Merge pull request #602 from a7i/balance-domains-aboveavg

TopologySpreadConstraint: advance above avg index when at ideal average
kubernetes-sigs · Aug 10, 2021 · 64d7901 · 64d7901
2 parents ab1015e + b0e5d64
commit 64d7901
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Showing 2 changed files with 57 additions and 1 deletion.
diff --git a/pkg/descheduler/strategies/topologyspreadconstraint.go b/pkg/descheduler/strategies/topologyspreadconstraint.go
@@ -281,7 +281,7 @@ func balanceDomains(
  j := len(sortedDomains) - 1
  for i < j {
  // if j has no more to give without falling below the ideal average, move to next aboveAvg
- if float64(len(sortedDomains[j].pods)) < idealAvg {
+ if float64(len(sortedDomains[j].pods)) <= idealAvg {
  j--
  }
 

diff --git a/pkg/descheduler/strategies/topologyspreadconstraint_test.go b/pkg/descheduler/strategies/topologyspreadconstraint_test.go
@@ -588,6 +588,62 @@ func TestTopologySpreadConstraint(t *testing.T) {
  strategy: api.DeschedulerStrategy{Params: &api.StrategyParameters{IncludeSoftConstraints: true}},
  namespaces: []string{"ns1"},
  },
+ {
+ name: "3 domains size [8 7 0], maxSkew=1, should move 5 to get [5 5 5]",
+ nodes: []*v1.Node{
+ test.BuildTestNode("n1", 2000, 3000, 10, func(n *v1.Node) { n.Labels["zone"] = "zoneA" }),
+ test.BuildTestNode("n2", 2000, 3000, 10, func(n *v1.Node) { n.Labels["zone"] = "zoneB" }),
+ test.BuildTestNode("n3", 2000, 3000, 10, func(n *v1.Node) { n.Labels["zone"] = "zoneC" }),
+ },
+ pods: createTestPods([]testPodList{
+ {
+ count: 8,
+ node: "n1",
+ labels: map[string]string{"foo": "bar"},
+ constraints: getDefaultTopologyConstraints(1),
+ },
+ {
+ count: 7,
+ node: "n2",
+ labels: map[string]string{"foo": "bar"},
+ constraints: getDefaultTopologyConstraints(1),
+ },
+ }),
+ expectedEvictedCount: 5,
+ strategy: api.DeschedulerStrategy{},
+ namespaces: []string{"ns1"},
+ },
+ {
+ name: "3 domains size [5 5 5], maxSkew=1, should move 0 to retain [5 5 5]",
+ nodes: []*v1.Node{
+ test.BuildTestNode("n1", 2000, 3000, 10, func(n *v1.Node) { n.Labels["zone"] = "zoneA" }),
+ test.BuildTestNode("n2", 2000, 3000, 10, func(n *v1.Node) { n.Labels["zone"] = "zoneB" }),
+ test.BuildTestNode("n3", 2000, 3000, 10, func(n *v1.Node) { n.Labels["zone"] = "zoneC" }),
+ },
+ pods: createTestPods([]testPodList{
+ {
+ count: 5,
+ node: "n1",
+ labels: map[string]string{"foo": "bar"},
+ constraints: getDefaultTopologyConstraints(1),
+ },
+ {
+ count: 5,
+ node: "n2",
+ labels: map[string]string{"foo": "bar"},
+ constraints: getDefaultTopologyConstraints(1),
+ },
+ {
+ count: 5,
+ node: "n3",
+ labels: map[string]string{"foo": "bar"},
+ constraints: getDefaultTopologyConstraints(1),
+ },
+ }),
+ expectedEvictedCount: 0,
+ strategy: api.DeschedulerStrategy{},
+ namespaces: []string{"ns1"},
+ },
  {
  name: "2 domains, sizes [2,0], maxSkew=1, move 1 pod since pod tolerates the node with taint",
  nodes: []*v1.Node{