start coupling network to clusters

cmd/create/createCluster.go

@@ -55,12 +55,14 @@ func NewCmdCreateCluster() *cobra.Command {
 	cmd.Flags().StringArrayP("api-port", "a", []string{"6443"}, "Specify the Kubernetes API server port (Format: `--api-port [HOST:]HOSTPORT[@NODEFILTER]`") // TODO: how to handle this for multi-master setups?
 	cmd.Flags().IntP("masters", "m", 1, "Specify how many masters you want to create")
 	cmd.Flags().IntP("workers", "w", 0, "Specify how many workers you want to create")
-	cmd.Flags().String("config", "", "Specify a cluster configuration file")                                     // TODO: to implement
+	// cmd.Flags().String("config", "", "Specify a cluster configuration file")                                     // TODO: to implement
 	cmd.Flags().String("image", k3d.DefaultK3sImageRepo, "Specify k3s image that you want to use for the nodes") // TODO: get image version
 	cmd.Flags().String("network", "", "Join an existing network")
 	cmd.Flags().String("secret", "", "Specify a cluster secret. By default, we generate one.")
 	cmd.Flags().StringArrayP("volume", "v", nil, "Mount volumes into the nodes (Format: `--volume [SOURCE:]DEST[@NODEFILTER[;NODEFILTER...]]`")
 	cmd.Flags().StringArrayP("port", "p", nil, "Map ports from the node containers to the host (Format: `[HOST:][HOSTPORT:]CONTAINERPORT[/PROTOCOL][@NODEFILTER]`)")
+	cmd.Flags().Bool("no-lb", false, "Disable automatic deployment of a load balancer in Multi-Master setups")
+	cmd.Flags().String("lb-port", "0.0.0.0:6443", "Specify port to be exposed by the master load balancer (Format: `[HOST:]HOSTPORT)")
 
 	// add subcommands
 
@@ -172,6 +174,18 @@ func parseCreateClusterCmd(cmd *cobra.Command, args []string) (runtimes.Runtime,
 		exposeAPIToFiltersMap[exposeAPI] = filters
 	}
 
+	// --no-lb
+	noLB, err := cmd.Flags().GetBool("no-lb")
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	// --lb-port
+	lbPort, err := cmd.Flags().GetString("lb-port")
+	if err != nil {
+		log.Fatalln(err)
+	}
+
 	// --volume
 	volumeFlags, err := cmd.Flags().GetStringArray("volume")
 	if err != nil {
@@ -303,5 +317,14 @@ func parseCreateClusterCmd(cmd *cobra.Command, args []string) (runtimes.Runtime,
 		}
 	}
 
+	// TODO: create load balancer and other util containers // TODO: for now, this will only work with the docker provider (?) -> can replace dynamic docker lookup with static traefik config (?)
+	if masterCount > 1 && !noLB { // TODO: add traefik to the same network and add traefik labels to the master node containers
+		log.Debugln("Creating LB in front of master nodes")
+		cluster.MasterLoadBalancer = &k3d.ClusterLoadbalancer{
+			Image:       k3d.DefaultLBImage,
+			ExposedPort: lbPort,
+		}
+	}
+
 	return runtime, cluster
 }

pkg/cluster/cluster.go

@@ -45,12 +45,19 @@ func CreateCluster(cluster *k3d.Cluster, runtime k3drt.Runtime) error {
 	}
 
 	// create cluster network or use an existing one
-	networkID, err := runtime.CreateNetworkIfNotPresent(cluster.Network)
+	networkID, networkExists, err := runtime.CreateNetworkIfNotPresent(cluster.Network)
 	if err != nil {
 		log.Errorln("Failed to create cluster network")
 		return err
 	}
 	cluster.Network = networkID
+	extraLabels := map[string]string{
+		"k3d.cluster.network":          networkID,
+		"k3d.cluster.network.external": "false",
+	}
+	if networkExists {
+		extraLabels["k3d.cluster.network.external"] = "true" // if the network wasn't created, we say that it's managed externally (important for cluster deletion)
+	}
 
 	/*
 	 * Cluster Secret
@@ -77,6 +84,11 @@ func CreateCluster(cluster *k3d.Cluster, runtime k3drt.Runtime) error {
 		node.Labels["k3d.cluster"] = cluster.Name
 		node.Env = append(node.Env, fmt.Sprintf("K3S_CLUSTER_SECRET=%s", cluster.Secret))
 
+		// append extra labels
+		for k, v := range extraLabels {
+			node.Labels[k] = v
+		}
+
 		// node role specific settings
 		suffix := 0
 		if node.Role == k3d.MasterRole {
@@ -121,7 +133,13 @@ func DeleteCluster(cluster *k3d.Cluster, runtime k3drt.Runtime) error {
 		}
 	}
 
