From f09af53894ac7037e28360f8593ea91c3fa3c5b7 Mon Sep 17 00:00:00 2001
From: Sarah Christoff <sarah.christoff13@gmail.com>
Date: Fri, 28 Jun 2019 12:40:07 -0500
Subject: [PATCH] Remove failed nodes from serfWAN (#6028)

* Prune Servers from WAN and LAN

* cleaned up and fixed LAN to WAN

* moving things around

* force-leave remove from serfWAN, create pruneSerfWAN

* removed serfWAN remove, reduced complexity, fixed comments

* add another place to remove from serfWAN

* add nil check

* Update agent/consul/server.go

Co-Authored-By: Paul Banks <banks@banksco.de>
---
 agent/consul/autopilot.go           |  6 +++++-
 agent/consul/autopilot/autopilot.go | 27 ++++++++++++++++++---------
 agent/consul/server.go              |  6 ++++++
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/agent/consul/autopilot.go b/agent/consul/autopilot.go
index 59741efc9120..54e2bcd661f4 100644
--- a/agent/consul/autopilot.go
+++ b/agent/consul/autopilot.go
@@ -77,6 +77,10 @@ func (d *AutopilotDelegate) Raft() *raft.Raft {
 	return d.server.raft
 }
 
-func (d *AutopilotDelegate) Serf() *serf.Serf {
+func (d *AutopilotDelegate) SerfLAN() *serf.Serf {
 	return d.server.serfLAN
 }
+
+func (d *AutopilotDelegate) SerfWAN() *serf.Serf {
+	return d.server.serfWAN
+}
diff --git a/agent/consul/autopilot/autopilot.go b/agent/consul/autopilot/autopilot.go
index b54935b5e14a..39d094f590f8 100644
--- a/agent/consul/autopilot/autopilot.go
+++ b/agent/consul/autopilot/autopilot.go
@@ -22,7 +22,8 @@ type Delegate interface {
 	NotifyHealth(OperatorHealthReply)
 	PromoteNonVoters(*Config, OperatorHealthReply) ([]raft.Server, error)
 	Raft() *raft.Raft
-	Serf() *serf.Serf
+	SerfLAN() *serf.Serf
+	SerfWAN() *serf.Serf
 }
 
 // Autopilot is a mechanism for automatically managing the Raft
@@ -182,7 +183,7 @@ func (a *Autopilot) pruneDeadServers() error {
 
 	// Failed servers are known to Serf and marked failed, and stale servers
 	// are known to Raft but not Serf.
-	var failed []string
+	var failed []serf.Member
 	staleRaftServers := make(map[string]raft.Server)
 	raftNode := a.delegate.Raft()
 	future := raftNode.GetConfiguration()
@@ -194,8 +195,8 @@ func (a *Autopilot) pruneDeadServers() error {
 	for _, server := range raftConfig.Servers {
 		staleRaftServers[string(server.Address)] = server
 	}
-
-	serfLAN := a.delegate.Serf()
+	serfWAN := a.delegate.SerfWAN()
+	serfLAN := a.delegate.SerfLAN()
 	for _, member := range serfLAN.Members() {
 		server, err := a.delegate.IsServer(member)
 		if err != nil {
@@ -214,8 +215,12 @@ func (a *Autopilot) pruneDeadServers() error {
 				if found && s.Suffrage == raft.Nonvoter {
 					a.logger.Printf("[INFO] autopilot: Attempting removal of failed server node %q", member.Name)
 					go serfLAN.RemoveFailedNode(member.Name)
+					if serfWAN != nil {
+						go serfWAN.RemoveFailedNode(member.Name)
+					}
 				} else {
-					failed = append(failed, member.Name)
+					failed = append(failed, member)
+
 				}
 			}
 		}
@@ -231,8 +236,12 @@ func (a *Autopilot) pruneDeadServers() error {
 	peers := NumPeers(raftConfig)
 	if removalCount < peers/2 {
 		for _, node := range failed {
-			a.logger.Printf("[INFO] autopilot: Attempting removal of failed server node %q", node)
-			go serfLAN.RemoveFailedNode(node)
+			a.logger.Printf("[INFO] autopilot: Attempting removal of failed server node %q", node.Name)
+			go serfLAN.RemoveFailedNode(node.Name)
+			if serfWAN != nil {
+				go serfWAN.RemoveFailedNode(fmt.Sprintf("%s.%s", node.Name, node.Tags["dc"]))
+			}
+
 		}
 
 		minRaftProtocol, err := a.MinRaftProtocol()
@@ -260,7 +269,7 @@ func (a *Autopilot) pruneDeadServers() error {
 
 // MinRaftProtocol returns the lowest supported Raft protocol among alive servers
 func (a *Autopilot) MinRaftProtocol() (int, error) {
-	return minRaftProtocol(a.delegate.Serf().Members(), a.delegate.IsServer)
+	return minRaftProtocol(a.delegate.SerfLAN().Members(), a.delegate.IsServer)
 }
 
 func minRaftProtocol(members []serf.Member, serverFunc func(serf.Member) (*ServerInfo, error)) (int, error) {
@@ -369,7 +378,7 @@ func (a *Autopilot) updateClusterHealth() error {
 	// Get the the serf members which are Consul servers
 	var serverMembers []serf.Member
 	serverMap := make(map[string]*ServerInfo)
-	for _, member := range a.delegate.Serf().Members() {
+	for _, member := range a.delegate.SerfLAN().Members() {
 		if member.Status == serf.StatusLeft {
 			continue
 		}
diff --git a/agent/consul/server.go b/agent/consul/server.go
index 6b68e6ac1cff..f9c20dc1ded5 100644
--- a/agent/consul/server.go
+++ b/agent/consul/server.go
@@ -13,6 +13,7 @@ import (
 	"path/filepath"
 	"reflect"
 	"strconv"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -1003,6 +1004,11 @@ func (s *Server) RemoveFailedNode(node string) error {
 	if err := s.serfLAN.RemoveFailedNode(node); err != nil {
 		return err
 	}
+	// The Serf WAN pool stores members as node.datacenter
+	// so the dc is appended if not present
+	if !strings.HasSuffix(node, "."+s.config.Datacenter) {
+		node = node + "." + s.config.Datacenter
+	}
 	if s.serfWAN != nil {
 		if err := s.serfWAN.RemoveFailedNode(node); err != nil {
 			return err