From 295ade4f7c3ede12b47c9ff75418e13c75c68c7d Mon Sep 17 00:00:00 2001
From: Allen Zhong <zhongbenli@pingcap.com>
Date: Thu, 17 Dec 2020 21:53:28 +0800
Subject: [PATCH] manager/deploy: do not allow deploying of empty topology
 (#994)

Co-authored-by: SIGSEGV <gnu.crazier@gmail.com>
Co-authored-by: Ti Prow Robot <71242396+ti-community-prow-bot@users.noreply.github.com>
---
 pkg/cluster/manager/deploy.go | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/pkg/cluster/manager/deploy.go b/pkg/cluster/manager/deploy.go
index a6053ea31f..14b5f20675 100644
--- a/pkg/cluster/manager/deploy.go
+++ b/pkg/cluster/manager/deploy.go
@@ -87,6 +87,23 @@ func (m *Manager) Deploy(
 		return err
 	}
 
+	instCnt := 0
+	topo.IterInstance(func(inst spec.Instance) {
+		switch inst.ComponentName() {
+		// monitoring components are only useful when deployed with
+		// core components, we do not support deploying any bare
+		// monitoring system.
+		case spec.ComponentGrafana,
+			spec.ComponentPrometheus,
+			spec.ComponentAlertmanager:
+			return
+		}
+		instCnt++
+	})
+	if instCnt < 1 {
+		return fmt.Errorf("no valid instance found in the input topology, please check your config")
+	}
+
 	spec.ExpandRelativeDir(topo)
 
 	base := topo.BaseTopo()