problem

Before the upgrade to version 4.21.0, the DHCP server for VPC Guest Network tier included both the Guest Network Gateway and the DNS server defined in the zone as nameservers. However, after upgrading from version 4.20.1 to 4.21.0, the DHCP server only announces the DNS server defined in the zone. Consequently, all internal DNS resolutions fail due to this change.

in 4.20.1 VPC VR

/etc/dnsmasq.d/cloud.conf

dhcp-option=tag:interface-eth0-0,6,10.2.1.1,172.17.2.1

in 4.21.0 VPC VR

/etc/dnsmasq.d/cloud.conf

dhcp-option=tag:interface-eth0-0,6,172.17.2.1

versions

ACS: 4.21.0
OS: OL9 x86_64
hypervisors: KVM
storage: NFS(SharedMountPoint)
network: vxlan

The steps to reproduce the bug

1. Create a VPC with "Default VPC offering"
2. Create a guest network with "DefaultIsolatedNetworkOfferingForVpcNetworks" under that VPC
3. launch a VM
4. verify /etc/resolv.conf are missing guest network gateway ip as nameserver

What to do about it?

No response