single-cluster#

Overview#

This project simplifies ScyllaDB cluster configuration with 3 nodes for local testing using Docker and Docker Compose. It facilitates easy deployment and testing of ScyllaDB, a highly scalable NoSQL database.

Prerequisites#

Before you begin, make sure the following software is installed on your system:

Getting Started#

Clone this repository#

git clone https://github.com/gvieira18/ws-scylla.git

Configure ScyllaDB settings#

Before starting the cluster, ensure the aio-max-nr value is sufficient (e.g., 1048576 or more). Check and adjust the value with the following commands:

cat /proc/sys/fs/aio-max-nr

Attention

The next command adds a file inside the /etc/sysctl.d folder for startup loading.

echo fs.aio-max-nr=1048576 | sudo tee /etc/sysctl.d/41-aio_max_nr.conf && sudo sysctl --system

Optional

Modify the docker-compose.yml file to customize ScyllaDB settings, such as port mappings, volume mounts, and network configurations.

Start the ScyllaDB container#

Use the following command to pull the ScyllaDB Docker image (if not already downloaded) and start the container in the background:

docker compose up --detach # or docker compose up -d

Maintenance#

Accessing the Database#

CQLSH (Cassandra Query Language Shell)

docker compose exec -it ws-scylla-1 cqlsh
# or
docker compose exec -it ws-scylla-2 cqlsh
# or
docker compose exec -it ws-scylla-3 cqlsh

CQLSH is the command-line interface for interacting with ScyllaDB using the Cassandra Query Language (CQL). It allows you to execute CQL queries and manage the database.

Nodetool

docker compose exec -it ws-scylla-1 nodetool status
# or
docker compose exec -it ws-scylla-2 nodetool status
# or
docker compose exec -it ws-scylla-3 nodetool status

Nodetool is a command-line utility for managing and monitoring ScyllaDB clusters. It provides various operations, such as checking the status of nodes, compaction, repair, and more.

Inside the Docker Network

The docker-compose.yml file defines a specific network (ws-scylla) for internal usage. Integration with other projects within different Docker Compose specifications is possible.

services:
  custom-service:
    networks:
      - ws-scylla
networks:
  ws-scylla:
    external: true

After starting the custom service, it registers within the ws-scylla network. The ScyllaDB configuration already defines default ports for access.

Service Name	Host	Port
ws-scylla-1	ws-scylla-1	9042
ws-scylla-2	ws-scylla-2	9042
ws-scylla-3	ws-scylla-3	9042

const client = new cassandra.Client({
  contactPoints: ['ws-scylla-1:9042', 'ws-scylla-2:9042', 'ws-scylla-3:9042'],
  localDataCenter: 'datacenter1',
  keyspace: 'system'
});

Outside the Docker Network

The default docker-compose.yml file enables the following ports for external access to the DBMS/SGDB or directly to the database driver:

Service Name	Host	Port
ws-scylla-1	localhost	9040
ws-scylla-2	localhost	9041
ws-scylla-3	localhost	9042

Using the same example from internal access:

const client = new cassandra.Client({
  contactPoints: ['localhost:9040', 'localhost:9041', 'localhost:9042'],
  localDataCenter: 'datacenter1',
  keyspace: 'system'
});

Access via Datagrip, which belongs to IntelliJ, follows the JDBC standard. You can build the JDBC URL as follows:

URL="jdbc:cassandra://localhost:9040,localhost:9041,localhost:9042/system"

Stop and Remove Cluster/Container#

Stop the Cluster

docker compose stop

Stop and Remove Containers

docker compose down

Danger

Removing the volume also means removing any information stored in the database

So proceed with caution and make a backup if necessary.

docker compose down --volumes # or docker compose down -v

single-cluster#

Overview#

Prerequisites#

Getting Started#

Clone this repository#

Configure ScyllaDB settings#

Start the ScyllaDB container#

Maintenance#

Accessing the Database#

Stop and Remove Cluster/Container#

References#