Connect to an In-Memory DB Instance from the Kubernetes Cluster

This topic describes connecting to the In-Memory DB instance from your managed Kubernetes cluster.

Prerequisites

Ensure that the following are available before connecting to the In-Memory DB instance:

• A datacenter with the following 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 the following IP address: 10.1.1.5/24.
• A Kubernetes cluster with the following id: xyz-my-cluster.
• ionosctl.

Connect to the In-Memory DB Instance from the cluster

In the following example, DHCP is used to assign IP addresses to node pools. Therefore, the database must be in the same subnet as the DHCP server.

To enable connectivity, follow these steps:

1. Connect node pools to the private LAN, which is connected to the database:

ionosctl k8s nodepool create --cluster-id xyz-my-cluster --datacenter-id xyz-my-datacenter --lan-ids 3 --dhcp=true --name=my_nodepool

Note: It may take a while for the node pool to be ready.

1. Create a pod to test the connectivity. Schedule the pod exclusively for the node pools connected to the additional LAN if you have several node pools.

# pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: connectivity-test
  labels:
    role: connectivity-test
spec:
  containers:
  - name: connectivity-test
    image: redis 
    stdin: true
    tty: true
    command:
      - "/bin/bash"

Alternatively, you can also use the following commands:

1. Create the pod using either of these commands: kubectl run redis-client --rm -it --image=redis -- /bin/bash or kubectl apply -f pod.yaml
2. Attach the pod and test connectivity:

Prerequisites:

• Ensure that the connectivity-test pod already exists and that the node pool on which it is running has the same private LAN attached as the In-Memory DB instance.
• To establish a secure connection through TLS, the --tls and --cacert command line options must be passed to the redis-cli.
• All IONOS CLOUD DBaaS certificates are issued by Let’s Encrypt. To get --cacert (CA certificate), see Chains of Trust.

kubectl attach -it connectivity-test
redis-cli --tls --cacert --user <USERNAME> --pass <PASSWORD> -h <DNS_NAME> PING

Result: The database starts accepting connections.