Set up a Cloudberry demo cluster

This step walks through setting up a Cloudberry demo cluster, and testing basic functionality. The demo cluster includes a coordinator, standby coordinator, and multiple primary/mirror segments all running on a single development host.

Set up initial container (not required for all environments)

Container environments typically don't start the SSH daemon process by default. Since Cloudberry relies heavily on SSH for inter-process communication, we need to initialize and start the SSH server:

if ! pgrep sshd > /dev/null; then
    echo "SSH daemon not running. Starting it now..."
    sudo ssh-keygen -A
    echo "PasswordAuthentication yes" | sudo tee -a /etc/ssh/sshd_config
    sudo /usr/sbin/sshd
else
    echo "SSH daemon is already running"
fi

Configure SSH for Cloudberry

Cloudberry uses SSH for coordinator-segment communication. The following commands ensure SSH is properly configured for the gpadmin user by adding the host to known_hosts and verifying SSH connectivity:

ssh-keyscan $(hostname) >> ~/.ssh/known_hosts
ssh $(hostname) date

Set up Cloudberry environment variables

Load Cloudberry environment variables that set up paths for binaries, libraries, and other essential components:

source /usr/local/cloudberry-db/greenplum_path.sh

Create development cluster

Create a demo cluster that simulates a full Cloudberry deployment on a single machine. This includes 1 coordinator, 1 standby coordinator, 3 primary segments, and 3 mirror segments:

make create-demo-cluster --directory=~/cloudberry

In the demo cluster, the cooradinator, standby coordinator and segments ports will be as follows:

    COORDINATOR PORT (PGPORT). : 7000
    STANDBY PORT ............. : 7001
    SEGMENT PORTS ............ : 7002 7003 7004 7005 7006 7007

Configure cluster environment

After cluster creation, verify and load cluster-specific variables that point to the coordinator port and data directory:

source ~/cloudberry/gpAux/gpdemo/gpdemo-env.sh

Validate cluster deployment

Verify the cluster is running correctly with these essential commands:

# Displays detailed cluster state including segment status
gpstate

# Tests cluster shutdown and startup
gpstop -a
gpstart -a

# Confirms Cloudberry version and build
psql template1 -c 'SELECT version()'

# Views segment configuration showing primary/mirror relationships
psql template1 -c 'SELECT * from gp_segment_configuration'

# Checks available PostgreSQL extensions
psql template1 -c 'SELECT * FROM pg_available_extensions'

Connect to the default postgres database

To connect to the default postgres database, use the following command:

psql -p 7000 postgres

Or

psql postgres

The output will be like this:

[gpadmin@cdw cloudberry]$ psql -p 7000 postgres
psql (14.4, server 14.4)
Type "help" for help.

postgres=# select version();
                                                                                                             version
------------------------------------------------------------------------------------------------------------------------
 PostgreSQL 14.4 (Apache Cloudberry 2.0.0-devel+dev.1959.g94a81765e6 build dev) on x86_64-pc-linux-gnu, compiled by gcc (GCC
) 11.5.0 20240719 (Red Hat 11.5.0-5), 64-bit compiled on May 28 2025 19:57:16 (with assert checking)
(1 row)

postgres=# \q

Extension Testing Example: pg_stat_statements

This example demonstrates how to enable and test the pg_stat_statements extension, which provides statistics about SQL query execution:

# Creates a database for testing
createdb gpadmin

# Enables the extension by adding it to shared libraries
echo "shared_preload_libraries='pg_stat_statements'" >> $COORDINATOR_DATA_DIRECTORY/postgresql.conf

# Restarts cluster to load the new library (-r flag means "restart")
gpstop -ar

# Creates the extension in the database
psql gpadmin -e -c 'CREATE EXTENSION pg_stat_statements'

# Runs test queries to generate statistics
psql gpadmin --echo-queries <<EOF
-- Create a sample table
CREATE TABLE employees (
    id SERIAL PRIMARY KEY,
    name TEXT,
    department TEXT,
    salary NUMERIC
);

-- Insert sample data
INSERT INTO employees (name, department, salary)
VALUES
('Alice', 'HR', 60000),
('Bob', 'Engineering', 80000),
('Charlie', 'Marketing', 70000);

-- Query the data to generate some statistics
SELECT * FROM employees WHERE department = 'Engineering';
SELECT AVG(salary) FROM employees;

-- View most frequently called queries
SELECT query, calls, total_exec_time AS total_time, rows
FROM pg_stat_statements
ORDER BY calls DESC
LIMIT 5;

-- View most time-consuming queries
SELECT query, calls, total_exec_time AS total_time, rows
FROM pg_stat_statements
ORDER BY total_exec_time DESC
LIMIT 5;
EOF

Destroy development cluster

To clean up and start fresh, you can destroy the demo cluster:

make destroy-demo-cluster --directory=~/cloudberry

This command removes all cluster data and configuration, allowing you to create a new clean cluster if needed.

Troubleshoot SSH connection issues

When running create-demo-cluster, the process may hang if SSH host verification hasn't been completed. This typically manifests as a stalled process waiting for user input to verify the host identity.

This is why we run:

ssh-keyscan $(hostname) >> ~/.ssh/known_hosts

before creating the cluster. This command automatically adds the host's SSH keys to the known_hosts file, preventing interactive prompts during cluster creation.

If you still encounter SSH issues:

1. Verify that the SSH daemon is running
2. Check that the known_hosts file exists and has the correct permissions
3. Test SSH connectivity with ssh $(hostname) date before proceeding with cluster creation