For testing and development deployments, the quickest and easiest way is to configure a local cluster. For a production deployment, refer to the clustering section.

Local standalone cluster

Starting a cluster

Run the following to deploy an etcd cluster as a standalone cluster:

$ ./etcd
...

If the etcd binary is not present in the current working directory, it might be located either at $GOPATH/bin/etcd or at /usr/local/bin/etcd. Run the command appropriately.

The running etcd member listens on localhost:2379 for client requests.

Interacting with the cluster

Use etcdctl to interact with the running cluster:

• Store an example key-value pair in the cluster:

  $ ./etcdctl put foo bar
  OK

If OK is printed, storing key-value pair is successful.

• Retrieve the value of foo:

$ ./etcdctl get foo
bar

If bar is returned, interaction with the etcd cluster is working as expected.

Local multi-member cluster

Starting a cluster

A Procfile at the base of the etcd git repository is provided to easily configure a local multi-member cluster. To start a multi-member cluster, navigate to the root of the etcd source tree and perform the following:

• Install goreman to control Procfile-based applications:

$ go get github.com/mattn/goreman

• Start a cluster with goreman using etcd’s stock Procfile:

$ goreman -f Procfile start

The members start running. They listen on localhost:2379, localhost:22379, and localhost:32379 respectively for client requests.

Interacting with the cluster

Use etcdctl to interact with the running cluster:

• Print the list of members:

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

The list of etcd members are displayed as follows:

+------------------+---------+--------+------------------------+------------------------+
|        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 |
+------------------+---------+--------+------------------------+------------------------+

• Store an example key-value pair in the cluster:

$ etcdctl put foo bar
OK

If OK is printed, storing key-value pair is successful.

Testing fault tolerance

To exercise etcd’s fault tolerance, kill a member and attempt to retrieve the key.

• Identify the process name of the member to be stopped.

The Procfile lists the properties of the multi-member cluster. For example, consider the member with the process name, etcd2.

• Stop the member:

# kill etcd2
$ goreman run stop etcd2

• Store a key:

$ etcdctl put key hello
OK

• Retrieve the key that is stored in the previous step:

$ etcdctl get key
hello

• Retrieve a key from the stopped member:

$ etcdctl --endpoints=localhost:22379 get key

The command should display an error caused by connection failure:

2017/06/18 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 stopped member:

$ goreman run restart etcd2

• Get the key from the restarted member:

$ etcdctl --endpoints=localhost:22379 get key
hello

Restarting the member re-establish the connection. etcdctl will now be able to retrieve the key successfully. To learn more about interacting with etcd, read interacting with etcd section.