[Dnsmasq-discuss] dhcp vendor-option and grub net_pxe_extensionspath

[Carl Karsten]

I am pondering something I am not sure I even want: I guess we can call it
a default option 209

Is this valid, reliable, predictable?

dhcp-option-force=209,"partman-auto/disk=/dev/sda"

dhcp-host=00:26:9e:03:9d:e5,set:negk,negk
dhcp-option-force=tag:negk,209,"partman-auto/disk=/dev/sdb"


The hope is ...sda except for the tag:negk case.

personally I only touch 20 machines a year, so setting up the extra 19
lines
is easy.  I like to understand my tools, and maybe someone with 100''s will
be interested in my setup.  probaly not ;)




On Sun, Apr 30, 2017 at 11:58 PM, Carl Karsten <carl at nextdayvideo.com>
wrote:

> woked - yay.
>
> dhcp-host=00:26:9e:03:9d:e5,set:negk,negk
> dhcp-option-force=tag:negk,209,"partman-auto/disk=/dev/sda"
>
> # grub/grub.cfg
> net_get_dhcp_option appends ${net_default_interface} 209 string
>
> menuentry "Install Ubuntu preseed" {
> set gfxpayload=keep
> linux /ubuntu-installer/amd64/linux gfxpayload=800x600x16,800x600 ---
> auto=true url=dc10b DEBCONF_DEBUG=5 tasks="" hostname=
> interface=${net_default_mac} ${appends}
> initrd /ubuntu-installer/amd64/initrd.gz
> }
>
> ~ # head /var/log/syslog
> May  1 04:30:40 kernel: [    0.000000] Command line:
> BOOT_IMAGE=/ubuntu-installer/amd64/linux gfxpayload=800x600x16,800x600
> --- auto=true url=dc10b DEBCONF_DEBUG=5 tasks= hostname=
> interface=00:26:9e:03:9d:e5 partman-auto/disk=/dev/sda
>
>
>
> On Fri, Apr 28, 2017 at 5:53 PM, Simon Kelley <simon at thekelleys.org.uk>
> wrote:
>
>> On 27/04/17 17:42, Carl Karsten wrote:
>> > I am looking for the syntax of dhcp vendor options, and then how to
>> > access them in grub-net.  I think.  maybe there is a better way.
>> >
>> > I pxe boot grub, which boots di (Debian Installer) and pass a preseed
>> file.
>> >
>> > I am trying to work out a nice way to pass host specific info to di
>> > example, most use:
>> > partman-auto/disk="/dev/sda"
>> > but one machine has an onboard ssd nvme which needs /dev/nvme0n1
>> >
>> > di will read values appended to the kernel boot line, so I can hard code
>> > it like this:
>> >
>> > menuentry "Install Ubuntu preseed" {
>> > set gfxpayload=keep
>> > linux /ubuntu-installer/amd64/linux gfxpayload=800x600x16,800x600 ---
>> > auto=true url=dc10b hostname= partman-auto/disk="/dev/nvme0n1"
>> > interface=${net_default_mac}
>> > initrd /ubuntu-installer/amd64/initrd.gz
>> > }
>> >
>> > interface=${net_default_mac} - use the nic that pxe booted.
>> >
>> > Now I get lost in conf options and syntax.  forgive me for making stuff
>> > up here, if it worked I wouldn't be asking for help.
>> >
>> > I am hoping for something like
>> > partman-auto/disk=$(net_pxe_extensionspath/disk}
>> >
>> > in dnsmasq conf:
>> > dhcp-host=40:8d:5c:7f:bb:90,,gator
>> >
>> > dhcp-option-force=host:gator,209,"disk=/dev/nvme0n1"
>> >
>>
>> Look for "tags" in the man page, in this case, set a tag in the
>> dhcp-host line (it can be the same as the hostname)
>>
>> dhcp-host=40:8d:5c:7f:bb:90,set:gator,gator
>>
>>
>> and make the option conditional on that tag
>>
>> dhcp-option-force=tag:gator,209,"disk=/dev/nvme0n1"
>>
>> >
>> > So yeah, how do I send random strings based on mac/hostname
>> See above
>>
>>
>> > and how do I read what was sent in grub?
>>
>> Set the "log-dhcp" flag in the dnsmasq configuration to get lots of
>> useful information.
>>
>> Cheers,
>>
>> Simon.
>>
>> >
>>
>>
>>
>> > --
>> > Carl K
>> >
>> >
>> >
>> > _______________________________________________
>> > Dnsmasq-discuss mailing list
>> > Dnsmasq-discuss at lists.thekelleys.org.uk
>> > http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>> >
>>
>>
>>
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>
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