How to use this image

All examples in this guide use the public image. If you've mirrored the repository for your own use (for example, to your Docker Hub namespace), update your commands to reference the mirrored image instead of the public one.

For example:

• Public image: dhi.io/nominatim:<tag>
• Mirrored image: <your-namespace>/dhi-nominatim:<tag>

For the examples, you must first use docker login dhi.io to authenticate to the registry to pull the images.

What's included in this Nominatim image

This Docker Hardened Nominatim image is an all-in-one geocoding server. It includes:

• nominatim: the command-line tool to import, update, query, and administer the Nominatim database.
• osm2pgsql: loads OpenStreetMap data into PostgreSQL; nominatim import runs it.
• psql: the PostgreSQL terminal for the embedded PostgreSQL 17 and PostGIS database.

The API is served by gunicorn on port 8080. See the Nominatim documentation⁠ for the API and the administration commands.

Start a Nominatim image

On first start the container downloads or reads an OpenStreetMap extract, imports it into the embedded database, and then serves the API. Later starts on the same data skip the import. You must set exactly one of PBF_URL or PBF_PATH; without either, the container prints an error and exits 1.

Basic usage

This imports the Monaco extract, which takes about a minute:

$ docker run -d --name nominatim -p 8080:8080 \
  -e PBF_URL=https://download.geofabrik.de/europe/monaco-latest.osm.pbf \
  dhi.io/nominatim:<tag>

Follow the logs until --> Nominatim is ready to accept requests appears, then query the API:

$ docker logs -f nominatim
$ curl "http://localhost:8080/search?q=Monaco&format=json"
$ curl "http://localhost:8080/status"

The command-line tool runs against the same database:

$ docker exec nominatim nominatim search --query Monaco --limit 1

Persist the database

The PostgreSQL data directory is /var/lib/postgresql/17/main. Mount a volume there so the import survives container replacement:

$ docker run -d --name nominatim -p 8080:8080 \
  -e PBF_URL=https://download.geofabrik.de/europe/monaco-latest.osm.pbf \
  -v nominatim-data:/var/lib/postgresql/17/main \
  dhi.io/nominatim:<tag>

Import a local extract

Mount the extract and point PBF_PATH at it:

$ docker run -d --name nominatim -p 8080:8080 \
  -e PBF_PATH=/nominatim/data/monaco-latest.osm.pbf \
  -v /path/to/osm-maps:/nominatim/data:ro \
  dhi.io/nominatim:<tag>

The extract must be readable by UID 65532.

Environment variables

The image reads the same environment variables as mediagis/nominatim. The main ones:

On a small host, lower the PostgreSQL memory settings:

$ docker run -d --name nominatim -p 8080:8080 \
  -e PBF_URL=https://download.geofabrik.de/europe/monaco-latest.osm.pbf \
  -e POSTGRES_SHARED_BUFFERS=256MB \
  -e POSTGRES_MAINTENANCE_WORK_MEM=256MB \
  -e POSTGRES_EFFECTIVE_CACHE_SIZE=1GB \
  dhi.io/nominatim:<tag>

Connect to the database

Set NOMINATIM_PASSWORD to open PostgreSQL on port 5432 with password (SCRAM-SHA-256) authentication:

$ docker run -d --name nominatim -p 8080:8080 -p 5432:5432 \
  -e PBF_URL=https://download.geofabrik.de/europe/monaco-latest.osm.pbf \
  -e NOMINATIM_PASSWORD=<password> \
  dhi.io/nominatim:<tag>
$ psql "host=localhost user=nominatim dbname=nominatim"

Inside the container, psql connects over the local socket as nominatim:

$ docker exec nominatim psql -d nominatim -c "SELECT count(*) FROM placex"

Non-hardened images vs. Docker Hardened Images

• PostgreSQL 17 instead of 16.mediagis/nominatim stores data in /var/lib/postgresql/16/main. This image runs PostgreSQL 17 with data in /var/lib/postgresql/17/main. A PostgreSQL 16 data directory cannot be used; import again or migrate the database with pg_dump and pg_restore.
• Non-root. PostgreSQL, the import, and the API run as UID 65532 instead of root with sudo. A bind-mounted data directory or flatnode directory must be writable by UID 65532. The dev variants run as root, which PostgreSQL refuses; start them with --user 65532:65532 to run the import and API.
• No default database password.mediagis/nominatim sets a default NOMINATIM_PASSWORD and accepts MD5 logins from any address. This image has no default: PostgreSQL listens only on its local socket unless you set NOMINATIM_PASSWORD, and then it requires SCRAM-SHA-256.
• Supplementary data from files only.IMPORT_WIKIPEDIA, IMPORT_SECONDARY_WIKIPEDIA, IMPORT_GB_POSTCODES, IMPORT_US_POSTCODES, and IMPORT_TIGER_ADDRESSES accept a path to a file you mount. The value true, which makes mediagis/nominatim download from a server that project hosts, is rejected. Download the files from the Nominatim import documentation⁠ instead.
• Logs. PostgreSQL and replication output go to the container log rather than to files under /var/log.
• Working directory. The working directory is the project directory /nominatim instead of /app, so docker exec <container> nominatim ... uses the project configuration without --project-dir.

