Add admin api to return sys config info (#12988)

The intention is to list values of sys config that can potentially
impact the performance of minio.

At present, it will return max value configured for rlimit

Signed-off-by: Shireesh Anjal <shireesh@minio.io>

Co-authored-by: Harshavardhana <harsha@minio.io>

cmd/admin-handlers.go

@@ -1567,6 +1567,22 @@ func (a adminAPIHandlers) HealthInfoHandler(w http.ResponseWriter, r *http.Reque
 		}
 	}
 
+	getAndWriteSysConfig := func() {
+		if query.Get(string(madmin.HealthDataTypeSysConfig)) == "true" {
+			localSysConfig := madmin.GetSysConfig(deadlinedCtx, globalLocalNodeName)
+			anonymizeAddr(&localSysConfig)
+			healthInfo.Sys.SysConfig = append(healthInfo.Sys.SysConfig, localSysConfig)
+			partialWrite(healthInfo)
+
+			peerSysConfig := globalNotificationSys.GetSysConfig(deadlinedCtx)
+			for _, sc := range peerSysConfig {
+				anonymizeAddr(&sc)
+				healthInfo.Sys.SysConfig = append(healthInfo.Sys.SysConfig, sc)
+			}
+			partialWrite(healthInfo)
+		}
+	}
+
 	getAndWriteSysServices := func() {
 		if query.Get(string(madmin.HealthDataTypeSysServices)) == "true" {
 			localSysServices := madmin.GetSysServices(deadlinedCtx, globalLocalNodeName)
@@ -1575,9 +1591,9 @@ func (a adminAPIHandlers) HealthInfoHandler(w http.ResponseWriter, r *http.Reque
 			partialWrite(healthInfo)
 
 			peerSysServices := globalNotificationSys.GetSysServices(deadlinedCtx)
-			for _, sli := range peerSysServices {
-				anonymizeAddr(&sli)
-				healthInfo.Sys.SysServices = append(healthInfo.Sys.SysServices, sli)
+			for _, ss := range peerSysServices {
+				anonymizeAddr(&ss)
+				healthInfo.Sys.SysServices = append(healthInfo.Sys.SysServices, ss)
 			}
 			partialWrite(healthInfo)
 		}
@@ -1758,6 +1774,7 @@ func (a adminAPIHandlers) HealthInfoHandler(w http.ResponseWriter, r *http.Reque
 		getAndWriteNetPerfInfo()
 		getAndWriteSysErrors()
 		getAndWriteSysServices()
+		getAndWriteSysConfig()
 
 		if query.Get("minioinfo") == "true" {
 			infoMessage := getServerInfo(ctx, r)

cmd/notification.go

@@ -1051,6 +1051,32 @@ func (sys *NotificationSys) GetOSInfo(ctx context.Context) []madmin.OSInfo {
 	return reply
 }
 
+// GetSysConfig - Get information about system config
+// (only the config that are of concern to minio)
+func (sys *NotificationSys) GetSysConfig(ctx context.Context) []madmin.SysConfig {
+	reply := make([]madmin.SysConfig, len(sys.peerClients))
+
+	g := errgroup.WithNErrs(len(sys.peerClients))
+	for index, client := range sys.peerClients {
+		if client == nil {
+			continue
+		}
+		index := index
+		g.Go(func() error {
+			var err error
+			reply[index], err = sys.peerClients[index].GetSysConfig(ctx)
+			return err
+		}, index)
+	}
+
+	for index, err := range g.Wait() {
+		if err != nil {
+			sys.addNodeErr(&reply[index], sys.peerClients[index], err)
+		}
+	}
+	return reply
+}
+
 // GetSysServices - Get information about system services
 // (only the services that are of concern to minio)
 func (sys *NotificationSys) GetSysServices(ctx context.Context) []madmin.SysServices {

cmd/peer-rest-client.go

@@ -411,7 +411,18 @@ func (client *peerRESTClient) GetSELinuxInfo(ctx context.Context) (info madmin.S
 	return info, err
 }
 
