Drone-runner-kube: Pipeline cannot resolve service hostname that contains underscore '_'

Drone Bugs
1

I trying to setup drone on kubernetes runner.
I found a document that Kubernetes runner required to specify a port in yaml file.
http://discuss.harness.io/t/drone-on-k8s-services-arent-accessable-at-there-hostname/3511

Strangely, if hostname contains an underscore, the service cannot be accessed from the pipeline step.
When I was delete underscore on service name, It works properly.

Here is the example.

kind: pipeline
type: kubernetes
name: default
services:
- name: db_db
  image: mysql:5.7
  environment:
    MYSQL_DATABASE: test
    MYSQL_ROOT_PASSWORD: test
  ports:
  - 3306
steps:
- name: ping-mysql
  image: mysql:5.7
  environment:
    DATABASE_HOSTNAME: db_db
    DATABASE_USERNAME: root
    DATABASE_PASSWORD: test
  commands:
  # wait for mysql service to become available
  - |
    export RETRY_COUNT=10

    count=0
    until ( mysqladmin -u$DATABASE_USERNAME -p$DATABASE_PASSWORD -h$DATABASE_HOSTNAME ping --connect_timeout=2 )
    do
      count=$((count+1))
      if [ $count -gt $RETRY_COUNT ]
      then
        echo "Failed to start required services."
        exit 1
      fi
      echo "Checking the services(retry = $count)"
      sleep 10
    done

step ping-mysql output:

mysqladmin: connect to server at 'db_db' failed
error: 'Unknown MySQL server host 'db_db' (0)'
Check that mysqld is running on db_db and that the port is 3306.
You can check this by doing 'telnet db_db 3306'
Checking the services(retry = 1)

I am using kubernetes with kops on AWS.
The kubernetes version was v1.14.8
Drone server Image: docker.io/drone/drone:1.6.1

2

Here is a reference example:
https://docs.drone.io/pipeline/kubernetes/examples/service/mysql/

One thing that jumps out is that steps with commands should be placed in the steps section, not in the service section. Also can you confirm you installed the drone/drone-kube-runner:1 image? If you installed from Helm stable please read this comment.

3

also meant to say that Drone uses the host aliases feature to map the hostname to the container. https://kubernetes.io/docs/concepts/services-networking/add-entries-to-pod-etc-hosts-with-host-aliases/#adding-additional-entries-with-hostaliases

4

I apologize for my inconvenience.
steps are missing while creating example configuration yaml file. I fixed it now.

No, I installed drone enterprise. with helm https://github.com/helm/charts/tree/master/stable/drone

Here is more information for kubernetes executor:
Image: drone/controller:1.6.0

5

The charts in Helm stable are broken and are not an officially supported installation method. We recommend using gtaylor/drone-charts instead, which we plan to adopt as our official charts in the coming weeks.

If you used helm stable your installation is not going to work.

6

Here is more information for kubernetes executor:
Image: drone/controller:1.6.0

This image was used by an experimental kubernetes integration that was deprecated almost a year ago. The stable helm chart produces an invalid installation that uses this deprecated feature and should therefore be avoided. Instead use gtaylor/drone-charts.