We will look at

 

  • How to Setup Apache Cassandra on Oracle Compute Cloud
  • Develop: some implementation details
  • Deploy: Run it on Oracle Application Container Cloud using CI/CD feature in Oracle Developer Cloud
  • Secure access: secure channel b/w your application and Cassandra

 

 

 

Hello Cassandra

Apache Cassandra is an open source,  NoSQL database. It's written in Java, (originally) developed at Facebook and it's design is based on/inspired by Amazon's Dynamo and Google’s Bigtable. Some of its salient characteristics are as follows

 

  • Belongs to the Row-oriented family (of NoSQL databases)
  • Distributed, decentralized & elastically scalable
  • Highly available & fault-tolerant
  • Supports Tunable consistency

 

You can read more about Cassandra here

About the sample application

  • The sample application exposes REST endpoints - implemented using Jersey (JAX-RS)
  • Employee - serves as the domain object. You would need to bootstrap the required table
  • DataStax Java driver is used to interact with Cassandra
    • Leverages Cassandra object mapper for CRUD operations

 

It is available here

 

Locking down access to Cassandra

The goal is to allow exclusive access to Cassandra from our application without exposing it's port (e.g. 9042) to the public internet. To enable this, Oracle Application Container Cloud ensures that when you deploy an application, a Security IP list is automatically generated which can be added to a Security rule for a virtual machine (VM) in Oracle Compute Cloud Service. This allows your application and the VM to communicate.

 

The setup details are discussed in an upcoming section

 

Setup Cassandra on Oracle Compute Cloud

 

Quick start using Bitnami

We will use a pre-configured Cassandra image from Bitnami via the Oracle Cloud Marketplace

 

  • Login to your Oracle Compute Cloud dashboard,
  • choose the Create Instance wizard, and then
  • select the required machine image from the Marketplace tab

 

More details here

 

 

 

 

Activate SSH access

We now need to allow SSH connections to our Cassandra virtual machine on Oracle Compute cloud

 

Create a Security Rule

 

 

You should see it in the list once its done

 

 

SSH into the VM

 

 

Reset password

You will need to reset Cassandra password as per this documentation https://docs.bitnami.com/oracle/infrastructure/cassandra/#how-to-reset-the-cassandra-administrator-password. Once you're done, log in using the new credentials

 

 

Oracle Developer Cloud: setup & application deployment

 

You would need to configure Developer Cloud for the Continuous Build as well as Deployment process. You can refer to previous blogs for the same (some of the details specific to this example will be highlighted here)

 

References

 

Provide Oracle Application Container Cloud (configuration) descriptor

 

 

 

Check application details on Oracle Application Container Cloud

 

Deployed Application

 

 

Environment Variables

 

 

Check Security IP List

 

After successful deployment, you will be able to see the application as well the Security IP List information in Oracle Application Container Cloud

 

 

Please note that you will not be able to access/test the application now since the secure communication channel b/w your application and Cassandra is not setup. The next section covers the details

 

Oracle Compute Cloud security configurations

 

Confirm Security IP List

 

You will see the Security IP list created when you had deployed the application on Oracle Application Container cloud (mentioned above). It ensures that the IP of the application deployed on Oracle Application Container cloud is whitelisted for accessing our Cassandra VM on Oracle Compute Cloud

 

 

 

Create Security Application

 

This represents the component you are protecting along with its access type and port number - in this case its TCP and 9042 respectively

 

Create Security Rule

 

The default Security list is created by Oracle Compute Cloud (after the Bitnami image was provisioned)

 

We will create a Security Rule to make use of Security IP list, Security application and Security List

 

 

You should see it in the list of rules

 

 

Test the application

 

Bootstrap the keyspace and table

 

The sample application uses the test keyspace and a table named employee - you would need to create these entities in the Cassandra instance

 

CREATE KEYSPACE test
  WITH REPLICATION = { 
   'class' : 'SimpleStrategy', 
   'replication_factor' : 1 
  };
  
  
 CREATE TABLE test.employee (emp_id uuid PRIMARY KEY, name text);

 

Access REST endpoints

 

Create a few employees

 

curl -X POST <ACCS_APP_URL>/employees -d abhishek // 'abhishek' is the name
curl -X POST <ACCS_APP_URL>/employees -d john // 'john' is the name

 

  • You will receive HTTP 201 (Created) in response
  • The Location (response) header will have the (REST) co-ordinates (URI) for the newly created employee record - use this for search (next step)

 

Search for the new employee

 

curl -X GET <ACCS_APP_URL>/employees/<emp_id>

 

You will receive a XML payload with employee ID and name

 

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<employee>
    <empId>18df5fd1-88d8-4820-984e-3cf0293c3051</empId>
    <name>test1</name>
</employee>

 

Search for all employees

 

curl -X GET <ACCS_APP_URL>/employees/

 

You will receive a XML payload with employees info

 

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<employees>
    <employee>
        <empId>8a841167-6aaf-428f-bc2b-02269f04ce93</empId>
        <name>abhirockzz</name>
    </employee>
    <employee>
        <empId>2e2cfb3c-1530-4099-b6e9-a550f11b25de</empId>
        <name>test2</name>
    </employee>
    <employee>
        <empId>18df5fd1-88d8-4820-984e-3cf0293c3051</empId>
        <name>test1</name>
    </employee>
    <employee>
        <empId>2513a12d-5fc7-4bc6-9f94-d13cea23fe7a</empId>
        <name>abhishek</name>
    </employee>
</employees>

 

Test the CI/CD flow

Make some code changes and push them to the Developer Cloud service Git repo. This should

  • Automatically trigger the build, which once successful will
  • Automatically trigger the deployment process, and
  • Redeploy the new application version to Application Container Cloud

 

 

**The views expressed in this post are my own and do not necessarily reflect the views of Oracle.