Implement resource constraints on nodes

go.sum

@@ -47,6 +47,7 @@ github.com/go-openapi/swag v0.0.0-20160704191624-1d0bd113de87/go.mod h1:DXUve3Dp
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
+github.com/gogo/protobuf v1.3.1 h1:DqDEcV5aeaTmdFBePNpYsp3FlcVH/2ISVVM9Qf8PSls=
 github.com/gogo/protobuf v1.3.1/go.mod h1:SlYgWuQ5SjCEi6WLHjHCa1yvBfUnHcTbrrZtXPKa29o=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20160516000752-02826c3e7903/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
@@ -60,8 +61,8 @@ github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/google/gofuzz v1.1.0 h1:Hsa8mG0dQ46ij8Sl2AYJDUv1oA9/d6Vk+3LG99Oe02g=
 github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
-github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/gnostic v0.0.0-20170729233727-0c5108395e2d/go.mod h1:sJBsCZ4ayReDTBIg8b9dl28c5xFWyhBTVRp3pOg5EKY=
 github.com/googleapis/gnostic v0.1.0/go.mod h1:sJBsCZ4ayReDTBIg8b9dl28c5xFWyhBTVRp3pOg5EKY=
@@ -109,7 +110,6 @@ github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+W
 github.com/onsi/ginkgo v1.11.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/gomega v0.0.0-20170829124025-dcabb60a477c/go.mod h1:C1qb7wdrVGGVU+Z6iS04AVkA3Q65CEZX59MT0QO5uiA=
 github.com/onsi/gomega v1.7.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
-github.com/pelletier/go-toml v1.2.0 h1:T5zMGML61Wp+FlcbWjRDT7yAxhJNAiPPLOFECq181zc=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/pelletier/go-toml v1.7.0 h1:7utD74fnzVc/cpcyy8sjrlFr5vYpypUixARcHIMIGuI=
 github.com/pelletier/go-toml v1.7.0/go.mod h1:vwGMzjaWMwyfHwgIBhI2YUM4fB6nL6lVAvS1LBMMhTE=
@@ -201,6 +201,7 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
+gopkg.in/inf.v0 v0.9.1 h1:73M5CoZyi3ZLMOyDlQh031Cx6N9NDJ2Vvfl76EDAgDc=
 gopkg.in/inf.v0 v0.9.1/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
 gopkg.in/resty.v1 v1.12.0/go.mod h1:mDo4pnntr5jdWRML875a/NmxYqAlA73dVijT2AXvQQo=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
@@ -220,7 +221,6 @@ k8s.io/klog v1.0.0/go.mod h1:4Bi6QPql/J/LkTDqv7R/cd3hPo4k2DG6Ptcz060Ez5I=
 k8s.io/kube-openapi v0.0.0-20200121204235-bf4fb3bd569c/go.mod h1:GRQhZsXIAJ1xR0C9bd8UpWHZ5plfAS9fzPjJuQ6JL3E=
 sigs.k8s.io/structured-merge-diff/v3 v3.0.0-20200116222232-67a7b8c61874/go.mod h1:PlARxl6Hbt/+BC80dRLi1qAmnMqwqDg62YvvVkZjemw=
 sigs.k8s.io/structured-merge-diff/v3 v3.0.0/go.mod h1:PlARxl6Hbt/+BC80dRLi1qAmnMqwqDg62YvvVkZjemw=
-sigs.k8s.io/yaml v1.1.0 h1:4A07+ZFc2wgJwo8YNlQpr1rVlgUDlxXHhPJciaPY5gs=
 sigs.k8s.io/yaml v1.1.0/go.mod h1:UJmg0vDUVViEyp3mgSv9WPwZCDxu4rQW1olrI1uml+o=
 sigs.k8s.io/yaml v1.2.0 h1:kr/MCeFWJWTwyaHoR9c8EjH9OumOmoF9YGiZd7lFm/Q=
 sigs.k8s.io/yaml v1.2.0/go.mod h1:yfXDCHCao9+ENCvLSE62v9VSji2MKu5jeNfTrofGhJc=

pkg/apis/config/v1alpha4/types.go

@@ -16,6 +16,10 @@ limitations under the License.
 
