Set guest timezone from host setting

Allow explicit override via lima.yaml.

Signed-off-by: Jan Dubois <jan.dubois@suse.com>

examples/default.yaml

@@ -259,6 +259,11 @@ rosetta:
   # 🟢 Builtin default: false
   binfmt: null
 
+# Specify the timezone name (as used by the zoneinfo database). Specify the empty string
+# to not set a timezone in the instance.
+# 🟢 Builtin default: use name from /etc/timezone or deduce from symlink target of /etc/localtime
+timezone: null
+
 firmware:
   # Use legacy BIOS instead of UEFI. Ignored for aarch64.
   # 🟢 Builtin default: false

pkg/cidata/cidata.TEMPLATE.d/user-data

@@ -14,6 +14,10 @@ mounts:
 {{- end }}
 {{- end }}
 
+{{- if .TimeZone }}
+timezone: {{.TimeZone}}
+{{- end }}
+
 users:
   - name: "{{.User}}"
     uid: "{{.UID}}"

pkg/cidata/cidata.go

@@ -136,6 +136,7 @@ func GenerateISO9660(instDir, name string, y *limayaml.LimaYAML, udpDNSLocalPort
 		VMType:         *y.VMType,
 		VSockPort:      vsockPort,
 		Plain:          *y.Plain,
+		TimeZone:       *y.TimeZone,
 	}
 
 	firstUsernetIndex := limayaml.FirstUsernetIndex(y)

pkg/cidata/template.go

@@ -82,6 +82,7 @@ type TemplateArgs struct {
 	VMType                          string
 	VSockPort                       int
 	Plain                           bool
+	TimeZone                        string
 }
 
 func ValidateTemplateArgs(args TemplateArgs) error {

pkg/limayaml/defaults.go

@@ -9,20 +9,20 @@ import (
 	"path/filepath"
 	"runtime"
 	"strconv"
+	"strings"
 	"text/template"
 
 	"github.com/docker/go-units"
-	"github.com/lima-vm/lima/pkg/networks"
-	"github.com/lima-vm/lima/pkg/ptr"
 	"github.com/pbnjay/memory"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/cpu"
 
 	"github.com/lima-vm/lima/pkg/guestagent/api"
+	"github.com/lima-vm/lima/pkg/networks"
 	"github.com/lima-vm/lima/pkg/osutil"
+	"github.com/lima-vm/lima/pkg/ptr"
 	"github.com/lima-vm/lima/pkg/store/dirnames"
 	"github.com/lima-vm/lima/pkg/store/filenames"
-	"github.com/sirupsen/logrus"
-
-	"golang.org/x/sys/cpu"
 )
 
 const (
@@ -83,6 +83,26 @@ func MACAddress(uniqueID string) string {
 	return hw.String()
 }
 
+func hostTimeZone() string {
+	// WSL2 will automatically set the timezone
+	if runtime.GOOS != "windows" {
+		tz, err := os.ReadFile("/etc/timezone")
+		if err == nil {
+			return strings.TrimSpace(string(tz))
+		}
+		zoneinfoFile, err := filepath.EvalSymlinks("/etc/localtime")
+		if err == nil {
+			for baseDir := filepath.Dir(zoneinfoFile); baseDir != "/"; baseDir = filepath.Dir(baseDir) {
+				if _, err = os.Stat(filepath.Join(baseDir, "Etc/UTC")); err == nil {
+					return strings.TrimPrefix(zoneinfoFile, baseDir+"/")
+				}
+			}
+			logrus.Warnf("could not locate zoneinfo directory from %q", zoneinfoFile)
+		}
+	}
+	return ""
+}
+
 func defaultCPUs() int {
 	const x = 4
 	if hostCPUs := runtime.NumCPU(); hostCPUs < x {
@@ -325,6 +345,16 @@ func FillDefault(y, d, o *LimaYAML, filePath string) {
 		}
 	}
 
+	if y.TimeZone == nil {
+		y.TimeZone = d.TimeZone
+	}
+	if o.TimeZone != nil {
+		y.TimeZone = o.TimeZone
+	}
+	if y.TimeZone == nil {
+		y.TimeZone = ptr.Of(hostTimeZone())
+	}
+
 	if y.SSH.LocalPort == nil {
 		y.SSH.LocalPort = d.SSH.LocalPort
 	}
@@ -731,6 +761,7 @@ func fixUpForPlainMode(y *LimaYAML) {
 	y.Containerd.User = ptr.Of(false)
 	y.Rosetta.BinFmt = ptr.Of(false)
 	y.Rosetta.Enabled = ptr.Of(false)
+	y.TimeZone = ptr.Of("")
 }
 
 func executeGuestTemplate(format string) (bytes.Buffer, error) {

pkg/limayaml/defaults_test.go

@@ -85,6 +85,7 @@ func TestFillDefault(t *testing.T) {
 			ForwardX11:        ptr.Of(false),
 			ForwardX11Trusted: ptr.Of(false),
 		},
+		TimeZone: ptr.Of(hostTimeZone()),
 		Firmware: Firmware{
 			LegacyBIOS: ptr.Of(false),
 		},
@@ -181,6 +182,7 @@ func TestFillDefault(t *testing.T) {
 				"-----BEGIN CERTIFICATE-----\nYOUR-ORGS-TRUSTED-CA-CERT\n-----END CERTIFICATE-----\n",
 			},
 		},
+		TimeZone: ptr.Of("Antarctica"),
 		Firmware: Firmware{
 			LegacyBIOS: ptr.Of(false),
 			Images: []FileWithVMType{
@@ -273,6 +275,7 @@ func TestFillDefault(t *testing.T) {
 		},
 	}
 
+	expect.TimeZone = y.TimeZone
 	expect.Firmware = y.Firmware
 
 	expect.Rosetta = Rosetta{
@@ -320,6 +323,7 @@ func TestFillDefault(t *testing.T) {
 			ForwardX11:        ptr.Of(false),
 			ForwardX11Trusted: ptr.Of(false),
 		},
+		TimeZone: ptr.Of("Zulu"),
 		Firmware: Firmware{
 			LegacyBIOS: ptr.Of(true),
 			Images: []FileWithVMType{
@@ -512,6 +516,7 @@ func TestFillDefault(t *testing.T) {
 			ForwardX11:        ptr.Of(false),
 			ForwardX11Trusted: ptr.Of(false),
 		},
+		TimeZone: ptr.Of("Universal"),
 		Firmware: Firmware{
 			LegacyBIOS: ptr.Of(true),
 		},

pkg/limayaml/limayaml.go

@@ -39,6 +39,7 @@ type LimaYAML struct {
 	CACertificates    CACertificates `yaml:"caCerts,omitempty" json:"caCerts,omitempty"`
 	Rosetta           Rosetta        `yaml:"rosetta,omitempty" json:"rosetta,omitempty"`
 	Plain             *bool          `yaml:"plain,omitempty" json:"plain,omitempty"`
+	TimeZone          *string        `yaml:"timezone,omitempty" json:"timezone,omitempty"`
 }
 
 type (