Setup a local cluster

Local standalone cluster

运行一个standalone集群非常简单。只需一个命令：

$ ./etcd

etcd将监听localhost:2379端口。

可以通过etcdctl与集群交互：

# use API version 3
$ export ETCDCTL_API=3

$ ./etcdctl put foo bar
OK

$ ./etcdctl get foo
bar

Local multi-member cluster

可以通过Procfile可以运行一个multi-member cluster：

#install goreman program to control Profile-based applications.
$ go get github.com/mattn/goreman
$ goreman -f Procfile start

集群将启动，并监听localhost:2379，localhost:22379和localhost:32379端口。

可以通过etcdctl与集群交互：

# use API version 3
$ export ETCDCTL_API=3

$ etcdctl --write-out=table --endpoints=localhost:2379 member list

| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS | | —- | :—- | :—- | :—- | :—- | | 8211f1d0f64f3269 | started | infra1 | http://127.0.0.1:2380 | http://127.0.0.1:2379 | | 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 put foo bar
OK

ETCD的容错功能可以通过杀掉其中一个member体验：

# kill etcd2
$ goreman run stop etcd2

$ etcdctl put key hello
OK

$ etcdctl 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