K
Q

Kubernetes 1.16 Nginx Ingress (0.26.1) TCP Mariadb/MySQL service not working

12/9/2019

I want to expose my Mariadb pod using Nginx ingress TCP service by following this step https://kubernetes.github.io/ingress-nginx/user-guide/exposing-tcp-udp-services/. Mariadb running in default name space, with mariadb service type as ClusterIP. I am running Nginx Ingress controller in nginx-ingress namespace, also defined tcp-services cofigmap for mariadb service. But I am unable to connect MariaDB database from outside of the cluster.

From Nginx controller log I can see its reading tcp-services.

Ingress configuration

containers:
      - args:
        - /nginx-ingress-controller
        - --default-backend-service=nginx-ingress/nginx-ingress-default-backend
        - --election-id=ingress-controller-leader
        - --ingress-class=nginx
        - --configmap=nginx-ingress/nginx-ingress-controller
        - --default-ssl-certificate=nginx-ingress/ingress-tls
        - --tcp-services-configmap=nginx-ingress/tcp-services
        - --udp-services-configmap=nginx-ingress/udp-services

ConfigMap:

apiVersion: v1
kind: ConfigMap
metadata:
  name: tcp-services
  namespace: nginx-ingress
data:
  3306: "default/mariadb:3306"

Ingress controller nginx config for TCP Service

 # TCP services

        server {
                preread_by_lua_block {
                        ngx.var.proxy_upstream_name="tcp-default-mariadb-3306";
                }

                listen                  3306;

                proxy_timeout           600s;
                proxy_pass              upstream_balancer;

        }

when I connect from external server, getting this message:

ERROR 2002 (HY000): Can't connect to MySQL server on

any tips to troubleshoot this issue?

thanks

I was missing my service with TCP Port info, after adding it I was able to access the MySQL with my service Port Number. Thanks for Emanuel Bennici pointing this one out.

Here is my service:

apiVersion: v1
kind: Service
metadata:
  name: nginx-ingress-controller  
spec:
  externalTrafficPolicy: Cluster
  ports:
  - name: http
    port: 80
    protocol: TCP
    targetPort: http
  - name: https
    port: 443
    protocol: TCP
    targetPort: https
  - name: 3066-tcp
    port: 3066
    protocol: TCP
    targetPort: 3066-tcp
  selector:
    app: nginx-ingress
    component: controller
    release: nginx-ingress
  sessionAffinity: None
  type: NodePort
-- sfgroups
kubernetes
kubernetes-ingress
nginx-ingress

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1 Answer

12/18/2019

Please check if you have opened the MySQL port in the Pod So to open the port on the Kubernetes-Port you have to create a pod like this:

apiVersion: v1
kind: Pod
metadata:
  name: mysql
  namespace: default
  labels:
    name: mysql
spec:
  containers:
  - name: mysql
    image: docker.io/bitnami/mariadb:10.3.20-debian-9-r19
    ports:
    - containerPort: 3306
      protocol: TCP

Then you have to create a service so you can talk directly to the MySQL Pod through the service:

apiVersion: v1
kind: Service
metadata:
  name: svc-mysql
  namespace: default
  labels:
    run: mysql
spec:
  ports:
  - port: 3306
    targetPort: 3306
    protocol: TCP
  selector:
    name: mysql

If the Nginx Ingress Controller is working correctly you can now add the following line to your tcp-services-configmap:

3306: "default/svc-mysql:3306"

Please note that you have to add the MySQL port to the Nginx Ingress Service, like this:

apiVersion: v1
kind: Service
metadata:
  name: ingress-nginx
  namespace: nginx-ingress
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: LoadBalancer
  ports:
    - name: http
      port: 80
      targetPort: 80
      protocol: TCP
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
    - name: proxie-tcp-mysql
      port: 3306
      targetPort: 3306
      protocol: TCP
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

Now you can use the external IP of the Nginx Ingress Controller to connect to your MySQL Server.

Please provide more information about your setup in future Questions :)

-- Emanuel Bennici
Source: StackOverflow