Bitnami Cassandra Virtual Machine

Description

Apache Cassandra is an open source distributed database management system designed to handle large amounts of data across many servers, providing high availability with no single point of failure.

First steps with the Bitnami Cassandra Stack

Welcome to your new Bitnami application! This guide includes some basic information you will need to get started with your application.

How to import a Bitnami Virtual Machine?

Check the following instructions to import a Bitnami Virtual Machine:

Importing a Bitnami Virtual Machine in VirtualBox

Select the "File -> Import Appliance" menu option and select the .ova file downloaded from the Bitnami website. Then click "Continue".
Once it is imported, click the "Start" button in the VirtualBox toolbar.

For a detailed walkthrough, check our Virtualbox tutorial.

Importing a Bitnami Virtual Machine in a VMware product

Select the "File -> Import" menu option and select the .ova file downloaded from the Bitnami website. Then click "Continue".
Once the import is complete, click "Finish" to start the virtual machine.

For a detailed walkthrough, check our VMware tutorial, which uses VMware Fusion as an example. To learn how to use our virtual machines with other VMware products, refer to the VMware Workstation documentation or the VMware vSphere documentation.

What credentials do I need?

You need two sets of credentials:

The application credentials, consisting of a username and password. These credentials allow you to log in to your new Bitnami application.
The server credentials, consisting of an SSH username and password. These credentials allow you to log in to your Virtual Machines server using an SSH client and execute commands on the server using the command line.

What is the administrator username set for me to log in to the application for the first time?

Username: cassandra

What is the administrator password?

Password: The administrator password to log in to your application is randomly generated during the first boot. Check the FAQ to learn how to retrieve it.

What SSH username should I use for secure shell access to my application?

SSH username: bitnami

What is my server IP address?

The IP address is displayed on screen at the end of the boot process, but you can check it at any time by running the following command:

  $ sudo ifconfig

How do I get my SSH key or password?

You can obtain the SSH password from the virtual machine console when it starts up. Click here for more information.

How to start or stop the services?

Each Bitnami stack includes a control script that lets you easily stop, start and restart services. The script is located at /opt/bitnami/ctlscript.sh. Call it without any service name arguments to start all services:

$ sudo /opt/bitnami/ctlscript.sh start

Or use it to restart a single service, such as Apache only, by passing the service name as argument:

$ sudo /opt/bitnami/ctlscript.sh restart apache

Use this script to stop all services:

$ sudo /opt/bitnami/ctlscript.sh stop

Restart the services by running the script without any arguments:

$ sudo /opt/bitnami/ctlscript.sh restart

Obtain a list of available services and operations by running the script without any arguments:

$ sudo /opt/bitnami/ctlscript.sh

What is the default configuration?

The Cassandra admin user for all databases is automatically generated. The administrator user name is cassandra and you can get the password from the server dashboard for your server.

You can connect to the Cassandra server locally or remotely using the cqlsh command line tool:

$ cqlsh -u cassandra
Password:
Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 2.1.1 | CQL spec 3.2.0 | Native protocol v3]
Use HELP for help.

The Cassandra server is configured to accept incoming connections on the default Cassandra client port 9042. This could be a security issue so it is strongly advisable to close this port or open it only for a specific IP address. Other ports for configuring nodes are closed by default in the firewall.

Cassandra configuration file

The Cassandra configuration file is located at /opt/bitnami/cassandra/conf/cassandra.yaml.

Cassandra ports

Cassandra client: 9042
Cassandra client thrift port: 9160
Cassandra transport port: 7000
Cassandra transport secure port: 7001
Cassandra jmx port: 7199

Cassandra log file

The Cassandra log file is created at /opt/bitnami/cassandra/log/system.log.

What are the default ports?

A port is an endpoint of communication in an operating system that identifies a specific process or a type of service. Bitnami stacks include several services or servers that require a port.

Remember that if you need to open some ports you can follow the instructions given in the FAQ to learn how to open the server ports for remote access.

Port 22 is the default port for SSH connections.

The Cassandra access port is 9042. This port is closed by default, you must open it to enable remote access.

How to find the database credentials?

Database username: cassandra.
Database password: The same as the application password. Find out how to obtain application credentials.

How to connect to the Cassandra server?

You can connect to Cassandra from the same server. Obtain the password from the dashboard for your server.

