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can't ping/ssh VM - dhcp namespace

asked 2020-05-28 05:21:18 -0500

GPOZ gravatar image

Hello, I'm trying to configure Openstack Queens on ubuntu 16.04. I configured Neutron following the "network option 1: provider network" guideline. - I created a flat network and an allocation-pool with the option --no-dhcp to avoid possible issues with existing DHCP services on the physical network. - I created new security group rules to allow icmp/tcp traffic but i can't ping my VM. After all these steps I still can't ping my VMs. I checked the dhcp namespace typing "ip netns" and i did't have any result. So i was wondering if the problem was the "--no-dhcp" option i setted. Why don't I have the dhcp namespace?

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answered 2020-05-28 06:07:11 -0500

updated 2020-05-28 06:08:51 -0500

You disabled DHCP. This is why you have no DHCP namespace. DHCP servers run in network namespaces so that they can have overlapping IP address ranges. Without a DHCP server, no namespace is required.

Most images obtain IP addresses from DHCP, and I would bet yours is no exception. I don't know why it doesn't get its IP address from the existing DHCP servers, but most probably they are configured to only serve certain MAC addresses.

You can confirm this by looking at the instance's console log: openstack console log show INSTANCENAME.

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I deleted the previous allocation-pool and created a new one with dchp enabled. Now checking the instance's console log, it has an ip assigned but it is out of the range i've setted! is it due to the fact that physical network dhcp in network config 1 doesn't respect allocation-pool specification?

GPOZ gravatar imageGPOZ ( 2020-05-29 12:24:11 -0500 )edit

i try to explain better: The allocation-pool i setted is Console log of the instance shows Checking the output of the command "openstack server list" the instance has How is it possible?

GPOZ gravatar imageGPOZ ( 2020-05-29 12:28:50 -0500 )edit

Did the instance receive the IP address from another DHCP server?

Bernd Bausch gravatar imageBernd Bausch ( 2020-05-29 17:33:14 -0500 )edit

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Asked: 2020-05-28 05:21:18 -0500

Seen: 105 times

Last updated: May 28 '20