Apache Cassandra (cluster)

Deploy Apache Cassandra, an open source, distributed NoSQL database designed to handle large amounts of data across multiple commodity servers, providing high availability with no single point of failure. Cassandra offers robust support for clusters with asynchronous masterless replication, allowing low-latency operations for all clients.

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Cluster deployment

The app is deployed with three or five Linode instances to create a distributed Apache Cassandra cluster, each with the plan type and size you select.

Each of these Linode instances will appear on your invoice as separate items.

1. Deploy Apache Cassandra cluster

 Estimated deployment time: 10–15 minutes

Base distribution and plan

• Supported distribution: Ubuntu 24.04 LTS
• Recommended plan: All plan types and sizes can be used. For best results, use at least an 8GB Dedicated CPU or Shared Compute Instance.

Configuration options

StackScript ID: 1350845

Note: After the app deployment completes, the password for your limited sudo user is generated and stored in the .credentials file in the home directory, along with application-specific passwords. Log in to your instance as root through the Lish console or SSH, then run cat /home/$USERNAME/.credentials to view its contents.

Use API, CLI, or Terraform

curl --location 'https://api.linode.com/v4/linode/instances' \
    --header 'Content-Type: application/json' \
    --header 'Accept: application/json' \
    --header 'Authorization: Bearer abc123def456hij789klm' \
    --data-raw '{
        "region": "us-east",
        "type": "g6-standard-4",
        "image": "linode/ubuntu24.04",
        "label": "my-cassandra-cluster-one-click-app",
        "root_pass": "@C0mpl3x#P@ssw0rd",
        "stackscript_id": 1350845,
        "stackscript_data": {
            "token_password": "abc123def456hij789klm",
            "sudo_username": "jsmith",
            "db_superuser": "jsmith-admin",
            "country_name": "US",
            "state_or_province_name": "Massachusetts",
            "locality_name": "Cambridge",
            "organization_name": "Akamai Technologies",
            "email_address": "jsmith@example.com",
            "cluster_name": "my-cluster",
            "client_count": "5"
        }
    }'

linode-cli linodes create \
    --region us-east \
    --type g6-standard-4 \
    --label my-cassandra-cluster-one-click-app \
    --image linode/ubuntu24.04 \
    --root_pass @C0mpl3x#P@ssw0rd \
    --stackscript_id 1350845 \
    --stackscript_data '{"token_password":"abc123def456hij789klm", "sudo_username":"jsmith", "db_superuser":"jsmith-admin", "country_name":"US", "state_or_province_name":"Massachusetts", "locality_name":"Cambridge", "organization_name":"Akamai Technologies", "email_address":"jsmith@example.com", "cluster_name":"my-cluster", "client_count":"5"}'

resource "linode_instance" "my-linode" {
    region         = "us-east"
    type           = "g6-standard-4"
    label          = "my-cassandra-cluster-one-click-app"
    image          = "linode/ubuntu24.04"
    root_pass      = "@C0mpl3x#P@ssw0rd"
    stackscript_id = 1350845
    stackscript_data = {
        "token_password"         = "abc123def456hij789klm"
        "sudo_username"          = "jsmith"
        "db_superuser"           = "jsmith-admin"
        "country_name"           = "US"
        "state_or_province_name" = "Massachusetts"
        "locality_name"          = "Cambridge"
        "organization_name"      = "Akamai Technologies"
        "email_address"          = "jsmith@example.com"
        "cluster_name"           = "my-cluster"
        "client_count"           = "5"
    }
}

2. Connect to Cassandra

This app creates a 3-5 node cluster using Apache Cassandra. Authentication to the cluster is secured via a user-supplied username. The default cassandra database role is removed and superseded by the new user role provided by the client. In addition, cluster communication is secured via SSL/TLS with self-signed keystores.

You can find both certificates and keystores on every node in the /etc/cassandra/ssl directory. Only the first Cassandra server will have client certificates. This app also creates the specified number of client certificates so that applications can connect to the Cassandra cluster.

Connect to Cassandra with cqlsh that uses client or server certificates:

1. You need four components to connect to the cluster:

   • Username and password generated during deployment. You can find the credentials in /home/$SUDO_USER/.credentials, where $SUDO_USER is your sudo user created during deployment.
   • Client certificate
   • Client key
   • CA certificate

2. On the client node, create the /home/$SUDO_USER/cassandra_ssl directory, where $SUDO_USER is your sudo user created during deployment.

3. From the first Cassandra node, securely transfer these three files to the /home/$SUDO_USER/cassandra_ssl directory on the client node:

   • /etc/cassandra/ssl/cert/client1.crt
   • /etc/cassandra/ssl/key/client1.key
   • /etc/cassandra/ssl/ca/ca.crt

4. Create a Cassandra resource file to use our client certificate. Create the /home/$SUDO_USER/.cassandra directory, in which you add a cqlshrc file with this content:

   Bash

   [connection]
   ssl = true
   factory = cqlshlib.ssl.ssl_transport_factory
   [ssl]
   certfile = /home/$SUDO_USER/cassandra_ssl/ca.crt
   userkey = /home/$SUDO_USER/cassandra_ssl/client1.key
   usercert = /home/$SUDO_USER/cassandra_ssl/client1.crt
   validate = true

5. Connect to one of the Cassandra servers with cqlsh, replacing 192.168.139.160 with the private IP address of one of the Cassandra nodes and superuser with the Cassandra database user you provided when deploying the cluster.

   Bash

   cqlsh 192.168.139.160 -u superuser --ssl

6. Once you're connected, enter the password from /home/$SUDO_USER/.credentials at the prompt to authenticate to the cluster.

   Connected to Cassandra Cluster at 192.168.139.160:9042
   [cqlsh 6.1.0 | Cassandra 4.1.5 | CQL spec 3.4.6 | Native protocol v5]
   Use HELP for help.
   superadmin@cqlsh>

   You can distribute the remainder of client certificates to the rest of the nodes.

Additional resources

For more information about the installed packages, see their official documentation.

• Apache Cassandra Documentation