Docker executor in GitLab runner doesn't found executable

Question

I have GitLab CI/CD integration, and use follow yaml as project CI config:

stages:
  - test

test_job:
  stage: test
  tags:
    - runner
  script:
    - pwd
    - ls -la
    - ls -la ./project
    - ls -la ./project/build.sh
    - ./project/build.sh

This is config.toml part of the executor:

[[runners]]
  name = "GitLab Runner"
  url = "https://srvgitlab.maxi-net.ru/"
  token = "UJLBiJ86coJT5iPKghNx"
  tls-ca-file = "/etc/gitlab-runner/certs/srvgitlab.maxi-net.ru.crt"
  executor = "docker"
  [runners.custom_build_dir]
  [runners.cache]
    [runners.cache.s3]
    [runners.cache.gcs]
    [runners.cache.azure]
  [runners.docker]
    tls_verify = false
    image = "runner:latest"
    privileged = false
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["/cache"]
    pull_policy = ["if-not-present"]
    shm_size = 0

This is contents of Dockerfile:

FROM alpine:latest
LABEL maintainer='psheom@maxi-net.ru'

Than I build an image:

docker build -t runner .

This is contents of build.sh:

#!/bin/bash

sleep 10

And this is output of a job:

$ pwd
/builds/devs/tg/reps/gitlab-runner
$ ls -la
total 36
drwxrwxrwx    4 root     root          4096 May 17 15:40 .
drwxrwxrwx    4 root     root          4096 May 17 15:25 ..
drwxrwxrwx    6 root     root          4096 May 17 15:40 .git
-rw-rw-rw-    1 root     root           175 May 17 15:40 .gitlab-ci.yml
drwxrwxrwx    3 root     root          4096 May 17 15:30 project
$ ls -la ./project
total 28
drwxrwxrwx    3 root     root          4096 May 17 15:30 .
drwxrwxrwx    4 root     root          4096 May 17 15:40 ..
-rw-rw-rw-    1 root     root           141 May 17 15:25 Dockerfile
-rwxrwxrwx    1 root     root            20 May 17 15:30 build.sh
$ ls -la ./project/build.sh
-rwxrwxrwx    1 root     root            20 May 17 15:30 ./project/build.sh
$ ./project/build.sh
/bin/sh: eval: line 113: ./project/build.sh: not found
Cleaning up file based variables
00:01
ERROR: Job failed: exit code 127

Why /bin/sh doesn't see a file?

Answer 1

/bin/sh: eval: line 113: ./project/build.sh: not found

Yes, the file ./project/build.sh does exist, but when it's a shell script, the first line gets processed as the executable to run:

#!/bin/bash

Since alpine doesn't ship with bash, you'll get a file not found (unfortunately the error message from Linux isn't very helpful here). This can also happen if you have windows linefeeds in the shell script, since it would look for /bin/bash\r (where \r is the carriage return character).

To fix, with your simple script, you can just use /bin/sh instead, there's nothing bash specific about a sleep command:

#!/bin/sh