Trouble connecting to postgres from outside Kubernetes cluster - postgresql

Question

I've launched a postgresql server in minikube, and I'm having difficulty connecting to it from outside the cluster.
Update
It turned out my cluster was suffering from unrelated problems, causing all sorts of broken behavior. I ended up nuking the whole cluster and vm and starting from scratch. Now I've got working. I changed the deployment to a statefulset, though I think it could work either way.
Setup and test:
kubectl --context=minikube create -f postgres-statefulset.yaml
kubectl --context=minikube create -f postgres-service.yaml
url=$(minikube service postgres --url --format={{.IP}}:{{.Port}})
psql --host=${url%:*} --port=${url#*:} --username=postgres --dbname=postgres \
--command='SELECT refobjid FROM pg_depend LIMIT 1'
Password for user postgres:
refobjid
----------
1247
postgres-service.yaml
apiVersion: v1
kind: Service
metadata:
name: postgres
labels:
app: postgres
role: service
spec:
selector:
app: postgres
type: NodePort
ports:
- name: postgres
port: 5432
targetPort: 5432
protocol: TCP
postgres-statefulset.yaml
apiVersion: apps/v1beta2
kind: StatefulSet
metadata:
name: postgres
labels:
app: postgres
role: service
spec:
replicas: 1
selector:
matchLabels:
app: postgres
role: service
serviceName: postgres
template:
metadata:
labels:
app: postgres
role: service
spec:
containers:
- name: postgres
image: postgres:9.6
env:
- name: POSTGRES_USER
value: postgres
- name: POSTGRES_PASSWORD
value: postgres
- name: POSTGRES_DB
value: postgres
ports:
- containerPort: 5432
name: postgres
protocol: TCP
Original question
I created a deployment running one container (postgres-container) and a NodePort (postgres-service). I can connect to postgresql from within the pod itself:
$ kubectl --context=minikube exec -it postgres-deployment-7fbf655986-r49s2 \
-- psql --port=5432 --username=postgres --dbname=postgres
But I can't connect through the service.
$ minikube service --url postgres-service
http://192.168.99.100:32254
$ psql --host=192.168.99.100 --port=32254 --username=postgres --dbname=postgres
psql: could not connect to server: Connection refused
Is the server running on host "192.168.99.100" and accepting
TCP/IP connections on port 32254?
I think postgres is correctly configured to accept remote TCP connections:
$ kubectl --context=minikube exec -it postgres-deployment-7fbf655986-r49s2 \
-- tail /var/lib/postgresql/data/pg_hba.conf
host all all 127.0.0.1/32 trust
...
host all all all md5
$ kubectl --context=minikube exec -it postgres-deployment-7fbf655986-r49s2 \
-- grep listen_addresses /var/lib/postgresql/data/postgresql.conf
listen_addresses = '*'
My service definition looks like:
apiVersion: v1
kind: Service
metadata:
name: postgres-service
spec:
selector:
app: postgres-container
type: NodePort
ports:
- port: 5432
targetPort: 5432
protocol: TCP
And the deployment is:
apiVersion: apps/v1beta2
kind: Deployment
metadata:
name: postgres-deployment
spec:
replicas: 1
selector:
matchLabels:
app: postgres-container
template:
metadata:
labels:
app: postgres-container
spec:
containers:
- name: postgres-container
image: postgres:9.6
env:
- name: POSTGRES_USER
value: postgres
- name: POSTGRES_PASSWORD
value: postgres
- name: POSTGRES_DB
value: postgres
ports:
- containerPort: 5432
The resulting service configuration:
$ kubectl --context=minikube get service postgres-service -o yaml
apiVersion: v1
kind: Service
metadata:
creationTimestamp: 2018-12-07T05:29:22Z
name: postgres-service
namespace: default
resourceVersion: "194827"
selfLink: /api/v1/namespaces/default/services/postgres-service
uid: 0da6bc36-f9e1-11e8-84ea-080027a52f02
spec:
clusterIP: 10.109.120.251
externalTrafficPolicy: Cluster
ports:
- nodePort: 32254
port: 5432
protocol: TCP
targetPort: 5432
selector:
app: postgres-container
sessionAffinity: None
type: NodePort
status:
loadBalancer: {}
I can connect if I use port-forward, but I'd like to use the nodePort instead. What am I missing?

Answer 1

I just deployed postgres and exposed its service through NodePort and following is my pod and service.
[root#master postgres]# kubectl get pods
NAME READY STATUS RESTARTS AGE
postgres-7ff9df5765-2mpsl 1/1 Running 0 1m
[root#master postgres]# kubectl get svc postgres
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
postgres NodePort 10.100.199.212 <none> 5432:31768/TCP 20s
And this is how connected to postgres though the nodeport:
[root#master postgres]# kubectl exec -it postgres-7ff9df5765-2mpsl -- psql -h 10.6.35.83 -U postgresadmin --password -p 31768 postgresdb
Password for user postgresadmin:
psql (10.4 (Debian 10.4-2.pgdg90+1))
Type "help" for help.
postgresdb=#
In above, 10.6.35.83 is my node/host IP (not pod IP or clusterIP) and port is the NodePort defined in service. The issue is you're not using the right IP to connect to the postgresql.

Answer 2

I had this challenge when working with PostgreSQL database server in Kubernetes using Minikube.
Below is my statefulset yaml file:
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: postgresql-db
spec:
serviceName: postgresql-db-service
replicas: 2
selector:
matchLabels:
app: postgresql-db
template:
metadata:
labels:
app: postgresql-db
spec:
containers:
- name: postgresql-db
image: postgres:latest
ports:
- containerPort: 5432
name: postgresql-db
volumeMounts:
- name: postgresql-db-data
mountPath: /data
env:
- name: POSTGRES_PASSWORD
valueFrom:
secretKeyRef:
name: postgresql-db-secret
key: DATABASE_PASSWORD
- name: PGDATA
valueFrom:
configMapKeyRef:
name: postgresql-db-configmap
key: PGDATA
volumeClaimTemplates:
- metadata:
name: postgresql-db-data
spec:
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 25Gi
To access your PostgreSQL database server outside your cluster simple run the command below in a separate terminal:
minikube service --url your-postgresql-db-service
In my case my PostgreSQL db service was postgresql-db-service:
minikube service --url postgresql-db-service
After you run the command you will get an IP address and a port to access your database. In my case it was:
http://127.0.0.1:61427
So you can access the database on the IP address and port with your defined database username and password.