Customize node exporter target

cmd/config.go

@@ -77,11 +77,16 @@ func LoadConfig(fileSystem afero.Fs) (*agent.Config, error) {
 		DiscoveriesPeriodsConfig: discoveryPeriodsConfig,
 	}
 
+	prometheusTargets := discovery.PrometheusTargets{
+		discovery.NodeExporterName: viper.GetString("node-exporter-target"),
+	}
+
 	return &agent.Config{
 		AgentID:           agentID,
 		InstanceName:      hostname,
 		DiscoveriesConfig: discoveriesConfig,
 		FactsServiceURL:   viper.GetString("facts-service-url"),
 		PluginsFolder:     viper.GetString("plugins-folder"),
+		PrometheusTargets: prometheusTargets,
 	}, nil
 }

cmd/config_test.go

@@ -69,6 +69,9 @@ func (suite *AgentCmdTestSuite) SetupTest() {
 		},
 		FactsServiceURL: "amqp://guest:guest@serviceurl:5672",
 		PluginsFolder:   "/usr/etc/trento/plugins/",
+		PrometheusTargets: map[string]string{
+			"node_exporter": "10.0.0.5:9100",
+		},
 	}
 }
 
@@ -85,6 +88,7 @@ func (suite *AgentCmdTestSuite) TestConfigFromFlags() {
 		"--api-key=some-api-key",
 		"--force-agent-id=some-agent-id",
 		"--facts-service-url=amqp://guest:guest@serviceurl:5672",
+		"--node-exporter-target=10.0.0.5:9100",
 	})
 
 	_ = suite.cmd.Execute()
@@ -107,6 +111,7 @@ func (suite *AgentCmdTestSuite) TestConfigFromEnv() {
 	os.Setenv("TRENTO_API_KEY", "some-api-key")
 	os.Setenv("TRENTO_FORCE_AGENT_ID", "some-agent-id")
 	os.Setenv("TRENTO_FACTS_SERVICE_URL", "amqp://guest:guest@serviceurl:5672")
+	os.Setenv("TRENTO_NODE_EXPORTER_TARGET", "10.0.0.5:9100")
 
 	_ = suite.cmd.Execute()
 

cmd/start.go

@@ -123,6 +123,14 @@ func NewStartCmd() *cobra.Command {
 
 	startCmd.Flags().String("facts-service-url", "amqp://guest:guest@localhost:5672", "Facts service queue url")
 
+	startCmd.Flags().
+		String(
+			"node-exporter-target",
+			"",
+			"Node exporter target address in ip:port notation. If not given the lowest "+
+				"ipv4 address with the default 9100 port is used",
+		)
+
 	return startCmd
 }
 

internal/agent/agent.go

@@ -36,6 +36,7 @@ type Config struct {
 	DiscoveriesConfig *discovery.DiscoveriesConfig
 	FactsServiceURL   string
 	PluginsFolder     string
+	PrometheusTargets discovery.PrometheusTargets
 }
 
 // NewAgent returns a new instance of Agent with the given configuration
@@ -48,7 +49,7 @@ func NewAgent(config *Config) (*Agent, error) {
 		discovery.NewSAPSystemsDiscovery(collectorClient, *config.DiscoveriesConfig),
 		discovery.NewCloudDiscovery(collectorClient, *config.DiscoveriesConfig),
 		discovery.NewSubscriptionDiscovery(collectorClient, config.InstanceName, *config.DiscoveriesConfig),
-		discovery.NewHostDiscovery(collectorClient, config.InstanceName, *config.DiscoveriesConfig),
+		discovery.NewHostDiscovery(collectorClient, config.InstanceName, config.PrometheusTargets, *config.DiscoveriesConfig),
 		discovery.NewSaptuneDiscovery(collectorClient, *config.DiscoveriesConfig),
 	}
 

