Amazon Elastic Cache for Redis Lecture Notes

Introduction

• Presenter: Sambhu from CloudTech
• Topic: Amazon Elastic Cache for Redis
• Purpose: Demonstration on configuration and usage

Key Points

What is Amazon Elastic Cache?

• In-memory caching service
• Reduces backend server calls by storing cache entries

Caching Mechanisms Supported

• Redis Cache
• Memcached

Advantages and Disadvantages

Advantages

• Performance improvement by reducing database queries
• Scalability (scale in/out)
• Cost-effective
• Reliable
• Optimizes deployment and management of distributed caching environment

Disadvantages

• None specifically mentioned

Use Cases

• Backup applications
• E-commerce sites
• Streaming platforms like Netflix
• Applications with high database query loads benefited by caching

Configuration Steps for Redis Cache

Prerequisites

• AWS Console logged in

Configuration Process

1. Select Region: Example used Virginia
2. Search & Select Elastic Cache on AWS Console
3. Create Subnet Group: Necessary before creating cache
   • Use default VPC
   • Select at least 2 subnets
4. Create Cluster: Using Redis
   • Default VPC and settings
   • Subnet group created previously
   • Network settings (IPV4, Subnet group)
   • Security group and parameters
   • Optional: Replication, encryption, automatic backup
5. Launch Cluster
6. Create Lambda Function
   • Specify Python version
   • Configure VPC, subnets, and security groups
   • Add Redis dependency using AWS layer
   • Configure environment variables (host, port, password)
   • Deploy function

Example Code for Lambda Function

import os
import redis

host = os.environ['HOST']
port = os.environ['PORT']
password = os.environ['PASSWORD']

if not host or not port:
   return {'statusCode': 500, 'body': 'Missing required parameters'}

client = redis.StrictRedis(host=host, port=port, password=password, decode_responses=True)
client.set('CloudTech', 'Elastic Cache Demo from Lambda Python')
value = client.get('CloudTech')

return {'statusCode': 200, 'body': f'Value from cache: {value}'}

Connect to Redis from EC2

1. Launch EC2 instance
2. Configure security group
3. Connect via SSH and install redis-cli

Commands for Redis Connection

• Set and Get values:
  • redis-cli set key value
  • redis-cli get key
• List all keys: redis-cli keys *

Additional Notes

• Telnet Option: Alternative for redis-cli
• Updating Configuration: Modify environment variables in Lambda instead of redeploying

Conclusion

• Redis cache effectively bridges backend and improves application performance.
• Telnet can be used as a workaround for redis-cli installation issues.
• Encouragement to subscribe and share the channel for more tutorials.

Next Steps

• Upcoming videos on Memcached configuration and other caching mechanisms.