feat: add possibility for multiple targets with one exporter

README.md

@@ -53,17 +53,26 @@ $ ./pbs-exporter -help
 
 You can use the following flags to configure the exporter. All flags can also be set using environment variables. Environment variables take precedence over flags.
 
-| Flag                     | Environment Variable | Description                                          | Default                 |
-| ------------------------ | -------------------- | ---------------------------------------------------- | ----------------------- |
-| `pbs.loglevl`            | `PBS_LOGLEVEL`       | Log level (debug, info)                              | `info`                  |
-| `pbs.api.token`          | `PBS_API_TOKEN`      | API token to use for authentication                  |                         |
-| `pbs.api.token.name`     | `PBS_API_TOKEN_NAME` | Name of the API token to use for authentication      | `pbs-exporter`          |
-| `pbs.endpoint`           | `PBS_ENDPOINT`       | Address of the Proxmox Backup Server                 | `http://localhost:8007` |
-| `pbs.username`           | `PBS_USERNAME`       | Username to use for authentication                   | `root@pam`              |
-| `pbs.timeout`            | `PBS_TIMEOUT`        | Timeout for requests to Proxmox Backup Server        | `5s`                    |
-| `pbs.insecure`           | `PBS_INSECURE`       | Disable TLS certificate verification                 | `false`                 |
-| `pbs.metrics-path`       | `PBS_METRICS_PATH`   | Path under which to expose metrics                   | `/metrics`              |
-| `pbs.web.listen-address` | `PBS_LISTEN_ADDRESS` | Address to listen on for web interface and telemetry | `:9101`                 |
+| Flag                     | Environment Variable | Description                                          | Default                                                |
+| ------------------------ | -------------------- | ---------------------------------------------------- | ------------------------------------------------------ |
+| `pbs.loglevl`            | `PBS_LOGLEVEL`       | Log level (debug, info)                              | `info`                                                 |
+| `pbs.api.token`          | `PBS_API_TOKEN`      | API token to use for authentication                  |                                                        |
+| `pbs.api.token.name`     | `PBS_API_TOKEN_NAME` | Name of the API token to use for authentication      | `pbs-exporter`                                         |
+| `pbs.endpoint`           | `PBS_ENDPOINT`       | Address of the Proxmox Backup Server                 | `http://localhost:8007` (if no parameter `target` set) |
+| `pbs.username`           | `PBS_USERNAME`       | Username to use for authentication                   | `root@pam`                                             |
+| `pbs.timeout`            | `PBS_TIMEOUT`        | Timeout for requests to Proxmox Backup Server        | `5s`                                                   |
+| `pbs.insecure`           | `PBS_INSECURE`       | Disable TLS certificate verification                 | `false`                                                |
+| `pbs.metrics-path`       | `PBS_METRICS_PATH`   | Path under which to expose metrics                   | `/metrics`                                             |
+| `pbs.web.listen-address` | `PBS_LISTEN_ADDRESS` | Address to listen on for web interface and telemetry | `:9101`                                                |
+
+## Multiple Proxmox Backup Servers
+
+If you want to monitor multiple Proxmox Backup Servers, you can use the `targets` parameter in the query string. Instead of setting the `pbs.endpoint` flag (or `PBS_ENDPOINT` env), you can use the `target` parameter in the query string to specify the Proxmox Backup Server to monitor. You would then use following URL to scrape metrics: `http://localhost:9101/metrics?target=http://10.10.10.10:8007`.
+
+This is useful if you are using Prometheus and want to monitor multiple Proxmox Backup Servers with one "pbs-exporter" instance.
+You find examples for Prometheus static configuration in the [prometheus/static-config](prometheus/static-config) directory.
+
+:warning: **Important**: if `pbs.endpoint` or `PBS_ENDPOINT` is set, the `target` parameter is ignored.
 