internal/core/hosts/discovered_host.go

@@ -1,14 +1,15 @@
 package hosts
 
 type DiscoveredHost struct {
-	OSVersion                string   `json:"os_version"`
-	HostIPAddresses          []string `json:"ip_addresses"`
-	Netmasks                 []int    `json:"netmasks"`
-	HostName                 string   `json:"hostname"`
-	CPUCount                 int      `json:"cpu_count"`
-	SocketCount              int      `json:"socket_count"`
-	TotalMemoryMB            int      `json:"total_memory_mb"`
-	AgentVersion             string   `json:"agent_version"`
-	InstallationSource       string   `json:"installation_source"`
-	FullyQualifiedDomainName *string  `json:"fully_qualified_domain_name,omitempty"`
+	OSVersion                string            `json:"os_version"`
+	HostIPAddresses          []string          `json:"ip_addresses"`
+	Netmasks                 []int             `json:"netmasks"`
+	HostName                 string            `json:"hostname"`
+	CPUCount                 int               `json:"cpu_count"`
+	SocketCount              int               `json:"socket_count"`
+	TotalMemoryMB            int               `json:"total_memory_mb"`
+	AgentVersion             string            `json:"agent_version"`
+	InstallationSource       string            `json:"installation_source"`
+	FullyQualifiedDomainName *string           `json:"fully_qualified_domain_name,omitempty"`
+	PrometheusTargets        map[string]string `json:"prometheus_targets"`
 }

internal/discovery/host.go

@@ -1,9 +1,11 @@
 package discovery
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"net"
+	"slices"
 	"strconv"
 	"time"
 
@@ -20,23 +22,31 @@ import (
 const HostDiscoveryID string = "host_discovery"
 const HostDiscoveryMinPeriod time.Duration = 1 * time.Second
 
+const NodeExporterName string = "node_exporter"
+const NodeExporterPort int = 9100
+
+type PrometheusTargets map[string]string
+
 type HostDiscovery struct {
-	id              string
-	collectorClient collector.Client
-	host            string
-	interval        time.Duration
+	id                string
+	collectorClient   collector.Client
+	host              string
+	prometheusTargets PrometheusTargets
+	interval          time.Duration
 }
 
 func NewHostDiscovery(
 	collectorClient collector.Client,
 	hostname string,
+	prometheusTargets PrometheusTargets,
 	config DiscoveriesConfig,
 ) Discovery {
 	return HostDiscovery{
-		id:              HostDiscoveryID,
-		collectorClient: collectorClient,
-		host:            hostname,
-		interval:        config.DiscoveriesPeriodsConfig.Host,
+		id:                HostDiscoveryID,
+		collectorClient:   collectorClient,
+		host:              hostname,
+		prometheusTargets: prometheusTargets,
+		interval:          config.DiscoveriesPeriodsConfig.Host,
 	}
 }
 
@@ -55,6 +65,8 @@ func (d HostDiscovery) Discover(ctx context.Context) (string, error) {
 		return "", err
 	}
 
+	updatedPrometheusTargets := updatePrometheusTargets(d.prometheusTargets, ipAddresses)
+
 	host := hosts.DiscoveredHost{
 		OSVersion:                getOSVersion(),
 		HostIPAddresses:          ipAddresses,
@@ -66,6 +78,7 @@ func (d HostDiscovery) Discover(ctx context.Context) (string, error) {
 		AgentVersion:             version.Version,
 		InstallationSource:       version.InstallationSource,
 		FullyQualifiedDomainName: getHostFQDN(),
+		PrometheusTargets:        updatedPrometheusTargets,
 	}
 
 	err = d.collectorClient.Publish(ctx, d.id, host)
@@ -107,6 +120,34 @@ func getNetworksData() ([]string, []int, error) {
 	return ipAddrList, netmasks, nil
 }
 
