Bug 2099544

Summary: Adding new subnet with DHCP to existing provider network fails
Product: Red Hat OpenStack Reporter: Ganesh Kadam <gkadam>
Component: python-networking-ovnAssignee: OSP Team <rhos-maint>
Status: CLOSED CURRENTRELEASE QA Contact: Eran Kuris <ekuris>
Severity: high Docs Contact:
Priority: high    
Version: 16.1 (Train)CC: apevec, chrisw, lhh, majopela, ralonsoh, scohen
Target Milestone: z8   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2022-06-22 11:43:24 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Ganesh Kadam 2022-06-21 08:23:16 UTC
Description of problem:

- Customer is not able to create a new subnet with DHCP enabled on existing network. 

- Customer wants to clarify, that extending the subnet is their end requirement. And since it was not possible to edit the existing subnets (as mentioned in earlier comments), they thought of adding new subnet to the same vlan, which was possible only with dhcp option disabled.
 
- They would like to know which DHCP IP is assigned the DHCP port MAC address?

- Reached out to #neutron team, and asked them to simply try adding a new subnet and see if it helps, it's not working well too, need more input in this case. 

Here is what they have done so far:
 
Step 1 -- Anitsu_gre network was created with subnet "anritsu-gre-v4" -- 172.26.32.64/28      
Step 2 -- The above subnet (dhcp enabled) had a DHCP IP configured (the IP we are not aware and only the MAC is displayed currently- refer screenshot)
Step 3 -- We wanted to extend the above subnet as the IP's exhausted
Step 4 -- We tried to add new IP's with subnet 172.26.32.80/28 with dhcp enabled, but failed with the below error:
 
                   Error: Failed to create subnet "172.26.32.80/28" for network "anritsu-gre": No more IP addresses available on network 54003d51-1f67-4972-ae30-b8b4e04660cb. Neutron server returns request_ids: ['req-3cbb9d25-fb46-4269-b74d-381d9f8dc376']
 
Step 5 -- Then we tried to add the subnet with DHCP set to false. It succeeded. (Maybe here, the existing DHCP IP was removed)
Step 6 -- We added another series with DHCP enabled, failed as well. But succeeded with DHCP set to false.
Step 7 -- We tried to enable DHCP on all the subnets via dashboard and now we see dhcp set to true for all three subnets under the same vlan, but no dhcp IP assigned.
 
Based on the above scenario, find below the questions for which we expect few clarifications:
 
1.  If DHCP is enabled now, which are the DHCP IP's??
2. If the subnet range is different from each other, why we were unable to add the second subnet with DHCP enabled? It should have just dedicated an IP from the second range and added it to the DHCP port. Why did it fail?
 
For justifying the above #2, we created an internal network and exhausted the initial subnet (DHCP enabled) and added a new subnet to the same internal network (DHCP enabled) and it went through.


Version-Release number of selected component (if applicable):

[gkadam@supportshell-1 03247296]$ cat 0040-sosreport-b52-41-2-47-27-2022-06-20-xtofyqu.tar.xz/sosreport-b52-41-2-47-27-2022-06-20-xtofyqu/etc/rhosp-release 
Red Hat OpenStack Platform release 16.1.6 GA (Train)


puppet-neutron-15.5.1-1.20210323133456.7d0406b.el8ost.noarch Wed Oct 13 16:33:58 2021

python3-neutronclient-6.14.1-1.20201113231846.a09e824.el8ost.noarch Wed Oct 13 16:34:01 2021

puppet-ovn-15.4.1-1.20201113171358.192ac4e.el8ost.noarch    Wed Oct 13 16:33:57 2021



Actual results:

Unable to add the IP to existing n/w with DHCP enabled

Expected results:

Should be able to add the IP to the n/w with DHCP 

Additional info: