Code to fix the systemd instatiated services when enabled/disabled vi…

…a ignition

internal/exec/stages/files/units.go

@@ -17,37 +17,66 @@ package files
 import (
 	"fmt"
 	"path/filepath"
+	"strconv"
 	"strings"
 
+	"github.com/coreos/go-systemd/dbus"
 	"github.com/coreos/ignition/v2/config/v3_1_experimental/types"
 	"github.com/coreos/ignition/v2/internal/distro"
 	"github.com/coreos/ignition/v2/internal/exec/util"
 )
 
+var (
+	enabledUnits  []types.Unit
+	disabledUnits []types.Unit
+	isEnableUnit  bool = false
+	isDisableUnit bool = false
+)
+
 // createUnits creates the units listed under systemd.units.
 func (s *stage) createUnits(config types.Config) error {
-	enabledOneUnit := false
+	var systemdVersion string
+	conn, err := dbus.New()
+	if err != nil {
+		return err
+	}
+	version, err := conn.GetManagerProperty("Version")
+	if err != nil {
+		return err
+	}
+	//for FCOS, the version of systemd is printed like 'v243.5-1.fc31'
+	if strings.HasPrefix(version, "v") {
+		arr := strings.Split(version, ".")
+		firsthalf := arr[0]
+		val := firsthalf[2:]
+		systemdVersion = val
+	} else {
+		//for RHCOS, the version of systemd is printed like '239'
+		systemdVersion = version[1 : len(version)-1]
+	}
+	if value, err := strconv.Atoi(systemdVersion); err == nil {
+		if value < 240 {
+			if err := s.Logger.Warning("The version of systemd is less than 240, Enabling/disabling instantiated units may not work. See https://github.com/coreos/ignition/issues/586 for more information."); err != nil {
+				return err
+			}
+		}
+	} else {
+		return err
+	}
+
 	for _, unit := range config.Systemd.Units {
 		if err := s.writeSystemdUnit(unit, false); err != nil {
 			return err
 		}
 		if unit.Enabled != nil {
 			if *unit.Enabled {
-				if err := s.Logger.LogOp(
-					func() error { return s.EnableUnit(unit) },
-					"enabling unit %q", unit.Name,
-				); err != nil {
-					return err
-				}
+				enabledUnits = append(enabledUnits, unit)
+				isEnableUnit = true
+
 			} else {
-				if err := s.Logger.LogOp(
-					func() error { return s.DisableUnit(unit) },
-					"disabling unit %q", unit.Name,
-				); err != nil {
-					return err
-				}
+				disabledUnits = append(disabledUnits, unit)
+				isDisableUnit = true
 			}
-			enabledOneUnit = true
 		}
 		if unit.Mask != nil && *unit.Mask {
 			relabelpath := ""
@@ -64,10 +93,79 @@ func (s *stage) createUnits(config types.Config) error {
 			s.relabel(relabelpath)
 		}
 	}
-	// and relabel the preset file itself if we enabled/disabled something
-	if enabledOneUnit {
-		s.relabel(util.PresetPath)
+	if err := s.createSystemdUnits(config); err != nil {
+		return err
+	}
+	return nil
+}
+
+// createSystemdUnits creates the enabled and disabled units listed under
+// systemd units. This function is written to support instantiated
+// units to be enabled via presets.For more information: https://github.com/systemd/systemd/pull/9901/files
+func (s *stage) createSystemdUnits(config types.Config) error {
+	var instantiatedEnableServices []string
+	if isEnableUnit {
+		var enabledServices = make(map[string]string)
+		for _, enableUnit := range enabledUnits {
+			if strings.Contains(enableUnit.Name, "@") {
+				var enableInstanceAppend []string
+				at := strings.Index(enableUnit.Name, "@")
+				dot := strings.Index(enableUnit.Name, ".")
+				instance := enableUnit.Name[at+1 : dot]
+				serviceInstance := enableUnit.Name[0:at+1] + enableUnit.Name[dot:len(enableUnit.Name)]
+				if val, ok := enabledServices[serviceInstance]; ok {
+					enableInstanceAppend = append(enableInstanceAppend, val, instance)
+					enabledServices[serviceInstance] = strings.Join(enableInstanceAppend, " ")
+				} else {
+					enableInstanceAppend = append(enableInstanceAppend, instance)
+					enabledServices[serviceInstance] = strings.Join(enableInstanceAppend, " ")
+				}
+
+			} else {
+				if err := s.Logger.LogOp(
+					func() error { return s.EnableUnit(enableUnit.Name) },
+					"enabling unit %q", enableUnit.Name); err != nil {
+					return err
+				}
+
+			}
+		}
+
+		if len(enabledServices) > 0 {
+			for key, value := range enabledServices {
+				instantiatedEnableServices = append(instantiatedEnableServices, key+" "+value)
+			}
+			if err := s.Logger.LogOp(
+				func() error { return s.EnableUnit(strings.Join(instantiatedEnableServices, " ")) },
+				"enabling instantiated units %q", strings.Join(instantiatedEnableServices, " "),
+			); err != nil {
+				return err
+			}
+		}
+	}
+
+	if isDisableUnit {
+		for _, disableUnit := range disabledUnits {
+			var disableSystemdUnit string
+			if strings.Contains(disableUnit.Name, "@") {
+				at := strings.Index(disableUnit.Name, "@")
+				dot := strings.Index(disableUnit.Name, ".")
+				instance := disableUnit.Name[at+1 : dot]
+				serviceInstance := disableUnit.Name[0:at+1] + disableUnit.Name[dot:len(disableUnit.Name)]
+				disableSystemdUnit = serviceInstance + " " + instance
+			} else {
+				disableSystemdUnit = disableUnit.Name
+			}
+			if err := s.Logger.LogOp(
+				func() error { return s.DisableUnit(disableSystemdUnit) },
+				"disabling unit %q", disableSystemdUnit,
+			); err != nil {
+				return err
+			}
+
+		}
 	}
+	s.relabel(util.PresetPath)
 	return nil
 }
 

internal/exec/util/unit.go

@@ -110,8 +110,8 @@ func (ut Util) MaskUnit(unit types.Unit) (string, error) {
 	return filepath.Join("/", SystemdUnitsPath(), unit.Name), nil
 }
 
-func (ut Util) EnableUnit(unit types.Unit) error {
-	return ut.appendLineToPreset(fmt.Sprintf("enable %s", unit.Name))
+func (ut Util) EnableUnit(enabledUnits string) error {
+	return ut.appendLineToPreset(fmt.Sprintf("enable %s", enabledUnits))
 }
 
 // presets link in /etc, which doesn't make sense for runtime units
@@ -145,8 +145,8 @@ func (ut Util) EnableRuntimeUnit(unit types.Unit, target string) error {
 	return ut.WriteLink(link)
 }
 
-func (ut Util) DisableUnit(unit types.Unit) error {
-	return ut.appendLineToPreset(fmt.Sprintf("disable %s", unit.Name))
+func (ut Util) DisableUnit(disabledUnit string) error {
+	return ut.appendLineToPreset(fmt.Sprintf("disable %s", disabledUnit))
 }
 
 func (ut Util) appendLineToPreset(data string) error {