doc: add local_cluster doc

Documentation/local_cluster.md

@@ -0,0 +1,90 @@
+# Setup a Local Cluster
+
+For testing and development deployments, the quickest and easiest way is to set up a local cluster. For a production deployment, refer to the [clustering][clustering] section.
+
+## Local Standalone Cluster
+
+Deploying an etcd cluster as a standalone cluster is straightforward. Start it with just one command:
+
+```
+$ ./etcd
+...
+```
+
+The started etcd member listens on `localhost:2379` for client requests.
+
+To interact with the started cluster by using etcdctl:
+
+```
+# use API version 3
+$ export ETCDCTL_API=3
+
+$ ./etcdctl put foo bar
+OK
+
+$ ./etcdctl get foo
+bar
+```
+
+## Local Multi-member Cluster
+
+A Procfile is provided to easily set up a local multi-member cluster. Start a multi-member cluster with a few commands:
+
+```
+# install goreman program to control Profile-based applications.
+$ go get github.com/mattn/goreman
+$ goreman -f Procfile start
+...
+```
+
+The started members listen on `localhost:12379`, `localhost:22379`, and `localhost:32379` for client requests respectively.
+
+To interact with the started cluster by using etcdctl:
+
+```
+# use API version 3
+$ export ETCDCTL_API=3
+
+$ etcdctl --endpoints=localhost:12379 member list
++------------------+---------+--------+------------------------+------------------------+
+|        ID        | STATUS  |  NAME  |       PEER ADDRS       |      CLIENT ADDRS      |
++------------------+---------+--------+------------------------+------------------------+
+| 8211f1d0f64f3269 | started | infra1 | http://127.0.0.1:12380 | http://127.0.0.1:12379 |
+| 91bc3c398fb3c146 | started | infra2 | http://127.0.0.1:22380 | http://127.0.0.1:22379 |
+| fd422379fda50e48 | started | infra3 | http://127.0.0.1:32380 | http://127.0.0.1:32379 |
++------------------+---------+--------+------------------------+------------------------+
+
+$ etcdctl --endpoints=localhost:12379 put foo bar
+OK
+```
+
+To exercise etcd's fault tolerance, kill a member:
+
+```
+# kill etcd2
+$ goreman run stop etcd2
+
+$ etcdctl --endpoints=localhost:12379 put key hello
+OK
+
+$ etcdctl --endpoints=localhost:12379 get key
+hello
+
+# try to get key from the killed member
+$ etcdctl --endpoints=localhost:22379 get key
+2016/04/18 23:07:35 grpc: Conn.resetTransport failed to create client transport: connection error: desc = "transport: dial tcp 127.0.0.1:22379: getsockopt: connection refused"; Reconnecting to "localhost:22379"
+Error:  grpc: timed out trying to connect
+
+# restart the killed member
+$ goreman run restart etcd2
+
+# get the key from restarted member
+$ etcdctl --endpoints=localhost:22379 get key
+hello
+```
+
+To learn more about interacting with etcd, read [interacting with etcd section][interacting].
+
+[interacting]: ./interacting_v3.md
+[clustering]: ./clustering.md
+