On 06/16/2017 12:21 PM, jean-christophe manciot wrote:

Yes, except that it *does not work*. As you can see below, libnss-libvirt is installed and configured, but the VM "KVM-Ubuntu-GNS3-Server-17.04" is not reachable through its DNS name.

libvirt-nss is not for translating DNS names, rather than libvirt guest names. That is, # virsh start myAwesomeDomain # ssh myAwesomeDomain

# apt-cache policy libnss-libvirt libnss-libvirt: Installed: 3.0.0-4 ... # cat /etc/nsswitch.conf passwd: compat group: compat shadow: compat

hosts: files libvirt libvirt_guest mdns4_minimal [NOTFOUND=return] resolve [!UNAVAIL=return] dns networks: files

protocols: db files services: db files ethers: db files rpc: db files

netgroup: nis

# systemctl status libvirtd ● libvirtd.service - Virtualization daemon Loaded: loaded (/lib/systemd/system/libvirtd.service; enabled; vendor preset: enabled) Active: active (running) since Fri 2017-06-16 11:44:59 CEST; 11min ago Docs: man:libvirtd(8) http://libvirt.org Main PID: 9448 (libvirtd) CPU: 1.790s CGroup: /system.slice/libvirtd.service ├─ 5556 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/virtual-mgt-5.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper ├─ 5557 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/virtual-mgt-5.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper ... ├─ 8805 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper ├─ 8806 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper ├─ 9448 /usr/sbin/libvirtd └─15116 qemu-system-x86_64 -enable-kvm -name guest=KVM-Ubuntu-GNS3-Server-17.04,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/

... Jun 16 11:55:14 samsung-ubuntu dnsmasq-dhcp[8805]: DHCPREQUEST(virbr0) 192.168.122.124 52:54:00:03:9f:9f Jun 16 11:55:14 samsung-ubuntu dnsmasq-dhcp[8805]: DHCPACK(virbr0) 192.168.122.124 52:54:00:03:9f:9f KVM-Ubuntu-GNS3-Server-17 # ping KVM-Ubuntu-GNS3-Server-17.04 ping: KVM-Ubuntu-GNS3-Server-17.04: Name or service not known # ping KVM-Ubuntu-GNS3-Server-17.04.actionmystique.net ping: KVM-Ubuntu-GNS3-Server-17.04.actionmystique.net: Name or service not known # ping 192.168.122.124 PING 192.168.122.124 (192.168.122.124) 56(84) bytes of data. 64 bytes from 192.168.122.124: icmp_seq=1 ttl=64 time=0.181 ms 64 bytes from 192.168.122.124: icmp_seq=2 ttl=64 time=0.165 ms

This suggests your DNS server might be misconfigured. Does it have a record for the guest you're running?

A few possible explanations for that issue are: - something is not configured correctly - there is an incompatibility with NetworkManager - there is a bug with libnss-libvirt

That's possible. Can you see the guest in: /var/lib/libvirt/dnsmasq/virbr0.{macs,status} That's where the nss module gets translations from. Also, looks like you're using 3.0.0 release. You need to restart the network after you've set up the NSS module. The decision whether to create those files is made when libvirt starts a network. Only in 3.3.0 release we're making that decision more frequently and thus the restart is not needed. virsh net-destroy virtual-mgt-5 virsh net-start virtual-mgt-5 Michal

libvirt-nss is not for translating DNS names, rather than libvirt guest names

I meant hostname/guest name. There is no static DNS in /etc/hosts for the VMs and no specific records in DNS server. Can you see the guest in: /var/lib/libvirt/dnsmasq/virbr0.{macs,status}

# cat /var/lib/libvirt/dnsmasq/virbr0.{macs,status} [ { "domain": "KVM-Ubuntu-GNS3-Server-17.04", "macs": [ "52:54:00:03:9f:9f" ] } ] [ { "ip-address": "192.168.122.124", "mac-address": "52:54:00:03:9f:9f", "hostname": "KVM-Ubuntu-GNS3-Server-17", "expiry-time": 1497617966 } ] You need to restart the network after you've set up the NSS module. I've rebooted the system. I am using something along the lines of:

$ cat /etc/dnsmasq.d/libvirt.conf

server=/virt/192.168.213.1 server=/213.168.192.in-addr.arpa/192.168.213.1/ I have no /etc/dnsmasq.d/libvirt.conf, but in */etc/dnsmasq.conf*: *local=/actionmystique.net/ <http://actionmystique.net/>* I thought this would add that domain name to the answers from whatever is found in DHCP leases. The comment says: # Add local-only domains here, queries in these domains are answered # from /etc/hosts or DHCP only. Since the first libvirt-nss module ("libvirt" plugin) looks into DHCP server leases, the above setting should work, shouldn't it? Actually, I've just realized that there is a discrepancy between the libvirt VM guest name and the Ubuntu hostname, where the trailing ".04" has been automatically removed. So, the* hostname (not guest name) is accessible*: # ping KVM-Ubuntu-GNS3-Server-17 PING KVM-Ubuntu-GNS3-Server-17 (192.168.122.124) 56(84) bytes of data. 64 bytes from KVM-Ubuntu-GNS3-Server-17 (192.168.122.124): icmp_seq=1 ttl=64 time=0.191 ms 64 bytes from KVM-Ubuntu-GNS3-Server-17 (192.168.122.124): icmp_seq=2 ttl=64 time=0.302 ms ... *but not he FQDN*: # ping KVM-Ubuntu-GNS3-Server-17.actionmystique.net ping: KVM-Ubuntu-GNS3-Server-17.actionmystique.net: Name or service not known On Fri, Jun 16, 2017 at 1:39 PM, Martin Kletzander <mkletzan@redhat.com> wrote:

