5_Using_templates.md

Using Templates

In this lab exercise we will learn how to use OpenShift Web Console to spin up a MySQL database using templates. We will then add a frontend PHP application that accesses this database using the service exposed by the database. We will provide a route (a URL) to access the frontend application from a browser.

Step 1: Create a Project

Based on the experience gained from the previous exercise, log into the OpenShift Web Console. You will see the list of Projects.

Using the New Project button, create a new project. We will call it consoleproject-UserName. Replace by your username to make this project unique. Type in a Display Name and Description of your choice.

Press the Create button to complete the project creation from the Web Console. This will accomplish the same job as oc new-project from CLI.

Step 2: Create a MYSQL database using the template

Click on Add to Project button and you will be taken to select an image or template. You will see the application create screen as shown below:

Scroll down and click on Data Stores session. Find MySQL (Ephemeral) template from the list and click Select. You will also notice MySQL (Persistent) template. But we will address that in a different lab exercise.

You will be taken to the mysql ephemeral creation screen. Click edit parameters and edit the values to use the following values:

Database Service Name: mysql
MySQL Connection Username: mysqluser
MySQL Connection Password: supersecret
MySQL Database Name: sample

In the next section you can add the label:

name=name
value=mysql

Click the Create button.

Click Continue to overview.

It will take you back to the project overview page and soon you will see an image of a running pod.

If pod does not show running, Click Applications and select Deployments, do the following:

1. Click onto mysql deployments config
2. Click on the Actions button and select Edit Health Checks
3. Under the Readiness Probe section remove the single quotes around $MYSQL_PASSWORD
4. Click Save
5. Click Applications and select Pods
6. Click onto the pod name
7. Click on the Actions button and select Delete

Browse over to Pods, Services and Deployments from the Applications tab to notice the additions to the project. You will note that the service has been assigned an IP address that starts with 172.*. Make a note of that. Also note the port that is exposed by this service. By default it exposes 3306.

Step 3: Add data to MySQL database

Let us see how we can enter the pod and access the database.

From the command line, change the project to the "consoleproject-UserName" using the following command:

Remember to substitute your username.

 oc project consoleproject-UserName

Based on what you learned previously get the list of running pods (Tip: oc get pods). You will find one pod for mysql running. Take a note of it's name.

Enter the pod by running the following command. Substitute the pod name with your mysql pod name.

$ oc rsh mysql-1-UserName

bash-4.2$

You will be taken to a bash prompt inside the running pod. Now using the service ip address you noted earlier, port number, username and password you used start the mysql client as shown below. You will have to substitute your values here.

Tip: If you need service ip address navigate to Applications->Services tab on the Web Console.

mysql -h127.0.0.1 -P3306 -umysqluser -psupersecret

You will be taken to the mysql prompt. See the list of databases. You will notice that the sample database that you requested is added and available.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| sampledb           |
+--------------------+
2 rows in set (0.00 sec)

Change over to use the sampledb database.

mysql> use sampledb;
Database changed

Now show tables shows an empty set. So let us create a table and add some records using the commands shown below.

Create the table:

create table users (user_id int not null auto_increment, username varchar(200),PRIMARY KEY(user_id));

Now we add some data:

insert into users values (null, 'joe');
insert into users values (null, 'alice');

Verify that the records you added are there

select * from users;

Now exit MySQL client and exit out of the pod.

Step 4: Add a PHP frontend to talk to this database

In this step we will add a PHP frontend application that talks to recently create database. The code is available on github to use at https://github.com/masauve/dbtest.

Browse through the code in this repository. It has a simple php file (dbtest.php) that connects to the database and reads the values from the users table and displays them.

To add a frontend again click on Add to Project to spin up a frontend application in the same consoleproject-UserName. It takes you to select image or template page and choose the PHP template under PHP apps.

Enter the following values for each parameters:

* Name: dbtest
* Git Repository URL: https://github.com/masauve/dbtest

Click onto the link "Show advanced options", go to Deployment Configuration section and enter the following environment variables:

In the next section add a label:

* name=name
* value=dbtest

Click Create to add this frontend application to talk to the database.

Click Continue to overview.

You will be taken back to the Project Overview page and you will start seeing that a new service is now available and exposed as a route.

Click "Group Service" next to DB test and select "mysql" service.

You will also notice that a build starts running very soon. Once the build completes, the application image created from the source code will be uploaded to the docker repository.

You can check the build logs using the following command:

$ oc logs build/dbtest-1

Cloning "https://github.com/VeerMuchandi/dbtest.git" ...
	Commit:	1bb0515221459a11ca2e7563dca903bb93d8150e (small change)
	Author:	VeerMuchandi <[email protected]>
	Date:	Tue Jan 26 12:53:35 2016 -0500

---> Installing application source...


Pushing image 172.30.89.28:5000/consoleproject-admin/dbtest:latest ...
Pushed 0/5 layers, 7% complete
Pushed 1/5 layers, 21% complete
Pushed 2/5 layers, 41% complete
Pushed 3/5 layers, 70% complete
Pushed 3/5 layers, 99% complete
Pushed 4/5 layers, 100% complete
Pushed 5/5 layers, 100% complete
Push successful

Once the build completes, OpenShift initiates a deploy process. Once the deployment is complete, the frontend pod starts running. You will find the running pod when you navigate to Applications->Pods on the Web console.

Now type in your application url in the browser or use curl with http://<<your application url>>/dbtest.php

You will notice that it displays the records read from the database

Hello All.. Here is the list of users:
User Id: 1 User Name: joe
User Id: 2 User Name: alice
End of the list

In this lab exercise you have seen a complete web application deployed using OpenShift templates in two parts. First we deployed the MySQL database. We added data manually by getting into the pod. Then we added the frontend code that was built using the OpenShift S2I process. You configured this frontend application to access the database using a service, in this case, the "mysql" service. The frontend is made accessible using a route for which you gave a URL.