The Cloud-Native API Gateway for APIs and Microservices
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Readme

Quick reference

Supported tags and respective Dockerfile links

Quick reference (cont.)

What is Kong?

Kong is a scalable, open source API Platform (also known as an API Gateway or API Middleware). Kong was originally built by Kong Inc. (formerly known as Mashape) to secure, manage, and extend over 15,000 Microservices for its API Marketplace, which generates billions of requests per month.

Under active development, Kong is now used in production at hundreds of organizations from startups, to large enterprises and governments including: The New York Times, Expedia, Healthcare.gov, The Guardian, Condè Nast, The University of Auckland, Ferrari, Rakuten, Cisco, SkyScanner, Yahoo! Japan, Giphy and so on.

Kong's official documentation can be found at docs.konghq.com.

How to use this image without a Database

Kong 1.1 added the capability to run Kong without a database, using only in-memory storage for entities: we call this DB-less mode. When running Kong DB-less, the configuration of entities is done in a second configuration file, in YAML or JSON, using declarative configuration.

$ docker run -d --name kong \
    -e "KONG_DATABASE=off" \
    -e "KONG_PROXY_ACCESS_LOG=/dev/stdout" \
    -e "KONG_ADMIN_ACCESS_LOG=/dev/stdout" \
    -e "KONG_PROXY_ERROR_LOG=/dev/stderr" \
    -e "KONG_ADMIN_ERROR_LOG=/dev/stderr" \
    -e "KONG_ADMIN_LISTEN=0.0.0.0:8001, 0.0.0.0:8444 ssl" \
    -p 8000:8000 \
    -p 8443:8443 \
    -p 8001:8001 \
    -p 8444:8444 \
    kong

Generate a skeleton configuration file to get you started

$ docker exec -it kong kong config init /home/kong/kong.yml
$ docker exec -it kong cat /home/kong/kong.yml >> kong.yml

Load a declarative configuration into a running Kong node via its Admin API using HTTPie

$ http :8001/config config=@kong.yml

Note: Not all Kong plugins are compatible with DB-less mode, since some of them by design require a central database coordination and/or dynamic creation of entities, see the doc for details at DB-less and Declarative Configuration

How to use this image with a Database

You can either use the official Cassandra/PostgreSQL containers, or use your own.

1. Link Kong to either a Cassandra or PostgreSQL container

It's up to you to decide which datastore between Cassandra or PostgreSQL you want to use, since Kong supports both.

Cassandra

Start a Cassandra container by executing:

$ docker run -d --name kong-database \
                -p 9042:9042 \
                cassandra:3

Postgres

Start a PostgreSQL container by executing:

$ docker run -d --name kong-database \
                -p 5432:5432 \
                -e "POSTGRES_USER=kong" \
                -e "POSTGRES_DB=kong" \
                -e "POSTGRES_PASSWORD=kong" \
                postgres:9.6

2. Prepare your database

Run the database migrations with an ephemeral Kong container:

$ docker run --rm \
    --link kong-database:kong-database \
    -e "KONG_DATABASE=postgres" \
    -e "KONG_PG_HOST=kong-database" \
    -e "KONG_PG_USER=kong" \
    -e "KONG_PG_PASSWORD=kong" \
    -e "KONG_CASSANDRA_CONTACT_POINTS=kong-database" \
    kong kong migrations bootstrap

In the above example, both Cassandra and PostgreSQL are configured, but you should update the KONG_DATABASE environment variable with either cassandra or postgres.

Note for Kong < 0.15: with Kong versions below 0.15 (up to 0.14), use the up sub-command instead of bootstrap. Also note that with Kong < 0.15, migrations should never be run concurrently; only one Kong node should be performing migrations at a time. This limitation is lifted for Kong 0.15, 1.0, and above.

Start Kong

Once the database has been started and prepared, we can start a Kong container and link it to the database container, and configuring the KONG_DATABASE environment variable with either cassandra or postgres depending on which database you decided to use:

$ docker run -d --name kong \
    --link kong-database:kong-database \
    -e "KONG_DATABASE=postgres" \
    -e "KONG_PG_HOST=kong-database" \
    -e "KONG_PG_PASSWORD=kong" \
    -e "KONG_CASSANDRA_CONTACT_POINTS=kong-database" \
    -e "KONG_PROXY_ACCESS_LOG=/dev/stdout" \
    -e "KONG_ADMIN_ACCESS_LOG=/dev/stdout" \
    -e "KONG_PROXY_ERROR_LOG=/dev/stderr" \
    -e "KONG_ADMIN_ERROR_LOG=/dev/stderr" \
    -e "KONG_ADMIN_LISTEN=0.0.0.0:8001, 0.0.0.0:8444 ssl" \
    -p 8000:8000 \
    -p 8443:8443 \
    -p 8001:8001 \
    -p 8444:8444 \
    kong

If everything went well, and if you created your container with the default ports, Kong should be listening on your host's 8000 (Proxy), 8443 (Proxy SSL), 8001 (Admin API) and 8444 (Admin API SSL) ports.

You can read the docs at docs.konghq.com to learn more about Kong.

3. Use Kong with a custom configuration (and a custom Cassandra/PostgreSQL cluster)

You can override any property of the Kong configuration file with environment variables. Just prepend any Kong configuration property with the KONG_ prefix, for example:

$ docker run -d --name kong \
    -e "KONG_DATABASE=postgres" \
    -e "KONG_PG_HOST=kong-database" \
    -e "KONG_LOG_LEVEL=info" \
    -e "KONG_CUSTOM_PLUGINS=helloworld" \
    -e "KONG_PG_HOST=1.1.1.1" \
    -e "KONG_ADMIN_LISTEN=0.0.0.0:8001, 0.0.0.0:8444 ssl" \
    -p 8000:8000 \
    -p 8443:8443 \
    -p 8001:8001 \
    -p 8444:8444 \
    kong

Reload Kong in a running container

If you change your custom configuration, reload Kong (without downtime) by running:

$ docker exec -it kong kong reload

This will run the kong reload command in your container.

Kubernetes Ingress

Among the many deployment options available, Kong also offers a Kubernetes Ingress Controller ready to use in your K8s environment.

Image Variants

The kong images come in many flavors, each designed for a specific use case.

kong:<version>

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.

kong:<version>-alpine

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).

License

View license information for the software contained in this image.

As with all Docker images, these likely also contain other software which may be under other licenses (such as Bash, etc from the base distribution, along with any direct or indirect dependencies of the primary software being contained).

Some additional license information which was able to be auto-detected might be found in the repo-info repository's kong/ directory.

As for any pre-built image usage, it is the image user's responsibility to ensure that any use of this image complies with any relevant licenses for all software contained within.