Connect from Kubernetes
This guide shows you how to connect to a database from your managed Kubernetes cluster.
We assume the following prerequisites:
- A datacenter with id
xyz-my-datacenter. - A private LAN with id 3 using the network
10.1.1.0/24. - A database connected to LAN 3 with IP
10.1.1.5/24. - A Kubernetes cluster with id
xyz-my-cluster.
In this guide we use DHCP to assign IPs to node pools. Therefore, it is important that the database is in the same subnet that is used by the DHCP server.
To enable connectivity, you must connect the node pools to the private LAN in which the database is exposed:
ionosctl k8s nodepool create --cluster-id xyz-my-cluster --datacenter-id xyz-my-datacenter --lan-ids 3 --dhcp=true --name=my_nodepool
Wait for the node pool to become available. To test the connectivity let's create a pod that contains the Postgres tool
pg_isready. If you have multiple node pools make sure to schedule the pod only the node pools that are attached to the additional LAN.# pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: connectivity-test
labels:
role: connectivity-test
spec:
containers:
- name: postgres
image: postgres
stdin: true
tty: true
command:
- "/bin/bash"
Let's create the pod...
kubectl apply -f pod.yaml
... and attach to it.
kubectl attach -it connectivity-test
If you don't see a command prompt, try pressing enter.
root@connectivity-test:/# pg_isready -h 10.1.1.5
10.1.1.5:5432 - accepting connections
If everything works, we should see that the database is accepting connections. If you see connection issues, make sure that the node is properly connected to the LAN. To debug the node start a debugging container ...
kubectl debug node/$(kubectl get po connectivity-test -o jsonpath="{.spec.nodeName}") -it --image=busybox
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