Spot termination exporter - fetch rebalance recommendations

README.md

@@ -11,22 +11,26 @@ Prometheus [exporters](https://prometheus.io/docs/instrumenting/writing_exporter
 
 ### Spot instance termination notice
 
-The Termination Notice is accessible to code running on the instance via the instance’s metadata at `http://169.254.169.254/latest/meta-data/spot/termination-time`. This field becomes available when the instance has been marked for termination and will contain the time when a shutdown signal will be sent to the instance’s operating system. 
-At that time, the Spot Instance Request’s bid status will be set to `marked-for-termination.`  
+The Termination Notice is accessible to code running on the instance via the instance’s metadata at `http://169.254.169.254/latest/meta-data/spot/termination-time`. This field becomes available when the instance has been marked for termination and will contain the time when a shutdown signal will be sent to the instance’s operating system.
+At that time, the Spot Instance Request’s bid status will be set to `marked-for-termination.`
 The bid status is accessible via the `DescribeSpotInstanceRequests` API for use by programs that manage Spot bids and instances.
 
+### Spot instance rebalance recommendations
+
+[Rebalance recommendations](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/rebalance-recommendations.html) are advance notice that a given spot instance is at elevated risk of spot disruption, they can either be accessed via AWS EventBridge or via the instance metadata endpoint. A number of AWS tools automatically handle rebalance recommendations, for instance [EKS managed node groups](https://docs.aws.amazon.com/eks/latest/userguide/managed-node-groups.html#managed-node-group-capacity-types).
+
 ### Quick start
 
 The project uses the [promu](https://github.com/prometheus/promu) Prometheus utility tool. To build the exporter `promu` needs to be installed. To install promu and build the exporter:
 