$ cqlsh -u cassandra

This will connect you to the Cassandra console and display a prompt. Once connected, you can run cqlsh commands to create and populate data. For example, the command below lists available keyspaces:

cassandra@cqlsh> describe keyspaces
system_traces  system_schema  system_auth  system  system_distributed

You can learn more about Cassandra in the Cassandra Getting Started guide.

How to connect to Cassandra from a different machine?

For security reasons, the Cassandra ports in this solution cannot be accessed over a public IP address. To connect to Cassandra from a different machine, you must open ports 9042, 9160, 7000, 7001 and 7199 for remote access. Refer to the FAQ for more information on this.

IMPORTANT: Making this application's network ports public is a significant security risk. You are strongly advised to only allow access to those ports from trusted networks. If, for development purposes, you need to access from outside of a trusted network, please do not allow access to those ports via a public IP address. Instead, use a secure channel such as a VPN or an SSH tunnel. Follow these instructions to remotely connect safely and reliably.

You can then access Cassandra using a command like the one below:

$ cqlsh -u cassandra SERVER-IP

How to check the Cassandra server version?

Use the commands below:

$ cqlsh -u cassandra
Password:
Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 2.1.1 | CQL spec 3.2.0 | Native protocol v3]
Use HELP for help.

cassandra@cqlsh> show version
[cqlsh 5.0.1 | Cassandra 2.1.1 | CQL spec 3.2.0 | Native protocol v3]

How to change the Cassandra administrator password?

You can modify the Cassandra password using the following command at the shell prompt:

$ cqlsh -u cassandra -p PASSWORD
Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 3.9 | CQL spec 3.4.2 | Native protocol v4]
Use HELP for help.

cqlsh> ALTER USER cassandra with PASSWORD 'NEWPASSWORD';
cqlsh> exit

How to reset the Cassandra administrator password?

You can reset the administrator password by following the steps below:

Edit the /opt/bitnami/cassandra/conf/cassandra.yaml file and replace the following lines:

   authenticator: PasswordAuthenticator
   authorizer: CassandraAuthorizer

with:

   authenticator: AllowAllAuthenticator
   authorizer: AllowAllAuthorizer

Restart your database:

   $ sudo /opt/bitnami/ctlscript.sh restart cassandra

Execute the following commands:

   $ cqlsh
   Connected to Test Cluster at 127.0.0.1:9042.
   [cqlsh 5.0.1 | Cassandra 3.9 | CQL spec 3.4.2 | Native protocol v4]
   Use HELP for help.
      
   cqlsh> UPDATE system_auth.roles SET salted_hash = '$2a$10$1gMPBy9zSkDzKxdbU2v/gOslcMRPDcXVqmwQYBmi8MVgYvNdRZw/.' WHERE role = 'cassandra';
   cqlsh> exit

Undo the changes made in /opt/bitnami/cassandra/conf/cassandra.yaml and restart Cassandra again. Now you can access your database using the user name cassandra and password cassandra:

     $ cqlsh -u cassandra -p cassandra
     Connected to Test Cluster at 127.0.0.1:9042.
     [cqlsh 5.0.1 | Cassandra 3.9 | CQL spec 3.4.2 | Native protocol v4]
     Use HELP for help.
     cqlsh>

Once you have access, don't forget to change the cassandra user account password to something else as described in the previous section. This is the default password and it's unsecure.

How to create a Cassandra cluster?

Create a Cluster with a Single Seed Node

Launch the Bitnami Cassandra Stack on each node.

 $ sudo /opt/bitnami/ctlscript.sh stop cassandra

Get the public and private IP address of each node in the cluster.
Select one of the nodes as the seed node for the cluster. In this guide, assume that the seed node has public IP address 130.1.1.1 and private IP address 10.1.1.1.
Open the Cassandra transport port (tcp:7000 by default) in your server firewall. Then, restart your Cassandra servers.
On each node in the cluster, modify the /opt/bitnami/cassandra/conf/cassandra.yaml file and update the following directives:
- -seeds: Use the public IP address of the seed node.
- listen_address: Use the current node's private IP address.
- broadcast_address: Use the current node's public IP address.
- endpoint_snitch: Select the correct snitch for your environment based on the official documentation.
For example, on the seed node, your configuration file might look like this:
```
   cluster_name: 'MyCassandraCluster'
   num_tokens: 256
   seed_provider:
     - class_name: org.apache.cassandra.locator.SimpleSeedProvider
       parameters:
            - seeds: "130.1.1.1"
   broadcast_address: 130.1.1.1
   listen_address: 10.1.1.1
   endpoint_snitch: GossipingPropertyFileSnitch
```
Repeat the above configuration for all the nodes in the cluster. Remember that you must modify the listen_address and broadcast_address on each node to reflect the node's IP addresses.
For all nodes apart from the seed node, delete the default data. This is necessary to avoid collisions between the system tables on different nodes.
```
 $ sudo rm -rf /opt/bitnami/cassandra/data/*
```
Start Cassandra on the seed node, followed by the other nodes, to have the changes take effect:
```
 $ sudo /opt/bitnami/ctlscript.sh start cassandra
```

