I have setup Percona MongoDB Exporter and when I attempt to scrape metrics for my MongDB instance I am getting an error :
An error has occurred while connecting to MongoDB:
cannot connect to MongoDB: server selection error: server selection timeout, current topology: { Type: Unknown, Servers: [{ Addr: mongodb-headless-service.labs.svc.cluster.local:27017, Type: Unknown, Last error: connection() error occured during connection handshake: dial tcp: lookup mongodb-headless-service.svc.cluster.local on 159.XX.XX.XX:XX: no such host }, ] }
Both MongoDB and Percona-MongoDB Exporter are deployed in the same namespace on Kubernetes and I have created a user (at admin level ) to extract the metrics :
db.createUser({ user: "promt", pwd: "abc123", roles: [ { role: "clusterMonitor", db: "admin" },{ role: "read", db: "local" } ], mechanisms:["SCRAM-SHA-1"]})
To verify if the exporter is able to scrape any metrics from the MongoDB instance I am using:
kubectl -n labs port-forward service/mongodb-exporter 9216
and I can access the Exporter at http://localhost:9216
And in the Percona MongoDB Exporter deployment I have specified Mongo-URI as below :
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: mongodb-exporter
namespace: labs
spec:
replicas: 1
selector:
matchLabels:
app: mongodb-exporter
template:
metadata:
labels:
app: mongodb-exporter
spec:
containers:
- name: mongodb-exporter
image: percona/mongodb_exporter:0.30
imagePullPolicy: "IfNotPresent"
args:
- "--mongodb.direct-connect=false"
- "--mongodb.uri=mongodb://promt:abc123@mongo-headless-service.svc.cluster.local/admin"
ports:
- name: metrics
containerPort: 9216
resources:
requests:
memory: 128Mi
cpu: 250m
I have tried a lot of options but they all result in the same error:
- Adding k8s namespace to the mongo-uri
--mongodb.uri=mongodb://promt:abc123@mongodb-headless-service.**labs**.svc.cluster.local/admin
- Adding option for SSL
--mongodb.uri=mongodb://promt:abc123@mongodb-headless-service.svc.cluster.local/admin?ssl=false
- Switching from using a k8s headless service to a ClusterIP
--mongodb.uri=mongodb://promt:abc123@mongo-single-clusterip.labs.svc.cluster.local/admin
- Enabling direct-connect option
- "--mongodb.direct-connect=true"
- "--mongodb.uri=mongodb://promt:abc123@mongodb-headless-service.svc.cluster.local/admin"
For all these options I also tried variations of adding the ssl option and namespace but that is failing with same error in all cases.
My MongoDB instance is a standalone deployment with the following definition :
apiVersion: apps/v1
kind: Deployment
metadata:
name: mongodb-deployment
namespace: labs
labels:
app: mongodb
spec:
replicas: 1
selector:
matchLabels:
app: mongodb
template:
metadata:
labels:
app: mongodb
spec:
containers:
- name: mongodb
image: docker.io/bitnami/mongodb:4.4.6-debian-10-r0
imagePullPolicy: "IfNotPresent"
securityContext:
runAsNonRoot: true
runAsUser: 1001
ports:
- containerPort: 27017
env:
- name: MONGO_INITDB_ROOT_USERNAME
valueFrom:
secretKeyRef:
name: mongodb-secret-amended
key: mongo-root-username
- name: MONGO_INITDB_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mongodb-secret-amended
key: mongo-root-password
volumeMounts:
- mountPath: /data/db
name: mongodb-vol
volumes:
- name: mongodb-vol
persistentVolumeClaim:
claimName: mongodb-claim
---
apiVersion: v1
kind: Service
metadata:
name: mongodb-service
namespace: labs
spec:
type: NodePort
selector:
app: mongodb
ports:
- protocol: TCP
port: 27017
targetPort: 27017
---
apiVersion: v1
kind: Service
metadata:
name: mongodb-headless-service
namespace: labs
spec:
selector:
app: mongodb
ports:
- protocol: TCP
port: 27017
targetPort: 27017
---
apiVersion: v1
kind: Service
metadata:
name: mongo-single-clusterip
namespace: labs
spec:
type: ClusterIP
selector:
app: mongodb
ports:
- protocol: TCP
port: 27017
targetPort: 27017
For context I am following the example given here and here
What am I missing ?