Merge pull request #5651 from hashicorp/f-peers-json-info

Update peers info with new raft config details

nomad/server.go

@@ -1470,10 +1470,47 @@ func (s *Server) ReplicationToken() string {
 // location.
 const peersInfoContent = `
 As of Nomad 0.5.5, the peers.json file is only used for recovery
-after an outage. It should be formatted as a JSON array containing the address
-and port (RPC) of each Nomad server in the cluster, like this:
-
-["10.1.0.1:4647","10.1.0.2:4647","10.1.0.3:4647"]
+after an outage. The format of this file depends on what the server has
+configured for its Raft protocol version. Please see the agent configuration
+page at https://www.consul.io/docs/agent/options.html#_raft_protocol for more
+details about this parameter.
+For Raft protocol version 2 and earlier, this should be formatted as a JSON
+array containing the address and port of each Consul server in the cluster, like
+this:
+[
+  "10.1.0.1:8300",
+  "10.1.0.2:8300",
+  "10.1.0.3:8300"
+]
+For Raft protocol version 3 and later, this should be formatted as a JSON
+array containing the node ID, address:port, and suffrage information of each
+Consul server in the cluster, like this:
+[
+  {
+    "id": "adf4238a-882b-9ddc-4a9d-5b6758e4159e",
+    "address": "10.1.0.1:8300",
+    "non_voter": false
+  },
+  {
+    "id": "8b6dda82-3103-11e7-93ae-92361f002671",
+    "address": "10.1.0.2:8300",
+    "non_voter": false
+  },
+  {
+    "id": "97e17742-3103-11e7-93ae-92361f002671",
+    "address": "10.1.0.3:8300",
+    "non_voter": false
+  }
+]
+The "id" field is the node ID of the server. This can be found in the logs when
+the server starts up, or in the "node-id" file inside the server's data
+directory.
+The "address" field is the address and port of the server.
+The "non_voter" field controls whether the server is a non-voter, which is used
+in some advanced Autopilot configurations, please see
+https://www.nomadproject.io/guides/operations/outage.html for more information. If
+"non_voter" is omitted it will default to false, which is typical for most
+clusters.
 
 Under normal operation, the peers.json file will not be present.