5. Cobbler Configuration

There are two main settings files which are located per default at /etc/cobbler/:

  • The file settings.yaml is following YAML specification.
  • The file modules.conf is following INI specification.


Since we are cleaning a lot of tech-debt this may change over time. We are trying to find the balance which format is the best for us to handle in the code and the best for admins to handle in the config files.


If you are using allow_dynamic_settings, then the comments in the YAML file will vanish after the first change due to the fact that PyYAML doesn’t support comments (Source)

There are additional configuration file locations which need to follow the YAML Syntax. These are loaded from the include directory in the settings.yaml file. Any key specified in one of these files overwrites values from the main file.


When using allow_dynamic_settings the values are only persisted in the file settings.yaml. This may lead to a non expected behaviour after cobblerd restarts. This is a known issue.

5.1. Updates to the yaml-settings-file

Starting with 3.2.1:

  • We require the extension .yaml on our settings file to indicate the format of the file to editors and comply to standards of the YAML specification.
  • We require the usage of booleans in the format of True and False. If you have old integer style booleans with 1 and 0 this is fine but you may should convert them as soon as possible. We may decide in a future version to enforce our new way in a stricter manner. Automatic conversion is only done on a best-effort/available-resources basis.
  • We enforce the types of values to the keys. Additional unexpected keys will throw errors. If you have those used in Cobbler please report this in our issue tracker. We have decided to go this way to be able to rely on the existence of the values. This gives us the freedom to write less access checks to the settings without loosing stability.

5.2. settings.yaml

5.2.1. allow_duplicate_hostnames

If True, Cobbler will allow insertions of system records that duplicate the --dns-name information of other system records. In general, this is undesirable and should be left False.

default: False

5.2.2. allow_duplicate_ips

If True, Cobbler will allow insertions of system records that duplicate the IP address information of other system records. In general, this is undesirable and should be left False.

default: False

5.2.3. allow_duplicate_macs

If True, Cobbler will allow insertions of system records that duplicate the mac address information of other system records. In general, this is undesirable.

default: False

5.2.4. allow_dynamic_settings

If True, Cobbler will allow settings to be changed dynamically without a restart of the cobblerd daemon. You can only change this variable by manually editing the settings file, and you MUST restart cobblerd after changing it.

default: False

5.2.5. always_write_dhcp_entries

Always write DHCP entries, regardless if netboot is enabled.

default: False

5.2.6. anamon_enabled

By default, installs are not set to send installation logs to the Cobbler server. With anamon_enabled, automatic installation templates may use the pre_anamon snippet to allow remote live monitoring of their installations from the Cobbler server. Installation logs will be stored under /var/log/cobbler/anamon/.


This does allow an XML-RPC call to send logs to this directory, without authentication, so enable only if you are ok with this limitation.

default: False

5.2.7. auth_token_expiration

How long the authentication token is valid for, in seconds.

default: 3600

5.2.8. authn_pam_service

If using authn_pam in the modules.conf, this can be configured to change the PAM service authentication will be tested against.

default: "login"

5.2.9. autoinstall_snippets_dir

This is a directory of files that Cobbler uses to make templating easier. See the Wiki for more information. Changing this directory should not be required.

default: /var/lib/cobbler/snippets

5.2.10. autoinstall_templates_dir

This is a directory of files that Cobbler uses to make templating easier. See the Wiki for more information. Changing this directory should not be required.

default: /var/lib/cobbler/templates

5.2.11. bind_chroot_path

Set to path of bind chroot to create bind-chroot compatible bind configuration files. This should be automatically detected.

default: ""

5.2.12. bind_master

Set to the ip address of the master bind DNS server for creating secondary bind configuration files.


5.2.13. boot_loader_conf_template_dir

Location of templates used for boot loader config generation.

default: "/etc/cobbler/boot_loader_conf"

5.2.14. bootloaders_dir

The location where Cobbler searches for the bootloaders to copy into the web directory.

default: /var/lib/cobbler/loaders

5.2.15. grubconfig_dir

The location where Cobbler searches for GRUB configuration files.

default: /var/lib/cobbler/grub_config

5.2.16. build_reporting_*

Email out a report when Cobbler finishes installing a system.

