add config options to configure extra hosts

cmd/cluster/clusterCreate.go

@@ -32,6 +32,7 @@ import (
 
 	"github.com/docker/go-connections/nat"
 	"github.com/sirupsen/logrus"
+	"inet.af/netaddr"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
@@ -266,6 +267,9 @@ func NewCmdClusterCreate() *cobra.Command {
 	cmd.Flags().String("registry-create", "", "Create a k3d-managed registry and connect it to the cluster (Format: `NAME[:HOST][:HOSTPORT]`\n - Example: `k3d cluster create --registry-create mycluster-registry:0.0.0.0:5432`")
 	_ = ppViper.BindPFlag("cli.registries.create", cmd.Flags().Lookup("registry-create"))
 
+	cmd.Flags().StringArray("host-alias", nil, "Add `ip:host[,host,...]` mappings")
+	_ = ppViper.BindPFlag("hostaliases", cmd.Flags().Lookup("host-alias"))
+
 	/* k3s */
 	cmd.Flags().StringArray("k3s-arg", nil, "Additional args passed to k3s command (Format: `ARG@NODEFILTER[;@NODEFILTER]`)\n - Example: `k3d cluster create --k3s-arg \"--disable=traefik@server:0\"")
 	_ = ppViper.BindPFlag("cli.k3sargs", cmd.Flags().Lookup("k3s-arg"))
@@ -593,7 +597,38 @@ func applyCLIOverrides(cfg conf.SimpleConfig) (conf.SimpleConfig, error) {
 			cfg.Registries.Create.Host = exposeAPI.Host
 			cfg.Registries.Create.HostPort = exposeAPI.Binding.HostPort
 		}
+	}
+
+	// --host-alias
+	hostAliasFlags := ppViper.GetStringSlice("hostaliases")
+	if len(hostAliasFlags) > 0 {
+		for _, ha := range hostAliasFlags {
+
+			// split on :
+			s := strings.Split(ha, ":")
+			if len(s) != 2 {
+				return cfg, fmt.Errorf("invalid format of host-alias %s (exactly one ':' allowed)", ha)
+			}
+
+			// 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)
+			}
+
+			// hostnames
+			hostnames := strings.Split(s[1], ",")
+			for _, hostname := range hostnames {
+				if err := k3dCluster.ValidateHostname(hostname); err != nil {
+					return cfg, fmt.Errorf("invalid hostname '%s' in host-alias '%s': %w", hostname, ha, err)
+				}
+			}
 
+			cfg.HostAliases = append(cfg.HostAliases, k3d.HostAlias{
+				IP:        ip.String(),
+				Hostnames: hostnames,
+			})
+		}
 	}
 
 	return cfg, nil

go.mod

@@ -40,14 +40,19 @@ require (
 	sigs.k8s.io/yaml v1.3.0
 )
 
-require github.com/spf13/pflag v1.0.5
+require (
+	github.com/goodhosts/hostsfile v0.1.1
+	github.com/spf13/pflag v1.0.5
+)
 
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
+	github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/containerd/continuity v0.2.1 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/dimchansky/utfbom v1.1.1 // indirect
 	github.com/docker/distribution v2.7.1+incompatible // indirect
 	github.com/docker/go v1.5.1-1.0.20160303222718-d30aec9fd63c // indirect
 	github.com/fsnotify/fsnotify v1.5.1 // indirect