+func updatePrometheusTargets(targets PrometheusTargets, ipAddresses []string) PrometheusTargets {
+	// Return exporter details if they are given by the user
+	nodeExporterTarget, ok := targets[NodeExporterName]
+	if ok && nodeExporterTarget != "" {
+		return PrometheusTargets{
+			NodeExporterName: nodeExporterTarget,
+		}
+	}
+
+	// Fallback to lowest IP address value to replace empty exporter targets
+	ips := make([]net.IP, 0, len(ipAddresses))
+	for _, ip := range ipAddresses {
+		parsedIP := net.ParseIP(ip)
+		if parsedIP.To4() != nil && !parsedIP.IsLoopback() {
+			ips = append(ips, parsedIP)
+		}
+
+	}
+
+	slices.SortFunc(ips, func(a, b net.IP) int {
+		return bytes.Compare(a, b)
+	})
+
+	return PrometheusTargets{
+		NodeExporterName: fmt.Sprintf("%s:%d", ips[0], NodeExporterPort),
+	}
+}
+
 func getHostFQDN() *string {
 
 	fqdn, err := fqdn.FqdnHostname()

internal/discovery/host_internal_test.go

@@ -0,0 +1,42 @@
+package discovery
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type HostInternalTestSuite struct {
+	suite.Suite
+	ipAddresses []string
+}
+
+func TestHostInternalTestSuite(t *testing.T) {
+	suite.Run(t, new(HostInternalTestSuite))
+}
+
+func (suite *HostInternalTestSuite) SetupSuite() {
+	suite.ipAddresses = []string{"127.0.0.1", "::1", "10.1.1.5", "10.1.1.4", "10.1.1.6", "6c62:7cc9:3936:e802:2bbe"}
+}
+
+func (suite *HostInternalTestSuite) TestUpdatePrometheusTargets() {
+	initialTargets := PrometheusTargets{
+		"node_exporter": "",
+	}
+
+	expectedTargets := PrometheusTargets{
+		"node_exporter": "10.1.1.4:9100",
+	}
+
+	updatedTargets := updatePrometheusTargets(initialTargets, suite.ipAddresses)
+	suite.Equal(expectedTargets, updatedTargets)
+}
+
+func (suite *HostInternalTestSuite) TestUpdatePrometheusTargetsGivenByUser() {
+	initialTargets := PrometheusTargets{
+		"node_exporter": "192.168.1.60:9123",
+	}
+
+	updatedTargets := updatePrometheusTargets(initialTargets, suite.ipAddresses)
+	suite.Equal(initialTargets, updatedTargets)
+}

internal/discovery/mocks/discovered_host_mock.go

@@ -16,5 +16,8 @@ func NewDiscoveredHostMock() hosts.DiscoveredHost {
 		AgentVersion:             "trento-agent-version",
 		InstallationSource:       "Community",
 		FullyQualifiedDomainName: &fqdn,
+		PrometheusTargets: map[string]string{
+			"node_exporter": "10.1.1.4:9100",
+		},
 	}
 }

packaging/config/agent.yaml

@@ -94,4 +94,12 @@
 
 ## Facts gathering service URL
 
-# facts-service-url: amqp://guest:guest@localhost:5672
+# facts-service-url: amqp://guest:guest@localhost:5672
+
+###############################################################################
+
+## Prometheus exporters targets
+## Configure the prometheus targets. If not given, the lowest discovered IP address
+## with a default port number is used
+
+# node-exporter-target: 192.168.1.10:9100

test/fixtures/config/agent.yaml

@@ -8,3 +8,4 @@ server-url: http://serverurl
 api-key: some-api-key
 force-agent-id: some-agent-id
 facts-service-url: amqp://guest:guest@serviceurl:5672
+node-exporter-target: 10.0.0.5:9100

test/fixtures/discovery/host/expected_published_host_discovery.json

@@ -19,6 +19,9 @@
     "total_memory_mb": 4096,
     "agent_version": "trento-agent-version",
     "installation_source": "Community",
-    "fully_qualified_domain_name": "com.example.trento.host"
+    "fully_qualified_domain_name": "com.example.trento.host",
+    "prometheus_targets": {
+      "node_exporter": "10.1.1.4:9100"
+    }
   }
 }