From 'Kickstart default PXELinux', can I determine if a host is a VM?

Stefan_Lasiewski · June 3, 2016, 12:16am

I would like to modify the 'Kickstart default PXELinux' template, so for
VMware hosts, to append the following two kernel parameters:

net.ifnames=0 biosdevname=0

I'm doing in an attempt to avoid the dreaded ‘consistent network device
naming’ problem with CentOS 7 & VMware, which creates strange network
device names like 'eno1234567', instead of the more familiar names like
'eth0' or 'eno1'.

From the 'Kickstart default PXELinux' template, can I determine if a
machine is virtual or not?

I added the following to Kickstart default PXELinux [1], but it doesn't
seem to work during the PXEboot. Probably because it relies on Puppet
facts, and nothing has been installed yet.

<%-# If VMware, than avoid ‘consistent network device naming’ by passing
kernel params. Else, use the default. -%>
<% if @host.facts['virtual'] == 'vmware' -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network
ks.sendmac net.ifnames=0 biosdevname=0
<% else -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network
ks.sendmac
<% end -%>

Is there another parameter the I can use instead?

-= Stefan

[1] https://github.com/theforeman/foreman/blob/7b966530c9ba48b2a37416465a3c9619f7143387/app/views/unattended/kickstart/PXELinux.erb

Dominic_Cleal2 · June 3, 2016, 7:26am

You could probably do:

<% if @host.compute_resource.nil? %>

to check if it's bare metal, or invert (unless @host …) for virtual.

···

On 03/06/16 01:16, Stefan Lasiewski wrote: > I would like to modify the 'Kickstart default PXELinux' template, so for > VMware hosts, to append the following two kernel parameters: > > > > net.ifnames=0biosdevname=0 > > > > > > I'm doing in an attempt to avoid the dreaded ‘consistent network device > naming’ problem with CentOS 7 & VMware, which creates strange network > device names like 'eno1234567', instead of the more familiar names like > 'eth0' or 'eno1'. > > From the 'Kickstart default PXELinux' template, can I determine if a > machine is virtual or not?

–
Dominic Cleal
dominic@cleal.org

Duncan_Innes · June 6, 2016, 11:31am

Bit late with this, but the syntax we use at the moment is:

<% if @host.operatingsystem.name == 'RedHat' and @osver == 7 and
(@host.mac.start_with?("00:50:56:") or @host.mac.start_with?("00:0c:29:"))
-%>
open-vm-tools.x86_64
-microcode_ctl
<% end -%>

during the package list section to add open-vm-tools to RHEL 7 builds when
necessary.

D

···

On Friday, 3 June 2016 01:16:45 UTC+1, Stefan Lasiewski wrote: > > I would like to modify the 'Kickstart default PXELinux' template, so for > VMware hosts, to append the following two kernel parameters: > > net.ifnames=0 biosdevname=0 > > > > I'm doing in an attempt to avoid the dreaded ‘consistent network device > naming’ problem with CentOS 7 & VMware, which creates strange network > device names like 'eno1234567', instead of the more familiar names like > 'eth0' or 'eno1'. > > From the 'Kickstart default PXELinux' template, can I determine if a > machine is virtual or not? > > I added the following to Kickstart default PXELinux [1], but it doesn't > seem to work during the PXEboot. Probably because it relies on Puppet > facts, and nothing has been installed yet. > > <%-# If VMware, than avoid ‘consistent network device naming’ by passing > kernel params. Else, use the default. -%> > <% if @host.facts['virtual'] == 'vmware' -%> > append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network > ks.sendmac net.ifnames=0 biosdevname=0 > <% else -%> > append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network > ks.sendmac > <% end -%> > > > > Is there another parameter the I can use instead? > > > -= Stefan > > [1] > https://github.com/theforeman/foreman/blob/7b966530c9ba48b2a37416465a3c9619f7143387/app/views/unattended/kickstart/PXELinux.erb >

dLobatog · June 3, 2016, 10:44am

Just as a warning, this wouldn't work if you're discovering hosts with
foreman_discovery as those won't have a Compute Resource even if they're
actually VMs.

