add entry for host.k3d.internal to /etc/hosts in the node containers

cmd/util/filter.go

@@ -30,6 +30,8 @@ import (
 
 	k3d "github.com/rancher/k3d/v3/pkg/types"
 
+	"github.com/rancher/k3d/v3/pkg/util"
+
 	"regexp"
 )
 
@@ -99,7 +101,7 @@ func FilterNodes(nodes []*k3d.Node, filters []string) ([]*k3d.Node, error) {
 		}
 
 		// map capturing group names to submatches
-		submatches := mapSubexpNames(filterRegexp.SubexpNames(), match)
+		submatches := util.MapSubexpNames(filterRegexp.SubexpNames(), match)
 
 		// if one of the filters is 'all', we only return this and drop all others
 		if submatches["group"] == "all" {

cmd/util/util.go

@@ -20,13 +20,3 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 */
 package util
-
-// mapSubexpNames maps regex capturing group names to corresponding matches
-func mapSubexpNames(names, matches []string) map[string]string {
-	//names, matches = names[1:], matches[1:]
-	nameMatchMap := make(map[string]string, len(matches))
-	for index := range names {
-		nameMatchMap[names[index]] = matches[index]
-	}
-	return nameMatchMap
-}

pkg/cluster/cluster.go

@@ -262,6 +262,23 @@ func ClusterCreate(ctx context.Context, runtime k3drt.Runtime, cluster *k3d.Clus
 		}
 	}
 
+	/*
+	 * Networking Magic
+	 */
+
+	// add extra host
+	hostIP, err := GetHostIP(ctx, runtime, cluster)
+	if err != nil {
+		return err
+	}
+	hostsEntry := fmt.Sprintf("%s %s", hostIP, k3d.DefaultK3dInternalHostRecord)
+	log.Debugf("Adding extra host entry '%s'", hostsEntry)
+	for _, node := range cluster.Nodes {
+		if err := runtime.ExecInNode(ctx, node, []string{"sh", "-c", fmt.Sprintf("echo '%s' >> /etc/hosts", hostsEntry)}); err != nil {
+			log.Warnf("Failed to add extra entry '%s' to /etc/hosts in node '%s'", hostsEntry, node.Name)
+		}
+	}
+
 	/*
 	 * Auxiliary Containers
 	 */

pkg/cluster/host.go

@@ -0,0 +1,102 @@
+/*
+Copyright © 2020 The k3d Author(s)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+package cluster
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"net"
+	"regexp"
+	"runtime"
+
+	rt "github.com/rancher/k3d/v3/pkg/runtimes"
+	k3d "github.com/rancher/k3d/v3/pkg/types"
+	"github.com/rancher/k3d/v3/pkg/util"
+	log "github.com/sirupsen/logrus"
+)
+
+var nsLookupAddressRegexp = regexp.MustCompile(`^Address:\s+(?P<ip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})$`)
+
+// GetHostIP returns the routable IP address to be able to access services running on the host system from inside the cluster.
+// This depends on the Operating System and the chosen Runtime.
+func GetHostIP(ctx context.Context, rtime rt.Runtime, cluster *k3d.Cluster) (net.IP, error) {
+
+	// Docker Runtime
+	if rtime == rt.Docker {
+
+		log.Debugf("Runtime GOOS: %s", runtime.GOOS)
+
+		// "native" Docker on Linux
+		if runtime.GOOS == "linux" {
+			ip, err := rtime.GetHostIP(ctx, cluster.Network.Name)
+			if err != nil {
+				return nil, err
+			}
+			return ip, nil
+		}
+
+		// Docker (for Desktop) on MacOS or Windows
+		if runtime.GOOS == "windows" || runtime.GOOS == "darwin" {
+			ip, err := resolveHostnameFromInside(ctx, rtime, cluster.Nodes[0], "host.docker.internal")
+			if err != nil {
+				return nil, err
+			}
+			return ip, nil
+		}
+
+		// Catch all other GOOS cases
+		return nil, fmt.Errorf("GetHostIP only implemented for Linux, MacOS (Darwin) and Windows")
+
+	}
+
+	// Catch all other runtime selections
+	return nil, fmt.Errorf("GetHostIP only implemented for the docker runtime")
+
+}
+
+func resolveHostnameFromInside(ctx context.Context, rtime rt.Runtime, node *k3d.Node, hostname string) (net.IP, error) {
+
+	logreader, err := rtime.ExecInNodeGetLogs(ctx, node, []string{"sh", "-c", fmt.Sprintf("nslookup %s", hostname)})
+	if err != nil {
+		return nil, err
+	}
+
+	submatches := map[string]string{}
+	scanner := bufio.NewScanner(logreader)
+	for scanner.Scan() {
+		match := nsLookupAddressRegexp.FindStringSubmatch(scanner.Text())
+		if len(match) == 0 {
+			continue
+		}
+		submatches = util.MapSubexpNames(nsLookupAddressRegexp.SubexpNames(), match)
+		break
+	}
+	if _, ok := submatches["ip"]; !ok {
+		return nil, fmt.Errorf("Failed to read address for '%s' from nslookup response", hostname)
+	}
+
+	log.Debugf("Hostname '%s' -> Address '%s'", hostname, submatches["ip"])
+
+	return net.ParseIP(submatches["ip"]), nil
+
+}

