[Grml] Fwd: switching to dnsmasq when using grml-terminalserver

[洪朝貴]

Sorry, only just now after finishing an article about
grml customization did I realize that I didn't reply to the list...

My customized version with dnsmasq, etc. is here:
http://fs.cyut.edu.tw/gregslab/20/
(grml64-small-g20?.iso)

The customization process is documented here in zh_TW:
https://newtoypia.blogspot.com/2020/11/grml.html

--
顧好自己的隱私， 快停止網路裸奔！
請搜尋『貴哥的節慾手機』
Greg Chao-Kuei Hung 洪朝貴

PGP Key ID: 4096R/5828A7A7
Fingerprint: 67AF B5AB 5242 3E99 16D7  EAF8 A94D 2C92 5828 A7A7


---------- Forwarded message ---------
寄件者： 洪朝貴 <ckhung at cyut.edu.tw>
Date: 2020年10月29日 週四 下午10:56
Subject: Re: [Grml] switching to dnsmasq when using grml-terminalserver
To: gilberto dos santos alves <gsavix at gmail.com>


Thanks to mika for the detailed response. Here is my detailed use case.

I plan to install linux to two partitions of each computer in a Univ.
computer classroom
using only one usb flash drive containing a customized grml and a customized
linux mint 20 ulyana.
1. Boot one computer into ulyana, with a grml kvm running inside but bridged
    to the host's network as the pxe server.
2. Start pxe service serving grml image, with the "netscript=http://..."
option
    pointing to a pdmenu script full of admin options (details below).
3. Boot all other computers using pxe into grml and into the pdmenu script.
4. For each computer, choose from pdmenu the option to prepare the
partitions,
    one EFI and the other LVM with all required volumes. Also install grml
    using extlinux into the EFI partition, with an additional (not-yet
usable) ulyana entry.
5. For each computer, choose from pdmenu the option to receive, in
parallel,
    the rather large ulyana image using udp-receiver.
6. From the pxe server use udp-sender to start broadcasting the ulyana
image.
7. For each computer, choose from pdmenu the option to mount  the ulyana
image
    and copy files inside into an LVM volume, completing the ulyana
installation.

Some computers may go wrong after some use. A student should be able to
choose to boot the computer using pxe and repair/re-initialize his own
computer
using options in the pdmenu (this time using wget instead of udp-receive).
This may happen without requiring the teacher to pay attention while he (me)
gives the lecture and while other students are using their ulyana in the
classroom.

This computer classroom may boot into windows in other class hours.
There is already an existing DHCP service running all the time,
and It is best not to disrupt this service. So my pxe server should be a
proxy server,
which only provides boot-related files but does not hand out IP's.

Actually I have created a customized version of grml with manually installed
pxelinux, dnsmasq, udpcast, pdmenu, gdisk, ntfs-3g, apache2, ...
and have tested individual steps separately. So my problem is kind of
solved now.

Still it would be nice if grml comes with all of these pre-installed and
even
with some sample pdmenu script so that computer lab admins (in Taiwan's
high schools and primary schools these are mainly busy computer teachers)
can see that GNU/Linux and in particular grml can save a lot of work for
them.
Maybe even helping them distributing windows images (yuk).

I would also like to take this opportunity to thank you all contributors
for your great work on grml! It has saved me on several occasions
since I started using it around 2017. I have it in each and every one of
my bootable usb flash drive. I carry 3 of them with me all the time.
They give me great peace of mind :-)

--
顧好自己的隱私， 快停止網路裸奔！
請搜尋『貴哥的節慾手機』
Greg Chao-Kuei Hung 洪朝貴

PGP Key ID: 4096R/5828A7A7
Fingerprint: 67AF B5AB 5242 3E99 16D7  EAF8 A94D 2C92 5828 A7A7


gilberto dos santos alves <gsavix at gmail.com> 於 2020年10月29日 週四 上午7:05寫道：

> if we could see a use case explained with details, it will be more easy
> for opinions. regards.
>
> Em qua, 28 de out de 2020 14:25, Michael Prokop <mika at grml.org> escreveu:
>
>> Hi,
>>
>> * 洪朝貴 [Sat Oct 24, 2020 at 04:00:59PM +0800]:
>>
>> > Is it possible to replace isc dhcp server with dnsmasq for use with
>> > grml-terminalserver?
>> > There is an existing dhcp server in my environment that I cannot touch
>> > and therefore I need to set up a proxy dhcp server for
>> > distributing only pxe-related files but not ip addresses like this:
>> > https://www.theurbanpenguin.com/pxelinux-using-proxy-dhcp/
>> > Dnsmasq can do it but isc-dhcp-server does not seem to have this option.
>> > Thanks!
>>
>> Well, you can of course use dnsmasq instead of isc-dhcp-server in
>> your environment. But if you're asking for out-of-the-box support
>> within the grml-terminalserver user interface, then that's something
>> someone would need to implement yet. :)
>>
>> I'm not *yet* sure we'd want to use dnsmasq instead of
>> isc-dhcp-server by default, this would need some further research
>> regarding possible drawbacks, package dependency changes,.... One of
>> the major drawbacks of dnsmasq IMO is, that you need to pretty much
>> always *restart* it - instead of reload without real downtime - for
>> most of any config changes, like adding a new host. This shouldn't
>> be much of a problem for grml-terminalserver itself though, while
>> the proxydhcp feature sounds like a good argument in favor of
>> dnsmasq for grml-terminalserver. Any further opinions?
>>
>> regards
>> -mika-
>> _______________________________________________
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>
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