···

On 06/03, Dominic Cleal wrote: > On 03/06/16 01:16, Stefan Lasiewski wrote: > > I would like to modify the 'Kickstart default PXELinux' template, so for > > VMware hosts, to append the following two kernel parameters: > > > > > > > net.ifnames=0biosdevname=0 > > > > > > > > > > > I'm doing in an attempt to avoid the dreaded ‘consistent network device > > naming’ problem with CentOS 7 & VMware, which creates strange network > > device names like 'eno1234567', instead of the more familiar names like > > 'eth0' or 'eno1'. > > > > From the 'Kickstart default PXELinux' template, can I determine if a > > machine is virtual or not? > > You could probably do: > > <% if @host.compute_resource.nil? %> > > to check if it's bare metal, or invert (unless @host ...) for virtual. >

–
Daniel Lobato Garcia

@dLobatog
blog.daniellobato.me
daniellobato.me

GPG: http://keys.gnupg.net/pks/lookup?op=get&search=0x7A92D6DD38D6DE30
Keybase: https://keybase.io/elobato

Stefan_Lasiewski · June 3, 2016, 6:36pm

Thanks guys.

The following syntax in 'Kickstart default PXELinux' seems to work:

<% if @host.operatingsystem.name == 'Fedora' and @host.operatingsystem.major
.to_i > 16 -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%>
ks.device=bootif network ks.sendmac
<% elsif @host.operatingsystem.name != 'Fedora' and @host.operatingsystem.
major.to_i >= 7 -%>
<%-# If VMware (Actually, any VM), than avoid ‘consistent network device
naming’ by passing kernel params. Else, use the default. -%>
<% if @host.compute_resource.nil? -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network
ks.sendmac net.ifnames=0 biosdevname=0
<% else -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network
ks.sendmac
<% end -%>
<% else -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%>
ksdevice=bootif network kssendmac
<% end -%>

On the downside, I think this would affect all virtual machines, including
things like KVM & oVirt, and I'd like to only fix this for VMware. But for
what I need to do now, this is sufficient.

I was also referred issue 229 in community templates which uses a different
method. See "Add a conditional to set net.ifnames=0 on the kernel command
line #229 " at https://github.com/theforeman/community-templates/pull/229 .

I also wonder if the <%= options %> value could be used for this. I'm not
sure if I should also modify the bootloader lines in the 'Kickstart
default' template, but modifying 'Kickstart default PXELinux' seems to be
good enough. I believe that if the 'net.ifnames=0 biosdevname=0' options
are used when loading PXElinux during install, they may persist on the OS
during any reboots.

Thanks,

-= Stefan

···

On Friday, June 3, 2016 at 3:44:38 AM UTC-7, Daniel Lobato wrote: > > On 06/03, Dominic Cleal wrote: > > On 03/06/16 01:16, Stefan Lasiewski wrote: > > > I would like to modify the 'Kickstart default PXELinux' template, so > for > > > VMware hosts, to append the following two kernel parameters: > > > > > > > > > > net.ifnames=0biosdevname=0 > > > > > > > > > > > > > > > > I'm doing in an attempt to avoid the dreaded ‘consistent network > device > > > naming’ problem with CentOS 7 & VMware, which creates strange network > > > device names like 'eno1234567', instead of the more familiar names > like > > > 'eth0' or 'eno1'. > > > > > > From the 'Kickstart default PXELinux' template, can I determine if a > > > machine is virtual or not? > > > > You could probably do: > > > > <% if @host.compute_resource.nil? %> > > > > to check if it's bare metal, or invert (unless @host ...) for virtual. > > > > Just as a warning, this wouldn't work if you're discovering hosts with > foreman_discovery as those won't have a Compute Resource even if they're > actually VMs. > > -- > Daniel Lobato Garcia > > @dLobatog > blog.daniellobato.me > daniellobato.me > > GPG: http://keys.gnupg.net/pks/lookup?op=get&search=0x7A92D6DD38D6DE30 > Keybase: https://keybase.io/elobato >

Stefan_Lasiewski · June 3, 2016, 8:29pm

Actually, I got that wrong. The following should actually be negated,
because @host.compute_resource.nil?returns true if the host DOESN'T have
a compute_resource so:

<% if @host.compute_resource.nil? -%>

The following syntax might be even more explicit and apply to VMware only.
This uses the @host.provider parameter.

