2.7. Creating an application with a database

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

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

   注意

   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

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

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

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.