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@nuriel77 nuriel77/setHosts.py
Last active Jan 25, 2017

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After Overcloud deployment use this to output friendly names for /etc/hosts on undercloud
#!/usr/bin/env python
from novaclient import client
from subprocess import call
from os import environ, system, getuid
import sys
import re
"""
Script to set hostnames / IP addresses mapping
in /etc/hosts
"""
try:
USERNAME = environ['OS_USERNAME']
PASSWORD = environ['OS_PASSWORD']
AUTH_URL = environ['OS_AUTH_URL']
except Exception as e:
raise Exception("Missing one or more authentication details: %s" % e)
try:
PROJECT_NAME = environ['OS_PROJECT_NAME']
except Exception as e:
PROJECT_NAME = environ['OS_TENANT_NAME']
try:
OS_CLOUD = environ['OS_CLOUDNAME']
except Exception as e:
raise Exception("Missing OS_CLOUDNAME")
if OS_CLOUD != 'undercloud':
raise Exception("You need to load the undercloud authentication details")
def replace_in_file(output):
if getuid() != 0:
print "You need to be root to edit /etc/hosts."
print "Try to use 'sudo -E ...'"
sys.exit(1)
# Remove older entries if any
try:
# Yep, perl, funny ah?
call(["perl -i -p0e 's/###setHostsStart###.*?###setHostsEnd###\n//s' /etc/hosts"],
shell=True)
except OSError as e:
print "OSError > ",e.errno
print "OSError > ",e.strerror
print "OSError > ",e.filename
except:
print "Error > ",sys.exc_info()[0]
# Append new
try:
file = open('/etc/hosts', 'a')
except IOError as e:
raise IOError("Error opening file for write: %s", e)
else:
file.write(output)
file.close()
def main():
""" Example names:
overcloud-controller-2
overcloud-novacompute-0 """
# Regex to extract short name from
full_name_regex = r'^overcloud\-(.+?)$'
nova = client.Client('2', USERNAME, PASSWORD, PROJECT_NAME,
AUTH_URL, connection_pool=True)
prep_list = dict()
# Get all servers
servers = nova.servers.list()
for server in servers:
# Get networks/IP for ctlplane
networks = server.networks
if ('ctlplane' in networks and len(networks['ctlplane'])):
short_name = ''
# Extract shortnames
m = re.search(full_name_regex, server.name)
if m:
short_name_prep = m.group(1)
short_name_prep = re.sub('-','', short_name_prep)
short_name = re.sub('nova','', short_name_prep)
# Save in temporary dict
prep_list[networks['ctlplane'][0]] = server.name + ' ' + short_name
output = '###setHostsStart###\n'
for k, v in prep_list.items():
output += "%s\t%s\n" % (k ,v)
output += '###setHostsEnd###\n'
if '-a' in sys.argv:
replace_in_file(output)
else:
print "Add the following to your /etc/hosts:\n"
print output
if __name__ == "__main__":
if '-h' in sys.argv:
print """Script will output the overcloud hosts and their respective IP addresses.
Use -a to automatically update /etc/hosts"""
sys.exit(0)
main()
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