Re: How to make a VM guest look like just another metal machine on my LAN?
Just a simple Bridge configuration is too daunting to configure with QMEU.
serious some helper script /config is need to make this simpler for user of
qemu to use this.
On Sun, Feb 21, 2021 at 2:16 PM Steve Litt
wrote:
> Hi all,
>
> My LAN at home is on 192.168.0.0/24, connected to the Internet via a
> cablemodem/firewall/router/gateway at 192.168.0.1. My Daily Driver
> Desktop (DDD), which will after this be referred to as the "host" or
> "metal host" is at 192.168.0.2. I have a printer with an http interface
> at 192.168.0.13. Throughout this post I'm careful to discriminate
> between the metal host and the VM guest, which is created on the metal
> host, for all config options.
>
> What I'm trying to accomplish is to launch a VM guest (Devuan) on my
> metal host (Void Linux), such that the VM guest performs as if it were
> just another physical computer on my LAN.
>
> I've been reading and experimenting for four days and still don't have
> what I need. Here are some of the documents I've used trying to get
> this done:
>
> https://wiki.qemu.org/Documentation/Networking#User_Networking_.28SLIRP.29
>
>
> https://ahelpme.com/linux/howto-do-qemu-full-virtualization-with-bridged-networking/
>
> http://www.mpaoli.net/~root/bin/TEMPLATE
>
>
> https://www.debian.org/doc/manuals/debian-handbook/sect.virtualization.en.html#sect.lxc.network
>
> I'm trying to do it purely with ip commands, although I could use brctl
> if necessary. I'm staying away from virt-manager and aqemu because they
> don't work on my Void Linux metal host, and would just add even more
> variables and ambiguity.
>
> Speaking of ambiguity, every document I've read (and I've read dozens)
> has the following ambiguities:
>
> 1) When discussing a setting, they don't indicate whether that setting
>should be on the metal host or the VM guest. Perhaps to a person who
>thoroughly understands virtual machines, such a distinction would be
>obvious via context, but it's not obvious to me.
>
> 2) When specifying an "id=whatever", they don't indicate how the id
>would be used, or what other references to that id need to be made.
>
> 3) They include no realistic steps for troubleshooting a "warning:
>netdev mybridge0 has no peer" type warning, nor even explain what it
>means more than a few guesses and "have you tried...".
>
> Based on the previously listed links, I deduce that the TAP is created
> by the guest VM, in such a way that it attaches to the bridge created on
> the metal host, and therefore I have no need to create a TAP on the
> metal host.
>
> Here's my progress so far, based on the links listed above and my
> other readings and experimentation:
>
> ***
>
> I build the bridge purely with ip commands. Also, I don't mess
> with the firewall (which perhaps has been my problem all along). I'll
> investigate the firewall aspect tomorrow.
>
> Below are some scripts and stuff I'm using. The following is
> upnet.sh, which I use to set up networking on the metal host, which
> happens to run Void Linux, which has no /etc/network/interfaces:
>
> =
> #!/bin/sh
>
> use_bridge=1
> use_tap=0
>
> dev="enp40s0"
> ipaddr_major="192.168.0.2"
> ipaddr_minor="192.168.0.102"
> gateway="192.168.0.1"
>
> error_tap_without_bridge(){
>echo -n "ERROR: Can\'t set TAP without "
>echo -n "BRIDGE! "
>echo Aborting...
