Allow declaration of leader instance

examples/terraform/aws/output.tf

@@ -31,6 +31,7 @@ output "kubeone_hosts" {
       cloud_provider       = "aws"
       private_address      = aws_instance.control_plane.*.private_ip
       hostnames            = aws_instance.control_plane.*.private_dns
+      leader_ip            = aws_instance.control_plane.0.private_ip
       ssh_agent_socket     = var.ssh_agent_socket
       ssh_port             = var.ssh_port
       ssh_private_key_file = var.ssh_private_key_file

pkg/apis/kubeone/helpers.go

@@ -42,7 +42,13 @@ func (c KubeOneCluster) RandomHost() HostConfig {
 // Followers returns all but the first configured host. Only call
 // this after validating the cluster config to ensure hosts exist.
 func (c KubeOneCluster) Followers() []HostConfig {
-	return c.Hosts[1:]
+	followers := []HostConfig{}
+	for _, h := range c.Hosts {
+		if !h.IsLeader {
+			followers = append(followers, h)
+		}
+	}
+	return followers
 }
 
 // SetHostname sets the hostname for the given host

pkg/apis/kubeone/types.go

@@ -70,10 +70,10 @@ type HostConfig struct {
 	BastionPort       int    `json:"bastionPort"`
 	BastionUser       string `json:"bastionUser"`
 	Hostname          string `json:"hostname"`
+	IsLeader          bool   `json:"isLeader"`
 
 	// Information populated at the runtime
 	OperatingSystem string `json:"-"`
-	IsLeader        bool   `json:"-"`
 }
 
 // APIEndpoint is the endpoint used to communicate with the Kubernetes API

pkg/apis/kubeone/v1alpha1/defaults.go

@@ -50,14 +50,24 @@ func SetDefaults_Hosts(obj *KubeOneCluster) {
 		return
 	}
 
-	// Set first host to be the leader
-	obj.Hosts[0].IsLeader = true
+	setDefaultLeader := true
 
 	// Define a unique ID for each host
 	for idx := range obj.Hosts {
+		if setDefaultLeader && obj.Hosts[idx].IsLeader {
+			// override setting default leader, as explicit leader already
+			// defined
+			setDefaultLeader = false
+		}
 		obj.Hosts[idx].ID = idx
 		defaultHostConfig(&obj.Hosts[idx])
 	}
+
+	if setDefaultLeader {
+		// In absence of explicitly defined leader set the first host to be the
+		// default leader
+		obj.Hosts[0].IsLeader = true
+	}
 }
 
 func SetDefaults_APIEndpoints(obj *KubeOneCluster) {

pkg/apis/kubeone/v1alpha1/types.go

@@ -70,10 +70,10 @@ type HostConfig struct {
 	BastionPort       int    `json:"bastionPort"`
 	BastionUser       string `json:"bastionUser"`
 	Hostname          string `json:"hostname"`
+	IsLeader          bool   `json:"isLeader"`
 
 	// Information populated at the runtime
 	OperatingSystem string `json:"-"`
-	IsLeader        bool   `json:"-"`
 }
 
 // APIEndpoint is the endpoint used to communicate with the Kubernetes API

pkg/apis/kubeone/validation/validation.go

@@ -90,7 +90,14 @@ func ValidateCloudProviderSpec(p kubeone.CloudProviderSpec, fldPath *field.Path)
 func ValidateHostConfig(hosts []kubeone.HostConfig, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 
+	leaderFound := false
 	for _, h := range hosts {
+		if leaderFound && h.IsLeader {
+			allErrs = append(allErrs, field.Invalid(fldPath, h.IsLeader, "only 1 leader is allowed"))
+		}
+		if h.IsLeader {
+			leaderFound = true
+		}
 		if len(h.PublicAddress) == 0 {
 			allErrs = append(allErrs, field.Invalid(fldPath, h.PublicAddress, "no public IP/address given"))
 		}

pkg/installer/installation/kubeadm_leader.go

@@ -17,6 +17,8 @@ limitations under the License.
 package installation
 
 import (
+	"time"
+
 	kubeoneapi "github.com/kubermatic/kubeone/pkg/apis/kubeone"
 	"github.com/kubermatic/kubeone/pkg/scripts"
 	"github.com/kubermatic/kubeone/pkg/ssh"
@@ -50,7 +52,7 @@ func initKubernetesLeader(s *state.State) error {
 	return s.RunTaskOnLeader(func(s *state.State, node *kubeoneapi.HostConfig, conn ssh.Connection) error {
 		s.Logger.Infoln("Running kubeadm…")
 
-		cmd, err := scripts.KubeadmInit(s.WorkDir, node.ID, s.KubeadmVerboseFlag(), s.JoinCommand, "1h")
+		cmd, err := scripts.KubeadmInit(s.WorkDir, node.ID, s.KubeadmVerboseFlag(), s.JoinToken, time.Hour.String())
 		if err != nil {
 			return err
 		}

pkg/terraform/config.go

@@ -31,6 +31,7 @@ type controlPlane struct {
 	CloudProvider     *string  `json:"cloud_provider"`
 	PublicAddress     []string `json:"public_address"`
 	PrivateAddress    []string `json:"private_address"`
+	LeaderIP          string   `json:"leader_ip"`
 	Hostnames         []string `json:"hostnames"`
 	SSHUser           string   `json:"ssh_user"`
 	SSHPort           int      `json:"ssh_port"`
@@ -202,6 +203,7 @@ func newHostConfig(id int, publicIP, privateIP, hostname string, cp controlPlane
 		Bastion:           cp.Bastion,
 		BastionPort:       cp.BastionPort,
 		BastionUser:       cp.BastionUser,
+		IsLeader:          cp.LeaderIP == publicIP || cp.LeaderIP == privateIP,
 	}
 }