go.sum

@@ -68,6 +68,9 @@ github.com/Azure/go-autorest/tracing v0.6.0/go.mod h1:+vhtPC754Xsa23ID7GlGsrdKBp
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/DataDog/datadog-go v3.2.0+incompatible/go.mod h1:LButxg5PwREeZtORoXG3tL4fMGNddJ+vMq1mwgfaqoQ=
+github.com/Masterminds/glide v0.13.2/go.mod h1:STyF5vcenH/rUqTEv+/hBXlSTo7KYwg2oc2f4tzPWic=
+github.com/Masterminds/semver v1.4.2/go.mod h1:MB6lktGJrhw8PrUyiEoblNEGEQ+RzHPF078ddwwvV3Y=
+github.com/Masterminds/vcs v1.13.0/go.mod h1:N09YCmOQr6RLxC6UNHzuVwAdodYbbnycGHSmwVJjcKA=
 github.com/Microsoft/go-winio v0.4.11/go.mod h1:VhR8bwka0BXejwEJY73c50VrPtXAaKcyvVC4A4RozmA=
 github.com/Microsoft/go-winio v0.4.14/go.mod h1:qXqCSQ3Xa7+6tgxaGTIe4Kpcdsi+P8jBhyzoq1bpyYA=
 github.com/Microsoft/go-winio v0.4.15-0.20190919025122-fc70bd9a86b5/go.mod h1:tTuCMEN+UleMWgg9dVx4Hu52b1bJo+59jBh3ajtinzw=
@@ -113,6 +116,8 @@ github.com/armon/go-metrics v0.3.10/go.mod h1:4O98XIr/9W0sxpJ8UaYkvjk10Iff7SnFrb
 github.com/armon/go-radix v0.0.0-20180808171621-7fddfc383310/go.mod h1:ufUuZ+zHj4x4TnLV4JWEpy2hxWSpsRywHrMgIH9cCH8=
 github.com/armon/go-radix v1.0.0/go.mod h1:ufUuZ+zHj4x4TnLV4JWEpy2hxWSpsRywHrMgIH9cCH8=
 github.com/asaskevich/govalidator v0.0.0-20190424111038-f61b66f89f4a/go.mod h1:lB+ZfQJz7igIIfQNfa7Ml4HSf2uFQQRzpGGRXenZAgY=
+github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d h1:Byv0BzEl3/e6D5CLfI0j/7hiIEtvGVFPCZ7Ei2oq8iQ=
+github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d/go.mod h1:WaHUgvxTVq04UNunO+XhnAqY/wQc+bxr74GqbsZ/Jqw=
 github.com/aws/aws-sdk-go v1.15.11/go.mod h1:mFuSZ37Z9YOHbQEwBWztmVzqXrEkub65tZoCYDt7FT0=
 github.com/beorn7/perks v0.0.0-20150223135152-b965b613227f/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v0.0.0-20160804104726-4c0e84591b9a/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
@@ -172,6 +177,7 @@ github.com/cncf/xds/go v0.0.0-20211001041855-01bcc9b48dfe/go.mod h1:eXthEFrGJvWH
 github.com/cncf/xds/go v0.0.0-20211011173535-cb28da3451f1/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20211130200136-a8f946100490/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cockroachdb/datadriven v0.0.0-20190809214429-80d97fb3cbaa/go.mod h1:zn76sxSg3SzpJ0PPJaLDCu+Bu0Lg3sKTORVIj19EIF8=
+github.com/codegangsta/cli v1.20.0/go.mod h1:/qJNoX69yVSKu5o4jLyXAENLRyk1uhi7zkbQ3slBdOA=
 github.com/containerd/aufs v0.0.0-20200908144142-dab0cbea06f4/go.mod h1:nukgQABAEopAHvB6j7cnP5zJ+/3aVcE7hCYqvIwAHyE=
 github.com/containerd/aufs v0.0.0-20201003224125-76a6863f2989/go.mod h1:AkGGQs9NM2vtYHaUen+NljV0/baGCAPELGm2q9ZXpWU=
 github.com/containerd/aufs v0.0.0-20210316121734-20793ff83c97/go.mod h1:kL5kd6KM5TzQjR79jljyi4olc1Vrx6XBlcyj3gNv2PU=
@@ -279,6 +285,8 @@ github.com/coreos/go-systemd/v22 v22.1.0/go.mod h1:xO0FLkIi5MaZafQlIrOotqXZ90ih+
 github.com/coreos/go-systemd/v22 v22.3.2/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
+github.com/corpix/uarand v0.1.1 h1:RMr1TWc9F4n5jiPDzFHtmaUXLKLNUFK0SgCLo4BhX/U=
+github.com/corpix/uarand v0.1.1/go.mod h1:SFKZvkcRoLqVRFZ4u25xPmp6m9ktANfbpXZ7SJ0/FNU=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/cpuguy83/go-md2man/v2 v2.0.1/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
@@ -301,6 +309,8 @@ github.com/denverdino/aliyungo v0.0.0-20190125010748-a747050bb1ba/go.mod h1:dV8l
 github.com/dgrijalva/jwt-go v0.0.0-20170104182250-a601269ab70c/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
+github.com/dimchansky/utfbom v1.1.1 h1:vV6w1AhK4VMnhBno/TPVCoK9U/LP0PkLCS9tbxHdi/U=
+github.com/dimchansky/utfbom v1.1.1/go.mod h1:SxdoEBH5qIqFocHMyGOXVAybYJdr71b1Q/j0mACtrfE=
 github.com/dnaeon/go-vcr v1.0.1/go.mod h1:aBB1+wY4s93YsC3HHjMBMrwTj2R9FHDzUr9KyGc8n1E=
 github.com/docker/cli v0.0.0-20191017083524-a8ff7f821017/go.mod h1:JLrzqnKDaYBop7H2jaqPtU4hHvMKP+vjCwu2uszcLI8=
 github.com/docker/cli v20.10.12+incompatible h1:lZlz0uzG+GH+c0plStMUdF/qk3ppmgnswpR5EbqzVGA=
@@ -451,6 +461,8 @@ github.com/golang/protobuf v1.5.1/go.mod h1:DopwsBzvsk0Fs44TXzsVbJyPhcCPeIwnvohx
 github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw=
 github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/golang/snappy v0.0.3/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
+github.com/goodhosts/hostsfile v0.1.1 h1:SqRUTFOshOCon0ZSXDrW1bkKZvs4+5pRgYFWySdaLno=
+github.com/goodhosts/hostsfile v0.1.1/go.mod h1:lXcUP8xO4WR5vvuQ3F/N0bMQoclOtYKEEUnyY2jTusY=
 github.com/google/btree v0.0.0-20180813153112-4030bb1f1f0c/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.1/go.mod h1:xXMiIv4Fb/0kKde4SpL7qlzvu5cMJDRkFDxJfI9uaxA=
@@ -560,6 +572,8 @@ github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpO
 github.com/iancoleman/strcase v0.2.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
+github.com/icrowley/fake v0.0.0-20180203215853-4178557ae428 h1:Mo9W14pwbO9VfRe+ygqZ8dFbPpoIK1HFrG/zjTuQ+nc=
+github.com/icrowley/fake v0.0.0-20180203215853-4178557ae428/go.mod h1:uhpZMVGznybq1itEKXj6RYw9I71qK4kH+OGMjRC4KEo=
 github.com/imdario/mergo v0.3.5/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
 github.com/imdario/mergo v0.3.8/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
 github.com/imdario/mergo v0.3.10/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
@@ -691,6 +705,7 @@ github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8m
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f/go.mod h1:ZdcZmHo+o7JKHSa8/e818NopupXU1YMK5fe1lsApnBw=
 github.com/ncw/swift v1.0.47/go.mod h1:23YIA4yWVnGwv2dQlN4bB7egfYX6YLn0Yo/S6zZO/ZM=
+github.com/ngdinhtoan/glide-cleanup v0.2.0/go.mod h1:UQzsmiDOb8YV3nOsCxK/c9zPpCZVNoHScRE3EO9pVMM=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=

