Introduction
Cobbler manages:
- Distros (Debian, Ubuntu, RHEL, Rocky, CentOS)
- Profiles (distro + kernel options + preseed combinations)
- Systems (individual machines, identified by MAC)
- Repos (local apt/yum mirrors for acceleration)
- Integrated or external DHCP / DNS / TFTP
- REST API + CLI + Web UI
You describe a target system (MAC, hostname, IP, profile), Cobbler handles the rest: generates TFTP files, updates DHCP, serves preseed via HTTP.
Prerequisites
- VPS Debian / Ubuntu / Rocky
- Root access
- Provisioning LAN
Step 1: Install (Rocky / RHEL)
sudo dnf install -y epel-release
sudo dnf install -y cobbler cobbler-web tftp-server httpd
sudo systemctl enable --now cobblerd httpd tftp.socket
Step 2: Install (Debian / Ubuntu)
sudo apt update
sudo apt install -y cobbler cobbler-web debmirror apache2 tftpd-hpa
sudo systemctl enable --now cobblerd apache2 tftpd-hpa
Step 3: Base configuration
sudo nano /etc/cobbler/settings.yaml
server: 192.168.50.1
next_server: 192.168.50.1
default_password_crypted: "$6$rounds=4096$abc..."
manage_dhcp: 1
manage_dns: 0
manage_tftpd: 1
pxe_just_once: 1
nopxe_with_image: 1
sudo cobbler sync
sudo cobbler check
check lists actions needed to fix config (firewall, services).
Step 4: DHCP managed by Cobbler
sudo nano /etc/cobbler/dhcp.template
subnet 192.168.50.0 netmask 255.255.255.0 {
option routers 192.168.50.1;
option domain-name-servers 1.1.1.1;
range dynamic-bootp 192.168.50.100 192.168.50.200;
filename "/pxelinux.0";
next-server $next_server;
}
sudo cobbler sync
Step 5: Import a distro
sudo mkdir -p /mnt/iso
sudo mount -o loop debian-12.iso /mnt/iso
sudo cobbler import --path=/mnt/iso --name=debian-12 --arch=x86_64
sudo cobbler distro list
sudo cobbler profile list
Step 6: Add kickstart / preseed
Cobbler calls it "automated install template".
sudo nano /var/lib/cobbler/templates/debian-default.preseed
Put your standard preseed (see PXE tutorial).
Associate with profile:
sudo cobbler profile edit --name=debian-12 --autoinstall=debian-default.preseed
Step 7: Define a system
sudo cobbler system add \
--name=web01 \
--hostname=web01.example.com \
--profile=debian-12 \
--interface=eth0 \
--mac=AA:BB:CC:DD:EE:01 \
--ip-address=192.168.50.10 \
--netmask=255.255.255.0 \
--gateway=192.168.50.1 \
--dns-name=web01.example.com
Cobbler auto-generates:
- Static DHCP entry for this MAC
- Dedicated PXELINUX file
- Preseed accessible via HTTP with substituted variables
sudo cobbler sync
Step 8: Boot the server
Power on web01 in PXE mode. Cobbler recognizes it by MAC, serves PXE menu, installs Debian 12 with defined preseed.
After install:
sudo cobbler system edit --name=web01 --netboot-enabled=False
Prevents re-install on next reboot.
Step 9: Web UI
If cobbler-web is installed:
https://192.168.50.1/cobbler_web
Default creds: cobbler / cobbler (change immediately):
sudo htdigest /etc/cobbler/users.digest "Cobbler" cobbler
UI lets you:
- List distros, profiles, systems
- Edit a system
- Launch re-install
- View events
Step 10: Snippets and templating
Cobbler uses Cheetah as template engine. Preseeds can contain variables:
d-i netcfg/get_hostname string $hostname
d-i netcfg/get_domain string $dns_name
#if $getVar('install_docker', '0') == '1'
d-i pkgsel/include string docker.io docker-compose
#end if
Reusable snippets:
sudo nano /var/lib/cobbler/snippets/install-docker
d-i preseed/late_command string \
in-target curl -fsSL https://get.docker.com | sh
In preseed:
$SNIPPET('install-docker')
Step 11: Inherited profiles
sudo cobbler profile add --name=debian-12-web --parent=debian-12 --kickstart-meta="install_nginx=1 install_php=1"
Profile inherits from debian-12 and adds variables:
#if $getVar('install_nginx', '0') == '1'
d-i pkgsel/include string nginx
#end if
Step 12: REST API
Cobbler exposes XML-RPC and REST API.
curl -s http://192.168.50.1/cobbler_api \
-H "Content-Type: application/xml" \
-d '<methodCall><methodName>find_system</methodName><params><param><value><struct><member><name>name</name><value>web01</value></member></struct></value></param></params></methodCall>'
Easier with Python SDK:
import xmlrpc.client
server = xmlrpc.client.ServerProxy("http://192.168.50.1/cobbler_api")
token = server.login("cobbler", "cobbler")
systems = server.find_system({"profile": "debian-12"})
print(systems)
Troubleshooting
cobbler check returns errors
Each error has an action. Examples:
- "iptables is blocking PXE": open ports 67, 68 (UDP), 69 (UDP), 80, 443
- "SELinux is enabled": configure SELinux or disable for testing
Re-run cobbler check after fix.
"Distribution import failed"
Check ISO is mounted and readable:
sudo tail -f /var/log/cobbler/cobbler.log
PXE menu doesn't show
sudo cobbler sync
sudo systemctl restart dhcpd cobblerd
Preseed fails with "syntax error"
Cheetah templating error:
sudo cobbler validate-autoinstalls
Unwanted re-install
Cobbler reprovisions by default:
sudo cobbler system edit --name=web01 --netboot-enabled=False
Useful commands
sudo cobbler check
sudo cobbler sync
sudo cobbler distro list
sudo cobbler profile list
sudo cobbler system list
sudo cobbler system report --name=web01
sudo cobbler distro add --name=... --kernel=... --initrd=...
sudo cobbler profile add --name=... --distro=...
sudo cobbler system add --name=... --profile=... --mac=...
sudo cobbler system remove --name=web01
sudo cobbler system edit --name=web01 --netboot-enabled=True
sudo cobbler profile edit --name=debian-12 --autoinstall=my.preseed
sudo cobbler validate-autoinstalls
sudo cobbler buildiso --iso=/tmp/cobbler.iso
sudo tail -f /var/log/cobbler/cobbler.log
Conclusion
Cobbler simplifies large-scale Linux provisioning:
- All-in-one (DHCP, TFTP, preseed, profiles)
- API and Web UI
- Powerful templating with snippets
- Multi-OS, multi-arch
Limits:
- Complex initial setup
- Less maintained than MAAS or Foreman
- More Linux-oriented (limited Windows support OOB)
Going further:
- Combine with Ansible for post-install config
- For large infra, check Foreman (full lifecycle management)
- For managed MAAS, consider Ubuntu MAAS
Resources
- Official docs: https://cobbler.readthedocs.io
- GitHub: https://github.com/cobbler/cobbler
- Foreman (alternative): https://www.theforeman.org
- MAAS: https://maas.io