On Sat, Jun 10, 2017 at 08:53:16PM +0200, jean-christophe manciot wrote:

...

Hello everyone,

I have multiple virtual networks defined on my Server: # virsh net-list --all Name State Autostart Persistent ---------------------------------------------------------- default active yes yes ... virtual-mgt-5 active yes yes ...

I am using something along the lines of:

$ cat /etc/dnsmasq.d/libvirt.conf server=/virt/192.168.213.1 server=/213.168.192.in-addr.arpa/192.168.213.1/

And all guests have .virt in their hostname, so I'm at least able to use that. That way guests are available by their names in the .virt domain. You should be able to do that with your domain name as well. Let me know if that works for you or not.

Have a nice day, Martin

-- Jean-Christophe

On Fri, Jun 16, 2017 at 02:38:21PM +0200, jean-christophe manciot wrote:

...

libvirt-nss is not for translating DNS names, rather than libvirt guest names

I meant hostname/guest name. There is no static DNS in /etc/hosts for the VMs and no specific records in DNS server.

Can you see the guest in: /var/lib/libvirt/dnsmasq/virbr0.{macs,status}

...

# cat /var/lib/libvirt/dnsmasq/virbr0.{macs,status} [ { "domain": "KVM-Ubuntu-GNS3-Server-17.04", "macs": [ "52:54:00:03:9f:9f" ] } ] [ { "ip-address": "192.168.122.124", "mac-address": "52:54:00:03:9f:9f", "hostname": "KVM-Ubuntu-GNS3-Server-17", "expiry-time": 1497617966 } ]

You need to restart the network after you've set up the NSS module.

I've rebooted the system.

I am using something along the lines of:

...

$ cat /etc/dnsmasq.d/libvirt.conf

server=/virt/192.168.213.1

server=/213.168.192.in-addr.arpa/192.168.213.1/

I have no /etc/dnsmasq.d/libvirt.conf, but in */etc/dnsmasq.conf*: *local=/actionmystique.net/ <http://actionmystique.net/>*

That doesn't matter, i created libvirt.conf myself and my /etc/dnsmasq.conf includes everything from /etc/dnsmasq.d/ that ends with .conf. the line you are using means it will not forward those hostnames anywhere. But the problem is that you have 2 different dnsmasq daemons running at the same time and one doesn't know about the other. The one ran by libvirt will not be accessed anyhow unless you tell it to your system-wide one. So similarly to what I was suggesting, you'd need: server=/actionmystique.net/192.168.213.1 server=/213.168.192.in-addr.arpa/192.168.213.1/ instead of the local= line.

I thought this would add that domain name to the answers from whatever is found in DHCP leases.

But the leases are offered by different dnsmasq than which one the ping is asking.

The comment says: # Add local-only domains here, queries in these domains are answered # from /etc/hosts or DHCP only.

But there is nothing in /etc/hosts and nothing will ever be added there automatically. The only one who knows the hostname <-> IP address mapping is libvirt and its dnsmasq.

Since the first libvirt-nss module ("libvirt" plugin) looks into DHCP server leases, the above setting should work, shouldn't it?

Actually, I've just realized that there is a discrepancy between the libvirt VM guest name and the Ubuntu hostname, where the trailing ".04" has been automatically removed. So, the* hostname (not guest name) is accessible*: # ping KVM-Ubuntu-GNS3-Server-17 PING KVM-Ubuntu-GNS3-Server-17 (192.168.122.124) 56(84) bytes of data. 64 bytes from KVM-Ubuntu-GNS3-Server-17 (192.168.122.124): icmp_seq=1 ttl=64 time=0.191 ms 64 bytes from KVM-Ubuntu-GNS3-Server-17 (192.168.122.124): icmp_seq=2 ttl=64 time=0.302 ms ... *but not he FQDN*: # ping KVM-Ubuntu-GNS3-Server-17.actionmystique.net ping: KVM-Ubuntu-GNS3-Server-17.actionmystique.net: Name or service not known

It all comes down to what is your usage, what are your use cases, basically what are you trying to achieve here. Unless we know that, there is no one clear answer. P.S.: About the .04, that is yet another level of domain that, I think, might get stripped, or just used differently when nsswitch is actually asking for it.