disable logind on systemd 239 by default

agent/confgroup/group.go

@@ -8,6 +8,7 @@ import (
 	"regexp"
 	"strings"
 
+	"github.com/netdata/go.d.plugin/agent/hostinfo"
 	"github.com/netdata/go.d.plugin/agent/module"
 
 	"github.com/ilyam8/hashstructure"
@@ -99,7 +100,7 @@ func firstPositive(value int, others ...int) int {
 }
 
 func urlResolveHostname(rawURL string) string {
-	if hostname == "" || !strings.Contains(rawURL, "hostname") {
+	if hostinfo.Hostname == "" || !strings.Contains(rawURL, "hostname") {
 		return rawURL
 	}
 
@@ -108,19 +109,19 @@ func urlResolveHostname(rawURL string) string {
 		return rawURL
 	}
 
-	u.Host = strings.Replace(u.Host, "hostname", hostname, 1)
+	u.Host = strings.Replace(u.Host, "hostname", hostinfo.Hostname, 1)
 
 	return u.String()
 }
 
 func jobNameResolveHostname(name string) string {
-	if hostname == "" || !strings.Contains(name, "hostname") {
+	if hostinfo.Hostname == "" || !strings.Contains(name, "hostname") {
 		return name
 	}
 
 	if name != "hostname" && !strings.HasPrefix(name, "hostname.") && !strings.HasPrefix(name, "hostname_") {
 		return name
 	}
 
-	return strings.Replace(name, "hostname", hostname, 1)
+	return strings.Replace(name, "hostname", hostinfo.Hostname, 1)
 }

agent/confgroup/hostname.go → agent/hostinfo/hostinfo.go

@@ -1,4 +1,6 @@
-package confgroup
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package hostinfo
 
 import (
 	"bytes"
@@ -7,7 +9,9 @@ import (
 	"time"
 )
 
-var hostname = func() string {
+var Hostname = getHostname()
+
+func getHostname() string {
 	path, err := exec.LookPath("hostname")
 	if err != nil {
 		return ""
@@ -22,4 +26,4 @@ var hostname = func() string {
 	}
 
 	return string(bytes.TrimSpace(bs))
-}()
+}

agent/hostinfo/hostinfo_common.go

@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+//go:build !linux
+
+package hostinfo
+
+var SystemdVersion int

agent/hostinfo/hostinfo_linux.go

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+//go:build linux
+
+package hostinfo
+
+import (
+	"context"
+	"regexp"
+	"strconv"
+
+	"github.com/coreos/go-systemd/v22/dbus"
+)
+
+var SystemdVersion = getSystemdVersion()
+
+func getSystemdVersion() int {
+	var reVersion = regexp.MustCompile(`[0-9][0-9][0-9]`)
+
+	conn, err := dbus.NewWithContext(context.Background())
+	if err != nil {
+		return 0
+	}
+	defer conn.Close()
+
+	version, err := conn.GetManagerProperty("Version")
+	if err != nil {
+		return 0
+	}
+
+	major := reVersion.FindString(version)
+	if major == "" {
+		return 0
+	}
+
+	ver, err := strconv.Atoi(major)
+	if err != nil {
+		return 0
+	}
+
+	return ver
+}

agent/setup.go

@@ -11,6 +11,7 @@ import (
 	"github.com/netdata/go.d.plugin/agent/discovery"
 	"github.com/netdata/go.d.plugin/agent/discovery/dummy"
 	"github.com/netdata/go.d.plugin/agent/discovery/file"
+	"github.com/netdata/go.d.plugin/agent/hostinfo"
 	"github.com/netdata/go.d.plugin/agent/module"
 	"github.com/netdata/go.d.plugin/agent/vnodes"
 
@@ -54,17 +55,22 @@ func (a *Agent) loadEnabledModules(cfg config) module.Registry {
 		if !all && a.RunModule != name {
 			continue
 		}
-		if all && creator.Disabled && !cfg.isExplicitlyEnabled(name) {
-			a.Infof("'%s' module disabled by default, should be explicitly enabled in the config", name)
-			continue
-		}
-		if all && !cfg.isImplicitlyEnabled(name) {
-			a.Infof("'%s' module disabled in the config file", name)
-			continue
+		if all {
+			// Known issue: go.d/logind high CPU usage on Alma Linux8 (https://github.com/netdata/netdata/issues/15930)
+			if !cfg.isExplicitlyEnabled(name) && (creator.Disabled || name == "logind" && hostinfo.SystemdVersion == 239) {
+				a.Infof("'%s' module disabled by default, should be explicitly enabled in the config", name)
+				continue
+			}
+			if !cfg.isImplicitlyEnabled(name) {
+				a.Infof("'%s' module disabled in the config file", name)
+				continue
+			}
 		}
 		enabled[name] = creator
 	}
+
 	a.Infof("enabled/registered modules: %d/%d", len(enabled), len(a.ModuleRegistry))
+
 	return enabled
 }