Esempio n. 1
0
// FindOverlappingHPAs scans the graph in search of HorizontalPodAutoscalers that are attempting to scale the same set of pods.
// This can occur in two ways:
//   - 1. label selectors for two ReplicationControllers/DeploymentConfigs/etc overlap
//   - 2. multiple HorizontalPodAutoscalers are attempting to scale the same ReplicationController/DeploymentConfig/etc
// Case 1 is handled by deconflicting the area of influence of ReplicationControllers/DeploymentConfigs/etc, and therefore we
// can assume that it will be handled before this step. Therefore, we are only concerned with finding HPAs that are trying to
// scale the same resources.
//
// The algorithm that is used to implement this check is described as follows:
//  - create a sub-graph containing only HPA nodes and other nodes that can be scaled, as well as any scaling edges or other
//    edges used to connect between objects that can be scaled
//  - for every resulting edge in the new sub-graph, create an edge in the reverse direction
//  - find the shortest paths between all HPA nodes in the graph
//  - shortest paths connecting two horizontal pod autoscalers are used to create markers for the graph
func FindOverlappingHPAs(graph osgraph.Graph, namer osgraph.Namer) []osgraph.Marker {
	markers := []osgraph.Marker{}

	nodeFilter := osgraph.NodesOfKind(
		kubenodes.HorizontalPodAutoscalerNodeKind,
		kubenodes.ReplicationControllerNodeKind,
		deploynodes.DeploymentConfigNodeKind,
	)
	edgeFilter := osgraph.EdgesOfKind(
		kubegraph.ScalingEdgeKind,
		deploygraph.DeploymentEdgeKind,
		kubeedges.ManagedByControllerEdgeKind,
	)

	hpaSubGraph := graph.Subgraph(nodeFilter, edgeFilter)
	for _, edge := range hpaSubGraph.Edges() {
		osgraph.AddReversedEdge(hpaSubGraph, edge.From(), edge.To(), sets.NewString())
	}

	hpaNodes := hpaSubGraph.NodesByKind(kubenodes.HorizontalPodAutoscalerNodeKind)

	for _, firstHPA := range hpaNodes {
		// we can use Dijkstra's algorithm as we know we do not have any negative edge weights
		shortestPaths := path.DijkstraFrom(firstHPA, hpaSubGraph)

		for _, secondHPA := range hpaNodes {
			if firstHPA == secondHPA {
				continue
			}

			shortestPath, _ := shortestPaths.To(secondHPA)

			if shortestPath == nil {
				// if two HPAs have no path between them, no error exists
				continue
			}

			markers = append(markers, osgraph.Marker{
				Node:         firstHPA,
				Severity:     osgraph.WarningSeverity,
				RelatedNodes: shortestPath[1:],
				Key:          HPAOverlappingScaleRefWarning,
				Message: fmt.Sprintf("%s and %s overlap because they both attempt to scale %s",
					namer.ResourceName(firstHPA), namer.ResourceName(secondHPA), nameList(shortestPath[1:len(shortestPath)-1], namer)),
			})
		}
	}

	return markers
}
Esempio n. 2
0
func TestDijkstraFrom(t *testing.T) {
	for _, test := range shortestPathTests {
		g := test.g()
		for _, e := range test.edges {
			g.SetEdge(e, e.Cost)
		}

		var (
			pt path.Shortest

			panicked bool
		)
		func() {
			defer func() {
				panicked = recover() != nil
			}()
			pt = path.DijkstraFrom(test.query.From(), g.(graph.Graph))
		}()
		if panicked || test.negative {
			if !test.negative {
				t.Errorf("%q: unexpected panic", test.name)
			}
			if !panicked {
				t.Errorf("%q: expected panic for negative edge weight", test.name)
			}
			continue
		}

		if pt.From().ID() != test.query.From().ID() {
			t.Fatalf("%q: unexpected from node ID: got:%d want:%d", pt.From().ID(), test.query.From().ID())
		}

		p, weight := pt.To(test.query.To())
		if weight != test.weight {
			t.Errorf("%q: unexpected weight from Between: got:%f want:%f",
				test.name, weight, test.weight)
		}
		if weight := pt.WeightTo(test.query.To()); weight != test.weight {
			t.Errorf("%q: unexpected weight from Weight: got:%f want:%f",
				test.name, weight, test.weight)
		}

		var got []int
		for _, n := range p {
			got = append(got, n.ID())
		}
		ok := len(got) == 0 && len(test.want) == 0
		for _, sp := range test.want {
			if reflect.DeepEqual(got, sp) {
				ok = true
				break
			}
		}
		if !ok {
			t.Errorf("%q: unexpected shortest path:\ngot: %v\nwant from:%v",
				test.name, p, test.want)
		}

		np, weight := pt.To(test.none.To())
		if pt.From().ID() == test.none.From().ID() && (np != nil || !math.IsInf(weight, 1)) {
			t.Errorf("%q: unexpected path:\ngot: path=%v weight=%f\nwant:path=<nil> weight=+Inf",
				test.name, np, weight)
		}
	}
}