pkg/actions/nodehooks.go

@@ -27,9 +27,11 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"strings"
 
 	"github.com/rancher/k3d/v5/pkg/runtimes"
 	k3d "github.com/rancher/k3d/v5/pkg/types"
+	"github.com/rancher/k3d/v5/pkg/util"
 
 	l "github.com/rancher/k3d/v5/pkg/logger"
 )
@@ -65,6 +67,11 @@ type RewriteFileAction struct {
 	RewriteFunc func([]byte) ([]byte, error)
 	Mode        os.FileMode
 	Description string
+	Opts        RewriteFileActionOpts
+}
+
+type RewriteFileActionOpts struct {
+	NoCopy bool // do not copy over the file, but rather overwrite the contents of the target (e.g. to avoid "Resource busy" error on /etc/hosts)
 }
 
 func (act RewriteFileAction) Name() string {
@@ -99,7 +106,29 @@ func (act RewriteFileAction) Run(ctx context.Context, node *k3d.Node) error {
 
 	l.Log().Tracef("Rewritten:\n%s", string(file))
 
-	return act.Runtime.WriteToNode(ctx, file, act.Path, act.Mode, node)
+	// default way: copy over file
+	if !act.Opts.NoCopy {
+		return act.Runtime.WriteToNode(ctx, file, act.Path, act.Mode, node)
+	}
+
+	// non-default: overwrite file contents
+	tmpPath := fmt.Sprintf(
+		"/tmp/%s-%s",
+		strings.ReplaceAll(act.Path, "/", "-"),
+		util.GenerateRandomString(20),
+	)
+
+	if err := act.Runtime.WriteToNode(ctx, file, tmpPath, act.Mode, node); err != nil {
+		return fmt.Errorf("error creating temp file %s: %w", tmpPath, err)
+	}
+
+	cmd := fmt.Sprintf("cat %s > %s", tmpPath, act.Path)
+
+	if err := act.Runtime.ExecInNode(ctx, node, []string{"sh", "-c", cmd}); err != nil {
+		return fmt.Errorf("error overwriting contents of %s: %w", act.Path, err)
+	}
+
+	return nil
 
 }