K
Q

Error accessing External SQL server from inside the Minikube

3/20/2020

I have an external SQL server, (On the Internet accessible from my local system) that I am trying to call from inside the Minikube. I am unable to do that. I have tried the Calling an external service from within Minikube

Error that i am getting is "sqlalchemy.exc.OperationalError: (pymssql.OperationalError) (20009, b'DB-Lib error message 20009, severity 9:\nUnable to connect: Adaptive Server is unavailable or does not exist "

I have already created pod --> service --> Endpoints. All my Clusters are under an ingress. Please see the below code for the configuration that I have done.

Currently, I am passing the DB HOST (1.1.1.1) as an environment variable to the POD and after this configuration, I am trying to pass the service name (sql-server) instead of DB Host Name is this correct? Moreover, I am unable to ping the IP from inside the container.

Can anyone please help me.

apiVersion: v1
kind: Endpoints
metadata:
  name: sql-server
subsets:
  - addresses:
      - ip: 1.1.1.1
    ports:
      - port: 1433
apiVersion: v1
kind: Service
metadata:
  name: sql-server
spec:
  type: ClusterIP
  ports:
    - port: 1433
      targetPort: 1433
-- Nimble Fungus
kubectl
kubernetes
kubernetes-ingress
minikube

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1 Answer

3/20/2020

I reproduced a similar scenario in my minikube system and this solution works as described. I will drive you through the setup and how to troubleshoot this issue.

I have a linux server (hostname http-server) and I installed a http server (apache2) in on it that's serving a hello world message:

user@http-server:~$ netstat -tan | grep ::80
tcp6       0      0 :::80                   :::*                    LISTEN     
user@minikube-server:~$ curl 10.128.15.209
Hello World!

Now that we confirmed that my service is accessible from the machine where I have minikube installed, lets connect to minikube VM and check if I can access this http service:

user@minikube-server:~$ minikube ssh
                         _             _            
            _         _ ( )           ( )           
  ___ ___  (_)  ___  (_)| |/')  _   _ | |_      __  
/' _ ` _ `\| |/' _ `\| || , <  ( ) ( )| '_`\  /'__`\
| ( ) ( ) || || ( ) || || |\`\ | (_) || |_) )(  ___/
(_) (_) (_)(_)(_) (_)(_)(_) (_)`\___/'(_,__/'`\____)

$ curl 10.128.15.209
Hello World!

Great! This is looking good. If you can't access your service here, you have to check your network, something is preventing your minikube server from communicating with your service.

Now let's exit from this minikube ssh and create our endpoint:

My endpoint manifest is looking like this:

apiVersion: v1
kind: Endpoints
metadata:
  name: http-server
subsets:
  - addresses:
      - ip: 10.128.15.209
    ports:
      - port: 80
user@minikube-server:~$ kubectl apply -f http-server-endpoint.yaml
endpoints/http-server configured

Let's create our service:

apiVersion: v1
kind: Service
metadata:
  name: http-server
spec:
  ports:
    - port: 80
      targetPort: 80

user@minikube-server:~$ kubectl apply -f http-server-service.yaml
service/http-server created

Checking if our service exists and save it's clusterIP for letter usage:

user@minikube-server:~$ kubectl get service
NAME          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
http-server   ClusterIP   10.96.228.220   <none>        80/TCP    30m
kubernetes    ClusterIP   10.96.0.1       <none>        443/TCP   10d

Now it's time to verify if we can access our service from a pod:

kubectl run ubuntu -it --rm=true --restart=Never --image=ubuntu bash

This command will create and open a bash session inside a ubuntu pod.

In my case I'll install curl to be able to check if I can access my http server. You may need install mysql:

root@ubuntu:/# apt update; apt install -y curl

Checking connectivity with my service using clusterIP:

root@ubuntu:/# curl 10.128.15.209:80
Hello World!

And finally using the service name (DNS):

root@ubuntu:/# curl http-server
Hello World!

Please run into all these steps and let me know if you have trouble on any and where.

-- mWatney
Source: StackOverflow