    You can get this list from the CLI using: 

    $ oc get csv

  3. On the Installed Operators page, click the etcd Operator to view more details and available actions.

    As shown under Provided APIs, this Operator makes available three new resource types, including one for an etcd Cluster (the EtcdCluster resource). These objects work similar to the built-in native Kubernetes ones, such as Deployment or ReplicaSet, but contain logic specific to managing etcd.

  4. Create a new etcd cluster:

    1. In the etcd Cluster API box, click Create instance.
    2. The next screen allows you to make any modifications to the minimal starting template of an EtcdCluster object, such as the size of the cluster. For now, click Create to finalize. This triggers the Operator to start up the pods, services, and other components of the new etcd cluster.

  5. Click on the example etcd cluster, then click the Resources tab to see that your project now contains a number of resources created and configured automatically by the Operator.

    Verify that a Kubernetes service has been created that allows you to access the database from other pods in your project.

  6. All users with the edit role in a given project can create, manage, and delete application instances (an etcd cluster, in this example) managed by Operators that have already been created in the project, in a self-service manner, just like a cloud service. If you want to enable additional users with this ability, project administrators can add the role using the following command: 

    $ oc policy add-role-to-user edit <user> -n <target_project>

You now have an etcd cluster that will react to failures and rebalance data as pods become unhealthy or are migrated between nodes in the cluster. Most importantly, cluster administrators or developers with proper access can now easily use the database with their applications.

3.3. Creating applications using the CLI

You can create an OpenShift Container Platform application from components that include source or binary code, images, and templates by using the OpenShift Container Platform CLI.

The set of objects created by new-app depends on the artifacts passed as input: source repositories, images, or templates.

3.3.1. Creating an application from source code

With the new-app command you can create applications from source code in a local or remote Git repository.

The new-app command creates a build configuration, which itself creates a new application image from your source code. The new-app command typically also creates a Deployment object to deploy the new image, and a service to provide load-balanced access to the deployment running your image.

OpenShift Container Platform automatically detects whether the pipeline, source, or docker build strategy should be used, and in the case of source build, detects an appropriate language builder image.

3.3.1.1. Local

To create an application from a Git repository in a local directory: 

$ oc new-app /<path to source code>
Note

If you use a local Git repository, the repository must have a remote named origin that points to a URL that is accessible by the OpenShift Container Platform cluster. If there is no recognized remote, running the new-app command will create a binary build.

3.3.1.2. Remote

To create an application from a remote Git repository: 

$ oc new-app https://github.com/sclorg/cakephp-ex

To create an application from a private remote Git repository: 

$ oc new-app https://github.com/youruser/yourprivaterepo --source-secret=yoursecret
Note

If you use a private remote Git repository, you can use the --source-secret flag to specify an existing source clone secret that will get injected into your build config to access the repository.

You can use a subdirectory of your source code repository by specifying a --context-dir flag. To create an application from a remote Git repository and a context subdirectory: 

$ oc new-app https://github.com/sclorg/s2i-ruby-container.git \
    --context-dir=2.0/test/puma-test-app

Also, when specifying a remote URL, you can specify a Git branch to use by appending #<branch_name> to the end of the URL: 

$ oc new-app https://github.com/openshift/ruby-hello-world.git#beta4

3.3.1.3. Build strategy detection

OpenShift Container Platform automatically determines which build strategy to use by detecting certain files:

  • If a Jenkins file exists in the root or specified context directory of the source repository when creating a new application, OpenShift Container Platform generates a pipeline build strategy.

    Note

    The pipeline build strategy is deprecated; consider using Red Hat OpenShift Pipelines instead.

  • If a Dockerfile exists in the root or specified context directory of the source repository when creating a new application, OpenShift Container Platform generates a docker build strategy.
  • If neither a Jenkins file nor a Dockerfile is detected, OpenShift Container Platform generates a source build strategy.

Override the automatically detected build strategy by setting the --strategy flag to docker, pipeline, or source. 

$ oc new-app /home/user/code/myapp --strategy=docker
Note

The oc command requires that files containing build sources are available in a remote Git repository. For all source builds, you must use git remote -v.

3.3.1.4. Language detection

If you use the source build strategy, new-app attempts to determine the language builder to use by the presence of certain files in the root or specified context directory of the repository:

Table 3.1. Languages detected by new-app
LanguageFiles

dotnet

project.json, *.csproj

jee

pom.xml

nodejs

app.json, package.json

perl

cpanfile, index.pl

php

composer.json, index.php

python

requirements.txt, setup.py

ruby

Gemfile, Rakefile, config.ru

scala

build.sbt

golang

Godeps, main.go

After a language is detected, new-app searches the OpenShift Container Platform server for image stream tags that have a supports annotation matching the detected language, or an image stream that matches the name of the detected language. If a match is not found, new-app searches the Docker Hub registry for an image that matches the detected language based on name.

