This example describes how to deploy and connect a database to a front-end application.

Prerequisites
  • odo is installed.

  • oc client is installed.

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

  • Service Catalog is enabled.

Creating a project

Procedure
  1. Log in to an OpenShift Container Platform cluster:

    $ odo login -u developer -p developer
  2. Create a new directory for your components:

    $ mkdir my_components
    $ cd my_components
  3. Download the example front-end application:

    $ git clone https://github.com/openshift/nodejs-ex
  4. Create a new project:

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

Deploying the front-end component

Procedure
  1. Change the current directory to the front-end directory:

    $ cd <directory-name>
  2. List the contents of the directory to see that the front end is a Node.js application.

    $ ls
    assets  bin  index.html  kwww-frontend.iml  package.json  package-lock.json  playfield.png  README.md  server.js

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

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

    $ odo create nodejs frontend
     ✓  Validating component [5ms]
    Please use `odo push` command to create the component with source deployed
  4. Create a URL to access the frontend interface.

    $ odo url create myurl
     ✓  URL myurl created for component: nodejs-nodejs-ex-pmdp
  5. Push the component to the OpenShift Container Platform cluster.

    $ odo push
    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
    ? 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
    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
      ***********************        | *****************************************************
      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
     ✓  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:

    $ oc get pods
    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
    
    $ oc rsh nodejs-nodejs-ex-mhbb-app-4-vkn9l
    sh-4.2$ env
    uri=mongodb://172.30.126.3:27017
    password=dHIOpYneSkX3rTLn
    database_name=sampledb
    username=user43U
    admin_password=NCn41tqmx7RIqmfv
    sh-4.2$
  3. Open the URL in the browser and notice the database configuration in the bottom right:

    $ odo url list
    Request information
    Page view count: 24
    
    DB Connection Info:
    Type:	MongoDB
    URL:	mongodb://172.30.126.3:27017/sampledb