Remove and stop FOG to act as a DHCP server

msi

Hi,
Initially, when we started to use fog, we didn’t have any existing DHCP server. Therefore, we made FOG it self to act as a DHCP server. Now, we decided to have our own Cisco base DHCP server. How can I stop FOG to act as a DHCP server? What additional step we should take to continue use our FOG? Do we have to put any configuration to Cisco router, switch, firewall, and LAN Controller? We’re using CentOS and 1.4.2 FOG version.

Sebastian Roth

@msi As we don’t know your CentOS version it’s a bit of a guess. Older versions use systemv init and with centos there is/was a tool called chkconfig to manage (start, stop, disable, enable) services - see here. With recent versions like CentOS 7 you’d use systemd tools:

sudo systemctl stop dhcpd
sudo systemctl disable dhcpd

Wayne Workman

You’ll also want to turn off DHCP in the fog config file, otherwise it’ll just turn back on the next time you update. Here: /opt/fog/.fogsettings look for dodhcp and set it to ='N'

msi

@wayne-workman @Sebastian-Roth Is there any configuration we need do in our DHCP server. We use Cisco DHCP server according to our network engineer.

george1421

@msi Once you have the fog dhcp server disabled and the service stopped, then you can use your cisco dhcp server, no problem. You will need to configure it to send dhcp option 66 {next-server} which is the IP address of your fog server. And then configure dhcp option 67 {boot-file} to either undionly.kpxe for bios (legacy) systems or ipxe.efi for uefi based systems. If you have a mixed environment (uefi and bios) systems then you will need to configure the cisco dhcp server to send the correct {boot-file} based on the pxe booting client. This is done by the dhcp server watching the Arch type that is sent in the dhcp discover packet.

If your dhcp server isn’t capable of dynamically sending the right pxe boot-file, then you still have some luck, you can install dnsmasq on the fog server and have it supply only the {next-server} and {boot-file} dhcp options for the pxe booting clients. The main dhcp server is still responsible for IP address assignments and the fog server is responsible for sending the pxe information.

msi

Hi,
Thank you for all of your contribution. I made the changes, but it didn’t work. Below is our DHCP configuration on Cisco Switch Version 12.2 (55)SE5

ip dhcp pool fog
network 192.168.1.0 255.255.255.0
bootfile ipxe.efi
next-server 192.168.1.230
default-router 192.168.1.1
dns-server 192.168.1.15 192.168.1.16
domain-name xcel-domain.local
option 66 ip 192.168.1.230
option 67 ascii ipxe.efi
lease infinite

Also, is it possible to have both legacy and uefi boot. If yes, how?

george1421

@msi Well we have two directions to move in here.

Debug what is wrong with your cisco setup.
Because you asked can we support both, change plans a bit to support both.

Option 2 would give you the most flexibility.

george1421

@msi So lets work with option 2. We can go back to option 1 if we run into a road block with option 2.

For option 2:

Remove the next server and boot file entries from your cisco router. Also remove dhcp options 66 and 67 from your dhcp server. We ar e going to use dnsmasq to provide these dynamic boot file names.
Follow my posts here to download and compile dnsmasq version 2.76 (actually 2.77 has been released and if you want to attempt that the instructions should be the same).
Install dnsmasq on your fog server using the ltsp.conf file listed in that post. Don’t forget to update the fog server IP every place in that file (there are quite a few).
Start the dnsmasq service and pxe boot a target computer on the same vlan as your fog server. If your pxe client computers are going to be pxe booting on a different subnet than your fog server you will need to add your fog server listed last in your dhcp-helper / dhcp-relay service on your vlan router.

msi

@george1421 whats option 2 is for? did you mean ipxe.efi? We are trying to find the problem with Cisco configuration. So far no luck. By the way, we have install new fog with latest 1.4.4, and deiced to decommission the existing one by backing up.

msi

@george1421 I am sorry that I am asking a lot. Can you tell me more about how to configure dnsmasq? I heard about before and failed to configure it in right way when I tried to use cobbler.

Sebastian Roth

@msi This is what George is referring to: https://forums.fogproject.org/topic/8725/compiling-dnsmasq-2-76-if-you-need-uefi-support

He provided instructions on how to compile and configure dnsmasq… As a starter you could skip the compile step and install dnsmasq from your official package repository sudo yum install dnsmasq. When you get this up and running you can still go ahead, save the config, purge/uninstall dnsmasq and compile the latest version as suggested because it has fixed UEFI/BIOS support.

george1421

@msi said in Remove and stop FOG to act as a DHCP server:

@george1421 I am sorry that I am asking a lot. Can you tell me more about how to configure dnsmasq? I heard about before and failed to configure it in right way when I tried to use cobbler.

