Memcached

​

Overview

• Run it directly to get a managed Memcached container with sensible defaults
• Inherit it in your own runnable to seamlessly add a distributed memory cache to your stack

​

What this template manages

• Memcached container (bitnamilegacy/memcached image, configurable tag)
• Network service on port 11211
• Memory allocation and cache management
• Optional authentication with username and password
• Performance tuning via threads, connections, and cache size

​

Quick start (run directly)

1. Load templates

monk load MANIFEST

2. Run Memcached with defaults

monk run memcached/memcached

3. Customize configuration (recommended via inheritance)

• Preferred: inherit and replace variables with secret("...") as shown below.
• Alternative: fork/clone and edit the variables in memcached/memcached.yaml, then monk load MANIFEST and run.

​

Configuration

variables:
  memcached-image: "latest"            # container image tag
  memcached_cache_size: 128            # cache size in MB (env: MEMCACHED_CACHE_SIZE)
  memcached_max_connections: 2000      # max simultaneous connections (env: MEMCACHED_MAX_CONNECTIONS)
  memcached_threads: 4                 # number of worker threads (env: MEMCACHED_THREADS)
  memcached_max_item_size: 8388608     # max item size in bytes (env: MEMCACHED_MAX_ITEM_SIZE)
  memcached_username: "monk"           # authentication username (env: MEMCACHED_USERNAME)
  memcached_password: "monk"           # authentication password (env: MEMCACHED_PASSWORD)
  memcached_extra_flags: ""            # additional flags for memcached (env: MEMCACHED_EXTRA_FLAGS)

​

Use by inheritance (recommended for apps)

namespace: myapp
cache:
  defines: runnable
  inherits: memcached/memcached
api:
  defines: runnable
  containers:
    api:
      image: myorg/api
  connections:
    cache:
      runnable: cache
      service: memcached
  variables:
    cache-host:
      value: <- connection-hostname("cache")
    cache-user:
      value: <- secret("memcached-user")
    cache-password:
      value: <- secret("memcached-password")

monk secrets add -g memcached-user="cacheuser"
monk secrets add -g memcached-password="STRONG_CACHE_PASSWORD"
monk run myapp/api

​

Ports and connectivity

• Service: memcached on TCP port 11211
• From other runnables in the same process group, use connection-hostname("\<connection-name>") to resolve the cache host.

​

Features

• Simple key-value storage
• Fast in-memory caching
• Distributed architecture
• Multiple client libraries
• LRU eviction policy
• Configurable cache size and performance tuning
• Optional authentication support

​

Related templates

• See other templates in this repository for complementary services
• Combine with monitoring tools (prometheus-grafana/) for observability
• Integrate with your application stack as needed

​

Troubleshooting

• If you changed memcached_password after initial setup, ensure your client applications use the updated credentials.
• Adjust memcached_cache_size if you’re experiencing evictions or have available memory.
• Increase memcached_max_connections if you’re seeing connection refused errors under high load.
• Check logs:

monk logs -l 500 -f memcached/memcached