Complex configuration
$ docker run --name my-custom-nginx-container -v /host/path/nginx.conf:/etc/nginx/nginx.conf:ro -d nginx
For information on the syntax of the nginx configuration files, see the official documentation (specifically the Beginner's Guide).
If you wish to adapt the default configuration, use something like the following to copy it from a running nginx container:
$ docker run --name tmp-nginx-container -d nginx
$ docker cp tmp-nginx-container:/etc/nginx/nginx.conf /host/path/nginx.conf
$ docker rm -f tmp-nginx-container
This can also be accomplished more cleanly using a simple Dockerfile (in /host/path/):
FROM nginx
COPY nginx.conf /etc/nginx/nginx.conf
If you add a custom CMD in the Dockerfile, be sure to include -g daemon off; in the CMD in order for nginx to stay in the foreground, so that Docker can track the process properly (otherwise your container will stop immediately after starting)!
Then build the image with docker build -t custom-nginx . and run it as follows:
$ docker run --name my-custom-nginx-container -d custom-nginx
Using environment variables in nginx configuration (new in 1.19)
Out-of-the-box, nginx doesn't support environment variables inside most configuration blocks. But this image has a function, which will extract environment variables before nginx starts.
Here is an example using docker-compose.yml:
web:
image: nginx
volumes:
- ./templates:/etc/nginx/templates
ports: - "8080:80"
environment: - NGINX_HOST=foobar.com
- NGINX_PORT=80
By default, this function reads template files in /etc/nginx/templates/*.template and outputs the result of executing envsubst to /etc/nginx/conf.d.
So if you place templates/default.conf.template file, which contains variable references like this:
listen ${NGINX_PORT};
outputs to /etc/nginx/conf.d/default.conf like this:
listen 80;
This behavior can be changed via the following environment variables:
NGINX_ENVSUBST_TEMPLATE_DIR
A directory which contains template files (default: /etc/nginx/templates)
When this directory doesn't exist, this function will do nothing about template processing.
NGINX_ENVSUBST_TEMPLATE_SUFFIX
A suffix of template files (default: .template)
This function only processes the files whose name ends with this suffix.
NGINX_ENVSUBST_OUTPUT_DIR
A directory where the result of executing envsubst is output (default: /etc/nginx/conf.d)
The output filename is the template filename with the suffix removed.
ex.) /etc/nginx/templates/default.conf.template will be output with the filename /etc/nginx/conf.d/default.conf.
This directory must be writable by the user running a container.
Running nginx in read-only mode
To run nginx in read-only mode, you will need to mount a Docker volume to every location where nginx writes information. The default nginx configuration requires write access to /var/cache and /var/run. This can be easily accomplished by running nginx as follows:
$ docker run -d -p 80:80 --read-only -v $(pwd)/nginx-cache:/var/cache/nginx -v $(pwd)/nginx-pid:/var/run nginx
If you have a more advanced configuration that requires nginx to write to other locations, simply add more volume mounts to those locations.
Running nginx in debug mode
Images since version 1.9.8 come with nginx-debug binary that produces verbose output when using higher log levels. It can be used with simple CMD substitution:
$ docker run --name my-nginx -v /host/path/nginx.conf:/etc/nginx/nginx.conf:ro -d nginx nginx-debug -g 'daemon off;'
Similar configuration in docker-compose.yml may look like this:
web:
image: nginx
volumes:
- ./nginx.conf:/etc/nginx/nginx.conf:ro
command: [nginx-debug, '-g', 'daemon off;']
Entrypoint quiet logs
Since version 1.19.0, a verbose entrypoint was added. It provides information on what's happening during container startup. You can silence this output by setting environment variable NGINX_ENTRYPOINT_QUIET_LOGS:
$ docker run -d -e NGINX_ENTRYPOINT_QUIET_LOGS=1 nginx
User and group id
Since 1.17.0, both alpine- and debian-based images variants use the same user and group ids to drop the privileges for worker processes:
$ id
uid=101(nginx) gid=101(nginx) groups=101(nginx)
Running nginx as a non-root user
It is possible to run the image as a less privileged arbitrary UID/GID. This, however, requires modification of nginx configuration to use directories writeable by that specific UID/GID pair:
$ docker run -d -v $PWD/nginx.conf:/etc/nginx/nginx.conf nginx
where nginx.conf in the current directory should have the following directives re-defined:
pid /tmp/nginx.pid;
And in the http context:
http {
client_body_temp_path /tmp/client_temp;
proxy_temp_path /tmp/proxy_temp_path;
fastcgi_temp_path /tmp/fastcgi_temp;
uwsgi_temp_path /tmp/uwsgi_temp;
scgi_temp_path /tmp/scgi_temp;
...
}
Alternatively, check out the official Docker NGINX unprivileged image.
Image Variants
The nginx images come in many flavors, each designed for a specific use case.
nginx:
This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of.
nginx:
Starting with nginx:1.13.0 / mainline and nginx:1.12.0 / stable, the perl module has been removed from the default images. A separate -perl tag variant is available if you wish to use the perl module.
nginx:
This image is based on the popular Alpine Linux project, available in the alpine official image. Alpine Linux is much smaller than most distribution base images (~5MB), and thus leads to much slimmer images in general.
This variant is useful when final image size being as small as possible is your primary concern. The main caveat to note is that it does use musl libc instead of glibc and friends, so software will often run into issues depending on the depth of their libc requirements/assumptions. See this Hacker News comment thread for more discussion of the issues that might arise and some pro/con comparisons of using Alpine-based images.
To minimize image size, it's uncommon for additional related tools (such as git or bash) to be included in Alpine-based images. Using this image as a base, add the things you need in your own Dockerfile (see the alpine image description for examples of how to install packages if you are unfamiliar).