Adds support for new-style peers.json recovery for newer Raft protocol versions.

consul/server.go

@@ -518,10 +518,17 @@ func (s *Server) setupRaft() error {
 			}
 		} else if _, err := os.Stat(peersFile); err == nil {
 			s.logger.Printf("[INFO] consul: found peers.json file, recovering Raft configuration...")
-			configuration, err := raft.ReadPeersJSON(peersFile)
+
+			var configuration raft.Configuration
+			if s.config.RaftConfig.ProtocolVersion < 3 {
+				configuration, err = raft.ReadPeersJSON(peersFile)
+			} else {
+				configuration, err = raft.ReadConfigJSON(peersFile)
+			}
 			if err != nil {
 				return fmt.Errorf("recovery failed to parse peers.json: %v", err)
 			}
+
 			tmpFsm, err := NewFSM(s.tombstoneGC, s.config.LogOutput)
 			if err != nil {
 				return fmt.Errorf("recovery failed to make temp FSM: %v", err)
@@ -530,6 +537,7 @@ func (s *Server) setupRaft() error {
 				log, stable, snap, trans, configuration); err != nil {
 				return fmt.Errorf("recovery failed: %v", err)
 			}
+
 			if err := os.Remove(peersFile); err != nil {
 				return fmt.Errorf("recovery failed to delete peers.json, please delete manually (see peers.info for details): %v", err)
 			}
@@ -965,10 +973,54 @@ func (s *Server) GetWANCoordinate() (*coordinate.Coordinate, error) {
 // location.
 const peersInfoContent = `
 As of Consul 0.7.0, the peers.json file is only used for recovery
-after an outage. It should be formatted as a JSON array containing the address
+after an outage. The format of this file depends on what the server has
-and port of each Consul server in the cluster, like this:
+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.
 
-["10.1.0.1:8300","10.1.0.2:8300","10.1.0.3:8300"]
+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.consul.io/docs/guides/autopilot.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.
 

website/source/docs/guides/outage.html.markdown

@@ -124,21 +124,60 @@ periodic basis.
 
 The next step is to go to the [`-data-dir`](/docs/agent/options.html#_data_dir)
 of each Consul server. Inside that directory, there will be a `raft/`
-sub-directory. We need to create a `raft/peers.json` file. It should look
+sub-directory. We need to create a `raft/peers.json` file. The format of this file
-something like:
+depends on what the server has configured for its
+[Raft protocol](/docs/agent/options.html#_raft_protocol) version.
 
-```javascript
+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:
+
+```json
 [
-"10.0.1.8:8300",
+  "10.1.0.1:8300",
-"10.0.1.6:8300",
+  "10.1.0.2:8300",
-"10.0.1.7:8300"
+  "10.1.0.3:8300"
 ]
 ```
 
-Simply create entries for all remaining servers. You must confirm
+For Raft protocol version 3 and later, this should be formatted as a JSON
-that servers you do not include here have indeed failed and will not later
+array containing the node ID, address:port, and suffrage information of each
-rejoin the cluster. Ensure that this file is the same across all remaining
+Consul server in the cluster, like this:
-server nodes.
+
+```
+[
+  {
+    "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
+  }
+]
+```
+
+- `id` `(string: <required>)` - Specifies the [node ID](/docs/agent/options.html#_node_id)
+  of the server. This can be found in the logs when the server starts up if it was auto-generated,
+  and it can also be found inside the `node-id` file in the server's data directory.
+
+- `address` `(string: <required>)` - Specifies the IP and port of the server. The port is the
+  server's RPC port used for cluster communications.
+
+- `non_voter` `(bool: <false>)` - This controls whether the server is a non-voter, which is used
+  in some advanced [Autopilot](/docs/guides/autopilot.html) configurations. If omitted, it will
+  default to false, which is typical for most clusters.
+
+Simply create entries for all servers. You must confirm that servers you do not include here have
+indeed failed and will not later rejoin the cluster. Ensure that this file is the same across all
+remaining server nodes.
 
 At this point, you can restart all the remaining servers. In Consul 0.7 and
 later you will see them ingest recovery file:
@@ -177,8 +216,8 @@ command to inspect the Raft configuration:
 
 ```
 $ consul operator raft -list-peers
-Node     ID              Address         State     Voter
+Node     ID              Address         State     Voter  RaftProtocol
-alice    10.0.1.8:8300   10.0.1.8:8300   follower  true
+alice    10.0.1.8:8300   10.0.1.8:8300   follower  true   2
-bob      10.0.1.6:8300   10.0.1.6:8300   leader    true
+bob      10.0.1.6:8300   10.0.1.6:8300   leader    true   2
-carol    10.0.1.7:8300   10.0.1.7:8300   follower  true
+carol    10.0.1.7:8300   10.0.1.7:8300   follower  true   2
 ```