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Last pushed: a year ago
Short Description
FreeNAS version of the jrcs/letsencrypt-nginx-proxy-companion container
Full Description

Version 1

FreeNAS Configuration

letsencrypt-nginx-proxy-companion is a lightweight companion container for the nginx-proxy. It allows the creation/renewal of Let's Encrypt certificates automatically. See Let's Encrypt section for configuration details.


  • Automatic creation/renewal of Let's Encrypt certificates using original nginx-proxy container.
  • Support creation of Multi-Domain (SAN) Certificates.
  • Automatically creation of a Strong Diffie-Hellman Group (for having an A+ Rate on the Qualsys SSL Server Test).
  • Work with all versions of docker.

NOTE: The first time this container is launched it generates a new Diffie-Hellman group file. This process can take several minutes to complete (be patient).


To use it with original nginx-proxy container you must declare 3 writable volumes from the nginx-proxy container:

  • /etc/nginx/certs to create/renew Let's Encrypt certificates
  • /etc/nginx/vhost.d to change the configuration of vhosts (needed by Let's Encrypt)
  • /usr/share/nginx/html to write challenge files.

Example of use:

  • First start nginx with the 3 volumes declared:

    $ docker run -d -p 80:80 -p 443:443 \
      --name nginx-proxy \
      -v /path/to/certs:/etc/nginx/certs:ro \
      -v /etc/nginx/vhost.d \
      -v /usr/share/nginx/html \
      -v /var/run/docker.sock:/tmp/docker.sock:ro \
  • Second start this container:

    $ docker run -d \
      -v /path/to/certs:/etc/nginx/certs:rw \
      --volumes-from nginx-proxy \
      -v /var/run/docker.sock:/var/run/docker.sock:ro \

Then start any containers you want proxied with a env var

$ docker run -e "" ...

The containers being proxied must expose the port to be proxied, either by using the EXPOSE directive in their Dockerfile or by using the --expose flag to docker run or docker create. See nginx-proxy for more informations. To generate automatically Let's Encrypt certificates see next section.

Separate Containers (recommended method)

nginx proxy can also be run as two separate containers using the jwilder/docker-gen
image and the official nginx image.

You may want to do this to prevent having the docker socket bound to a publicly exposed container service (avoid to mount the docker socket in the nginx exposed container). It's better in a security point of view.

To run nginx proxy as a separate container you'll need:

1) To mount the template file nginx.tmpl into the docker-gen container. You can get the latest official nginx.tmpl with a command like:

curl > /path/to/nginx.tmpl

2) Set the NGINX_DOCKER_GEN_CONTAINER environment variable to the name or id of the docker-gen container.


  • First start nginx (official image) with volumes:

    $ docker run -d -p 80:80 -p 443:443 \
      --name nginx \
      -v /etc/nginx/conf.d  \
      -v /etc/nginx/vhost.d \
      -v /usr/share/nginx/html \
      -v /path/to/certs:/etc/nginx/certs:ro \
  • Second start the docker-gen container with the shared volumes and the template file:

    $ docker run -d \
      --name nginx-gen \
      --volumes-from nginx \
      -v /path/to/nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl:ro \
      -v /var/run/docker.sock:/tmp/docker.sock:ro \
      jwilder/docker-gen \
      -notify-sighup nginx -watch -wait 5s:30s /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
  • Then start this container (NGINX_DOCKER_GEN_CONTAINER variable must contain the docker-gen container name or id):

    $ docker run -d \
      --name nginx-letsencrypt \
      -e "NGINX_DOCKER_GEN_CONTAINER=nginx-gen" \
      --volumes-from nginx \
      -v /path/to/certs:/etc/nginx/certs:rw \
      -v /var/run/docker.sock:/var/run/docker.sock:ro \

    Then start any containers to be proxied as described previously.

Let's Encrypt

To use the Let's Encrypt service to automatically create a valid certificate for virtual host(s).

Set the following environment variables to enable Let's Encrypt support for a container being proxied. This environment variables need to be declared in each to-be-proxied application containers.


The LETSENCRYPT_HOST variable most likely needs to be the same as the VIRTUAL_HOST variable and must be publicly reachable domains. Specify multiple hosts with a comma delimiter.

multi-domain (SAN) certificates

If you want to create multi-domain (SAN) certificates add the base domain as the first domain of the LETSENCRYPT_HOST environment variable.

test certificates

If you want to create test certificates that don't have the 5 certs/week/domain limits define the LETSENCRYPT_TEST environment variable with a value of true.

Automatic certificate renewal

Every hour (3600 seconds) the certificates are checked and every certificate that will expire in the next 30 days (90 days / 3) are renewed.

$ docker run -d \
    --name example-app \
    -e ",," \
    -e ",," \
    -e "" \

Optional container environment variables

Optional letsencrypt-nginx-proxy-companion container environment variables for custom configuration.

  • ACME_CA_URI - Directory URI for the CA ACME API endpoint (default: If you set it's value to letsencrypt will use test servers that don't have the 5 certs/week/domain limits. You can also create test certificates per container (see let's encrypt test certificates)

For example

$ docker run -d \
    -e "ACME_CA_URI=" \
    -v /path/to/certs:/etc/nginx/certs:rw \
    --volumes-from nginx-proxy \
    -v /var/run/docker.sock:/var/run/docker.sock:ro \
  • DEBUG - Set it to true to enable debugging of the entrypoint script and generation of LetsEncrypt certificates, which could help you pin point any configuration issues.

  • NGINX_PROXY_CONTAINER- If for some reason you can't use the docker --volumes-from option, you can specify the name or id of the nginx-proxy container with this variable.


If you want other examples how to use this container, look at:

Docker Pull Command
Source Repository