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Creating an application with a database

Prerequisites

  • odo is installed.

  • oc client is installed.

  • You have a running cluster. Developers can use CodeReady Containers (CRC) to deploy a local cluster quickly.

  • The Service Catalog is installed and enabled on your cluster.

    Service Catalog is deprecated on OpenShift Container Platform 4 and later.

Creating a project

Create a project to keep your source code, tests, and libraries organized in a separate single unit.

Procedure

  1. Log in to an OpenShift Container Platform cluster:

    $ odo login -u developer -p developer

  2. Create a project:

    $ odo project create myproject
    Example output
     ✓  Project 'myproject' is ready for use
 ✓  New project created and now using project : myproject

Deploying the front-end component

To create and deploy a front-end component, download the Node.js application and push the source code to your cluster with odo.

Procedure

  1. Download the example front-end application:

    $ git clone https://github.com/openshift/nodejs-ex frontend

  2. Change the current directory to the front-end directory:

    $ cd frontend

  3. List the contents of the directory to see that the front end is a Node.js application.

    $ ls
    Example output
    README.md       openshift       server.js       views
helm            package.json    tests

    The front-end component is written in an interpreted language (Node.js); it does not need to be built.

  4. Create a component configuration of Node.js component-type named frontend:

    $ odo create nodejs frontend
    Example output
     ✓  Validating component [5ms]
Please use `odo push` command to create the component with source deployed

  5. Create a URL to access the frontend interface.

    $ odo url create myurl
    Example output
     ✓  URL myurl created for component: nodejs-nodejs-ex-pmdp

  6. Push the component to the OpenShift Container Platform cluster.

    $ odo push
    Example output
    Validation
 ✓  Checking component [7ms]

 Configuration changes
 ✓  Initializing component
 ✓  Creating component [134ms]

 Applying URL changes
 ✓  URL myurl: http://myurl-app-myproject.192.168.42.79.nip.io created

 Pushing to component nodejs-nodejs-ex-mhbb of type local
 ✓  Checking files for pushing [657850ns]
 ✓  Waiting for component to start [6s]
 ✓  Syncing files to the component [408ms]
 ✓  Building component [7s]
 ✓  Changes successfully pushed to component

Deploying a database in interactive mode

odo provides a command-line interactive mode which simplifies deployment.

Procedure

  • Run the interactive mode and answer the prompts:

    $ odo service create
    Example output
    ? Which kind of service do you wish to create database
? Which database service class should we use mongodb-persistent
? Enter a value for string property DATABASE_SERVICE_NAME (Database Service Name): mongodb
? Enter a value for string property MEMORY_LIMIT (Memory Limit): 512Mi
? Enter a value for string property MONGODB_DATABASE (MongoDB Database Name): sampledb
? Enter a value for string property MONGODB_VERSION (Version of MongoDB Image): 3.2
? Enter a value for string property VOLUME_CAPACITY (Volume Capacity): 1Gi
? Provide values for non-required properties No
? How should we name your service  mongodb-persistent
? Output the non-interactive version of the selected options No
? Wait for the service to be ready No
 ✓  Creating service [32ms]
 ✓  Service 'mongodb-persistent' was created
Progress of the provisioning will not be reported and might take a long time.
You can see the current status by executing 'odo service list'

Your password or username will be passed to the front-end application as environment variables.

Deploying a database manually

  1. List the available services:

    $ odo catalog list services
    Example output
    NAME                         PLANS
django-psql-persistent       default
jenkins-ephemeral            default
jenkins-pipeline-example     default
mariadb-persistent           default
mongodb-persistent           default
mysql-persistent             default
nodejs-mongo-persistent      default
postgresql-persistent        default
rails-pgsql-persistent       default

  2. Choose the mongodb-persistent type of service and see the required parameters:

    $ odo catalog describe service mongodb-persistent
    Example output
      ***********************        | *****************************************************
  Name                           | default
  -----------------              | -----------------
  Display Name                   |
  -----------------              | -----------------
  Short Description              | Default plan
  -----------------              | -----------------
  Required Params without a      |
  default value                  |
  -----------------              | -----------------
  Required Params with a default | DATABASE_SERVICE_NAME
  value                          | (default: 'mongodb'),
                                 | MEMORY_LIMIT (default:
                                 | '512Mi'), MONGODB_VERSION
                                 | (default: '3.2'),
                                 | MONGODB_DATABASE (default:
                                 | 'sampledb'), VOLUME_CAPACITY
                                 | (default: '1Gi')
  -----------------              | -----------------
  Optional Params                | MONGODB_ADMIN_PASSWORD,
                                 | NAMESPACE, MONGODB_PASSWORD,
                                 | MONGODB_USER

  3. Pass the required parameters as flags and wait for the deployment of the database:

    $ odo service create mongodb-persistent --plan default --wait -p DATABASE_SERVICE_NAME=mongodb -p MEMORY_LIMIT=512Mi -p MONGODB_DATABASE=sampledb -p VOLUME_CAPACITY=1Gi

Connecting the database to the front-end application

  1. Link the database to the front-end service:

    $ odo link mongodb-persistent
    Example output
     ✓  Service mongodb-persistent has been successfully linked from the component nodejs-nodejs-ex-mhbb

Following environment variables were added to nodejs-nodejs-ex-mhbb component:
- database_name
- password
- uri
- username
- admin_password

  2. See the environment variables of the application and the database in the pod:

    1. Get the pod name:

      $ oc get pods
      Example output
      NAME                                READY     STATUS    RESTARTS   AGE
mongodb-1-gsznc                     1/1       Running   0          28m
nodejs-nodejs-ex-mhbb-app-4-vkn9l   1/1       Running   0          1m

    2. Connect to the pod:

      $ oc rsh nodejs-nodejs-ex-mhbb-app-4-vkn9l

    3. Check the environment variables:

      sh-4.2$ env
      Example output
      uri=mongodb://172.30.126.3:27017
password=dHIOpYneSkX3rTLn
database_name=sampledb
username=user43U
admin_password=NCn41tqmx7RIqmfv

  3. Open the URL in the browser and notice the database configuration in the bottom right:

    $ odo url list
    Example output
    Request information
Page view count: 24

DB Connection Info:
Type:	MongoDB
URL:	mongodb://172.30.126.3:27017/sampledb

Deleting an application

Deleting an application will delete all components associated with the application.
Procedure

  1. List the applications in the current project:

    $ odo app list
    Example output
        The project '<project_name>' has the following applications:
    NAME
    app

  2. List the components associated with the applications. These components will be deleted with the application:

    $ odo component list
    Example output
        APP     NAME                      TYPE       SOURCE        STATE
    app     nodejs-nodejs-ex-elyf     nodejs     file://./     Pushed

  3. Delete the application:

    $ odo app delete <application_name>
    Example output
        ? Are you sure you want to delete the application: <application_name> from project: <project_name>

  4. Confirm the deletion with Y. You can suppress the confirmation prompt using the -f flag.