 ## Node metrics
 

main.go

@@ -33,7 +33,7 @@ var (
 	}
 
 	// Flags
-	endpoint = flag.String("pbs.endpoint", "http://localhost:8007",
+	endpoint = flag.String("pbs.endpoint", "",
 		"Proxmox Backup Server endpoint")
 	username = flag.String("pbs.username", "root@pam",
 		"Proxmox Backup Server username")
@@ -710,15 +710,39 @@ func main() {
 		log.Printf("DEBUG: Using listen address: %s", *listenAddress)
 	}
 
-	// register exporter
-	exporter := NewExporter(*endpoint, *username, *apitoken, *apitokenname)
-	prometheus.MustRegister(exporter)
-	log.Printf("INFO: Using connection endpoint: %s", *endpoint)
+	if *endpoint != "" {
+		log.Printf("INFO: Using fix connection endpoint: %s", *endpoint)
+	}
 	log.Printf("INFO: Listening on: %s", *listenAddress)
 	log.Printf("INFO: Metrics path: %s", *metricsPath)
 
 	// start http server
-	http.Handle(*metricsPath, promhttp.Handler())
+	http.HandleFunc(*metricsPath, func(w http.ResponseWriter, r *http.Request) {
+		target := ""
+
+		// if endpoint was not set as flag or env variable, we try to get it from "target" query parameter
+		if *endpoint != "" {
+			target = *endpoint
+		} else {
+			target = r.URL.Query().Get("target")
+			if target == "" {
+				// if target is not set, we use the default
+				target = "http://localhost:8007"
+			}
+		}
+
+		// debug
+		if *loglevel == "debug" {
+			log.Printf("DEBUG: ----Using connection endpoint %s", target)
+		}
+
+		exporter := NewExporter(target, *username, *apitoken, *apitokenname)
+		prometheus.MustRegister(exporter)
+		promhttp.Handler().ServeHTTP(w, r) // Serve the metrics
+		prometheus.Unregister(exporter)    // Clean up after serving
+
+	})
+
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		w.Write([]byte(`<html>
             <head><title>PBS Exporter</title></head>

prometheus/static-config/multiple-exporter.yaml

@@ -0,0 +1,18 @@
+# Use Case: multiple Proxmox Backup Server, they have different authentication user/token
+#           configure multiple authentication for each exporter instance
+#           important: set env PBS_ENDPOINT per exporter instance!
+#
+# Setup:
+# - first exporter instance: pbs-exporter-1
+# - second exporter instance: pbs-exporter-2
+
+- job_name: 'pbs-exporter'
+  honor_timestamps: true
+  scrape_interval: 15s
+  scrape_timeout: 10s
+  metrics_path: /metrics
+  scheme: http
+  static_configs:
+  - targets:
+    - 'pbs-exporter-1:9101' # PBS_ENDPOINT set to target 1
+    - 'pbs-exporter-2:9101' # PBS_ENDPOINT set to target 2

prometheus/static-config/multiple-targets.yaml

@@ -0,0 +1,22 @@
+# Use Case: multiple Proxmox Backup Server, all have the same authentication user/token
+#
+# important: env PBS_ENDPOINT NOT SET!
+#
+scrape_configs:
+- job_name: 'pbs-exporter'
+  honor_timestamps: true
+  scrape_interval: 15s
+  scrape_timeout: 10s
+  metrics_path: /metrics
+  scheme: http
+  static_configs:
+  - targets:
+    - 'https://10.10.10.10:8007' # Proxmox Backup Server 1
+    - 'https://10.10.10.11:8007' # Proxmox Backup Server 2
+  relabel_configs:
+    - source_labels: [__address__]
+      target_label: __param_target
+    - source_labels: [__param_target]
+      target_label: instance
+    - target_label: __address__
+      replacement: pbs-exporter:9101 # pbs-exporter address

prometheus/example-target.yaml → prometheus/static-config/single-target.yaml

@@ -1,3 +1,9 @@
+# Use Case: single Proxmox Backup Server
+#
+# Setup:
+# - exporter instance: pbs-exporter:9101
+# - PBS target set in env PBS_ENDPOINT
+
 scrape_configs:
 - job_name: 'pbs-exporter'
   honor_timestamps: true
@@ -7,9 +13,10 @@ scrape_configs:
   scheme: http
   static_configs:
   - targets:
-    - 'pbs-exporter:9101'
+    - 'pbs-exporter:9101' # PBS_ENDPOINT set to target
+
 
-# example with relablings to have the host name (e.g. host-001) as a metric label
+# example with relablings to have the host name (e.g. host-001) as metric label "instance"
 - job_name: 'pbs-exporter-relabel'
   honor_timestamps: true
   scrape_interval: 15s
@@ -18,7 +25,7 @@ scrape_configs:
   scheme: http
   static_configs:
   - targets:
-    - 'pbs-exporter@host-001'
+    - 'pbs-exporter@host-001' # PBS_ENDPOINT set to target
   relabel_configs:
   - source_labels: [ __address__ ]
     regex: '.*@(.*)'