move host.k3d.internal /etc/hosts injection to hook action

cmd/cluster/clusterCreate.go

@@ -610,7 +610,7 @@ func applyCLIOverrides(cfg conf.SimpleConfig) (conf.SimpleConfig, error) {
 				return cfg, fmt.Errorf("invalid format of host-alias %s (exactly one ':' allowed)", ha)
 			}
 
-			// validate IP // TODO: move to pkg/ validate config?
+			// validate IP
 			ip, err := netaddr.ParseIP(s[0])
 			if err != nil {
 				return cfg, fmt.Errorf("invalid IP '%s' in host-alias '%s': %w", s[0], ha, err)

pkg/client/cluster.go

@@ -50,8 +50,6 @@ import (
 	"github.com/sirupsen/logrus"
 	"golang.org/x/sync/errgroup"
 	"gopkg.in/yaml.v2"
-
-	"github.com/goodhosts/hostsfile"
 )
 
 // ClusterRun orchestrates the steps of cluster creation, configuration and starting
@@ -76,6 +74,7 @@ func ClusterRun(ctx context.Context, runtime k3drt.Runtime, clusterConfig *confi
 	/*
 	 * Step 2: Pre-Start Configuration
 	 */
+	// Gather Environment information, e.g. the host gateway address
 	envInfo, err := GatherEnvironmentInfo(ctx, runtime, &clusterConfig.Cluster)
 	if err != nil {
 		return fmt.Errorf("failed to gather environment information used for cluster creation: %w", err)
@@ -252,55 +251,8 @@ func ClusterPrep(ctx context.Context, runtime k3drt.Runtime, clusterConfig *conf
 	 */
 
 	if len(clusterConfig.ClusterCreateOpts.HostAliases) > 0 {
-
-		hostAliasesInjectEtcHostsHook := k3d.NodeHook{
-			Stage: k3d.LifecycleStagePostStart,
-			Action: actions.RewriteFileAction{
-				Runtime:     runtime,
-				Path:        "/etc/hosts",
-				Mode:        0644,
-				Description: "Adding HostAliases to /etc/hosts in nodes",
-				Opts: actions.RewriteFileActionOpts{
-					NoCopy: true,
-				},
-				RewriteFunc: func(input []byte) ([]byte, error) {
-
-					// write copied hosts file to temp path (for hostsfile module to read)
-					tmpHosts, err := os.CreateTemp("", "k3d-hostsfile-*")
-					if err != nil {
-						return nil, fmt.Errorf("error creating temp hosts file: %w", err)
-					}
-					os.WriteFile(tmpHosts.Name(), input, 0777)
-
-					// read in temp hostsfile file
-					hostsfile, err := hostsfile.NewCustomHosts(tmpHosts.Name())
-					if err != nil {
-						return nil, fmt.Errorf("error reading temp hosts file: %w", err)
-					}
-
-					// add new entries
-					for _, hostAlias := range clusterConfig.ClusterCreateOpts.HostAliases {
-						if err := hostsfile.Add(hostAlias.IP, hostAlias.Hostnames...); err != nil {
-							return nil, fmt.Errorf("error adding hosts file entry for %s:%s: %w", hostAlias.IP, hostAlias.Hostnames, err)
-						}
-					}
-
-					// cleanup (de-duplicate, etc.)
-					hostsfile.Clean()
-
-					// write changes to temp file
-					hostsfile.Flush()
-
-					time.Sleep(time.Second)
-
-					return os.ReadFile(tmpHosts.Name())
-				},
-			},
-		}
-
 		// append new action to general nodehooks
-		clusterConfig.ClusterCreateOpts.NodeHooks = append(clusterConfig.ClusterCreateOpts.NodeHooks, hostAliasesInjectEtcHostsHook)
-
+		clusterConfig.ClusterCreateOpts.NodeHooks = append(clusterConfig.ClusterCreateOpts.NodeHooks, NewHostAliasesInjectEtcHostsHook(runtime, clusterConfig.ClusterCreateOpts.HostAliases))
 	}
 
 	return nil
@@ -1030,9 +982,18 @@ func ClusterStart(ctx context.Context, runtime k3drt.Runtime, cluster *k3d.Clust
 		/*** DNS ***/
 