-```
+```bash
 go get github.com/prometheus/promu
 promu build
 ```
 
 The following options can be configured when starting the exporter:
 
-```
+```bash
 ./spot-termination-exporter --help
 Usage of ./spot-termintation-exporter:
   -bind-addr string
@@ -42,19 +46,22 @@ Usage of ./spot-termintation-exporter:
 
 ### Test locally
 
-The AWS instance metadata is available at `http://169.254.169.254/latest/meta-data/`. By default this is the endpoint that is being queried by the exporter but it is quite hard to reproduce a termination notice on an AWS instance for testing, so the meta-data endpoint can be changed in the configuration.
-There is a test server in the `utils` directory that can be used to mock the behavior of the metadata endpoint. It listens on port 9092 and provides dummy responses for `/instance-id` and `/spot/instance-action`. It can be started with:
-```
+The AWS instance metadata is available at `http://169.254.169.254/latest/meta-data/`. By default this is the endpoint that is being queried by the exporter but it is quite hard to reproduce a termination notice or rebalance recommendation on an AWS instance for testing, so the meta-data endpoint can be changed in the configuration.
+There is a test server in the `utils` directory that can be used to mock the behavior of the metadata endpoint. It listens on port 9092 and provides dummy responses for `/instance-id`, `/spot/instance-action`, `instance-type`, and `events/recommendations/rebalance`. It can be started with:
+
+```bash
 go run util/test_server.go
 ```
+
 The exporter can be started with this configuration to query this endpoint locally:
-```
+
+```bash
 ./spot-termination-exporter --metadata-endpoint http://localhost:9092/latest/meta-data/ --log-level debug
 ```
 
 ### Metrics
 
-```
+```text
 # HELP aws_instance_metadata_service_available Metadata service available
 # TYPE aws_instance_metadata_service_available gauge
 aws_instance_metadata_service_available{instance_id="i-0d2aab13057917887"} 1

metadata.go

@@ -10,27 +10,37 @@ import (
 )
 
 type terminationCollector struct {
-	metadataEndpoint     string
-	scrapeSuccessful     *prometheus.Desc
-	terminationIndicator *prometheus.Desc
-	terminationTime      *prometheus.Desc
+	metadataEndpoint          string
+	rebalanceIndicator        *prometheus.Desc
+	rebalanceScrapeSuccessful *prometheus.Desc
+	scrapeSuccessful          *prometheus.Desc
+	terminationIndicator      *prometheus.Desc
+	terminationTime           *prometheus.Desc
 }
 
 type InstanceAction struct {
 	Action string    `json:"action"`
 	Time   time.Time `json:"time"`
 }
 
+type InstanceEvent struct {
+	NoticeTime time.Time `json:"noticeTime"`
+}
+
 func NewTerminationCollector(me string) *terminationCollector {
 	return &terminationCollector{
-		metadataEndpoint:     me,
-		scrapeSuccessful:     prometheus.NewDesc("aws_instance_metadata_service_available", "Metadata service available", []string{"instance_id"}, nil),
-		terminationIndicator: prometheus.NewDesc("aws_instance_termination_imminent", "Instance is about to be terminated", []string{"instance_action", "instance_id"}, nil),
-		terminationTime:      prometheus.NewDesc("aws_instance_termination_in", "Instance will be terminated in", []string{"instance_id"}, nil),
+		metadataEndpoint:          me,
+		rebalanceIndicator:        prometheus.NewDesc("aws_instance_rebalance_recommended", "Instance rebalance is recommended", []string{"instance_id", "instance_type"}, nil),
+		rebalanceScrapeSuccessful: prometheus.NewDesc("aws_instance_metadata_service_events_available", "Metadata service events endpoint available", []string{"instance_id"}, nil),
+		scrapeSuccessful:          prometheus.NewDesc("aws_instance_metadata_service_available", "Metadata service available", []string{"instance_id"}, nil),
+		terminationIndicator:      prometheus.NewDesc("aws_instance_termination_imminent", "Instance is about to be terminated", []string{"instance_action", "instance_id", "instance_type"}, nil),
+		terminationTime:           prometheus.NewDesc("aws_instance_termination_in", "Instance will be terminated in", []string{"instance_id", "instance_type"}, nil),
 	}
 }
 
 func (c *terminationCollector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- c.rebalanceIndicator
+	ch <- c.rebalanceScrapeSuccessful
 	ch <- c.scrapeSuccessful
 	ch <- c.terminationIndicator
 	ch <- c.terminationTime
@@ -57,6 +67,20 @@ func (c *terminationCollector) Collect(ch chan<- prometheus.Metric) {
 	body, _ := ioutil.ReadAll(idResp.Body)
 	instanceId = string(body)
 
