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The heart of everything are the service monitors, an intermediate layer between the application to be monitored and the Prometheus operator. Within this component it is necessary to indicate which are the "coordinates" of the K8s service associated with the application. In our case we are interested in the longhorn-backend service. Let's try to print some information about it
| Code Block |
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| language | bash |
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| title | LH services |
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| collapse | true |
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$ k get svc -n longhorn-system --show-labels
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE LABELS
csi-attacher ClusterIP 10.233.13.82 <none> 12345/TCP 24h app=csi-attacher,longhorn.io/managed-by=longhorn-manager
csi-provisioner ClusterIP 10.233.62.177 <none> 12345/TCP 24h app=csi-provisioner,longhorn.io/managed-by=longhorn-manager
csi-resizer ClusterIP 10.233.40.134 <none> 12345/TCP 24h app=csi-resizer,longhorn.io/managed-by=longhorn-manager
csi-snapshotter ClusterIP 10.233.19.24 <none> 12345/TCP 24h app=csi-snapshotter,longhorn.io/managed-by=longhorn-manager
longhorn-backend ClusterIP 10.233.19.4 <none> 9500/TCP 24h app.kubernetes.io/instance=longhorn,app.kubernetes.io/managed-by=Helm,app.kubernetes.io/name=longhorn,app.kubernetes.io/version=v1.1.2,app=longhorn-manager,helm.sh/chart=longhorn-1.1.2
longhorn-frontend ClusterIP 10.233.62.6 <none> 80/TCP 24h app.kubernetes.io/instance=longhorn,app.kubernetes.io/managed-by=Helm,app.kubernetes.io/name=longhorn,app.kubernetes.io/version=v1.1.2,app=longhorn-ui,helm.sh/chart=longhorn-1.1.2
$ k get -n longhorn-system svc longhorn-backend -oyaml
apiVersion: v1
kind: Service
metadata:
annotations:
meta.helm.sh/release-name: longhorn
meta.helm.sh/release-namespace: longhorn-system
labels:
app: longhorn-manager
app.kubernetes.io/instance: longhorn
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: longhorn
app.kubernetes.io/version: v1.1.2
helm.sh/chart: longhorn-1.1.2
name: longhorn-backend
namespace: longhorn-system
spec:
clusterIP: 10.233.19.4
clusterIPs:
- 10.233.19.4
ipFamilies:
- IPv4
ipFamilyPolicy: SingleStack
ports:
- name: manager
port: 9500
protocol: TCP
targetPort: manager
selector:
app: longhorn-manager
sessionAffinity: ClientIP
sessionAffinityConfig:
clientIP:
timeoutSeconds: 10800
type: ClusterIP
status:
loadBalancer: {} |
We note that by using the app=longhorn-manager label, we are able to isolate the longhorn-backend service. So we can write a service monitor like this
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| language | yml |
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| title | serviceMonitor |
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| collapse | true |
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apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: longhorn-prometheus-servicemonitor
namespace: monitoring
labels:
release: mon
spec:
selector:
matchLabels:
app: longhorn-manager
namespaceSelector:
matchNames:
- longhorn-system
endpoints:
- port: manager |