 		// add host.k3d.internal record to /etc/hosts in all nodes
-		postStartErrgrp.Go(func() error {
-			return prepInjectHostIP(postStartErrgrpCtx, runtime, cluster, &clusterStartOpts)
-		})
+		for _, node := range append(servers, agents...) {
+			currNode := node
+			postStartErrgrp.Go(func() error {
+				// inject host-gateway as host.k3d.internal in /etc/hosts of node containers
+				return NewHostAliasesInjectEtcHostsHook(runtime, []k3d.HostAlias{
+					{
+						IP:        clusterStartOpts.EnvironmentInfo.HostGateway.String(),
+						Hostnames: []string{"host.k3d.internal"},
+					},
+				}).Action.Run(postStartErrgrpCtx, currNode)
+			})
+		}
 
 		if len(servers) > 0 {
 			postStartErrgrp.Go(func() error {
@@ -1044,7 +1005,7 @@ func ClusterStart(ctx context.Context, runtime k3drt.Runtime, cluster *k3d.Clust
 
 				hosts := fmt.Sprintf("%s %s\n", clusterStartOpts.EnvironmentInfo.HostGateway.String(), k3d.DefaultK3dInternalHostRecord)
 
-				net, err := runtime.GetNetwork(ctx, &cluster.Network)
+				net, err := runtime.GetNetwork(postStartErrgrpCtx, &cluster.Network)
 				if err != nil {
 					return fmt.Errorf("failed to get cluster network %s to inject host records into CoreDNS: %w", cluster.Network.Name, err)
 				}
@@ -1093,10 +1054,10 @@ func ClusterStart(ctx context.Context, runtime k3drt.Runtime, cluster *k3d.Clust
 						if err != nil {
 							return err
 						}
-						if err := NodeWaitForLogMessage(ctx, runtime, n, "Cluster dns configmap", ts.Truncate(time.Second)); err != nil {
+						if err := NodeWaitForLogMessage(postStartErrgrpCtx, runtime, n, "Cluster dns configmap", ts.Truncate(time.Second)); err != nil {
 							return err
 						}
-						return act.Run(ctx, n)
+						return act.Run(postStartErrgrpCtx, n)
 					}
 				}
 				return nil
@@ -1194,33 +1155,6 @@ func corednsAddHost(ctx context.Context, runtime k3drt.Runtime, cluster *k3d.Clu
 	return nil
 }
 
-// prepInjectHostIP adds /etc/hosts entry for host.k3d.internal, referring to the host system
-func prepInjectHostIP(ctx context.Context, runtime k3drt.Runtime, cluster *k3d.Cluster, clusterStartOpts *k3d.ClusterStartOpts) error {
-	if cluster.Network.Name == "host" {
-		l.Log().Debugf("Not injecting host.k3d.internal into /etc/hosts as clusternetwork is 'host'")
-		return nil
-	}
-
-	hostIP := clusterStartOpts.EnvironmentInfo.HostGateway
-	hostsEntry := fmt.Sprintf("%s %s", hostIP.String(), k3d.DefaultK3dInternalHostRecord)
-	l.Log().Infof("Injecting '%s' into /etc/hosts of all nodes...", hostsEntry)
-
-	// entry in /etc/hosts
-	errgrp, errgrpctx := errgroup.WithContext(ctx)
-	for _, node := range cluster.Nodes {
-		n := node
-		errgrp.Go(func() error {
-			return runtime.ExecInNode(errgrpctx, n, []string{"sh", "-c", fmt.Sprintf("echo '%s' >> /etc/hosts", hostsEntry)})
-		})
-	}
-	if err := errgrp.Wait(); err != nil {
-		return fmt.Errorf("failed to add hosts entry %s: %w", hostsEntry, err)
-	}
-	l.Log().Debugf("Successfully added host record \"%s\" to /etc/hosts in all nodes", hostsEntry)
-
-	return nil
-}
-
 func prepCreateLocalRegistryHostingConfigMap(ctx context.Context, runtime k3drt.Runtime, cluster *k3d.Cluster) error {
 	success := false
 	for _, node := range cluster.Nodes {

