# Supported tags and respective `Dockerfile` links

-	[`1.4.25`, `1.4`, `1`, `latest` (*Dockerfile*)](https://github.com/docker-library/memcached/blob/1944b045661a2fabcf2b9677f7edaa07e04f8d8d/Dockerfile)

For more information about this image and its history, please see [the relevant manifest file (`library/memcached`)](https://github.com/docker-library/official-images/blob/master/library/memcached). This image is updated via pull requests to [the `docker-library/official-images` GitHub repo](https://github.com/docker-library/official-images).

For detailed information about the virtual/transfer sizes and individual layers of each of the above supported tags, please see [the `memcached/tag-details.md` file](https://github.com/docker-library/docs/blob/master/memcached/tag-details.md) in [the `docker-library/docs` GitHub repo](https://github.com/docker-library/docs).

# What is Memcached?

Memcached is a general-purpose distributed memory caching system. It is often used to speed up dynamic database-driven websites by caching data and objects in RAM to reduce the number of times an external data source (such as a database or API) must be read.

Memcached's APIs provide a very large hash table distributed across multiple machines. When the table is full, subsequent inserts cause older data to be purged in least recently used order. Applications using Memcached typically layer requests and additions into RAM before falling back on a slower backing store, such as a database.

> [wikipedia.org/wiki/Memcached](https://en.wikipedia.org/wiki/Memcached)

# How to use this image

```console
$ docker run --name my-memcache -d memcached
```

Start your memcached container with the above command and then you can connect you app to it with standard linking:

```console
$ docker run --link my-memcache:memcache -d my-app-image
```

The memcached server information would then be available through the ENV variables generated by the link as well as through DNS as `memcache` from `/etc/hosts`.

How to set the memory usage for memcached

```console
$ docker run --name my-memcache -d memcached memcached -m 64
```

This would set the memcache server to use 64 megabytes for storage.

For infomation on configuring your memcached server, see the extensive [wiki](https://code.google.com/p/memcached/wiki/NewStart).

# License

View [license information](https://github.com/memcached/memcached/blob/master/LICENSE) for the software contained in this image.

# Supported Docker versions

This image is officially supported on Docker version 1.9.1.

Support for older versions (down to 1.6) is provided on a best-effort basis.

Please see [the Docker installation documentation](https://docs.docker.com/installation/) for details on how to upgrade your Docker daemon.

# User Feedback

## Documentation

Documentation for this image is stored in the [`memcached/` directory](https://github.com/docker-library/docs/tree/master/memcached) of the [`docker-library/docs` GitHub repo](https://github.com/docker-library/docs). Be sure to familiarize yourself with the [repository's `README.md` file](https://github.com/docker-library/docs/blob/master/README.md) before attempting a pull request.

## Issues

If you have any problems with or questions about this image, please contact us through a [GitHub issue](https://github.com/docker-library/memcached/issues).

You can also reach many of the official image maintainers via the `#docker-library` IRC channel on [Freenode](https://freenode.net).

## Contributing

You are invited to contribute new features, fixes, or updates, large or small; we are always thrilled to receive pull requests, and do our best to process them as fast as we can.

Before you start to code, we recommend discussing your plans through a [GitHub issue](https://github.com/docker-library/memcached/issues), especially for more ambitious contributions. This gives other contributors a chance to point you in the right direction, give you feedback on your design, and help you find out if someone else is working on the same thing.