 package v1alpha4
 
+import (
+	"k8s.io/apimachinery/pkg/api/resource"
+)
+
 // Cluster contains kind cluster configuration
 type Cluster struct {
 	TypeMeta `yaml:",inline"`
@@ -106,6 +110,9 @@ type Node struct {
 	// binded to a host Port
 	ExtraPortMappings []PortMapping `yaml:"extraPortMappings,omitempty"`
 
+	// Constraints describes the node resources constraints
+	Constraints NodeResources `json:"constraints,omitempty"`
+
 	// KubeadmConfigPatches are applied to the generated kubeadm config as
 	// merge patches. The `kind` field must match the target object, and
 	// if `apiVersion` is specified it will only be applied to matching objects.
@@ -283,3 +290,11 @@ const (
 	// PortMappingProtocolSCTP specifies SCTP protocol
 	PortMappingProtocolSCTP PortMappingProtocol = "SCTP"
 )
+
+// NodeResources represents the node resources (CPU/Memory)
+type NodeResources struct {
+	// The maximum amount of memory the node can use.
+	Memory resource.Quantity `json:"memory,omitempty"`
+	// Specify how much of the available CPU resources a node can use
+	Cpus resource.Quantity `json:"cpus,omitempty"`
+}

pkg/cluster/internal/providers/docker/provision.go

@@ -231,13 +231,14 @@ func runArgsForNode(node *config.Node, clusterIPFamily config.ClusterIPFamily, n
 		args...,
 	)
 
-	// convert mounts and port mappings to container run args
+	// convert mounts, port mappings and resource constraints to container run args
 	args = append(args, generateMountBindings(node.ExtraMounts...)...)
 	mappingArgs, err := generatePortMappings(clusterIPFamily, node.ExtraPortMappings...)
 	if err != nil {
 		return nil, err
 	}
 	args = append(args, mappingArgs...)
+	args = append(args, generateNodeConstraints(node.Constraints)...)
 
 	// finally, specify the image to run
 	return append(args, node.Image), nil
@@ -376,3 +377,21 @@ func generatePortMappings(clusterIPFamily config.ClusterIPFamily, portMappings .
 	}
 	return args, nil
 }
+
+// generateNodeConstraints converts the nodesConstraints to a list of args for docker
+// https://docs.docker.com/config/containers/resource_constraints/
+func generateNodeConstraints(resources config.NodeResources) []string {
+	var args []string
+	if resources.Cpus.Sign() > 0 {
+		args = append(args, fmt.Sprintf("--cpus=%s", resources.Cpus.String()))
+	}
+
+	if resources.Memory.Sign() > 0 {
+		args = append(args, fmt.Sprintf("--memory=%s", resources.Memory.String()))
+		// prevent a container from using swap because we want to emulate a real node
+		// https://docs.docker.com/config/containers/resource_constraints/#prevent-a-container-from-using-swap
+		args = append(args, fmt.Sprintf("--memory-swap=%s", resources.Memory.String()))
+	}
+
+	return args
+}

pkg/internal/apis/config/types.go

@@ -16,6 +16,10 @@ limitations under the License.
 
 package config
 
+import (
+	"k8s.io/apimachinery/pkg/api/resource"
+)
+
 // Cluster contains kind cluster configuration
 type Cluster struct {
 	// Nodes contains the list of nodes defined in the `kind` Cluster
@@ -89,6 +93,9 @@ type Node struct {
 	// KubeadmConfigPatchesJSON6902 are applied to the generated kubeadm config
 	// as patchesJson6902 to `kustomize build`
 	KubeadmConfigPatchesJSON6902 []PatchJSON6902
+
+	// Constraints describes the node resources constraints
+	Constraints NodeResources
 }
 
