Connect to Postgresql from inside kubernetes cluster - postgresql

Question

I setup a series of VM 192.168.2.(100,105,101,104) where kubernetes master is on 100 and two workers on 101,104. Also setup the postgres on 192.168.2.105, followed this tutorial but it is still unreachable from within. Tried it in minikube inside a test VM where minikube and postgres were installed in the same VM, worked just fine.
Changed the postgers config file from localhost to *, changed listen at pg_hba.conf to 0.0.0.0/0
Installed postgesql-12 and postgresql-client-12 in the VM 192.168.2.105:5432, now i added headless service to kubernetes which is as follows
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
ports:
- protocol: TCP
port: 5432
targetPort: 5432
------
apiVersion: v1
kind: Endpoints
metadata:
name: my-service
subsets:
- addresses:
- ip: 192.168.2.105
ports:
- port: 5432
in my deployment I am defining this to access database
apiVersion: v1
kind: Service
metadata:
name: keycloak
labels:
app: keycloak
spec:
ports:
- name: http
port: 8080
targetPort: 8080
selector:
app: keycloak
type: LoadBalancer
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: keycloak
namespace: default
labels:
app: keycloak
spec:
replicas: 1
selector:
matchLabels:
app: keycloak
template:
metadata:
labels:
app: keycloak
spec:
containers:
- name: keycloak
image: quay.io/keycloak/keycloak:11.0.0
env:
- name: KEYCLOAK_USER
value: "admin"
- name: KEYCLOAK_PASSWORD
value: "admin"
- name: PROXY_ADDRESS_FORWARDING
value: "true"
- name: DB_ADDR
value: 'my-service:5432'
- name: DB_DATABASE
value: postgres
- name: DB_PASSWORD
value: admin
- name: DB_SCHEMA
value: public
- name: DB_USER
value: postgres
- name: DB_VENDOR
value: POSTGRES
ports:
- name: http
containerPort: 8080
- name: https
containerPort: 8443
readinessProbe:
httpGet:
path: /auth/realms/master
port: 8080
Also the VMs are bridged, not on NAT.
What i am doing wrong here ?

Answer 1

The first thing we have to do is create the headless service with custom endpoint. The IP in my solution is only specific for my machine.
Endpoint with service:
apiVersion: v1
kind: Service
metadata:
name: postgres-service
spec:
ports:
- protocol: TCP
port: 5432
targetPort: 5432
---
apiVersion: v1
kind: Endpoints
metadata:
name: postgres-service
subsets:
- addresses:
- ip: 192.168.2.105
ports:
- port: 5432
As for my particular specs, I haven't defined any ingress or loadbalancer so i'll change the selector type from LoadBalancer to NodePort in the service after its deployed.
Now i deployed the keycloak with the the mentioned .yaml file
apiVersion: v1
kind: Service
metadata:
name: keycloak
labels:
app: keycloak
spec:
ports:
- name: http
port: 8080
targetPort: 8080
- name: https
port: 8443
targetPort: 8443
selector:
app: keycloak
type: NodePort
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: keycloak
namespace: default
labels:
app: keycloak
spec:
replicas: 1
selector:
matchLabels:
app: keycloak
template:
metadata:
labels:
app: keycloak
spec:
containers:
- name: keycloak
image: quay.io/keycloak/keycloak:11.0.0
env:
- name: KEYCLOAK_USER
value: "admin" # TODO give username for master realm
- name: KEYCLOAK_PASSWORD
value: "admin" # TODO give password for master realm
- name: PROXY_ADDRESS_FORWARDING
value: "true"
- name: DB_ADDR
value: # <Node-IP>:<LoadBalancer-Port/ NodePort>
- name: DB_DATABASE
value: "keycloak" # Database to use
- name: DB_PASSWORD
value: "admin" # Database password
- name: DB_SCHEMA
value: public
- name: DB_USER
value: "postgres" # Database user
- name: DB_VENDOR
value: POSTGRES
ports:
- name: http
containerPort: 8080
- name: https
containerPort: 8443
readinessProbe:
httpGet:
path: /auth/realms/master
port: 8080
After mentioning all the possible values, it connects successfully to the postgres server that is hosted on another server away from kubernetes master and workers node !