# etcd

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### WARNING ###

The current `master` branch of etcd is under heavy development in anticipation of the forthcoming 0.5.0 release. 

It is strongly recommended that users work with the latest 0.4.x release (0.4.6), which can be found on the [releases](https://github.com/coreos/etcd/releases) page.

Unless otherwise noted, the etcd documentation refers to configuring and running 0.4.x releases.

## README version 0.4.6

A highly-available key value store for shared configuration and service discovery.
etcd is inspired by [Apache ZooKeeper][zookeeper] and [doozer][doozer], with a focus on being:

* *Simple*: curl'able user facing API (HTTP+JSON)
* *Secure*: optional SSL client cert authentication
* *Fast*: benchmarked 1000s of writes/s per instance
* *Reliable*: properly distributed using Raft

etcd is written in Go and uses the [Raft][raft] consensus algorithm to manage a highly-available replicated log.

See [etcdctl][etcdctl] for a simple command line client.
Or feel free to just use curl, as in the examples below.

[zookeeper]: http://zookeeper.apache.org/
[doozer]: https://github.com/ha/doozerd
[raft]: http://raftconsensus.github.io/
[etcdctl]: http://github.com/coreos/etcdctl/

If you're considering etcd for production use, please see: [production-ready.md](./Documentation/production-ready.md)

## Getting Started

### Getting etcd

The latest release and setup instructions are available at [GitHub][github-release].

[github-release]: https://github.com/coreos/etcd/releases/

### Running etcd

First start a single-machine cluster of etcd:

```sh
./bin/etcd
```

This will bring up etcd listening on port 4001 for client communication and on port 7001 for server-to-server communication.

Next, let's set a single key, and then retrieve it:

```
curl -L http://127.0.0.1:4001/v2/keys/mykey -XPUT -d value="this is awesome"
curl -L http://127.0.0.1:4001/v2/keys/mykey
```

You have successfully started an etcd on a single machine and written a key to the store. Now it's time to dig into the full etcd API and other guides.

### Next Steps

- Explore the full [API][api].
- Set up a [multi-machine cluster][clustering].
- Learn the [config format, env variables and flags][configuration].
- Find [language bindings and tools][libraries-and-tools].
- Learn about the dashboard, lock and leader election [modules][modules].
- Use TLS to [secure an etcd cluster][security].
- [Tune etcd][tuning].
- [Upgrade from old version][upgrade].

[api]: https://github.com/coreos/etcd/blob/master/Documentation/api.md
[clustering]: https://github.com/coreos/etcd/blob/master/Documentation/clustering.md
[configuration]: https://github.com/coreos/etcd/blob/master/Documentation/configuration.md
[libraries-and-tools]: https://github.com/coreos/etcd/blob/master/Documentation/libraries-and-tools.md
[modules]: https://github.com/coreos/etcd/blob/master/Documentation/modules.md
[security]: https://github.com/coreos/etcd/blob/master/Documentation/security.md
[tuning]: https://github.com/coreos/etcd/blob/master/Documentation/tuning.md
[upgrade]: https://github.com/coreos/etcd/blob/master/Documentation/upgrade.md

## Contact

- Mailing list: [etcd-dev](https://groups.google.com/forum/?hl=en#!forum/etcd-dev)
- IRC: #[coreos](irc://irc.freenode.org:6667/#coreos) on freenode.org
- Planning/Roadmap: [milestones](https://github.com/coreos/etcd/milestones)
- Bugs: [issues](https://github.com/coreos/etcd/issues)

## Contributing

See [CONTRIBUTING](CONTRIBUTING.md) for details on submitting patches and the contribution workflow.

## Project Details

### Versioning

#### Service Versioning

etcd uses [semantic versioning](http://semver.org)
New minor versions may add additional features to the API.

You can get the version of etcd by issuing a request to /version:

```sh
curl -L http://127.0.0.1:4001/version
```

#### API Versioning

The `v2` API responses should not change after the 0.2.0 release but new features will be added over time.

The `v1` API has been deprecated and will not be supported.

During the pre-v1.0.0 series of releases we may break the API as we fix bugs and get feedback.

#### 32-bit systems

etcd has known issues on 32-bit systems due to a bug in the Go runtime. See #[358][358] for more information.

[358]: https://github.com/coreos/etcd/issues/358

### License

etcd is under the Apache 2.0 license. See the [LICENSE](LICENSE) file for details.