pkg/runtimes/containerd/host.go

@@ -0,0 +1,32 @@
+/*
+Copyright © 2020 The k3d Author(s)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+package containerd
+
+import (
+	"context"
+	"net"
+)
+
+// GetHostIP returns the IP of the containerd host
+func (d Containerd) GetHostIP(ctx context.Context, network string) (net.IP, error) {
+	return nil, nil
+}

pkg/runtimes/containerd/node.go

@@ -23,6 +23,7 @@ THE SOFTWARE.
 package containerd
 
 import (
+	"bufio"
 	"context"
 	"io"
 	"time"
@@ -126,3 +127,8 @@ func (d Containerd) GetNodeLogs(ctx context.Context, node *k3d.Node, since time.
 func (d Containerd) ExecInNode(ctx context.Context, node *k3d.Node, cmd []string) error {
 	return nil
 }
+
+// ExecInNodeGetLogs execs a command inside a node and returns its logreader
+func (d Containerd) ExecInNodeGetLogs(ctx context.Context, node *k3d.Node, cmd []string) (*bufio.Reader, error) {
+	return nil, nil
+}

pkg/runtimes/docker/container.go

@@ -147,7 +147,7 @@ func getNodeContainer(ctx context.Context, node *k3d.Node) (*types.Container, er
 	for k, v := range node.Labels {
 		filters.Add("label", fmt.Sprintf("%s=%s", k, v))
 	}
-        // See https://github.com/moby/moby/issues/29997 for explanation around initial /
+	// See https://github.com/moby/moby/issues/29997 for explanation around initial /
 	filters.Add("name", fmt.Sprintf("^/?%s$", node.Name)) // regex filtering for exact name match
 
 	containers, err := docker.ContainerList(ctx, types.ContainerListOptions{

pkg/runtimes/docker/host.go

@@ -0,0 +1,43 @@
+/*
+Copyright © 2020 The k3d Author(s)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+package docker
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"runtime"
+)
+
+// GetHostIP returns the IP of the docker host (routable from inside the containers)
+func (d Docker) GetHostIP(ctx context.Context, network string) (net.IP, error) {
+	if runtime.GOOS == "linux" {
+		ip, err := GetGatewayIP(ctx, network)
+		if err != nil {
+			return nil, err
+		}
+		return ip, nil
+	}
+
+	return nil, fmt.Errorf("Docker Runtime: GetHostIP only implemented for Linux")
+
+}

pkg/runtimes/docker/network.go

@@ -23,6 +23,7 @@ package docker
 
 import (
 	"context"
+	"net"
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
@@ -104,3 +105,15 @@ func GetNetwork(ctx context.Context, ID string) (types.NetworkResource, error) {
 	defer docker.Close()
 	return docker.NetworkInspect(ctx, ID, types.NetworkInspectOptions{})
 }
+
+// GetGatewayIP returns the IP of the network gateway
+func GetGatewayIP(ctx context.Context, network string) (net.IP, error) {
+	bridgeNetwork, err := GetNetwork(ctx, network)
+	if err != nil {
+		return nil, err
+	}
+
+	gatewayIP := net.ParseIP(bridgeNetwork.IPAM.Config[0].Gateway)
+
+	return gatewayIP, nil
+}

pkg/runtimes/docker/node.go

@@ -23,6 +23,7 @@ THE SOFTWARE.
 package docker
 
 import (
+	"bufio"
 	"context"
 	"fmt"
 	"io"
@@ -303,22 +304,36 @@ func (d Docker) GetNodeLogs(ctx context.Context, node *k3d.Node, since time.Time
 	return logreader, nil
 }
 
+// ExecInNodeGetLogs executes a command inside a node and returns the logs to the caller, e.g. to parse them
+func (d Docker) ExecInNodeGetLogs(ctx context.Context, node *k3d.Node, cmd []string) (*bufio.Reader, error) {
+	resp, err := executeInNode(ctx, node, cmd)
+	if err != nil {
+		return nil, err
+	}
+	return resp.Reader, nil
+}
+
 // ExecInNode execs a command inside a node
 func (d Docker) ExecInNode(ctx context.Context, node *k3d.Node, cmd []string) error {
+	_, err := executeInNode(ctx, node, cmd)
+	return err
+}
+
+func executeInNode(ctx context.Context, node *k3d.Node, cmd []string) (*types.HijackedResponse, error) {
 
 	log.Debugf("Executing command '%+v' in node '%s'", cmd, node.Name)
 
 	// get the container for the given node
 	container, err := getNodeContainer(ctx, node)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	// create docker client
 	docker, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
 	if err != nil {
 		log.Errorln("Failed to create docker client")
-		return err
+		return nil, err
 	}
 	defer docker.Close()
 
