Set Minimum Buffer Size to 1 (#3749)

* Set Minimums for DesiredCapacity and Buffer to 1

* fix lint

* Fix TestApplyListPolicy

* review changes

* Prevent scaling down to zero replicas in scaleDown logic

* modify TestApplyCounterPolicy

* remove number of replicas check

* modified scaleDown method and used helper function

* suggested changes

---------

Co-authored-by: Mark Mandel <[email protected]>

pkg/fleetautoscalers/fleetautoscalers.go

@@ -28,16 +28,17 @@ import (
  "strings"
  "time"
 
+ "github.com/pkg/errors"
+ "k8s.io/apimachinery/pkg/util/intstr"
+ "k8s.io/apimachinery/pkg/util/uuid"
+
  agonesv1 "agones.dev/agones/pkg/apis/agones/v1"
  autoscalingv1 "agones.dev/agones/pkg/apis/autoscaling/v1"
  listeragonesv1 "agones.dev/agones/pkg/client/listers/agones/v1"
  "agones.dev/agones/pkg/fleets"
  "agones.dev/agones/pkg/gameservers"
  gssets "agones.dev/agones/pkg/gameserversets"
  "agones.dev/agones/pkg/util/runtime"
- "github.com/pkg/errors"
- "k8s.io/apimachinery/pkg/util/intstr"
- "k8s.io/apimachinery/pkg/util/uuid"
 )
 
 var tlsConfig = &tls.Config{}
@@ -319,6 +320,12 @@ func applyCounterOrListPolicy(c *autoscalingv1.CounterPolicy, l *autoscalingv1.L
  if err != nil {
  return 0, false, err
  }
+ // If the Aggregated Allocated Counts is 0 then desired capacity gets calculated as 0. If the
+ // capacity of 1 replica is equal to or greater than minimum capacity we can exit early.
+ if aggAllocatedCount <= 0 && capacity >= minCapacity {
+ return 1, true, nil
+ }
+
  // The desired TOTAL capacity based on the Aggregated Allocated Counts (see applyBufferPolicy for explanation)
  desiredCapacity := int64(math.Ceil(float64(aggAllocatedCount*100) / float64(100-bufferPercent)))
  // Convert into a desired AVAILABLE capacity aka the buffer

pkg/fleetautoscalers/fleetautoscalers_test.go

@@ -24,17 +24,18 @@ import (
  "net/http/httptest"
  "testing"
 
- agonesv1 "agones.dev/agones/pkg/apis/agones/v1"
- autoscalingv1 "agones.dev/agones/pkg/apis/autoscaling/v1"
- "agones.dev/agones/pkg/gameservers"
- agtesting "agones.dev/agones/pkg/testing"
- utilruntime "agones.dev/agones/pkg/util/runtime"
  "github.com/stretchr/testify/assert"
  admregv1 "k8s.io/api/admissionregistration/v1"
  metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
  "k8s.io/apimachinery/pkg/runtime"
  "k8s.io/apimachinery/pkg/util/intstr"
  k8stesting "k8s.io/client-go/testing"
+
+ agonesv1 "agones.dev/agones/pkg/apis/agones/v1"
+ autoscalingv1 "agones.dev/agones/pkg/apis/autoscaling/v1"
+ "agones.dev/agones/pkg/gameservers"
+ agtesting "agones.dev/agones/pkg/testing"
+ utilruntime "agones.dev/agones/pkg/util/runtime"
 )
 
 const (
@@ -1950,8 +1951,8 @@ func TestApplyListPolicy(t *testing.T) {
  }}}},
  },
  want: expected{
- replicas: 0,
- limited: false,
+ replicas: 1,
+ limited: true,
  wantErr: false,
  },
  },