-// GetSysErrors - fetch memory information for a remote node.
+// GetSysConfig - fetch sys config for a remote node.
+func (client *peerRESTClient) GetSysConfig(ctx context.Context) (info madmin.SysConfig, err error) {
+	respBody, err := client.callWithContext(ctx, peerRESTMethodSysConfig, nil, nil, -1)
+	if err != nil {
+		return
+	}
+	defer http.DrainBody(respBody)
+	err = gob.NewDecoder(respBody).Decode(&info)
+	return info, err
+}
+
+// GetSysErrors - fetch sys errors for a remote node.
 func (client *peerRESTClient) GetSysErrors(ctx context.Context) (info madmin.SysErrors, err error) {
 	respBody, err := client.callWithContext(ctx, peerRESTMethodSysErrors, nil, nil, -1)
 	if err != nil {

cmd/peer-rest-common.go

@@ -36,6 +36,7 @@ const (
 	peerRESTMethodProcInfo                 = "/procinfo"
 	peerRESTMethodSysErrors                = "/syserrors"
 	peerRESTMethodSysServices              = "/sysservices"
+	peerRESTMethodSysConfig                = "/sysconfig"
 	peerRESTMethodDispatchNetInfo          = "/dispatchnetinfo"
 	peerRESTMethodDeleteBucketMetadata     = "/deletebucketmetadata"
 	peerRESTMethodLoadBucketMetadata       = "/loadbucketmetadata"

cmd/peer-rest-server.go

@@ -510,6 +510,24 @@ func (s *peerRESTServer) GetMemInfoHandler(w http.ResponseWriter, r *http.Reques
 	logger.LogIf(ctx, gob.NewEncoder(w).Encode(info))
 }
 
+// GetSysConfigHandler - returns system config information.
+// (only the config that are of concern to minio)
+func (s *peerRESTServer) GetSysConfigHandler(w http.ResponseWriter, r *http.Request) {
+	if !s.IsValid(w, r) {
+		fmt.Println("Invalid request")
+		s.writeErrorResponse(w, errors.New("Invalid request"))
+		return
+	}
+
+	ctx, cancel := context.WithCancel(r.Context())
+	defer cancel()
+
+	info := madmin.GetSysConfig(ctx, r.Host)
+
+	defer w.(http.Flusher).Flush()
+	logger.LogIf(ctx, gob.NewEncoder(w).Encode(info))
+}
+
 // GetSysServicesHandler - returns system services information.
 // (only the services that are of concern to minio)
 func (s *peerRESTServer) GetSysServicesHandler(w http.ResponseWriter, r *http.Request) {
@@ -1320,6 +1338,7 @@ func registerPeerRESTHandlers(router *mux.Router) {
 	subrouter.Methods(http.MethodPost).Path(peerRESTVersionPrefix + peerRESTMethodMemInfo).HandlerFunc(httpTraceHdrs(server.GetMemInfoHandler))
 	subrouter.Methods(http.MethodPost).Path(peerRESTVersionPrefix + peerRESTMethodSysErrors).HandlerFunc(httpTraceHdrs(server.GetSysErrorsHandler))
 	subrouter.Methods(http.MethodPost).Path(peerRESTVersionPrefix + peerRESTMethodSysServices).HandlerFunc(httpTraceHdrs(server.GetSysServicesHandler))
+	subrouter.Methods(http.MethodPost).Path(peerRESTVersionPrefix + peerRESTMethodSysConfig).HandlerFunc(httpTraceHdrs(server.GetSysConfigHandler))
 	subrouter.Methods(http.MethodPost).Path(peerRESTVersionPrefix + peerRESTMethodOsInfo).HandlerFunc(httpTraceHdrs(server.GetOSInfoHandler))
 	subrouter.Methods(http.MethodPost).Path(peerRESTVersionPrefix + peerRESTMethodDiskHwInfo).HandlerFunc(httpTraceHdrs(server.GetPartitionsHandler))
 	subrouter.Methods(http.MethodPost).Path(peerRESTVersionPrefix + peerRESTMethodCPUInfo).HandlerFunc(httpTraceHdrs(server.GetCPUsHandler))