add node roles to pkg/cluster/constants

pkg/cluster/constants/constants.go

@@ -23,5 +23,34 @@ const DefaultClusterName = "kind"
 // ClusterLabelKey is applied to each "node" docker container for identification
 const ClusterLabelKey = "io.k8s.sigs.kind.cluster"
 
-// ClusterRoleKey is applied to each "node" docker container for categorization of nodes by role
-const ClusterRoleKey = "io.k8s.sigs.kind.role"
+// NodeRoleKey is applied to each "node" docker container for categorization
+// of nodes by role
+const NodeRoleKey = "io.k8s.sigs.kind.role"
+
+/* node role value constants */
+const (
+	// ControlPlaneNodeRoleValue identifies a node that hosts a Kubernetes
+	// control-plane.
+	//
+	// NOTE: in single node clusters, control-plane nodes act as worker nodes
+	ControlPlaneNodeRoleValue string = "control-plane"
+
+	// WorkerNodeRoleValue identifies a node that hosts a Kubernetes worker
+	WorkerNodeRoleValue string = "worker"
+
+	// ExternalLoadBalancerNodeRoleValue identifies a node that hosts an
+	// external load balancer for the API server in HA configurations.
+	//
+	// Please note that `kind` nodes hosting external load balancer are not
+	// kubernetes nodes
+	ExternalLoadBalancerNodeRoleValue string = "external-load-balancer"
+
+	// ExternalEtcdNodeRoleValue identifies a node that hosts an external-etcd
+	// instance.
+	//
+	// WARNING: this node type is not yet implemented!
+	//
+	// Please note that `kind` nodes hosting external etcd are not
+	// kubernetes nodes
+	ExternalEtcdNodeRoleValue string = "external-etcd"
+)

pkg/cluster/internal/create/createcontext.go

@@ -22,6 +22,8 @@ import (
 	"strings"
 	"time"
 
+	"sigs.k8s.io/kind/pkg/cluster/constants"
+
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 
@@ -140,12 +142,13 @@ func (cc *Context) ProvisionNodes() (nodeList map[string]*nodes.Node, err error)
 		var name = fmt.Sprintf("%s-%s", cc.Name(), configNode.Name)
 		var node *nodes.Node
 
-		switch configNode.Role {
-		case config.ExternalLoadBalancerRole:
+		// TODO(bentheelder): decouple from config objects further
+		switch string(configNode.Role) {
+		case constants.ExternalLoadBalancerNodeRoleValue:
 			node, err = nodes.CreateExternalLoadBalancerNode(name, configNode.Image, cc.ClusterLabel())
-		case config.ControlPlaneRole:
+		case constants.ControlPlaneNodeRoleValue:
 			node, err = nodes.CreateControlPlaneNode(name, configNode.Image, cc.ClusterLabel(), configNode.ExtraMounts)
-		case config.WorkerRole:
+		case constants.WorkerNodeRoleValue:
 			node, err = nodes.CreateWorkerNode(name, configNode.Image, cc.ClusterLabel(), configNode.ExtraMounts)
 		}
 		if err != nil {

pkg/cluster/nodes/create.go

@@ -130,7 +130,7 @@ func createNode(name, image, clusterLabel string, role config.NodeRole, mounts [
 		// label the node with the cluster ID
 		"--label", clusterLabel,
 		// label the node with the role ID
-		"--label", fmt.Sprintf("%s=%s", constants.ClusterRoleKey, role),
+		"--label", fmt.Sprintf("%s=%s", constants.NodeRoleKey, role),
 		// explicitly set the entrypoint
 		"--entrypoint=/usr/local/bin/entrypoint",
 	}

pkg/cluster/nodes/node.go

@@ -31,7 +31,6 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	"k8s.io/apimachinery/pkg/util/version"
-	"sigs.k8s.io/kind/pkg/cluster/config"
 	"sigs.k8s.io/kind/pkg/cluster/constants"
 
 	"sigs.k8s.io/kind/pkg/container/docker"
@@ -72,7 +71,7 @@ type nodeCache struct {
 	kubernetesVersion string
 	ip                string
 	ports             map[int]int
-	role              config.NodeRole
+	role              string
 	containerCmder    exec.Cmder
 }
 
@@ -264,20 +263,20 @@ func (n *Node) Ports(containerPort int) (hostPort int, err error) {
 }
 
 // Role returns the role of the node
-func (n *Node) Role() (role config.NodeRole, err error) {
+func (n *Node) Role() (role string, err error) {
 	// use the cached version first
 	if n.nodeCache.role != "" {
 		return n.nodeCache.role, nil
 	}
 	// retrive the role the node using docker inspect
-	lines, err := docker.Inspect(n.nameOrID, fmt.Sprintf("{{index .Config.Labels %q}}", constants.ClusterRoleKey))
+	lines, err := docker.Inspect(n.nameOrID, fmt.Sprintf("{{index .Config.Labels %q}}", constants.NodeRoleKey))
 	if err != nil {
-		return "", errors.Wrapf(err, "failed to get %q label", constants.ClusterRoleKey)
+		return "", errors.Wrapf(err, "failed to get %q label", constants.NodeRoleKey)
 	}
 	if len(lines) != 1 {
-		return "", errors.Errorf("%q label should only be one line, got %d lines", constants.ClusterRoleKey, len(lines))
+		return "", errors.Errorf("%q label should only be one line, got %d lines", constants.NodeRoleKey, len(lines))
 	}
-	n.nodeCache.role = config.NodeRole(strings.Trim(lines[0], "'"))
+	n.nodeCache.role = strings.Trim(lines[0], "'")
 	return n.nodeCache.role, nil
 }