DNS alias truncated by 2 chars!

[aperepel]

Hello, I've upgraded to compose 1.6 and docker 1.10, hoping to leverage the v2 config format and get rid of hostname workarounds. My cluster doesn't really work with these versions, and I narrowed it down to this very odd issue with hostnames that compose assigns to services.

Full config (in a current, somewhat broken form) is here: https://github.com/aperepel/docker-nifi/blob/master/nifi-cluster/docker-compose.yml. The actual service name is processing in case I haven't pushed the update to this branch yet.

05:57:07::nifi-cluster ♨ >  docker inspect nificluster_processing_1 | jq .[0].NetworkSettings.Networks
{
  "nificluster_default": {
    "IPAMConfig": null,
    "Links": null,
    "Aliases": [
      "processing",
      "f4c3cf526a"
    ],
    "NetworkID": "5f640667a6638b5524a4d155041a5c891be2906baeee26efc93f4e1d38c9bd97",
    "EndpointID": "0000db113d27382277f43338c3a094963d6daa13abd9f723a1d32634531c3bcb",
    "Gateway": "",
    "IPAddress": "10.0.3.2",
    "IPPrefixLen": 24,
    "IPv6Gateway": "",
    "GlobalIPv6Address": "",
    "GlobalIPv6PrefixLen": 0,
    "MacAddress": "02:42:0a:00:03:02"
  }
}

And now inside that container:

root@f4c3cf526ab8:/nifi-1.1.1.0-12/bin# hostname
f4c3cf526ab8

The generated alias from inspect and actual hostname alias have different lengths!: From inspect:

"Aliases": [
      "processing", // this is the service name from docker-compose.yml
      "f4c3cf526a" // this is the generated hostname
    ],

The hostname from above is resolvable from other containers on this app network. The hostname from the container (and in /etc/hosts) has 2 extra chars at the end and is not resolvable**.

My processing nodes report to the cluster manager using the $HOSTNAME. However, the manager node can't reach back to them because they are giving out the name which is not resolvable.

[dnephin]

Already fixed in master by #2853! Fix will be in 1.6.1

[aperepel]

Yo, thanks a lot :) :+1: I thought I was going insane.