Set hostname of guest during installation time

[Michal Privoznik]

On 5/5/20 11:25 AM, john doe wrote:
> On 5/5/2020 10:41 AM, Michal Privoznik wrote:
>> On 5/5/20 9:26 AM, john doe wrote:
>>> On 5/5/2020 8:29 AM, Michal Privoznik wrote:
>>>> Because interface type='bridge' and type='network' are not the same. 
>>>> The
>>>> libvirt_guest plugin needs a list of MAC addresses because it tries to
>>>> find a match across libvirt domain name -> list of domain's MAC
>>>> addresses -> list of leases. And whenever a domain is started, all its
>>>> interfaces with type='network' will notify the corresponding network 
>>>> and
>>>> the code that handles libvirt networks will dump the MAC address into a
>>>> file for the NSS plugin to use. But, if plain type='bridge' is used 
>>>> then
>>>> all that is done is that the TAP is plugged into the bridge (which
>>>> ensures the connectivity), but does not notify the network which in 
>>>> turn
>>>> means that the MAC dumping code is not run and hence the NSS plugin
>>>> won't find a match.
>>>>
>>>
>>> I don't understand why the network can not be notified, could it be a
>>> feature request?
>>
>> No. interface type='bridge' exists exactly for the reasons that users
>> want libvirt just to plug TAP device into a bridge they manage. And they
>> don't want libvirt to touch the bridge in any other way.
>>
>>>
>>>> Is there a reason why you are using interface type='bridge' with the
>>>> default network?
>>>>
>>>
>>> I'm just starting with libvirt, so I could be missing something.
>>>
>>> Yes, I don't need libvirt touching iptables at all.
>>>
>>> In other words, is there a way to be able to use libvirt_guest without
>>> having libvirt interacting with iptables.
>>
>> I'm not quite sure how to achieve NAT then - do you insert the NAT rules
>> yourself?
> 
> Yes, my frontent to iptables will do that.
> 
> 
>> If it is so, then what you may do is to change the type of the
>> default network to 'open' and then use interface type='network' from the
>> domain.
>>
> 
> Thank you, I'll need to look into that.
> 
> Is there a way to do that with virt-install?

Let me check the man page for you.

--network network=my_libvirt_virtual_net

> 
>>>
>>>>>
>>>>>
>>>>>
>>>>> Also, from (1):
>>>>>
>>>>> "virsh net-dhcp-leases $network
>>>>> where $network iterates through
>>>>> all running network..."
>>>>>
>>>>> If I understand correctly, the below should list all running network:
>>>>>
>>>>> $ virsh net-dhcp-leases $network
>>>>> error: command 'net-dhcp-leases' requires <network> option
>>>>
>>>> This lists DHCP leases for given network. To list all running networks
>>>> you can use 'virsh net-list'.
>>>>
>>>
>>> I would suggest rephrasing the above to something along the lines of:
>>>
>>> "virsh net-dhcp-leases $network, where '$network' is to be supstituted
>>> by the desired network (E.G, 'default') or use virsh net-list to list
>>> all available network."
>>
>> Actually, the whole statement (copied verbatim from the webpage) is:
>>
>>    The NSS module then merely consults the list trying to find the match.
>>    Users can view the list themselves:
>>
>>    virsh net-dhcp-leases $network
>>
>>    where $network iterates through all running networks.
>>
> '$network iterates through all running networks.' I don't understand
> what 'all networks' refers to?

Just like there can be multiple domains running there can be multiple 
networks.

> 
>> Maybe I'm assuming too much, but this doesn't say that net-dhcp-leases
>> will print all running networks. The way I read this is: The NSS module
>> then merely does equivalent of iterating over every running network and
>> executing 'net-dhcp-leases' and trying to find the match.
>>
>> I thought that using shell variables in a documentation for an UNIX-like
>> command is well understood, but maybe I am wrong.
>>
> 
> That is the first time that I see this syntax being used, simply adding
> somewhere that when an example for a command is shown like so, this
> should be substituted.

Our docs are kept in a repository. In this specific example it is 
docs/nss.html.in:

https://gitlab.com/libvirt/libvirt/-/blob/master/docs/nss.html.in

If you feel like our docs are misleading, please post a patch.

Michal