Wow, I apologize. I copied the link and never pasted in my post. Sebastian has the link in his post. That link contains the instructions on compiling dnsmasq 2.76 (minimum version required for dynamic bios/uefi support). It also contains a sample config file that does work.

Sebastian Roth

@msi Any news on this?

msi

@sebastian-roth I haven’t had chance to work on it. I will update you once I install dnsmasq. Thank you for checking on me.

msi

@sebastian-roth Hi Getting below error:
[root@localhost dnsmasq-2.76]# nano Makefile
[root@localhost dnsmasq-2.76]# sudo make install
/bin/sh: cc: command not found
/bin/sh: cc: command not found
Package dbus-1 was not found in the pkg-config search path.
Perhaps you should add the directory containing dbus-1.pc' to the PKG_CONFIG_PATH environment variable No package 'dbus-1' found Package libidn was not found in the pkg-config search path. Perhaps you should add the directory containing libidn.pc’
to the PKG_CONFIG_PATH environment variable
No package ‘libidn’ found
Package libnetfilter_conntrack was not found in the pkg-config search path.
Perhaps you should add the directory containing libnetfilter_conntrack.pc' to the PKG_CONFIG_PATH environment variable No package 'libnetfilter_conntrack' found Package nettle was not found in the pkg-config search path. Perhaps you should add the directory containing nettle.pc’
to the PKG_CONFIG_PATH environment variable
No package ‘nettle’ found
Package hogweed was not found in the pkg-config search path.
Perhaps you should add the directory containing hogweed.pc' to the PKG_CONFIG_PATH environment variable No package 'hogweed' found Package dbus-1 was not found in the pkg-config search path. Perhaps you should add the directory containing dbus-1.pc’
to the PKG_CONFIG_PATH environment variable
No package ‘dbus-1’ found
Package libidn was not found in the pkg-config search path.
Perhaps you should add the directory containing libidn.pc' to the PKG_CONFIG_PATH environment variable No package 'libidn' found Package libnetfilter_conntrack was not found in the pkg-config search path. Perhaps you should add the directory containing libnetfilter_conntrack.pc’
to the PKG_CONFIG_PATH environment variable
No package ‘libnetfilter_conntrack’ found
Package nettle was not found in the pkg-config search path.
Perhaps you should add the directory containing nettle.pc' to the PKG_CONFIG_PATH environment variable No package 'nettle' found Package hogweed was not found in the pkg-config search path. Perhaps you should add the directory containing hogweed.pc’
to the PKG_CONFIG_PATH environment variable
No package ‘hogweed’ found
/bin/sh: cc: command not found
/bin/sh: cc: command not found
make[1]: Entering directory /root/Downloads/dnsmasq-2.76/src' cc -Wall -W -O2 -DVERSION='"2.76"' -c cache.c make[1]: cc: Command not found make[1]: *** [cache.o] Error 127 make[1]: Leaving directory /root/Downloads/dnsmasq-2.76/src’
make: *** [all] Error 2
[root@localhost dnsmasq-2.76]# ls
Android.mk bld CHANGELOG CHANGELOG.archive contrib COPYING COPYING-v3 dbus dnsmasq.conf.example doc.html FAQ logo Makefile man po setup.html src trust-anchors.conf VERSION
[root@localhost dnsmasq-2.76]#

msi

@Sebastian-Roth @george1421
By the way I am using dnsmasq version 2.66 since my centos won’t let me upgrade to 2.76. I noticed that it is missing libdbus-1-dev libnetfilter-conntrack-dev idn libidn11-dev nettle-dev libval-dev dnssec-tools. So i ran yum install -y wget libdbus-1-dev libnetfilter-conntrack-dev idn libidn11-dev nettle-dev libval-dev dnssec-tools. I got below error:

No package libdbus-1-dev available.
No package libnetfilter-conntrack-dev available.
No package idn available.
No package libidn11-dev available.
No package nettle-dev available.
No package libval-dev available.
No package dnssec-tools available.
Nothing to do

george1421

@msi what version of linux are you using? You may need to install the developer tools to compile the code .

msi

@george1421 CentOS 7.3

george1421

@msi OK the instructions are for ubuntu, but for centos make sure the development tools are installed.
yum -y groupinstall "Development Tools"

msi

@george1421 development tools successfully installed. but still giving same error.

Remove and stop FOG to act as a DHCP server

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