+	typeResp, err := client.Get(c.metadataEndpoint + "instance-type")
+	var instanceType string
+	if err != nil {
+		log.Errorf("couldn't parse instance-type from metadata: %s", err.Error())
+		return
+	}
+	if typeResp.StatusCode == 404 {
+		log.Errorf("couldn't parse instance-type from metadata: endpoint not found")
+		return
+	}
+	defer typeResp.Body.Close()
+	body, _ = ioutil.ReadAll(typeResp.Body)
+	instanceType = string(body)
+
 	resp, err := client.Get(c.metadataEndpoint + "spot/instance-action")
 	if err != nil {
 		log.Errorf("Failed to fetch data from metadata service: %s", err)
@@ -67,7 +91,7 @@ func (c *terminationCollector) Collect(ch chan<- prometheus.Metric) {
 
 		if resp.StatusCode == 404 {
 			log.Debug("instance-action endpoint not found")
-			ch <- prometheus.MustNewConstMetric(c.terminationIndicator, prometheus.GaugeValue, 0, "", instanceId)
+			ch <- prometheus.MustNewConstMetric(c.terminationIndicator, prometheus.GaugeValue, 0, "", instanceId, instanceType)
 			return
 		} else {
 			defer resp.Body.Close()
@@ -80,15 +104,44 @@ func (c *terminationCollector) Collect(ch chan<- prometheus.Metric) {
 			// so parse error is not fatal
 			if err != nil {
 				log.Errorf("Couldn't parse instance-action metadata: %s", err)
-				ch <- prometheus.MustNewConstMetric(c.terminationIndicator, prometheus.GaugeValue, 0, instanceId)
+				ch <- prometheus.MustNewConstMetric(c.terminationIndicator, prometheus.GaugeValue, 0, instanceId, instanceType)
 			} else {
 				log.Infof("instance-action endpoint available, termination time: %v", ia.Time)
-				ch <- prometheus.MustNewConstMetric(c.terminationIndicator, prometheus.GaugeValue, 1, ia.Action, instanceId)
+				ch <- prometheus.MustNewConstMetric(c.terminationIndicator, prometheus.GaugeValue, 1, ia.Action, instanceId, instanceType)
 				delta := ia.Time.Sub(time.Now())
 				if delta.Seconds() > 0 {
-					ch <- prometheus.MustNewConstMetric(c.terminationTime, prometheus.GaugeValue, delta.Seconds(), instanceId)
+					ch <- prometheus.MustNewConstMetric(c.terminationTime, prometheus.GaugeValue, delta.Seconds(), instanceId, instanceType)
 				}
 			}
 		}
 	}
+
+	eventResp, err := client.Get(c.metadataEndpoint + "events/recommendations/rebalance")
+	if err != nil {
+		log.Errorf("Failed to fetch events data from metadata service: %s", err)
+		ch <- prometheus.MustNewConstMetric(c.rebalanceScrapeSuccessful, prometheus.GaugeValue, 0, instanceId)
+		return
+	} else {
+		ch <- prometheus.MustNewConstMetric(c.rebalanceScrapeSuccessful, prometheus.GaugeValue, 1, instanceId)
+
+		if eventResp.StatusCode == 404 {
+			log.Debug("rebalance endpoint not found")
+			ch <- prometheus.MustNewConstMetric(c.rebalanceIndicator, prometheus.GaugeValue, 0, instanceId, instanceType)
+			return
+		} else {
+			defer eventResp.Body.Close()
+			body, _ := ioutil.ReadAll(eventResp.Body)
+
+			var ie = InstanceEvent{}
+			err := json.Unmarshal(body, &ie)
+
+			if err != nil {
+				log.Errorf("Couldn't parse rebalance recommendation event metadata: %s", err)
+				ch <- prometheus.MustNewConstMetric(c.rebalanceIndicator, prometheus.GaugeValue, 0, instanceId, instanceType)
+			} else {
+				log.Infof("rebalance recommendation event endpoint available, recommendation time: %v", ie.NoticeTime)
+				ch <- prometheus.MustNewConstMetric(c.rebalanceIndicator, prometheus.GaugeValue, 1, instanceId, instanceType)
+			}
+		}
+	}
 }

util/test_server.go

@@ -8,7 +8,7 @@ import (
 )
 
 // use this minimal http server to test the exporter locally
-// change constant to have metadataEndpoint = "http://localhost:9092/latest/meta-data/spot/instance-action"
+// Run the exporter with the flag --metadata-endpoint = "http://localhost:9092/latest/meta-data/"
 func main() {
 	http.HandleFunc("/latest/meta-data/spot/instance-action", func(w http.ResponseWriter, r *http.Request) {
 		terminationTime := time.Now().Add(2 * time.Minute)
@@ -19,6 +19,14 @@ func main() {
 	http.HandleFunc("/latest/meta-data/instance-id", func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprint(w, "i-0d2aab13057917887")
 	})
+	http.HandleFunc("/latest/meta-data/instance-type", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, "c5.9xlarge")
+	})
+	http.HandleFunc("/latest/meta-data/events/recommendations/rebalance", func(w http.ResponseWriter, r *http.Request) {
+		noticeTime := time.Now()
+		utc, _ := time.LoadLocation("UTC")
+		fmt.Fprintf(w, "{\"noticeTime\":\"%s\"}", noticeTime.In(utc).Format(time.RFC3339))
+	})
 
 	log.Fatal(http.ListenAndServe(":9092", nil))