@@ -332,7 +347,7 @@ func (d Docker) ExecInNode(ctx context.Context, node *k3d.Node, cmd []string) er
 	})
 	if err != nil {
 		log.Errorf("Failed to create exec config for node '%s'", node.Name)
-		return err
+		return nil, err
 	}
 
 	execConnection, err := docker.ContainerExecAttach(ctx, exec.ID, types.ExecStartCheck{
@@ -340,13 +355,12 @@ func (d Docker) ExecInNode(ctx context.Context, node *k3d.Node, cmd []string) er
 	})
 	if err != nil {
 		log.Errorf("Failed to connect to exec process in node '%s'", node.Name)
-		return err
+		return nil, err
 	}
-	defer execConnection.Close()
 
 	if err := docker.ContainerExecStart(ctx, exec.ID, types.ExecStartCheck{Tty: true}); err != nil {
 		log.Errorf("Failed to start exec process in node '%s'", node.Name)
-		return err
+		return nil, err
 	}
 
 	for {
@@ -354,7 +368,7 @@ func (d Docker) ExecInNode(ctx context.Context, node *k3d.Node, cmd []string) er
 		execInfo, err := docker.ContainerExecInspect(ctx, exec.ID)
 		if err != nil {
 			log.Errorf("Failed to inspect exec process in node '%s'", node.Name)
-			return err
+			return &execConnection, err
 		}
 
 		// if still running, continue loop
@@ -375,13 +389,14 @@ func (d Docker) ExecInNode(ctx context.Context, node *k3d.Node, cmd []string) er
 			logs, err := ioutil.ReadAll(execConnection.Reader)
 			if err != nil {
 				log.Errorf("Failed to get logs from node '%s'", node.Name)
-				return err
+				return &execConnection, err
 			}
 
-			return fmt.Errorf("Logs from failed access process:\n%s", string(logs))
+			return &execConnection, fmt.Errorf("Logs from failed access process:\n%s", string(logs))
 		}
 
 	}
 
-	return nil
+	return &execConnection, nil
+
 }

pkg/runtimes/docker/translate.go

@@ -41,7 +41,8 @@ func TranslateNodeToContainer(node *k3d.Node) (*NodeInDocker, error) {
 	/* initialize everything that we need */
 	containerConfig := docker.Config{}
 	hostConfig := docker.HostConfig{
-		Init: &[]bool{true}[0],
+		Init:       &[]bool{true}[0],
+		ExtraHosts: node.ExtraHosts,
 	}
 	networkingConfig := network.NetworkingConfig{}
 

pkg/runtimes/runtime.go

@@ -22,9 +22,11 @@ THE SOFTWARE.
 package runtimes
 
 import (
+	"bufio"
 	"context"
 	"fmt"
 	"io"
+	"net"
 	"time"
 
 	"github.com/rancher/k3d/v3/pkg/runtimes/containerd"
@@ -63,9 +65,11 @@ type Runtime interface {
 	GetVolume(string) (string, error)
 	GetRuntimePath() string // returns e.g. '/var/run/docker.sock' for a default docker setup
 	ExecInNode(context.Context, *k3d.Node, []string) error
+	ExecInNodeGetLogs(context.Context, *k3d.Node, []string) (*bufio.Reader, error)
 	GetNodeLogs(context.Context, *k3d.Node, time.Time) (io.ReadCloser, error)
 	GetImages(context.Context) ([]string, error)
 	CopyToNode(context.Context, string, string, *k3d.Node) error
+	GetHostIP(context.Context, string) (net.IP, error)
 }
 
 // GetRuntime checks, if a given name is represented by an implemented k3d runtime and returns it

pkg/types/types.go

@@ -108,6 +108,9 @@ var DefaultNodeEnv = []string{
 	"K3S_KUBECONFIG_OUTPUT=/output/kubeconfig.yaml",
 }
 
+// DefaultK3dInternalHostRecord defines the default /etc/hosts entry for the k3d host
+const DefaultK3dInternalHostRecord = "host.k3d.internal"
+
 // DefaultImageVolumeMountPath defines the mount path inside k3d nodes where we will mount the shared image volume by default
 const DefaultImageVolumeMountPath = "/k3d/images"
 
@@ -234,6 +237,7 @@ type Node struct {
 	Restart    bool              `yaml:"restart" json:"restart,omitempty"`
 	Labels     map[string]string // filled automatically
 	Network    string            // filled automatically
+	ExtraHosts []string          // filled automatically
 	ServerOpts ServerOpts        `yaml:"server_opts" json:"serverOpts,omitempty"`
 	AgentOpts  AgentOpts         `yaml:"agent_opts" json:"agentOpts,omitempty"`
 	State      NodeState         // filled automatically

pkg/util/regexp.go

@@ -0,0 +1,33 @@
+/*
+Copyright © 2020 The k3d Author(s)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+package util
+
+// MapSubexpNames maps regex capturing group names to corresponding matches
+func MapSubexpNames(names, matches []string) map[string]string {
+	//names, matches = names[1:], matches[1:]
+	nameMatchMap := make(map[string]string, len(matches))
+	for index := range names {
+		nameMatchMap[names[index]] = matches[index]
+	}
+	return nameMatchMap
+}