kvm/qemu debian 10 vm network issue - networking

Question

I'm trying to run a default basic deb10 VM on my deb10 dedicated server but I can't reach the VM on the default network. I can't make it acquire any IP address nor reach it in any way. I tried many things on many threads found online, without success.
The easiest solution I found was to enable port forwarding (because of the NAT mode of default conf) and start over but it didnt worked either.
sudo sysctl -w net.ipv4.ip_forward=1
I'll try to give as many informations as I can.
Script
#!/bin/bash
vname="deb"
virt-builder debian-10 \
--size 15G \
--format qcow2 -o "disk/$vname.qcow2" \
--hostname "$vname.local" \
--ssh-inject "root:string:ssh-rsa somesuperrsapubkey user#host" \
--root-password disabled \
--timezone "Europe/Paris" \
--update
virt-install \
--import \
--name "$vname" \
--ram 1024 \
--vcpu 1 \
--disk "disk/$vname.qcow2" \
--os-variant debian10 \
--network default \
--noautoconsole
Nothing very fancy in this, I'm trying to stay as basic as possible.
IP interfaces
ansible#host:/kvm$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether x:x:x:x:x:x brd ff:ff:ff:ff:ff:ff
inet x.x.x.x/24 brd x.x.x.255 scope global dynamic eno1
valid_lft 57059sec preferred_lft 57059sec
inet6 x::x:x:x:x/64 scope link
valid_lft forever preferred_lft forever
3: eno2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether x:x:x:x:x:x brd ff:ff:ff:ff:ff:ff
42: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 52:54:00:9b:bf:4c brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
43: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
link/ether 52:54:00:9b:bf:4c brd ff:ff:ff:ff:ff:ff
44: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master virbr0 state UNKNOWN group default qlen 1000
link/ether fe:54:00:9a:81:24 brd ff:ff:ff:ff:ff:ff
inet6 fe80::fc54:ff:fe9a:8124/64 scope link
valid_lft forever preferred_lft forever
Firewall
ansible#host:/kvm$ sudo iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT udp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 udp dpt:53
0 0 ACCEPT tcp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:53
0 0 ACCEPT udp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 udp dpt:67
0 0 ACCEPT tcp -- virbr0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:67
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * virbr0 0.0.0.0/0 192.168.122.0/24 ctstate RELATED,ESTABLISHED
0 0 ACCEPT all -- virbr0 * 192.168.122.0/24 0.0.0.0/0
0 0 ACCEPT all -- virbr0 virbr0 0.0.0.0/0 0.0.0.0/0
0 0 REJECT all -- * virbr0 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable
0 0 REJECT all -- virbr0 * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT udp -- * virbr0 0.0.0.0/0 0.0.0.0/0 udp dpt:68
Virsh manipulations
ansible#host:/kvm$ sudo virsh
virsh # net-dumpxml default
<network connections='1'>
<name>default</name>
<uuid>75e2d7eb-389c-406b-a63e-7fe5e9f188f5</uuid>
<forward mode='nat'>
<nat>
<port start='1024' end='65535'/>
</nat>
</forward>
<bridge name='virbr0' stp='on' delay='0'/>
<mac address='52:54:00:9b:bf:4c'/>
<ip address='192.168.122.1' netmask='255.255.255.0'>
<dhcp>
<range start='192.168.122.2' end='192.168.122.254'/>
</dhcp>
</ip>
</network>
virsh # domifaddr deb
Name MAC address Protocol Address
-------------------------------------------------------------------------------
virsh # domiflist deb
Interface Type Source Model MAC
-------------------------------------------------------------
vnet0 network default virtio 52:54:00:9a:81:24
virsh # list
Id Name State
----------------------
19 deb running
virsh # net-list
Name State Autostart Persistent
--------------------------------------------
default active no yes
Is there anybody who can help me find my mistake ?
Thanks all

Answer 1

It happens that the VM network interface is not activated at first boot :
ifup enp1s0
I found this workaround for now but I'd like to have a better solution.
VM image build
virt-builder debian-10 \
--size 15G \
--format qcow2 -o "disk/deb.qcow2" \
--hostname "deb.local" \
--timezone "Europe/Paris" \
--upload 00-init:/etc/network/interfaces.d/00-init \
--update
00-init file
user#host:~/kvm$ cat 00-init
allow-hotplug enp1s0
iface enp1s0 inet dhcp
Then the VM does get an IP address from host DHCP