Fix removal of init node

Removing the initial node from the cluster would previously cause etcd to panic on startup. Fixes to etcd reconcile have stopped that from happening, but now the node will successfully come up and start a new cluster - which is not right either. Require either manual removal of DB files to create a new cluster, or setting server address to join an existing cluster.

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>

pkg/etcd/etcd.go

@@ -700,7 +700,10 @@ func (e *ETCD) Register(handler http.Handler) (http.Handler, error) {
 	if !e.config.DisableETCD {
 		tombstoneFile := filepath.Join(dbDir(e.config), "tombstone")
 		if _, err := os.Stat(tombstoneFile); err == nil {
-			logrus.Infof("tombstone file has been detected, removing data dir to rejoin the cluster")
+			if e.config.JoinURL == "" {
+				return nil, errors.New("tombstone file has been detected but --server is empty: backup and delete ${datadir}/server/db to create a new cluster, or set --server to rejoin the cluster")
+			}
+			logrus.Infof("tombstone file has been detected, removing ${datadir}/server/db to rejoin the cluster")
 			if _, err := backupDirWithRetention(dbDir(e.config), maxBackupRetention); err != nil {
 				return nil, err
 			}
@@ -1231,7 +1234,10 @@ func (e *ETCD) manageLearners(ctx context.Context) {
 			}
 
 			// verify if the member is healthy and set the status
-			if _, err := e.getETCDStatus(ctx, member.ClientURLs[0]); err != nil {
+			if len(member.ClientURLs) == 0 {
+				message = "etcd member ClientURLs list is empty"
+				status = StatusUnhealthy
+			} else if _, err := e.getETCDStatus(ctx, member.ClientURLs[0]); err != nil {
 				message = err.Error()
 				status = StatusUnhealthy
 			}

pkg/etcd/etcd_linux_test.go

@@ -213,6 +213,7 @@ func Test_UnitETCD_Register(t *testing.T) {
 				testutil.CleanupDataDir(cnf)
 				return nil
 			},
+			wantErr: true,
 		},
 	}
 	for _, tt := range tests {