  • enabled: Set to true to turn this feature on
  • email: Which addresses to email
  • ignorelist: TODO
  • sender: Optional
  • smtp_server: Used to specify another server for an MTA.
  • subject: Use the default subject unless overridden.


build_reporting_enabled: false
build_reporting_sender: ""
build_reporting_email: [ 'root@localhost' ]
build_reporting_smtp_server: "localhost"
build_reporting_subject: ""
build_reporting_ignorelist: [ "" ]

5.2.17. buildisodir

Used for caching the intermediate files for ISO-Building. You may want to use a SSD, a tmpfs or something which does not persist across reboots and can be easily thrown away but is also fast.

default: /var/cache/cobbler/buildiso

5.2.18. cache_enabled

If cache_enabled is True, a cache will keep converted records in memory to make checking them faster. This helps with use cases like writing out large numbers of records. There is a known issue with cache and remote XML-RPC API calls. If you will use Cobbler with config management or infrastructure-as-code tools such as Terraform, it is recommended to disable by setting to False.

default: True

5.2.19. cheetah_import_whitelist

Cheetah-language autoinstall templates can import Python modules. while this is a useful feature, it is not safe to allow them to import anything they want. This whitelists which modules can be imported through Cheetah. Users can expand this as needed but should never allow modules such as subprocess or those that allow access to the filesystem as Cheetah templates are evaluated by cobblerd as code.

  • random
  • re
  • time
  • netaddr

5.2.20. client_use_https

If set to True, all commands to the API (not directly to the XML-RPC server) will go over HTTPS instead of plain text. Be sure to change the http_port setting to the correct value for the web server.

default: False

5.2.21. client_use_localhost

If set to True, all commands will be forced to use the localhost address instead of using the above value which can force commands like cobbler sync to open a connection to a remote address if one is in the configuration and would traceback.

default: False

5.2.22. cobbler_master

Used for replicating the Cobbler instance.

default: ""

5.2.23. convert_server_to_ip

Convert hostnames to IP addresses (where possible) so DNS isn’t a requirement for various tasks to work correctly.

default: False

5.2.24. createrepo_flags

Default createrepo_flags to use for new repositories.

default: "-c cache -s sha"

5.2.25. default_autoinstall

If no autoinstall template is specified to profile add, use this template.

default: /var/lib/cobbler/autoinstall_templates/default.ks

5.2.26. default_name_*

Configure all installed systems to use these name servers by default unless defined differently in the profile. For DHCP configurations you probably do not want to supply this.


default_name_servers: []
default_name_servers_search: []

5.2.27. default_ownership

if using the authz_ownership module, objects created without specifying an owner are assigned to this owner and/or group.

  • admin

5.2.28. default_password_crypted

Cobbler has various sample automatic installation templates stored in /var/lib/cobbler/autoinstall_templates/. This controls what install (root) password is set up for those systems that reference this variable. The factory default is “cobbler” and Cobbler check will warn if this is not changed. The simplest way to change the password is to run openssl passwd -1 and put the output between the "".

default: "$1$mF86/UHC$WvcIcX2t6crBz2onWxyac."

5.2.29. default_template_type

The default template type to use in the absence of any other detected template. If you do not specify the template with #template=<template_type> on the first line of your templates/snippets, Cobbler will assume try to use the following template engine to parse the templates.


Over time we will try to deprecate and remove Cheetah3 as a template engine. It is hard to package and there are fewer guides then with Jinja2. Making the templating independent of the engine is a task which complicates the code. Thus, please try to use Jinja2. We will try to support a seamless transition on a best-effort basis.

Current valid values are: cheetah, jinja2

default: "cheetah"

5.2.30. default_virt_bridge

For libvirt based installs in Koan, if no virt-bridge is specified, which bridge do we try? For EL 4/5 hosts this should be xenbr0, for all versions of Fedora, try virbr0. This can be overridden on a per-profile basis or at the Koan command line though this saves typing to just set it here to the most common option.

default: xenbr0

5.2.31. default_virt_disk_driver

The on-disk format for the virtualization disk.

default: raw

5.2.32. default_virt_file_size

Use this as the default disk size for virt guests (GB).

default: 5

5.2.33. default_virt_ram

Use this as the default memory size for virt guests (MB).

default: 512

5.2.34. default_virt_type

If Koan is invoked without --virt-type and no virt-type is set on the profile/system, what virtualization type should be assumed?

Current valid values are:

  • xenpv
  • xenfv
  • qemu
  • vmware

NOTE: this does not change what virt_type is chosen by import.

default: xenpv

5.2.35. enable_gpxe

Enable gPXE booting? Enabling this option will cause Cobbler to copy the undionly.kpxe file to the TFTP root directory, and if a profile/system is configured to boot via gPXE it will chain load off pxelinux.0.