You can override the image the builder uses for a particular source repository by specifying the image, either an image stream or container specification, and the repository with a ~ as a separator. Note that if this is done, build strategy detection and language detection are not carried out.

For example, to use the myproject/my-ruby imagestream with the source in a remote repository: 

$ oc new-app myproject/my-ruby~https://github.com/openshift/ruby-hello-world.git

To use the openshift/ruby-20-centos7:latest container image stream with the source in a local repository: 

$ oc new-app openshift/ruby-20-centos7:latest~/home/user/code/my-ruby-app
Note

Language detection requires the Git client to be locally installed so that your repository can be cloned and inspected. If Git is not available, you can avoid the language detection step by specifying the builder image to use with your repository with the <image>~<repository> syntax.

The -i <image> <repository> invocation requires that new-app attempt to clone repository to determine what type of artifact it is, so this will fail if Git is not available.

The -i <image> --code <repository> invocation requires new-app clone repository to determine whether image should be used as a builder for the source code, or deployed separately, as in the case of a database image.

3.3.2. Creating an application from an image

You can deploy an application from an existing image. Images can come from image streams in the OpenShift Container Platform server, images in a specific registry, or images in the local Docker server.

The new-app command attempts to determine the type of image specified in the arguments passed to it. However, you can explicitly tell new-app whether the image is a container image using the --docker-image argument or an image stream using the -i|--image-stream argument.

Note

If you specify an image from your local Docker repository, you must ensure that the same image is available to the OpenShift Container Platform cluster nodes.

3.3.2.1. Docker Hub MySQL image

Create an application from the Docker Hub MySQL image, for example: 

$ oc new-app mysql

3.3.2.2. Image in a private registry

Create an application using an image in a private registry, specify the full container image specification: 

$ oc new-app myregistry:5000/example/myimage

3.3.2.3. Existing image stream and optional image stream tag

Create an application from an existing image stream and optional image stream tag: 

$ oc new-app my-stream:v1

3.3.3. Creating an application from a template

You can create an application from a previously stored template or from a template file, by specifying the name of the template as an argument. For example, you can store a sample application template and use it to create an application.

Upload an application template to your current project’s template library. The following example uploads an application template from a file called examples/sample-app/application-template-stibuild.json: 

$ oc create -f examples/sample-app/application-template-stibuild.json

Then create a new application by referencing the application template. In this example, the template name is ruby-helloworld-sample: 

$ oc new-app ruby-helloworld-sample

To create a new application by referencing a template file in your local file system, without first storing it in OpenShift Container Platform, use the -f|--file argument. For example: 

$ oc new-app -f examples/sample-app/application-template-stibuild.json

3.3.3.1. Template parameters

When creating an application based on a template, use the -p|--param argument to set parameter values that are defined by the template: 

$ oc new-app ruby-helloworld-sample \
    -p ADMIN_USERNAME=admin -p ADMIN_PASSWORD=mypassword

You can store your parameters in a file, then use that file with --param-file when instantiating a template. If you want to read the parameters from standard input, use --param-file=-. The following is an example file called helloworld.params: 

ADMIN_USERNAME=admin
ADMIN_PASSWORD=mypassword

Reference the parameters in the file when instantiating a template: 

$ oc new-app ruby-helloworld-sample --param-file=helloworld.params

3.3.4. Modifying application creation

The new-app command generates OpenShift Container Platform objects that build, deploy, and run the application that is created. Normally, these objects are created in the current project and assigned names that are derived from the input source repositories or the input images. However, with new-app you can modify this behavior.

Table 3.2. new-app output objects
ObjectDescription

BuildConfig

A BuildConfig object is created for each source repository that is specified in the command line. The BuildConfig object specifies the strategy to use, the source location, and the build output location.

ImageStreams

For the BuildConfig object, two image streams are usually created. One represents the input image. With source builds, this is the builder image. With Docker builds, this is the FROM image. The second one represents the output image. If a container image was specified as input to new-app, then an image stream is created for that image as well.

DeploymentConfig

A DeploymentConfig object is created either to deploy the output of a build, or a specified image. The new-app command creates emptyDir volumes for all Docker volumes that are specified in containers included in the resulting DeploymentConfig object .