Image variants

Docker Hardened Images come in different variants depending on their intended use. Image variants are identified by their tag.

• Runtime variants are designed to run your application in production. These images are intended to be used either directly or as the FROM image in the final stage of a multi-stage build. These images typically:

  • Run as a nonroot user
  • Do not include a shell or a package manager
  • Contain only the minimal set of libraries needed to run the app

• Build-time variants typically include dev in the tag name and are intended for use in the first stage of a multi-stage Dockerfile. These images typically:

  • Run as the root user
  • Include a shell and package manager
  • Are used to build or compile applications

• FIPS variants include fips in the variant name and tag. They come in both runtime and build-time variants. These variants use cryptographic modules that have been validated under FIPS 140, a U.S. government standard for secure cryptographic operations. For example, usage of MD5 fails in FIPS variants.

To view the image variants and get more information about them, select the Tags tab for this repository, and then select a tag.

Migrate to a Docker Hardened Image

To migrate your application to a Docker Hardened Image, you must update your Dockerfile. At minimum, you must update the base image in your existing Dockerfile to a Docker Hardened Image. This and a few other common changes are listed in the following table of migration notes.

The following steps outline the general migration process.

1. Find hardened images for your app.

   A hardened image may have several variants. Inspect the image tags and find the image variant that meets your needs.

2. Update the base image in your Dockerfile.

   Update the base image in your application's Dockerfile to the hardened image you found in the previous step. For framework images, this is typically going to be an image tagged as dev because it has the tools needed to install packages and dependencies.

3. For multi-stage Dockerfiles, update the runtime image in your Dockerfile.

   To ensure that your final image is as minimal as possible, you should use a multi-stage build. All stages in your Dockerfile should use a hardened image. While intermediary stages will typically use images tagged as dev, your final runtime stage should use a non-dev image variant.

4. Install additional packages

   Docker Hardened Images contain minimal packages in order to reduce the potential attack surface. You may need to install additional packages in your Dockerfile. Inspect the image variants to identify which packages are already installed.

   Only images tagged as dev typically have package managers. You should use a multi-stage Dockerfile to install the packages. Install the packages in the build stage that uses a dev image. Then, if needed, copy any necessary artifacts to the runtime stage that uses a non-dev image.

   For Alpine-based images, you can use apk to install packages. For Debian-based images, you can use apt-get to install packages.

Troubleshooting migration

The following are common issues that you may encounter during migration.

General debugging

The hardened images intended for runtime don't contain a shell nor any tools for debugging. The recommended method for debugging applications built with Docker Hardened Images is to use Docker Debug⁠ to attach to these containers. Docker Debug provides a shell, common debugging tools, and lets you install other tools in an ephemeral, writable layer that only exists during the debugging session.

Permissions

By default image variants intended for runtime, run as the nonroot user. Ensure that necessary files and directories are accessible to the nonroot user. You may need to copy files to different directories or change permissions so your application running as the nonroot user can access them.

Privileged ports

Non-dev hardened images run as a nonroot user by default. As a result, applications in these images can't bind to privileged ports (below 1024) when running in Kubernetes or in Docker Engine versions older than 20.10. To avoid issues, configure your application to listen on port 1025 or higher inside the container, even if you map it to a lower port on the host. For example, docker run -p 80:8080 my-image will work because the port inside the container is 8080, and docker run -p 80:81 my-image won't work because the port inside the container is 81.

No shell

By default, image variants intended for runtime don't contain a shell. Use dev images in build stages to run shell commands and then copy any necessary artifacts into the runtime stage. In addition, use Docker Debug to debug containers with no shell.

Entry point

Docker Hardened Images may have different entry points than images such as Docker Official Images. Use docker inspect to inspect entry points for Docker Hardened Images and update your Dockerfile if necessary.