Cannot connect to Postgres deployed to Kubernetes

Question

I am stuck trying to debug a connection issue with PostgreSQL deployed with minikube. I've tried creating the postgres-service with both type NodePort and LoadBalancer but I cannot seem to connect with psql from my localhost.

I've copied in all the config (apologies), as I'm sure there's probably just a silly mistake somewhere!

apiVersion: v1
kind: Secret
metadata:
  name: postgres-credentials
type: Opaque
data:
  user: YWRtaW4=
  password: YWRtaW4=
  database: YWRtaW4=
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres-pvc
  labels:
    type: local
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 2Gi
  volumeName: postgres-pv
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: postgres-pv
  labels:
    type: local
spec:
  capacity:
    storage: 2Gi
  storageClassName: standard
  accessModes:
    - ReadWriteMany
  hostPath:
    path: /data/postgres-pv-local
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: postgres
spec:
  replicas: 1
  selector:
    matchLabels:
      name: postgres-container
  template:
    metadata:
      labels:
        name: postgres-container
        tier: backend
    spec:
      containers:
        - name: postgres-container
          image: mdillon/postgis:10
          ports:
            - containerPort: 5432
          env:
            - name: POSTGRES_USER
              valueFrom:
                secretKeyRef:
                  name: postgres-credentials
                  key: user

            - name: POSTGRES_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: postgres-credentials
                  key: password

            - name: POSTGRES_DB
              valueFrom:
                secretKeyRef:
                  name: postgres-credentials
                  key: database

          volumeMounts:
            - name: postgres-volume-mount
              mountPath: /var/lib/postgresql/data
      volumes:
        - name: postgres-volume-mount
          persistentVolumeClaim:
            claimName: postgres-pvc
---
apiVersion: v1
kind: Service
metadata:
  name: postgres-service
spec:
  type: NodePort
  selector:
    app: postgres-container
  ports:
    - protocol: TCP
      port: 5432
      targetPort: 5432

Trying to connect on my localhost:

$ kubectl get services
NAME               TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
kubernetes         ClusterIP   10.96.0.1       <none>        443/TCP          30h
postgres-service   NodePort    10.105.42.187   <none>        5432:32252/TCP   7m32s

$ export PGPASSWORD=admin
$ psql -h localhost -U admin -p 32252 admin
psql: could not connect to server: Connection refused

I've also tried creating a Ubuntu deployment in the cluster, using kubectl run -i --tty --attach --image=ubuntu -- bash, installing psql and connecting on 5432/32252, localhost/postgres-service, etc... but that doesn't work either.

nightfury1204 · Accepted Answer · 2019-01-09 04:44:07Z

4

Minikube run in a VM. In here, psql -h localhost -U admin -p 32252 admin you are trying to connect to postgres that is exposed in localhost. But it is not exposed in the localhost. Since you defined NodePort type service, you can access it using Node ip. So, instead of using localhost, try Minikube ip.

 $ minikube ip

answered Jan 9, 2019 at 4:44

nightfury1204

4,70422 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Greg Brown Over a year ago

Thanks for the input and for clarifying that. The issue was caused by a mismatch in labels (see my answer). Cheers

Nicos Karalis Over a year ago

This is probably the best answer, but I need to elaborate for future reference. If you are on a mac and running minikube on top of docker, this will not work. minikube can't get an IP other than 127.0.0.1 on docker. Use with --vm-driver hyperkit and minikube tunnel this will give you an usable and accessible ip

Greg Brown · Accepted Answer · 2019-01-09 10:47:45Z

1

The cause turned out to be a mismatch in label key in the service selector, app: postgres-container, and the deployment label, name: postgres-container.

Now I can connect, using the minikube ip for NodePort:

$ export PGPASSWORD=admin
$ psql -h 192.168.99.100 -U admin -p 30917 admin

or localhost when the service is type LoadBalancer.

answered Jan 9, 2019 at 10:47

Greg Brown

1,3782 gold badges18 silver badges34 bronze badges

2 Comments

Andrea Richiardi Over a year ago

Super newbie here, what was the mismatch about? The spelling seems the same. Asking because I might have the same problem.

Greg Brown Over a year ago

It was because the label in the Deployment config (spec -> template -> metadata -> labels) had 'name' as the key, i.e. name: postgres-container, whereas the selector in the Service config (spec -> selector) was selecting on app: postgres-container. I just needed to change the selector to name: postgres-container. Hope that helps solve your problem!

Mircea Sirghi · Accepted Answer · 2025-05-22 20:28:53Z

0

With kind it is easy to configure, however you need to correctly map your cluster ports.

In kind cluster config add these lines:

extraPortMappings:
    - containerPort: 30000
      hostPort: 5432

And these lines in your postgres service:

ports:
    - port: 5432
      targetPort: 5432
      nodePort: 30000
      protocol: TCP

This clearly indicates that nodePort == containerport and your host port is mapped to postgres port.

edited May 22 at 20:28

answered Mar 31 at 18:56

Mircea Sirghi

6485 silver badges14 bronze badges

Collectives™ on Stack Overflow

Cannot connect to Postgres deployed to Kubernetes

3 Answers 3

2 Comments

2 Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

2 Comments

Comments

Related