problemA VM deployed on Apache CloudStack (ACS) is unable to acquire a DHCP-assigned IP address from the Virtual Router (VR). The DHCP request is visible in the VR’s tcpdump, but the VM does not receive an IP. However, manually assigning an IP to the VM allows it to reach both the VR and the internet. versionsEnvironment Details The steps to reproduce the bug
What to do about it?No response |
Replies: 30 comments 1 reply
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i saw this post earlier, but didn't get solution by that method.. Do you suggest that i post it there or continue here? |
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On VM: New VR Logs: Tue Mar 18 09:43:11 PM UTC 2025 Starting guest services for kvm |
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@rbaweja, can you check |
the worst part is there are 2 routers and both have same issue, i tried with default 5.5 centos template but same Mar 24 15:58:34 dnsmasq-dhcp[3006]: DHCPOFFER(eth2) 10.0.0.138 02:01:00:de:00:01 |
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that log looks ok, you said
do you mean you see the request coming in, but no response going out from the VR using tcpdump? |
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as per response i see that the response is also tehre but VM is not receiving the response. tcpdump for VR: 17:15:21.881789 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 02:01:00:cc:00:16, length 300 |
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are there firewall rules in the vm ? are there firewall rules with the kvm host ? |
No firewall rules. Even the fresh VM of centos 5.5 doesn’t get IP |
Are the vm and vr running on the same host ? |
all on one host for now. |
@rbaweja please use |
this is what i get - 09:35:47.319133 IP (tos 0xc0, ttl 64, id 6910, offset 0, flags [none], proto UDP (17), length 372) |
is it the output inside the guest vm ? |
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this is from VR |
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VR looks ok any packets received in the vm ? |
it looks like no packets received. do you use linux bridge or openvswitch ? if you use linux bridge, can you capture the packets of the linux bridge |
that also seems to be passing 10:42:23.421152 IP (tos 0xc0, ttl 64, id 11870, offset 0, flags [none], proto UDP (17), length 372) |
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explaining the scenario: i was using it with above scenario. now i tried with all different versions but nothing worked. so i used cloudbr0 for both management and guest the VM got the IP. since cloudbr0 is in access mode the traffic of other VLAN will not go to other hosts since it will not communicate. now my question is how to keep all 3 networks isolated? shall i configure cloudbr1 with management vlan in native and rest as trunk ? or all should be like that? |
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@rbaweja @weizhouapache , could this be a matter of asymetric routing? (just having a wild stab at it) |
Not really sure. |
@rbaweja refer to "Choose which traffic types will be carried by the physical network" section on https://docs.cloudstack.apache.org/en/latest/installguide/configuration.html |
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yes the label and configuration is perfect. below for your reference: network: /etc/cloudstack/agent/agent.properties |
@rbaweja |
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1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 |
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@rbaweja for example |
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Thank you for your help. i was able to resolve this on networking level... seems the management IP VLAN needs to be in access mode and rest of VLAN should be in trunk mode and this problem was resolved. |


Thank you for your help. i was able to resolve this on networking level...
seems the management IP VLAN needs to be in access mode and rest of VLAN should be in trunk mode and this problem was resolved.