>exit 1
> }
>
>
> enable_ip_forwarding(){
>echo 1 > /proc/sys/net/ipv4/ip_forward
> }
>
> unset_everything(){
>dev=$1
>ip_maj=$2
>ip_min=$3
>gateway=$4
>echo "Unsetting everything for $dev, $ip_maj and $ip_min"
>ip link set dev tap0 down
>brctl delif br0 tap0
>ip link del tap0
>ip link set dev br0 down
>ip addr del $ip_min/24 dev br0
>ip addr del $ip_maj/24 dev br0
>brctl delbr br0
>ip link set dev $dev down
>ip addr del $ip_min/24 dev $dev
>ip addr del $ip_maj/24 dev $dev
>echo ""
> }
>
> set_hostname_and_localhost(){
>echo "Setting hostname and localhost"
>hostname=`grep -v "^\s*#" /etc/hostname | head -n1`
>ip link set dev lo up
>echo ""
> }
>
> create_phys_device_link(){
>dev=$1
>echo Creating device link for $dev
>ip link set dev $dev up
>echo ""
> }
>
> set_phys_device_addr(){
>dev=$1
>ip_maj=$2
>ip_min=$3
>gateway=$4
>echo -n "Setting physical device addresses "
>echo -n "$ip_maj "
>echo -n "and $ip_min "
>echo -n "for $physdev "
>echo "with gateway $gateway"
>ip link set dev $dev down
>ip addr add $ip_maj/24 dev $dev
>ip addr add $ip_min/24 dev $dev
>ip link set dev $dev up
>ip route add default via $gateway
>echo ""
> }
>
> set_bridge(){
>dev=$1
>ip_maj=$2
>ip_min=$3
>gateway=$4
>echo Setting bridge for $dev
>echo -n "Creating and setting bridge addresses "
>echo -n "$ip_maj "
>echo -n "and $ip_min "
>echo -n "for $physdev "
>echo "with gateway $gateway"
>
>ip link add
Re: How to make a VM guest look like just another metal machine on my LAN?
Hi, Am 21.02.21 um 09:46 schrieb Steve Litt: > Hi all, > . . . > > Steve Litt > Autumn 2020 featured book: Thriving in Tough Times > http://www.troubleshooters.com/thrive > i have only partly read your mail. but i think it sounds like a problem similar to one i have had with the "firewalld" and ssh from outside to a virtual machine. (a year or so in past) (i am here at host opensuse tumbleweed and different virtual machines startet by virtmanager. so i have set inside yast (host) the bridge device "br0" and have permanent set the hardware-network-card (host) as a slave to this bridge. the connection to the guest will be done automaticaly by virt-manager. no need to write a script.) BUT i run into a routing problem, solved here: i was following this: https://superuser.com/questions/990855/configure-firewalld-to-allow-bridged-virtual-machine-network-access in detail: firewall-cmd --permanent --direct --passthrough ipv4 -I FORWARD -i br0 -j ACCEPT firewall-cmd --permanent --direct --passthrough ipv4 -O FORWARD -i br0 -j ACCEPT firewall-cmd --reload this will create a file: /etc/firewalld/direct.xml with the above entries. i tested also then: iptables-save -f dateiname iptables-restore -f dateiname iptables -L now there is a line more inside: -A FORWARD -i br0 -j ACCEPT but i do not recall why i have done this. my working configuration did not have the last "-A" line inside. hope this will help you. for test purpose i would (if possible inside your enviorement) stop the firewall (host) completely and check if its then running. if its running, you know for sure its a firewall problem. simoN -- www.becherer.de signature.asc Description: OpenPGP digital signature
How to make a VM guest look like just another metal machine on my LAN?
Hi all,
My LAN at home is on 192.168.0.0/24, connected to the Internet via a
cablemodem/firewall/router/gateway at 192.168.0.1. My Daily Driver
Desktop (DDD), which will after this be referred to as the "host" or
"metal host" is at 192.168.0.2. I have a printer with an http interface
at 192.168.0.13. Throughout this post I'm careful to discriminate
between the metal host and the VM guest, which is created on the metal
host, for all config options.
What I'm trying to accomplish is to launch a VM guest (Devuan) on my
metal host (Void Linux), such that the VM guest performs as if it were
just another physical computer on my LAN.
I've been reading and experimenting for four days and still don't have
what I need. Here are some of the documents I've used trying to get
this done:
https://wiki.qemu.org/Documentation/Networking#User_Networking_.28SLIRP.29
https://ahelpme.com/linux/howto-do-qemu-full-virtualization-with-bridged-networking/
http://www.mpaoli.net/~root/bin/TEMPLATE
https://www.debian.org/doc/manuals/debian-handbook/sect.virtualization.en.html#sect.lxc.network
I'm trying to do it purely with ip commands, although I could use brctl
if necessary. I'm staying away from virt-manager and aqemu because they
don't work on my Void Linux metal host, and would just add even more
variables and ambiguity.
