Added scaling limits.

Author: lamai93

pkg/apis/deployment/v1alpha/server_group_spec.go

@@ -39,6 +39,10 @@ import (
 type ServerGroupSpec struct {
 	// Count holds the requested number of servers
 	Count *int `json:"count,omitempty"`
+	// MinCount specifies a lower limit for count
+	MinCount *int `json:"minCount,omitempty"`
+	// MaxCount specifies a upper limit for count
+	MaxCount *int `json:"maxCount,omitempty"`
 	// Args holds additional commandline arguments
 	Args []string `json:"args,omitempty"`
 	// StorageClassName specifies the classname for storage of the servers.
@@ -110,8 +114,27 @@ func (s ServerGroupSpec) Validate(group ServerGroup, used bool, mode DeploymentM
 				minCount = 2
 			}
 		}
+		var specMinCount int
+		if s.MinCount != nil {
+			specMinCount = *s.MinCount
+			if specMinCount < 1 {
+				return maskAny(errors.Wrapf(ValidationError, "Invalid minCount: %d < 1", specMinCount))
+			}
+			if s.GetCount() < specMinCount {
+				return maskAny(errors.Wrapf(ValidationError, "Invalid count value %d. Expected >= %d", s.GetCount(), specMinCount))
+			}
+		}
+		if s.MaxCount != nil {
+			specMaxCount := *s.MaxCount
+			if specMaxCount < specMinCount {
+				return maskAny(errors.Wrapf(ValidationError, "Invalid maxCount: (maxCount) %d < %d (minCount)", specMaxCount, specMinCount))
+			}
+			if s.GetCount() > specMaxCount {
+				return maskAny(errors.Wrapf(ValidationError, "Invalid count value %d. Expected <= %d", s.GetCount(), specMaxCount))
+			}
+		}
 		if s.GetCount() < minCount {
-			return maskAny(errors.Wrapf(ValidationError, "Invalid count value %d. Expected >= %d", s.GetCount(), minCount))
+			return maskAny(errors.Wrapf(ValidationError, "Invalid count value %d. Expected >= %d (implicit minimum; by deployment mode)", s.GetCount(), minCount))
 		}
 		if s.GetCount() > 1 && group == ServerGroupSingle && mode == DeploymentModeSingle {
 			return maskAny(errors.Wrapf(ValidationError, "Invalid count value %d. Expected 1", s.GetCount()))
@@ -160,6 +183,8 @@ func (s *ServerGroupSpec) SetDefaults(group ServerGroup, used bool, mode Deploym
 		}
 	} else if s.GetCount() > 0 && !used {
 		s.Count = nil
+		s.MinCount = nil
+		s.MaxCount = nil
 	}
 	if _, found := s.Resources.Requests[v1.ResourceStorage]; !found {
 		switch group {
@@ -189,6 +214,12 @@ func (s *ServerGroupSpec) SetDefaultsFrom(source ServerGroupSpec) {
 	if s.Count == nil {
 		s.Count = util.NewIntOrNil(source.Count)
 	}
+	if s.MinCount == nil {
+		s.MinCount = util.NewIntOrNil(source.MinCount)
+	}
+	if s.MaxCount == nil {
+		s.MaxCount = util.NewIntOrNil(source.MaxCount)
+	}
 	if s.Args == nil {
 		s.Args = source.Args
 	}

pkg/apis/deployment/v1alpha/server_group_spec_test.go

@@ -48,6 +48,11 @@ func TestServerGroupSpecValidateCount(t *testing.T) {
 	assert.Nil(t, ServerGroupSpec{Count: util.NewInt(2)}.Validate(ServerGroupSyncMasters, true, DeploymentModeCluster, EnvironmentProduction))
 	assert.Nil(t, ServerGroupSpec{Count: util.NewInt(2)}.Validate(ServerGroupSyncWorkers, true, DeploymentModeCluster, EnvironmentProduction))
 
+	assert.Nil(t, ServerGroupSpec{Count: util.NewInt(2), MinCount: util.NewInt(2), MaxCount: util.NewInt(5)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentDevelopment))
+	assert.Nil(t, ServerGroupSpec{Count: util.NewInt(1), MaxCount: util.NewInt(5)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentDevelopment))
+	assert.Nil(t, ServerGroupSpec{Count: util.NewInt(6), MinCount: util.NewInt(2)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentDevelopment))
+	assert.Nil(t, ServerGroupSpec{Count: util.NewInt(2)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentDevelopment))
+
 	// Invalid
 	assert.Error(t, ServerGroupSpec{Count: util.NewInt(1)}.Validate(ServerGroupSingle, false, DeploymentModeCluster, EnvironmentDevelopment))
 	assert.Error(t, ServerGroupSpec{Count: util.NewInt(2)}.Validate(ServerGroupSingle, true, DeploymentModeSingle, EnvironmentDevelopment))
@@ -70,6 +75,11 @@ func TestServerGroupSpecValidateCount(t *testing.T) {
 	assert.Error(t, ServerGroupSpec{Count: util.NewInt(1)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentProduction))
 	assert.Error(t, ServerGroupSpec{Count: util.NewInt(1)}.Validate(ServerGroupSyncMasters, true, DeploymentModeCluster, EnvironmentProduction))
 	assert.Error(t, ServerGroupSpec{Count: util.NewInt(1)}.Validate(ServerGroupSyncWorkers, true, DeploymentModeCluster, EnvironmentProduction))
+
+	assert.Error(t, ServerGroupSpec{Count: util.NewInt(2), MinCount: util.NewInt(5), MaxCount: util.NewInt(1)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentDevelopment))
+	assert.Error(t, ServerGroupSpec{Count: util.NewInt(6), MaxCount: util.NewInt(5)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentDevelopment))
+	assert.Error(t, ServerGroupSpec{Count: util.NewInt(1), MinCount: util.NewInt(2)}.Validate(ServerGroupCoordinators, true, DeploymentModeCluster, EnvironmentDevelopment))
+
 }
 
 func TestServerGroupSpecDefault(t *testing.T) {

pkg/apis/deployment/v1alpha/zz_generated.deepcopy.go

@@ -170,6 +170,8 @@ func (ci *clusterScalingIntegration) inspectCluster(ctx context.Context, expectS
 	if dbserversChanged {
 		newSpec.DBServers.Count = util.NewInt(req.GetDBServers())
 	}
+	// Validate will additionally check if
+	// 		min <= count <= max holds for the given server groups
 	if err := newSpec.Validate(); err != nil {
 		// Log failure & create event
 		log.Warn().Err(err).Msg("Validation of updated spec has failed")