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Support configuration key to toggle using IPs or hostnames #7

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Jun 26, 2017
Merged

Support configuration key to toggle using IPs or hostnames #7

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21 changes: 21 additions & 0 deletions airflow/bin/airflow
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Original file line number Diff line number Diff line change
@@ -1,9 +1,30 @@
#!/usr/bin/env python
import logging
import os
import socket
import requests
from airflow import configuration
from airflow.bin.cli import CLIFactory

def get_private_ip(name=''):
r = requests.get("http://169.254.169.254/latest/meta-data/local-ipv4")
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Should "http://169.254.169.254/latest/meta-data/local-ipv4" also be a part of configuration?

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We could, but I see no reason to make it configurable unless it could change. This is the static address from which EC2 instances vend metadata - see the AWS docs for details.

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Wish boto3 had a nice wrapper around this, but boto/boto3#313 has been open for a while. There is boto.utils.get_instance_metadata() though:

>>> import boto.utils
>>> instance_metadata = boto.utils.get_instance_metadata()
>>> print instance_metadata['local-ipv4']
10.0.24.67

But that is a dependency to another library, which may be available though.

Overall looks like the hostname the node returns:

PRODUCTION: amalakar@etl-production-iad-d532cf46:~$ hostname
etl-production-iad-d532cf46

Doesn't seem to have a dns entry or an entry in /etc/hosts

PRODUCTION: amalakar@etl-production-iad-d532cf46:~$ host etl-production-iad-d532cf46
Host etl-production-iad-d532cf46 not found: 3(NXDOMAIN)

I have seen lot of systems do depend on the gethostname to resolve correctly on a DNS lookup. For example hadoop cli would fail when this is not satisfied. I think any instance that gets provisioned should have these pieces working which is an assumption for lot of systems out there.

@astahlman should we create a ticket against #provisioning to take care of this? We may end up patching/hacking startup script of many other systems otherwise.

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Yeah, provisioning is aware of it, and unfortunately it seems that this is by design. Lyft uses the hostname to encode some information about the host that's used for monitoring purposes, see the previous discussions in these two Slack threads:

  1. https://lyft.slack.com/archives/C3ASS377S/p1493405313083642
  2. https://lyft.slack.com/archives/C2U75K0H5/p1484849237000002

return str(r.text)


def getfqdn(name=''):
return get_private_ip()


should_patch_socket = False
try:
should_patch_socket = configuration.getboolean('lyft', 'prefer_ip_over_hostname')
except configuration.AirflowConfigException:
pass # Default to False if not configured

if should_patch_socket:
logging.info("Using IP addresses instead of hostnames.")
socket.gethostname = socket.getfqdn = getfqdn

if __name__ == '__main__':

if configuration.get("core", "security") == 'kerberos':
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