We now gPXE is not active anymore and try to transition the code, settings and guide we have to iPXE.

default: False

5.2.36. enable_menu

Controls whether Cobbler will add each new profile entry to the default PXE boot menu. This can be over-ridden on a per-profile basis when adding/editing profiles with --enable-menu=False/True. Users should ordinarily leave this setting enabled unless they are concerned with accidental reinstall from users who select an entry at the PXE boot menu. Adding a password to the boot menus templates may also be a good solution to prevent unwanted reinstallations.

default: True

5.2.37. http_port

Change this port if Apache is not running plain text on port 80. Most people can leave this alone.

default: 80

5.2.38. include

Include other configuration snippets with this regular expression. This is a list of folders.

default: [ "/etc/cobbler/settings.d/*.settings" ]

5.2.39. iso_template_dir

Folder to search for the ISO templates. These will build the boot-menu of the built ISO.

default: /etc/cobbler/iso

5.2.40. jinja2_includedir

This is a directory of files that Cobbler uses to include files into Jinja2 templates. Per default this settings is commented out.

default: /var/lib/cobbler/jinja2

5.2.41. kernel_options

Kernel options that should be present in every Cobbler installation. Kernel options can also be applied at the distro/profile/system level.

default: {}

5.2.42. ldap_*

Configuration options if using the authn_ldap module. See the Wiki for details. This can be ignored if you are not using LDAP for WebUI/XML-RPC authentication.


ldap_server: "ldap.example.com"
ldap_base_dn: "DC=example,DC=com"
ldap_port: 389
ldap_tls: true
ldap_anonymous_bind: true
ldap_search_bind_dn: ''
ldap_search_passwd: ''
ldap_search_prefix: 'uid='
ldap_tls_cacertfile: ''
ldap_tls_keyfile: ''
ldap_tls_certfile: ''

5.2.43. bind_manage_ipmi

When using the Bind9 DNS server, you can enable or disable if the BMCs should receive own DNS entries.

default: False

5.2.44. manage_dhcp

Set to True to enable Cobbler’s DHCP management features. The choice of DHCP management engine is in /etc/cobbler/modules.conf.

default: True

5.2.45. manage_dns

Set to True to enable Cobbler’s DNS management features. The choice of DNS management engine is in /etc/cobbler/modules.conf.

default: False

5.2.46. manage_*_zones

If using BIND (named) for DNS management in /etc/cobbler/modules.conf and manage_dns is enabled (above), this lists which zones are managed. See DNS configuration management for more information.


manage_forward_zones: []
manage_reverse_zones: []

5.2.47. manage_genders

Whether or not to manage the genders file. For more information on that visit: github.com/chaos/genders

default: False

5.2.48. manage_rsync

Set to True to enable Cobbler’s RSYNC management features.

default: False

5.2.49. manage_tftpd

Set to True to enable Cobbler’s TFTP management features. The choice of TFTP management engine is in /etc/cobbler/modules.conf.

default: True

5.2.50. mgmt_*

Cobbler has a feature that allows for integration with config management systems such as Puppet. The following parameters work in conjunction with --mgmt-classes and are described in further detail at Configuration Management Integrations.

mgmt_classes: []
    from_cobbler: true

5.2.51. next_server

If using Cobbler with manage_dhcp, put the IP address of the Cobbler server here so that PXE booting guests can find it. If you do not set this correctly, this will be manifested in TFTP open timeouts.


5.2.52. nsupdate_enabled

This enables or disables the replacement (or removal) of records in the DNS zone for systems created (or removed) by Cobbler.


There are additional settings needed when enabling this. Due to the limited number of resources, this won’t be done until 3.3.0. Thus please expect to run into troubles when enabling this setting.

default: False

5.2.53. nsupdate_log

The logfile to document what records are added or removed in the DNS zone for systems.


The functionality this settings is related to is currently not tested due to tech-debt. Please use it with caution. This note will be removed once we were able to look deeper into this functionality of Cobbler.

  • Required: No
  • Default: /var/log/cobbler/nsupdate.log

5.2.54. nsupdate_tsig_algorithm


The functionality this settings is related to is currently not tested due to tech-debt. Please use it with caution. This note will be removed once we were able to look deeper into this functionality of Cobbler.

  • Required: No
  • Default: hmac-sha512

5.2.55. nsupdate_tsig_key


The functionality this settings is related to is currently not tested due to tech-debt. Please use it with caution. This note will be removed once we were able to look deeper into this functionality of Cobbler.