 // NodeRole defines possible role for nodes in a Kubernetes cluster managed by `kind`
@@ -234,3 +241,11 @@ const (
 	// PortMappingProtocolSCTP specifies SCTP protocol
 	PortMappingProtocolSCTP PortMappingProtocol = "SCTP"
 )
+
+// NodeResources represents the node resources (CPU/Memory)
+type NodeResources struct {
+	// The maximum amount of memory the node can use.
+	Memory resource.Quantity
+	// Specify how much of the available CPU resources a node can use.
+	Cpus resource.Quantity
+}

pkg/internal/apis/config/validate.go

@@ -19,6 +19,8 @@ package config
 import (
 	"net"
 
+	"k8s.io/apimachinery/pkg/api/resource"
+
 	"sigs.k8s.io/kind/pkg/errors"
 )
 
@@ -101,6 +103,17 @@ func (n *Node) Validate() error {
 		}
 	}
 
+	// validate node resource constraints
+	if n.Constraints.Cpus.Sign() < 0 {
+		errs = append(errs, errors.New("invalid number of Cpus"))
+	}
+
+	// minimum memory size is 4m
+	minMemory := resource.MustParse("4m")
+	if n.Constraints.Memory.Sign() != 0 && n.Constraints.Memory.Cmp(minMemory) < 0 {
+		errs = append(errs, errors.New("invalid Memory Size (minimum 4m)"))
+	}
+
 	if len(errs) > 0 {
 		return errors.NewAggregate(errs)
 	}

pkg/internal/apis/config/validate_test.go

@@ -19,6 +19,8 @@ package config
 import (
 	"testing"
 
+	"k8s.io/apimachinery/pkg/api/resource"
+
 	"sigs.k8s.io/kind/pkg/errors"
 )
 
@@ -107,6 +109,21 @@ func TestClusterValidate(t *testing.T) {
 			}(),
 			ExpectErrors: 1,
 		},
+		{
+			Name: "wrong resources constraints node",
+			Cluster: func() Cluster {
+				c := Cluster{}
+				SetDefaultsCluster(&c)
+				n, n2 := Node{}, Node{}
+				SetDefaultsNode(&n)
+				SetDefaultsNode(&n2)
+				n.Constraints.Cpus = resource.MustParse("-12")
+				n.Constraints.Memory = resource.MustParse("1m")
+				c.Nodes = []Node{n, n2}
+				return c
+			}(),
+			ExpectErrors: 1,
+		},
 	}
 
 	for _, tc := range cases {
@@ -202,6 +219,24 @@ func TestNodeValidate(t *testing.T) {
 			}(),
 			ExpectErrors: 1,
 		},
+		{
+			TestName: "Negative CPU constraint",
+			Node: func() Node {
+				cfg := newDefaultedNode(ControlPlaneRole)
+				cfg.Constraints.Cpus = resource.MustParse("-12")
+				return cfg
+			}(),
+			ExpectErrors: 1,
+		},
+		{
+			TestName: "Minimum value for memory constraint",
+			Node: func() Node {
+				cfg := newDefaultedNode(ControlPlaneRole)
+				cfg.Constraints.Memory = resource.MustParse("2m")
+				return cfg
+			}(),
+			ExpectErrors: 1,
+		},
 		{
 			TestName: "Invalid HostPort",
 			Node: func() Node {

site/content/docs/user/quick-start.md

@@ -398,6 +398,25 @@ networking:
   ipFamily: ipv6
 ```
 
+#### Limit node resources
+You can set CPU and memory limits for your cluster nodes in the configuration file.
+
+```yaml
+kind: Cluster
+apiVersion: kind.x-k8s.io/v1alpha4
+nodes:
+# the control plane node
+- role: control-plane
+  constraints:
+    memory: "200m"
+    cpus: "2"
+- role: worker
+  constraints:
+    memory: "100m"
+    cpus: "1"
+```
+
+
 ### Configure kind to use a proxy
 If you are running kind in an environment that requires a proxy, you may need to configure kind to use it.