ElastiCache (Redis)

Overview

ElastiCache provides managed Redis caching clusters for your application. Tapitalee automatically provisions Amazon ElastiCache Redis instances in your AWS account, offering high-performance in-memory data storage for caching, session management, and real-time analytics.

Purpose and Benefits

• High-Performance Caching: In-memory data store with sub-millisecond latency
• Session Storage: Persistent session management across application restarts
• Data Structures: Rich data types including strings, hashes, lists, sets, and sorted sets
• Scalability: Easy scaling with cluster mode and read replicas
• Persistence: Optional data persistence with snapshots and append-only files
• Integration: Automatic environment variable injection for seamless app connectivity

CLI Usage

Create ElastiCache Redis Cluster

tapit  create elasticache engine=redis name=cluster_name [variable=REDIS_URL] [size=cache.t4g.micro] [cache_eviction=yes]

Required Parameters

• engine: Must be redis (currently the only supported engine)
• name: Cluster name (alphanumeric, used for ElastiCache cluster identifier)

Optional Parameters

• variable: Environment variable name for Redis connection URL (default: REDIS_URL)
• size: ElastiCache node type (default: cache.t4g.micro)
• cache_eviction: Enable automatic eviction of least recently used keys when memory is full (default: yes)

Examples

# Basic Redis cluster
tapit create elasticache engine=redis name=cache

# Redis with custom configuration
tapit create elasticache engine=redis name=sessionstore variable=SESSION_REDIS_URL size=cache.r7g.large

# Redis without eviction (for persistent data)
tapit create elasticache engine=redis name=datastore cache_eviction=no

List and Show ElastiCache Clusters

# List all addons (including ElastiCache)
tapit list addons

# Show specific ElastiCache details
tapit show addon name=cluster_name

Delete ElastiCache Cluster

tapit delete addon name=cluster_name

Warning: This permanently deletes the Redis cluster and all cached data. Consider creating a backup if you have important data.

Environment Variables

When you create an ElastiCache cluster, Tapitalee automatically injects connection details as environment variables:

• REDIS_URL (or custom variable name): Complete Redis connection string

Connection String Format

redis://[password@]hostname:6379[/database_number]

Security

• Encryption: Data encryption in transit is enabled by default
• Access Control: Only your Tapitalee application containers can access Redis by default
• VPC Security: Redis instances are isolated within your VPC

Instance Types and Performance

Burstable Performance (T4g)

• cache.t4g.micro: 2 vCPUs, 0.5 GB RAM - Development/testing
• cache.t4g.small: 2 vCPUs, 1.5 GB RAM - Small applications
• cache.t4g.medium: 2 vCPUs, 3.2 GB RAM - Medium workloads

Memory Optimized (R7g)

• cache.r7g.large: 2 vCPUs, 13.1 GB RAM - Memory-intensive caching
• cache.r7g.xlarge: 4 vCPUs, 26.3 GB RAM - High-performance applications
• cache.r7g.2xlarge: 8 vCPUs, 52.6 GB RAM - Large-scale caching

Compute Optimized (C7g)

• cache.c7g.large: 2 vCPUs, 3.4 GB RAM - CPU-intensive workloads
• cache.c7g.xlarge: 4 vCPUs, 6.8 GB RAM - High-performance computing

Cache Eviction Policies

With Eviction (cache_eviction=yes)

• By default, Redis removes least recently used keys when memory limit is reached
• Ideal for: caching, session storage, and temporary data

Without Eviction (cache_eviction=no)

• This sets the redis noeviction policy, which will return errors when memory limit is reached
• This guarantees existing data won’t be lost if you hit the memory limit
• Ideal for: Persistent data, queues, data that shouldn’t be lost