During local development with Kubernetes/minikube, how should I connect to postgres database running on localhost?

问题

I've set up an application stack running on Google Kubernetes Engine + Google Cloud SQL. When developing locally, I would like my application to connect to a postgres database server running outside the cluster to simulate the production environment.

It seems that the way to do this is by defining an external endpoint as described here: Minikube expose MySQL running on localhost as service

Unfortunately, I am not able to specify "127.0.0.1" as the Endpoint IP address:

kubectl apply -f kubernetes/local/postgres-service.yaml
service "postgres-db" unchanged
The Endpoints "postgres-db" is invalid: subsets[0].addresses[0].ip: 
Invalid value: "127.0.0.1": may not be in the loopback range (127.0.0.0/8)

So I am forced to bind postgres to my actual machine address.

It seems like there MUST be a way to map a port from my localhost into the local kubernetes cluster, but so far I can't find a way to do it.

Anybody know the trick? Or alternatively, can someone suggest an alternative solution which doesn't involve running postgres inside the cluster?

回答1:

May not be an answer for Minikube, but I ended up here so I share what I did for Kubernetes in Docker for Mac.

I added a service like this for PostgreSQL:

kind: Service
apiVersion: v1
metadata:
  name: postgres
  namespace: default
spec:
  type: ExternalName
  # https://docs.docker.com/docker-for-mac/networking/#use-cases-and-workarounds
  externalName: host.docker.internal
  ports:
    - name: port
      port: 5432

My application was able to connect to the locally running postgres server with this setup using the domain name postgres. The Postgres server can listen to 127.0.0.1 with this setup.

回答2:

There is a potential solution for this called Telepresence which allows to have a local workload to be proxied into the cluster as if it were actualy run within that kube cluster.

回答3:

K8s Native Approach

I had similar issues with developing cloud-native software directly inside Kubernetes. We took a look at tools like Telepresence and Skaffold, too but they are hard to configure and very time-consuming.

That's why I built the DevSpace CLI together with a colleague: https://github.com/covexo/devspace

Feel free to take a look and try it out. It will solve issues like yours by allowing you to easily run all your workloads directly inside Kubernetes while still being able to program with your desktop tools (local terminal, IDE, git etc).

Alternative: Minikube networking

As you are using minikube, you should take a look as the answers to this question: Routing an internal Kubernetes IP address to the host system

Alternative: Tunneling

You could also use local tunneling with tools like ngrok: https://ngrok.com/ (simply start it locally and connect to your ngrok address from anywhere)

回答4:

Mysql server should connect to private IP, and that private IP can be used in application.

Prefer way is to create kubernetes service+endpoint pointing to Mysql Server IP.

来源：https://stackoverflow.com/questions/49289009/during-local-development-with-kubernetes-minikube-how-should-i-connect-to-postg