Drone on Kubernetes with Docker plugin: Strange network problem

Drone Support
1

Dockerfile:

FROM php:7.4-apache
RUN pecl install grpc

.drone.yml

kind: pipeline
type: kubernetes
name: default

steps:
- name: install
  image: composer
  commands:
  - composer install
- name: docker
  image: plugins/docker
  settings:
    repo: ……

drone output:

Step 2/9 : RUN pecl install grpc
 ---> Running in 0b61c6790db4
No releases available for package "pecl.php.net/grpc"
install failed
The command '/bin/sh -c pecl install grpc' returned a non-zero code: 1
time="2020-11-28T01:29:26Z" level=fatal msg="exit status 1"

But I tried docker build . directly on my server, pecl can install grpc.

2

In .drone.yml

kind: pipeline
type: kubernetes
name: default

steps:
- name: test
  image: composer
  commands:
  - ping pecl.php.net

SUCCESS!

in Dockerfile in plugins/docker in Drone on Kubernetes

RUN ping pecl.php.net

FAILED.

3

Hi, Could you please check and confirm if you are able to ping pecl.php.net from the container/Kubernetes cluster directly.

4

The docker plugin uses docker-in-docker. In order for the docker-in-docker daemon to inherit dns settings you may need to set the plugins mtu value (see the plugin documentation for a list of available settings). From this relevant thread Issue - Kubernetes Runner - Cert validation issues with Plugin/Docker

5

Thank you very much for @bradrydzewski 's answer!
MTU is the key to solving the problem. Happily, this problem can be solved easily. For those who are still troubled by this question, the answer to the question is:

kind: pipeline
type: kubernetes
name: default

steps:
  - name: dockerize
    image: plugins/docker
    settings:
      ...
      mtu: 1000