Docker Twemproxy (Nutcracker)

Twemproxy (nutcracker) is a lightwieght proxy for memcached and redis.

Run

There are 2 ways to run the twemproxy container. A configuration can be dynamically configured through environment variables by specifying the servers (and other parameters) through the TWEMPROXY_SERVERS variable. If you are not specifiying the path to a configuration file, you must at least define TWEMPROXY_SERVERS. A full list of configuration options are listed below.

docker run -p 11211 -p 22222 \
  -e 'TWEMPROXY_SERVERS=127.0.0.1:11311:1,127.0.0.1:11411:1,127.0.0.1:11511:1' \
  -e 'TWEMPROXY_TIMEOUT=10' \
  kochava/twemproxy

The other way to start up twemproxy is to specify the TWEMPROXY_CONFIG variable to reference a config that has been prebaked into a container image or added to the image as part of it's initialization process in a scheduling framework such as Kubernetes or Marathon.

docker run -p 11211 -p 22222 \
  -e 'TWEMPROXY_CONFIG=/path/to/nutcracker.yml' \
  kochava/twemproxy

Environment Variables

Nutcracker command options

• TWEMPROXY_VERBOSE: Verbosity of nutcracker logging from 0 to 11. Default 5.
• TWEMPROXY_STATS_PORT: The port to expose stats on. Default 22222.
• TWEMPROXY_STATS_ADDRESS: The address to expose stats on. Default 127.0.0.1.
• TWEMPROXY_STATS_INTERVAL: The stats aggregation interval in msec. Default 30000.
• TWEMPROXY_MBUF_SIZE: Size of mbuf chunk in bytes. Default 16384.

Static pool configuration options

• TWEMPROXY_CONFIG: The path to a configuration artifact that has been added to the container. It is not set by default.

Dynamic pool configuration options

• TWEMPROXY_LISTEN: The host:port combination to listen on. Default 127.0.0.1:11211.
• TWEMPROXY_HASH: The name of the hash function. Default fnv1a_64.
• TWEMPROXY_DISTRIBUTION: The key distribution mode. Default ketama.
• TWEMPROXY_AUTO_EJECT_HOSTS: Whether or not a host should be temporarily ejected on failure. Default true.
• TWEMPROXY_SERVER_RETRY_TIMEOUT: The timeout value in msec to wait before retrying and ejected host. Default 30000 msec.
• TWEMPROXY_SERVER_FAILURE_LIMIT: The number of failures that would lead to a host being temporarily ejected. Default 2.
• TWEMPROXY_TIMEOUT: The timeout value in msec to wait for a connection to a server. Default 60000 msec.
• TWEMPROXY_BACKLOG: The TCP backlog argument. Default 512.
• TWEMPROXY_PRECONNECT: Whether or not twemproxy should pre-connect to all servers in the pool on startup. Default false.
• TWEMPROXY_REDIS: Whether or not the pools speaks as Redis. Default false.
• TWEMPROXY_REDIS_DB: The redis db number. There is no default and is only used when TWEMPROXY_REDIS is set to true.
• TWEMPROXY_REDIS_AUTH: Authenticate to the Redis server on connect. There is no default and is only used when TWEMPROXY_REDIS is set to true.
• TWEMPROXY_SERVERS: A comma seperated list of server:port:priority entries to use in the servers block of the nutcracker configuration.