I have successfully added my API metrics endpoint as a scrape target in my Grafana-Loki K8S deployment. When I check the state of the target in PrometheusUI (via kubectl port-forward service/loki-prometheus-server 80 ) the target is reporting as being down with error Connection refused as below :
I verified that the metrics endpoint is indeed up and that metrics are available by issuing the following command:
kubectl port-forward service/metrics-clusterip 80
Executing a call to http://localhost:80/metrics subsequently returns the metrics payload as expected.
This is my ServiceMonitor configuration :
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: reg
namespace: loki
labels:
app: reg
release: loki
spec:
selector:
matchLabels:
app: reg
release: loki
endpoints:
- port: reg
path: /metrics
interval: 15s
namespaceSelector:
matchNames:
- "labs"
And my Deployment configuration :
apiVersion: apps/v1
kind: Deployment
metadata:
name: reg
labels:
app: reg
namespace: labs
spec:
replicas: 1
selector:
matchLabels:
app: reg
release: loki
template:
metadata:
labels:
app: reg
release: loki
spec:
containers:
- name: reg
image: xxxxxx/sre-ops:dev-latest
imagePullPolicy: Always
ports:
- name: reg
containerPort: 80
resources:
limits:
memory: 500Mi
requests:
cpu: 100m
memory: 128Mi
nodeSelector:
kubernetes.io/hostname: xxxxxxxxxxxx
imagePullSecrets:
- name: xxxx
---
apiVersion: v1
kind: Service
metadata:
name: metrics-clusterip
namespace: labs
labels:
app: reg
release: loki
annotations:
prometheus.io/path: /metrics
prometheus.io/port: '80'
prometheus.io/scrape: "true"
spec:
type: ClusterIP
selector:
app: reg
release: loki
ports:
- port: 80
targetPort: reg
protocol: TCP
name: reg
Part of the ConfigMap for the Grafana-Loki deployment :
apiVersion: v1
kind: ConfigMap
metadata:
labels:
component: "server"
app: prometheus
release: loki
chart: prometheus-15.5.4
heritage: Helm
name: loki-prometheus-server
namespace: loki
data:
alerting_rules.yml: |
{}
alerts: |
{}
prometheus.yml: |
global:
evaluation_interval: 1m
scrape_interval: 1m
scrape_timeout: 10s
rule_files:
- /etc/config/recording_rules.yml
- /etc/config/alerting_rules.yml
- /etc/config/rules
- /etc/config/alerts
scrape_configs:
- job_name: kubernetes-service-endpoints
kubernetes_sd_configs:
- role: endpoints
relabel_configs:
- action: keep
regex: true
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_scrape
- action: drop
regex: true
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_scrape_slow
- action: replace
regex: (https?)
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_scheme
target_label: __scheme__
- action: replace
regex: (.+)
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_path
target_label: __metrics_path__
- action: replace
regex: ([^:]+)(?::\d+)?;(\d+)
replacement: $1:$2
source_labels:
- __address__
- __meta_kubernetes_service_annotation_prometheus_io_port
target_label: __address__
- action: labelmap
regex: __meta_kubernetes_service_annotation_prometheus_io_param_(.+)
replacement: __param_$1
- action: labelmap
regex: __meta_kubernetes_service_label_(.+)
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_service_name
target_label: service
- action: replace
source_labels:
- __meta_kubernetes_pod_node_name
target_label: node
For context Prometheus is scrapping metrics from a .Net Core 5 API and the API exposes metrics on the same port as the API itself (port 80). The configuration at the client side is simple (and working as expected) :
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
.....
services.AddSingleton<MetricReporter>();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseRouting();
// global cors policy
app.UseCors(x => x
.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader());
app.UseAuthentication();
app.UseAuthorization();
//place before app.UseEndpoints() to avoid losing some metrics
app.UseMetricServer();
app.UseMiddleware<ResponseMetricMiddleware>();
app.UseEndpoints(endpoints => endpoints.MapControllers());
}
}
}
Versions
Prometheus : 2.34.0
HelmChart : release: loki
chart: prometheus-15.5.4
What am I missing ?