Service

The new-app command attempts to detect exposed ports in input images. It uses the lowest numeric exposed port to generate a service that exposes that port. To expose a different port, after new-app has completed, simply use the oc expose command to generate additional services.

Other

Other objects can be generated when instantiating templates, according to the template.

3.3.4.1. Specifying environment variables

When generating applications from a template, source, or an image, you can use the -e|--env argument to pass environment variables to the application container at run time: 

$ oc new-app openshift/postgresql-92-centos7 \
    -e POSTGRESQL_USER=user \
    -e POSTGRESQL_DATABASE=db \
    -e POSTGRESQL_PASSWORD=password

The variables can also be read from file using the --env-file argument. The following is an example file called postgresql.env: 

POSTGRESQL_USER=user
POSTGRESQL_DATABASE=db
POSTGRESQL_PASSWORD=password

Read the variables from the file: 

$ oc new-app openshift/postgresql-92-centos7 --env-file=postgresql.env

Additionally, environment variables can be given on standard input by using --env-file=-: 

$ cat postgresql.env | oc new-app openshift/postgresql-92-centos7 --env-file=-
Note

Any BuildConfig objects created as part of new-app processing are not updated with environment variables passed with the -e|--env or --env-file argument.

3.3.4.2. Specifying build environment variables

When generating applications from a template, source, or an image, you can use the --build-env argument to pass environment variables to the build container at run time: 

$ oc new-app openshift/ruby-23-centos7 \
    --build-env HTTP_PROXY=http://myproxy.net:1337/ \
    --build-env GEM_HOME=~/.gem

The variables can also be read from a file using the --build-env-file argument. The following is an example file called ruby.env: 

HTTP_PROXY=http://myproxy.net:1337/
GEM_HOME=~/.gem

Read the variables from the file: 

$ oc new-app openshift/ruby-23-centos7 --build-env-file=ruby.env

Additionally, environment variables can be given on standard input by using --build-env-file=-: 

$ cat ruby.env | oc new-app openshift/ruby-23-centos7 --build-env-file=-

3.3.4.3. Specifying labels

When generating applications from source, images, or templates, you can use the -l|--label argument to add labels to the created objects. Labels make it easy to collectively select, configure, and delete objects associated with the application. 

$ oc new-app https://github.com/openshift/ruby-hello-world -l name=hello-world

3.3.4.4. Viewing the output without creation

To see a dry-run of running the new-app command, you can use the -o|--output argument with a yaml or json value. You can then use the output to preview the objects that are created or redirect it to a file that you can edit. After you are satisfied, you can use oc create to create the OpenShift Container Platform objects.

To output new-app artifacts to a file, run the following: 

$ oc new-app https://github.com/openshift/ruby-hello-world \
    -o yaml > myapp.yaml

Edit the file: 

$ vi myapp.yaml

Create a new application by referencing the file: 

$ oc create -f myapp.yaml

3.3.4.5. Creating objects with different names

Objects created by new-app are normally named after the source repository, or the image used to generate them. You can set the name of the objects produced by adding a --name flag to the command: 

$ oc new-app https://github.com/openshift/ruby-hello-world --name=myapp

3.3.4.6. Creating objects in a different project

Normally, new-app creates objects in the current project. However, you can create objects in a different project by using the -n|--namespace argument: 

$ oc new-app https://github.com/openshift/ruby-hello-world -n myproject

3.3.4.7. Creating multiple objects

The new-app command allows creating multiple applications specifying multiple parameters to new-app. Labels specified in the command line apply to all objects created by the single command. Environment variables apply to all components created from source or images.

To create an application from a source repository and a Docker Hub image: 

$ oc new-app https://github.com/openshift/ruby-hello-world mysql
Note

If a source code repository and a builder image are specified as separate arguments, new-app uses the builder image as the builder for the source code repository. If this is not the intent, specify the required builder image for the source using the ~ separator.

3.3.4.8. Grouping images and source in a single pod

The new-app command allows deploying multiple images together in a single pod. To specify which images to group together, use the + separator. The --group command line argument can also be used to specify the images that should be grouped together. To group the image built from a source repository with other images, specify its builder image in the group: 

$ oc new-app ruby+mysql

To deploy an image built from source and an external image together: 

$ oc new-app \
    ruby~https://github.com/openshift/ruby-hello-world \
    mysql \
    --group=ruby+mysql

3.3.4.9. Searching for images, templates, and other inputs

To search for images, templates, and other inputs for the oc new-app command, add the --search and --list flags. For example, to find all of the images or templates that include PHP: 

$ oc new-app --search php
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