Setting Up Apache Flink with SQL Gateway Using Podman

This document outlines the steps to configure Apache Flink with SQL Gateway running in Podman containers.

Prerequisites

• Podman installed on your machine.
• Apache Flink image available from the Docker Hub.

Step 1: Start the JobManager Container

Run the Flink JobManager container and enable the SQL Gateway by passing environment variables:

podman run -d \
  --name flink-jobmanager \
  -p 8081:8081 \        # Port for the Flink Web UI
  -p 8082:8082 \        # Port for the SQL Gateway
  -e FLINK_SQL_GATEWAY_ENABLED=true \  # Enable the SQL Gateway
  -e FLINK_SQL_GATEWAY_PORT=8082 \     # Set the SQL Gateway port
  apache/flink:latest jobmanager

Step 2: Start the TaskManager Container

Run the Flink TaskManager container, linking it to the JobManager:

podman run -d \
  --name flink-taskmanager \
  --link flink-jobmanager:jobmanager \  # Link to the JobManager
  -e JOBMANAGER_HOST=jobmanager \       # Specify the JobManager host
  -e JOBMANAGER_PORT=8081 \             # Specify the JobManager port
  apache/flink:latest taskmanager

Step 3: Verify the SQL Gateway

1. Open your web browser.
2. Navigate to http://localhost:8082 to access the SQL Gateway web interface.

Step 4: Connect to the SQL Gateway

You can connect to the Flink SQL Gateway using a SQL client (e.g., Aqua Studio) that supports JDBC.

• JDBC URL:

  
  jdbc:flink://localhost:8082
  

• Username and Password: Leave these fields blank if you haven't set authentication.

Step 5: Write and Execute SQL Queries

Once connected, you can write and execute SQL queries against your Flink tables and data streams.

Example Query

You can start with a simple query like:

sql

SELECT * FROM your_table_name;

Additional Configuration (Optional)

• Persistent Storage: To persist data, consider mounting volumes for the Flink containers.
• Environment Variables: You can set additional environment variables for specific configurations as needed.