pkg/client/hooks.go

@@ -0,0 +1,75 @@
+/*
+Copyright © 2020-2021 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 client
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/goodhosts/hostsfile"
+	"github.com/rancher/k3d/v5/pkg/actions"
+	"github.com/rancher/k3d/v5/pkg/runtimes"
+	k3d "github.com/rancher/k3d/v5/pkg/types"
+)
+
+func NewHostAliasesInjectEtcHostsHook(runtime runtimes.Runtime, hostAliases []k3d.HostAlias) k3d.NodeHook {
+	return k3d.NodeHook{
+		Stage: k3d.LifecycleStagePostStart,
+		Action: actions.RewriteFileAction{
+			Runtime:     runtime,
+			Path:        "/etc/hosts",
+			Mode:        0644,
+			Description: "Adding HostAliases to /etc/hosts in nodes",
+			Opts: actions.RewriteFileActionOpts{
+				NoCopy: true,
+			},
+			RewriteFunc: func(input []byte) ([]byte, error) {
+
+				tmpHosts, err := os.CreateTemp("", "k3d-hostsfile-*")
+				if err != nil {
+					return nil, fmt.Errorf("error creating temp hosts file: %w", err)
+				}
+				os.WriteFile(tmpHosts.Name(), input, 0777)
+
+				hostsfile, err := hostsfile.NewCustomHosts(tmpHosts.Name())
+				if err != nil {
+					return nil, fmt.Errorf("error reading temp hosts file: %w", err)
+				}
+
+				for _, hostAlias := range hostAliases {
+					if err := hostsfile.Add(hostAlias.IP, hostAlias.Hostnames...); err != nil {
+						return nil, fmt.Errorf("error adding hosts file entry for %s:%s: %w", hostAlias.IP, hostAlias.Hostnames, err)
+					}
+				}
+
+				hostsfile.Clean()
+
+				hostsfile.Flush()
+
+				time.Sleep(time.Second)
+
+				return os.ReadFile(tmpHosts.Name())
+			},
+		},
+	}
+}

pkg/client/node.go

@@ -30,7 +30,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"reflect"
 	"strconv"
 	"strings"
 	"time"
@@ -413,9 +412,9 @@ func NodeStart(ctx context.Context, runtime runtimes.Runtime, node *k3d.Node, no
 	// execute lifecycle hook actions
 	for _, hook := range nodeStartOpts.NodeHooks {
 		if hook.Stage == k3d.LifecycleStagePreStart {
-			l.Log().Tracef("Node %s: Executing preStartAction '%s'", node.Name, reflect.TypeOf(hook))
+			l.Log().Tracef("Node %s: Executing preStartAction '%s': %s", node.Name, hook.Action.Name(), hook.Action.Info())
 			if err := hook.Action.Run(ctx, node); err != nil {
-				l.Log().Errorf("Node %s: Failed executing preStartAction '%+v': %+v", node.Name, hook, err)
+				l.Log().Errorf("Node %s: Failed executing preStartAction '%s': %s: %+v", node.Name, hook.Action.Name(), hook.Action.Info(), err) // TODO: should we error out on failed preStartAction?
 			}
 		}
 	}

pkg/config/validate.go

@@ -31,6 +31,7 @@ import (
 	"github.com/rancher/k3d/v5/pkg/runtimes"
 	runtimeutil "github.com/rancher/k3d/v5/pkg/runtimes/util"
 	k3d "github.com/rancher/k3d/v5/pkg/types"
+	"inet.af/netaddr"
 
 	"fmt"
 
@@ -76,9 +77,29 @@ func ValidateClusterConfig(ctx context.Context, runtime runtimes.Runtime, config
 		}
 	}
 
-	// hostAliases not allowed in hostnetwork mode
-	if len(config.ClusterCreateOpts.HostAliases) > 0 && config.Cluster.Network.Name == "host" {
-		return fmt.Errorf("hostAliases not allowed in hostnetwork mode")
+	// hostAliases
+	if len(config.ClusterCreateOpts.HostAliases) > 0 {
+		// not allowed in hostnetwork mode
+		if config.Cluster.Network.Name == "host" {
+			return fmt.Errorf("hostAliases not allowed in hostnetwork mode")
+		}
+
+		// validate IP and hostname
+		for _, ha := range config.ClusterCreateOpts.HostAliases {
+			// validate IP
+			_, err := netaddr.ParseIP(ha.IP)
+			if err != nil {
+				return fmt.Errorf("invalid IP '%s' in hostAlias '%s': %w", ha.IP, ha, err)
+			}
+
+			// validate hostnames
+			for _, hostname := range ha.Hostnames {
+				if err := k3dc.ValidateHostname(hostname); err != nil {
+					return fmt.Errorf("invalid hostname '%s' in hostAlias '%s': %w", hostname, ha, err)
+				}
+			}
+		}
+
 	}
 
 	// validate nodes one by one