This an extension of the official Docker image for Kong, with support for easy clustering when running on a mesos/marathon platform.
This image is based heavily on LittleBayDigital's docker image.
The official docker-kong image allows for:
- linking
PostgresorCassandradatabase containers - connecting to external databases via custom
kong.ymlconfig file by replacing the/etc/kong/volume.
However when using Mesos and Marathon containers are deployed across multiple nodes in a cluster. Therefore it's not feasible to mount custom config files into volumes on each machine which are spun up and down on demand. See related question here.
When running multiple instances of Kong on multiple nodes there is a need to advertise to the rest of the cluster the ip and port a specific instance can be reached on.
Marathon injects the hostname and the mapped ports as environment variables into the container. By using these Kong can be configured to tell the other nodes in the cluster which external ip:port it can be reached.
0.8.3- (Dockerfile)latest- (Dockerfile)
Existing docker-kong usages still applies.
Marathon injects $HOST and $PORT{n} and more into the environment of the container. See the marathon documentation for full list of variables.
This image assumes that $PORT3 is the port used for inter-nodes communication. Example port configuration in marathon:
| Container Port | Env Var | TCP/UDP | Description |
|---|---|---|---|
| 8000 | $PORT0 |
tcp | proyxing |
| 8001 | $PORT1 |
tcp | admin api |
| 8443 | $PORT2 |
tcp | proxying https |
| 7946 | $PORT3 |
udp,tcp | inter-nodes communication |
The following extra Environment Variables are added:
| Env Var | Default | Description |
|---|---|---|
| DATABASE | postgres | either postgres or cassandra as per official image |
| Env Var | Default | Description |
|---|---|---|
| POSTGRES_HOST | kong-database | Mandatory. Specify custom values as an IP, hostname or use a internal service name |
| POSTGRES_PORT | 5432 | Optional |
| POSTGRES_DB | kong | Optional |
| POSTGRES_USER | kong | Optional |
| POSTGRES_PASSWORD | no password | Optional |
| Env Var | Default | Description |
|---|---|---|
| CLUSTER_TTL_ON_FAILURE | 3600 | Optional. |