-	// TODO: remove network
+	if network, ok := cluster.Nodes[0].Labels["k3d.cluster.network"]; ok {
+		if cluster.Nodes[0].Labels["k3d.cluster.network.external"] == "false" {
+			if err := runtime.DeleteNetwork(network); err != nil {
+				log.Warningf("Failed to delete cluster network '%s': Try to delete it manually", network)
+			}
+		}
+	}
 
 	if failed > 0 {
 		return fmt.Errorf("Failed to delete %d nodes: Try to delete them manually", failed)

pkg/runtimes/containerd/network.go

@@ -22,6 +22,11 @@ THE SOFTWARE.
 package containerd
 
 // CreateNetworkIfNotPresent creates a new docker network
-func (d Containerd) CreateNetworkIfNotPresent(name string) (string, error) {
-	return "", nil
+func (d Containerd) CreateNetworkIfNotPresent(name string) (string, bool, error) {
+	return "", false, nil
+}
+
+// DeleteNetwork deletes a network
+func DeleteNetwork(name string) error {
+	return nil
 }

pkg/runtimes/docker/network.go

@@ -23,6 +23,7 @@ package docker
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/client"
@@ -32,18 +33,20 @@ import (
 )
 
 // CreateNetworkIfNotPresent creates a new docker network
-func (d Docker) CreateNetworkIfNotPresent(name string) (string, error) {
+// @return: network name, exists, error
+func (d Docker) CreateNetworkIfNotPresent(name string) (string, bool, error) {
 
 	// (0) create new docker client
 	ctx := context.Background()
 	docker, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
 	if err != nil {
 		log.Errorln("Failed to create docker client")
-		return "", err
+		return "", false, err
 	}
 
 	// (1) configure list filters
-	args := GetDefaultObjectLabelsFilter(name)
+	args := GetDefaultObjectLabelsFilter("")
+	args.Del("label", fmt.Sprintf("k3d.cluster=%s", "")) // We don't filter for cluster name here
 	args.Add("name", name)
 
 	// (2) get filtered list of networks
@@ -52,7 +55,7 @@ func (d Docker) CreateNetworkIfNotPresent(name string) (string, error) {
 	})
 	if err != nil {
 		log.Errorln("Failed to list docker networks")
-		return "", err
+		return "", false, err
 	}
 
 	// (2.1) If possible, return an existing network
@@ -62,7 +65,7 @@ func (d Docker) CreateNetworkIfNotPresent(name string) (string, error) {
 
 	if len(networkList) > 0 {
 		log.Infof("Network with name '%s' already exists with ID '%s'", name, networkList[0].ID)
-		return networkList[0].ID, nil
+		return networkList[0].ID, true, nil
 	}
 
 	// (3) Create a new network
@@ -71,9 +74,14 @@ func (d Docker) CreateNetworkIfNotPresent(name string) (string, error) {
 	})
 	if err != nil {
 		log.Errorln("Failed to create network")
-		return "", err
+		return "", false, err
 	}
 
 	log.Infof("Created network '%s'", name)
-	return network.ID, nil
+	return network.ID, false, nil
+}
+
+// DeleteNetwork deletes a network
+func DeleteNetwork(name string) error {
+	return nil
 }

pkg/runtimes/runtime.go

@@ -41,8 +41,9 @@ type Runtime interface {
 	CreateNode(*k3d.Node) error
 	DeleteNode(*k3d.Node) error
 	GetNodesByLabel(map[string]string) ([]*k3d.Node, error)
-	CreateNetworkIfNotPresent(name string) (string, error)
+	CreateNetworkIfNotPresent(name string) (string, bool, error) // @return NETWORK_NAME, EXISTS, ERROR
 	GetKubeconfig(*k3d.Node) (io.ReadCloser, error)
+	DeleteNetwork(name string) error
 	// StartContainer() error
 	// ExecContainer() error
 	// StopContainer() error

pkg/types/types.go

@@ -35,6 +35,9 @@ const DefaultClusterNameMaxLength = 32
 // DefaultK3sImageRepo specifies the default image repository for the used k3s image
 const DefaultK3sImageRepo = "docker.io/rancher/k3s"
 
+// DefaultLBImage defines the default cluster load balancer image
+const DefaultLBImage = "docker.io/library/traefik:v2.0"
+
 // DefaultObjectNamePrefix defines the name prefix for every object created by k3d
 const DefaultObjectNamePrefix = "k3d"
 
@@ -71,10 +74,11 @@ var DefaultNodeEnv = []string{
 
 // Cluster describes a k3d cluster
 type Cluster struct {
-	Name    string  `yaml:"name" json:"name,omitempty"`
-	Network string  `yaml:"network" json:"network,omitempty"`
-	Secret  string  `yaml:"cluster_secret" json:"clusterSecret,omitempty"`
-	Nodes   []*Node `yaml:"nodes" json:"nodes,omitempty"`
+	Name               string               `yaml:"name" json:"name,omitempty"`
+	Network            string               `yaml:"network" json:"network,omitempty"`
+	Secret             string               `yaml:"cluster_secret" json:"clusterSecret,omitempty"`
+	Nodes              []*Node              `yaml:"nodes" json:"nodes,omitempty"`
+	MasterLoadBalancer *ClusterLoadbalancer `yaml:"master_loadbalancer" json:"masterLoadBalancer,omitempty"`
 }
 
 // Node describes a k3d node
@@ -113,3 +117,9 @@ type WorkerOpts struct{}
 func GetDefaultObjectName(name string) string {
 	return fmt.Sprintf("%s-%s", DefaultObjectNamePrefix, name)
 }
+
+// ClusterLoadbalancer describes a loadbalancer deployed in front of a multi-master cluster
+type ClusterLoadbalancer struct {
+	Image       string
+	ExposedPort string `yaml:"exposed_port" json:"exposedPort,omitempty"`
+}