Your cluster should now be operational with a single seed node. To verify, execute the command below on any node in the cluster:

$ /opt/bitnami/cassandra/bin/nodetool status

You can connect to any server of the cluster using the credentials for the first seed node.

You can also watch the Cassandra log file at /opt/bitnami/cassandra/log/system.log to check that the cluster nodes recognize and can communicate with each other.

Create a Cluster with Multiple Seed Nodes

IMPORTANT: Before creating a cluster with multiple seed nodes, ensure that you have a working cluster with a single seed node as described in the previous section. Then, repeat the steps below for each new seed node that you wish to add to the cluster.

Launch the Bitnami Cassandra Stack on a new node. This will be the new seed node for your cluster.

   $ sudo /opt/bitnami/ctlscript.sh stop cassandra

Get the public and private IP address of the new seed node. In this guide, assume that the new seed node has public IP address 140.1.1.1 and private IP address 20.1.1.1.
On the new node, edit the configuration file /opt/bitnami/cassandra/conf/cassandra.yaml and specify it as a seed node by adding its public IP address to the seeds list. Also specify the other configuration parameters, such as the listen_address and the broadcast_address, as described in the previous section. Here is what the configuration file would look like:
```
   cluster_name: 'MyCassandraCluster'
   num_tokens: 256
   seed_provider:
     - class_name: org.apache.cassandra.locator.SimpleSeedProvider
       parameters:
            - seeds: "130.1.1.1, 140.1.1.1"
   broadcast_address: 140.1.1.1
   listen_address: 20.1.1.1
   endpoint_snitch: GossipingPropertyFileSnitch
```
Delete the default data. This is necessary to avoid collisions between the system tables on different nodes.
```
   $ sudo rm -rf /opt/bitnami/cassandra/data/*
```
On each of the other nodes in the cluster, update the /opt/bitnami/cassandra/conf/cassandra.yaml file and add the public IP address of the new seed node to the seeds list.
Restart Cassandra on the seed nodes, followed by the non-seed nodes.
```
   $ sudo /opt/bitnami/ctlscript.sh start cassandra
```

Your cluster should now be operational with the new seed node. To verify, execute the command below on any node in the cluster:

$ /opt/bitnami/cassandra/bin/nodetool status

You can connect to any server of the cluster using the credentials for the first seed node.

You can also watch the Cassandra log file at /opt/bitnami/cassandra/log/system.log to check that the cluster nodes recognize and can communicate with each other.

How can I run a command in the Bitnami Cassandra Stack?

Log in to the server console as the bitnami user and run the command as usual. The required environment is automatically loaded for the bitnami user.

How to create a full backup of Cassandra?

Backup

The Bitnami Cassandra Stack is self-contained and the simplest option for performing a backup is to copy or compress the Bitnami stack installation directory. To do so in a safe manner, you will need to stop all servers, so this method may not be appropriate if you have people accessing the application continuously.

Follow these steps:

Change to the directory in which you wish to save your backup:
```
  $ cd /your/directory
```

Stop all servers:

  $ sudo /opt/bitnami/ctlscript.sh stop

Create a compressed file with the stack contents:

  $ sudo tar -pczvf application-backup.tar.gz /opt/bitnami

Restart all servers:

  $ sudo /opt/bitnami/ctlscript.sh start

You should now download or transfer the application-backup.tar.gz file to a safe location.

Restore

Follow these steps:

Change to the directory containing your backup:
```
  $ cd /your/directory
```

Stop all servers:

  $ sudo /opt/bitnami/ctlscript.sh stop

Move the current stack to a different location:

  $ sudo mv /opt/bitnami /tmp/bitnami-backup

Uncompress the backup file to the original directoryv

  $ sudo tar -pxzvf application-backup.tar.gz -C /

Start all servers:

  $ sudo /opt/bitnami/ctlscript.sh start

If you want to create only a database backup, refer to these instructions for MySQL and PostgreSQL.