<% if @host.operatingsystem.name == 'Fedora' and
@host.operatingsystem.major.to_i > 16 -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%>
ks.device=bootif network ks.sendmac
<% elsif @host.operatingsystem.name != 'Fedora' and
@host.operatingsystem.major.to_i >= 7 -%>
<%-# If host is VMware (If it uses the VMware provider), than pass kernel
params to avoid ‘consistent network device naming’. Else, use the default.
-%>
<% if @host.provider == 'VMware' -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network
ks.sendmac net.ifnames=0 biosdevname=0
<% else -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%> network
ks.sendmac
<% end -%>
<% else -%>
append initrd=<%= @initrd %> ks=<%= foreman_url('provision')%>
ksdevice=bootif network kssendmac
<% end -%>

Thanks,

-= Stefan

···

On Fri, Jun 3, 2016 at 11:36 AM, Stefan Lasiewski wrote:

Thanks guys.

The following syntax in ‘Kickstart default PXELinux’ seems to work:

<% if @host.operatingsystem.name == ‘Fedora’ and @host.operatingsystem.
major.to_i > 16 -%>
append initrd=<%= @initrd %> ks=<%= foreman_url(‘provision’)%>
ks.device=bootif network ks.sendmac
<% elsif @host.operatingsystem.name != ‘Fedora’ and @host.operatingsystem.
major.to_i >= 7 -%>
<%-# If VMware (Actually, any VM), than avoid ‘consistent network device
naming’ by passing kernel params. Else, use the default. -%>
<% if @host.compute_resource.nil? -%>
append initrd=<%= @initrd %> ks=<%= foreman_url(‘provision’)%> network
ks.sendmac net.ifnames=0 biosdevname=0
<% else -%>
append initrd=<%= @initrd %> ks=<%= foreman_url(‘provision’)%> network
ks.sendmac
<% end -%>
<% else -%>
append initrd=<%= @initrd %> ks=<%= foreman_url(‘provision’)%>
ksdevice=bootif network kssendmac
<% end -%>

On the downside, I think this would affect all virtual machines, including
things like KVM & oVirt, and I’d like to only fix this for VMware. But for
what I need to do now, this is sufficient.

I was also referred issue 229 in community templates which uses a
different method. See "Add a conditional to set net.ifnames=0 on the kernel
command line #229 " at
https://github.com/theforeman/community-templates/pull/229 .

I also wonder if the <%= options %> value could be used for this. I’m
not sure if I should also modify the bootloader lines in the ‘Kickstart
default’ template, but modifying ‘Kickstart default PXELinux’ seems to
be good enough. I believe that if the ‘net.ifnames=0 biosdevname=0’ options
are used when loading PXElinux during install, they may persist on the OS
during any reboots.

Thanks,

-= Stefan

On Friday, June 3, 2016 at 3:44:38 AM UTC-7, Daniel Lobato wrote:
On 06/03, Dominic Cleal wrote:
On 03/06/16 01:16, Stefan Lasiewski wrote:

I would like to modify the ‘Kickstart default PXELinux’ template, so
for
VMware hosts, to append the following two kernel parameters:
>
net.ifnames=0biosdevname=0
>
I’m doing in an attempt to avoid the dreaded ‘consistent network
device
naming’ problem with CentOS 7 & VMware, which creates strange network
device names like ‘eno1234567’, instead of the more familiar names
like

‘eth0’ or ‘eno1’.

From the ‘Kickstart default PXELinux’ template, can I determine if a
machine is virtual or not?

You could probably do:

<% if @host.compute_resource.nil? %>

to check if it’s bare metal, or invert (unless @host …) for virtual.
Just as a warning, this wouldn’t work if you’re discovering hosts with
foreman_discovery as those won’t have a Compute Resource even if they’re
actually VMs.

–
Daniel Lobato Garcia

@dLobatog
blog.daniellobato.me
daniellobato.me

GPG: http://keys.gnupg.net/pks/lookup?op=get&search=0x7A92D6DD38D6DE30
Keybase: https://keybase.io/elobato
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–
Stefan Lasiewski Email: stefanl@nersc.gov
Computer System Engineer III Email: slasiewski@lbl.gov
NERSC Data Infrastructure Group

National Energy Research Scientific Computing Center (NERSC
http://nersc.gov)
Lawrence Berkeley National Laboratory