How would work changing "enable_isolated_metadata" from false to true && `openstack-service restart neutron` on the fly on RDO Liberty ?

Posting is addressing  question been asked at ask.openstack.org ([1])

Question :-

  
Can meta-data co-exist in qrouter and qdhcp namespace at the same time

so that LANs without Routers involved can access meta-data ?

Answer is as follows :-

All private networks (having neutron router) created  before or after this change will continue provide metadata via neutron-ns-metadata-proxy running in corresponding qrouter-namespace for theirs VMs.

Any  isolated tenants network  been created after update will provide metadata via neutron-ns-metadata-proxy running in corresponding qdhcp-namespace for theirs VMs. See  http://techbackground.blogspot.com/2013/06/metadata-via-dhcp-namespace.html

******************************************************************
For routable qdhcp-namespace created  before update dhcp_agent.ini
******************************************************************
[root@vfedora22wks ~(keystone_admin)]# ip netns exec \
qdhcp-e86eebdb-71bd-4929-937c-2ab57db30e18   netstat -4 -anpt
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address        
State       PID/Program name    
tcp        0      0 50.0.0.10:53            0.0.0.0:*               
LISTEN      6773/dnsmasq        
tcp        0      0 169.254.169.254:53      0.0.0.0:*               
LISTEN      6773/dnsmasq        
tcp        0      0 50.0.0.10:42011         50.0.0.15:22            
ESTABLISHED 2784/ssh

So it still gets access to metadata via qrouter's ns-metadata-proxy

******************************************************************************
For isolated qdhcp-namespaces /bin/neutron-ns-metadata-proxy 
gets started in corresponding qdhcp-namespace
******************************************************************************            
[root@vfedora22wks ~(keystone_admin)]# ip netns exec \
qdhcp-e0f08063-2002-4cc9-b7b1-611925ad01e5   netstat -4 -anpt
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       
PID/Program name    
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      
6333/python2        
tcp        0      0 30.0.0.10:53            0.0.0.0:*               LISTEN      
6771/dnsmasq        
tcp        0      0 169.254.169.254:53      0.0.0.0:*               LISTEN      
6771/dnsmasq 

       
[root@vfedora22wks ~(keystone_admin)]# ps -f --pid 6333 | fold -s -w 82
UID        PID  PPID  C STIME TTY          TIME CMD
neutron   6333     1  0 20:38 ?        00:00:00 /usr/bin/python2 
/bin/neutron-ns-metadata-proxy 
--pid_file=/var/lib/neutron/external/pids/e0f08063-2002-4cc9-b7b1-611925ad01e5.pid
 --metadata_proxy_socket=/var/lib/neutron/metadata_proxy <====
--network_id=e0f08063-2002-4cc9-b7b1-611925ad01e5 --state_path=/var/lib/neutron 
--metadata_port=80 --metadata_proxy_user=983 --metadata_proxy_group=977 --verbose 
--log-file=neutron-ns-metadata-proxy-e0f08063-2002-4cc9-b7b1-611925ad01e5.log 
--log-dir=/var/log/neutron


For private_network having neutron router and created immediately after update
"enable_isolated_metadata=True" and service restart

[root@vfedora22wks ~(keystone_admin)]# ip netns exec \
qdhcp-6e4646d8-2c5f-4adc-a4dc-51884f090d09 netstat -4 -anpt

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       
PID/Program name    
tcp        0      0 0.0.0.0:80              0.0.0.0:*               
LISTEN      8654/python2        
tcp        0      0 60.0.0.10:53            0.0.0.0:*               
LISTEN      8626/dnsmasq        
tcp        0      0 169.254.169.254:53      0.0.0.0:*               
LISTEN      8626/dnsmasq
        
[root@vfedora22wks ~(keystone_admin)]# ps -f --pid 8654  | fold -s -w 82
UID        PID  PPID  C STIME TTY          TIME CMD
neutron   8654     1  0 20:43 ?        00:00:00 /usr/bin/python2 
/bin/neutron-ns-metadata-proxy 
--pid_file=/var/lib/neutron/external/pids/6e4646d8-2c5f-4adc-a4dc-51884f090d09.pid
 --metadata_proxy_socket=/var/lib/neutron/metadata_proxy <=====
--network_id=6e4646d8-2c5f-4adc-a4dc-51884f090d09 --state_path=/var/lib/neutron 
--metadata_port=80 --metadata_proxy_user=983 --metadata_proxy_group=977 --verbose 
--log-file=neutron-ns-metadata-proxy-6e4646d8-2c5f-4adc-a4dc-51884f090d09.log 
--log-dir=/var/log/neutron

However,I have noticed that nodes restart disables neutron-ns-metadata-proxy for route-able tenant's networks, e.g. neutron-router port exists on corresponding network.
VM's metadata request is routed via qdhcp-namespace to qrouter-namespace
VMs get metadata from neutron-ns-metadata-proxy running in qrouter-namespace.
For isolated qdhcp-namespaces node reboot still keeps neutron-ns-metadata-proxy in corresponding qdhcp-namespace
*******************************************************************************************************
All Nodes rebooted neutron-ns-metadata-proxy is no longer kept in route-able qdhcp-namespaces. VMs are serving via neutron-ns-metadata-proxy running in qrouter-namespace.
*******************************************************************************************************

 Launching CirrOS instance via isolated network

Verification neutron-ns-metadata-proxy status

    
Launching VF22Devs07  VM via route-able tenant's network demo_network
Verification neutron-ns-metadata-proxy status