Docker Kong admin API is unreachable

Question

I've upgraded the Docker Kong image to the version 0.14.0 and it stopped responding to connections from outside the container:

$ curl 127.0.0.1:8001 --trace-ascii dump.txt

== Info: Rebuilt URL to: 127.0.0.1:8001/
== Info:   Trying 127.0.0.1...
== Info: Connected to 127.0.0.1 (127.0.0.1) port 8001 (#0)
=> Send header, 78 bytes (0x4e)
0000: GET / HTTP/1.1
0010: Host: 127.0.0.1:8001
0026: User-Agent: curl/7.47.0
003f: Accept: */*
004c: 
== Info: Recv failure: Connection reset by peer
== Info: Closing connection 0

The ports mapping is

0.0.0.0:8000-8001->8000-8001/tcp, 0.0.0.0:8443-8444->8443-8444/tcp

Everything is ok when trying to connect from inside the container:

/ # curl 127.0.0.1:8001
{"plugins":{"enabled_in_cluster":[], ...

Port 8000 is available from outside and inside the container. What can that be?

Answer 1

I have encountered the same issue. The reason is the kong admin configuration set to loopback address by default. But I didn't modify the configuration file. Since Kong Docker Image providing an environment variable to expose the admin port.

KONG_ADMIN_LISTEN="0.0.0.0:8001, 0.0.0.0:8444 ssl"

This bind the admin port to the host machine port