Speaking of ambiguity, every document I've read (and I've read dozens)
has the following ambiguities:
1) When discussing a setting, they don't indicate whether that setting
should be on the metal host or the VM guest. Perhaps to a person who
thoroughly understands virtual machines, such a distinction would be
obvious via context, but it's not obvious to me.
2) When specifying an "id=whatever", they don't indicate how the id
would be used, or what other references to that id need to be made.
3) They include no realistic steps for troubleshooting a "warning:
netdev mybridge0 has no peer" type warning, nor even explain what it
means more than a few guesses and "have you tried...".
Based on the previously listed links, I deduce that the TAP is created
by the guest VM, in such a way that it attaches to the bridge created on
the metal host, and therefore I have no need to create a TAP on the
metal host.
Here's my progress so far, based on the links listed above and my
other readings and experimentation:
***
I build the bridge purely with ip commands. Also, I don't mess
with the firewall (which perhaps has been my problem all along). I'll
investigate the firewall aspect tomorrow.
Below are some scripts and stuff I'm using. The following is
upnet.sh, which I use to set up networking on the metal host, which
happens to run Void Linux, which has no /etc/network/interfaces:
=
#!/bin/sh
use_bridge=1
use_tap=0
dev="enp40s0"
ipaddr_major="192.168.0.2"
ipaddr_minor="192.168.0.102"
gateway="192.168.0.1"
error_tap_without_bridge(){
echo -n "ERROR: Can\'t set TAP without "
echo -n "BRIDGE! "
echo Aborting...
exit 1
}
enable_ip_forwarding(){
echo 1 > /proc/sys/net/ipv4/ip_forward
}
unset_everything(){
dev=$1
ip_maj=$2
ip_min=$3
gateway=$4
echo "Unsetting everything for $dev, $ip_maj and $ip_min"
ip link set dev tap0 down
brctl delif br0 tap0
ip link del tap0
ip link set dev br0 down
ip addr del $ip_min/24 dev br0
ip addr del $ip_maj/24 dev br0
brctl delbr br0
ip link set dev $dev down
ip addr del $ip_min/24 dev $dev
ip addr del $ip_maj/24 dev $dev
echo ""
}
set_hostname_and_localhost(){
echo "Setting hostname and localhost"
hostname=`grep -v "^\s*#" /etc/hostname | head -n1`
ip link set dev lo up
echo ""
}
create_phys_device_link(){
dev=$1
echo Creating device link for $dev
ip link set dev $dev up
echo ""
}
set_phys_device_addr(){
dev=$1
ip_maj=$2
ip_min=$3
gateway=$4
echo -n "Setting physical device addresses "
echo -n "$ip_maj "
echo -n "and $ip_min "
echo -n "for $physdev "
echo "with gateway $gateway"
ip link set dev $dev down
ip addr add $ip_maj/24 dev $dev
ip addr add $ip_min/24 dev $dev
ip link set dev $dev up
ip route add default via $gateway
echo ""
}
set_bridge(){
dev=$1
ip_maj=$2
ip_min=$3
gateway=$4
echo Setting bridge for $dev
echo -n "Creating and setting bridge addresses "
echo -n "$ip_maj "
echo -n "and $ip_min "
echo -n "for $physdev "
echo "with gateway $gateway"
ip link add name br0 type bridge
ip link set dev $dev master br0
ip addr add $ip_maj/24 dev br0
ip addr add $ip_min/24 dev br0
ip link set dev br0 up
ip route add default via $gateway
echo ""
}
set_tap(){
echo Setting tap
ip tuntap add tap0 mode tap
brctl addif br0 tap0
#ip addr add 192.168.0.66/24 dev tap0
ip link set dev tap0 up
echo ""
}
show_networking(){
echo -n "Networking follows in 3 seconds..."
sleep 3
echo "\n"
echo
