Kaniko: Running `nginx -t` causes "no such..." error

[WesCossick]

Actual behavior
With kaniko, running the nginx -t command produces either a No such file or directory or No such device or address error, even with an official, unmodified NGINX image. This does not happen with Docker.

Expected behavior
The nginx -t should not produce an error if the configuration file is valid.

To Reproduce

1. Attempt to build the Dockerfile below
2. Receive the following output:

INFO[2020-05-22T16:58:28Z] Running: [/bin/sh -c nginx -t;]              
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
2020/05/22 16:58:28 [emerg] 25#25: open() "/var/run/nginx.pid" failed (2: No such file or directory)
nginx: [emerg] open() "/var/run/nginx.pid" failed (2: No such file or directory)
nginx: configuration file /etc/nginx/nginx.conf test failed
error building image: error building stage: failed to execute command: waiting for process to exit: exit status 1

Additional Information

• Dockerfile

FROM nginx:alpine
RUN nginx -t

• Build Context
  No files other than the Dockerfile.

Sometimes we receive the following error, depending on NGINX's configuration:

INFO[2020-05-22T16:38:21Z] Running: [/bin/sh -c nginx -t;]              
nginx: [alert] could not open error log file: open() "/var/log/nginx/error.log" failed (6: No such device or address)
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
2020/05/22 16:38:21 [emerg] 134#134: open() "/dev/stderr" failed (6: No such device or address)
nginx: configuration file /etc/nginx/nginx.conf test failed
error building image: error building stage: failed to execute command: waiting for process to exit: exit status 1

Triage Notes for the Maintainers

| Description | Yes/No |
|----------------|---------------|
| Please check if this a new feature you are proposing |

• - [ ]

|
| Please check if the build works in docker but not in kaniko |

• - [x]

|
| Please check if this error is seen when you use --cache flag |

• - [x]

|
| Please check if your dockerfile is a multistage dockerfile |

• - [ ]

|

[tejal29]

I saw a related bug here https://github.com/nginxinc/nginx-amplify-agent/issues/166
I am not sure if you can run a nginx service inside a kaniko pod. Is there something else you want to do after running the nginx service?

[WesCossick]

NGINX runs without issue in the container built by either kaniko or Docker, it's just the nginx -t command that fails in kaniko exclusively. Does that answer your question?

[kamaln7]

This worked for me:

FROM nginx:alpine
RUN test -e /var/run || ln -s /run /var/run
RUN nginx -t

Seems like the /var/run -> /run symlink is not extracted from the base image rootfs due to the path being ignored by default.

docker run \
   -v $PWD:/workspace \
   gcr.io/kaniko-project/executor:latest \
  --dockerfile /workspace/Dockerfile \
  --context dir:///workspace/ \
  --no-push