  • Required: No
  • Default: []

5.2.56. power_management_default_type

Settings for power management features. These settings are optional. See Power Management to learn more.

Choices (refer to the fence-agents project for a complete list):

  • apc_snmp
  • bladecenter
  • bullpap
  • drac
  • ether_wake
  • ilo
  • integrity
  • ipmilan
  • ipmilanplus
  • lpar
  • rsa
  • virsh
  • wti

default: ipmilanplus

5.2.57. proxy_url_ext

External proxy which is used by the following commands: get-loaders, reposync, signature update



5.2.58. proxy_url_int

Internal proxy which is used by systems to reach Cobbler for kickstarts.

e.g.: proxy_url_int:

default: ""

5.2.59. puppet_auto_setup

If enabled, this setting ensures that puppet is installed during machine provision, a client certificate is generated and a certificate signing request is made with the puppet master server.

default: False

5.2.60. puppet_parameterized_classes

Choose whether to enable puppet parameterized classes or not. Puppet versions prior to 2.6.5 do not support parameters.

default: True

5.2.61. puppet_server

Choose a --server argument when running puppetd/puppet agent during autoinstall.

default: 'puppet'

5.2.62. puppet_version

Let Cobbler know that you’re using a newer version of puppet. Choose version 3 to use: ‘puppet agent’; version 2 uses status quo: ‘puppetd’.

default: 2

5.2.63. puppetca_path

Location of the puppet executable, used for revoking certificates.

default: "/usr/bin/puppet"

5.2.64. pxe_just_once

If this setting is set to True, Cobbler systems that pxe boot will request at the end of their installation to toggle the --netboot-enabled record in the Cobbler system record. This eliminates the potential for a PXE boot loop if the system is set to PXE first in it’s BIOS order. Enable this if PXE is first in your BIOS boot order, otherwise leave this disabled. See the manpage for --netboot-enabled.

default: True

5.2.65. nopxe_with_triggers

If this setting is set to True, triggers will be executed when systems will request to toggle the --netboot-enabled record at the end of their installation.

default: True

5.2.66. redhat_management_permissive

If using authn_spacewalk in modules.conf to let Cobbler authenticate against Satellite/Spacewalk’s auth system, by default it will not allow per user access into Cobbler Web and Cobbler XML-RPC. In order to permit this, the following setting must be enabled HOWEVER doing so will permit all Spacewalk/Satellite users of certain types to edit all of Cobbler’s configuration. these roles are: config_admin and org_admin. Users should turn this on only if they want this behavior and do not have a cross-multi-org separation concern. If you have a single org in your satellite, it’s probably safe to turn this on and then you can use CobblerWeb alongside a Satellite install.

default: False

5.2.67. redhat_management_server

This setting is only used by the code that supports using Uyuni/SUSE Manager/Spacewalk/Satellite authentication within Cobbler Web and Cobbler XML-RPC.

default: "xmlrpc.rhn.redhat.com"

5.2.68. redhat_management_key

Specify the default Red Hat authorization key to use to register system. If left blank, no registration will be attempted. Similarly you can set the --redhat-management-key to blank on any system to keep it from trying to register.

default: ""

5.2.69. register_new_installs

If set to True, allows /usr/bin/cobbler-register (part of the Koan package) to be used to remotely add new Cobbler system records to Cobbler. This effectively allows for registration of new hardware from system records.

default: False

5.2.70. remove_old_puppet_certs_automatically

When a puppet managed machine is reinstalled it is necessary to remove the puppet certificate from the puppet master server before a new certificate is signed (see above). Enabling the following feature will ensure that the certificate for the machine to be installed is removed from the puppet master server if the puppet master server is running on the same machine as Cobbler. This requires puppet_auto_setup above to be enabled

default: False

5.2.71. replicate_repo_rsync_options

Replication rsync options for repos set to override default value of -avzH.

default: "-avzH"

5.2.72. replicate_rsync_options

replication rsync options for distros, autoinstalls, snippets set to override default value of -avzH.

default: "-avzH"

5.2.73. reposync_flags

Flags to use for yum’s reposync. If your version of yum reposync does not support -l, you may need to remove that option.

default: "-l -n -d"

5.2.74. reposync_rsync_flags

Flags to use for rysync’s reposync. If archive mode (-a,–archive) is used then createrepo is not ran after the rsync as it pulls down the repodata as well. This allows older OS’s to mirror modular repos using rsync.

default: "-rltDv --copy-unsafe-links"

5.2.75. restart_*

When DHCP and DNS management are enabled, cobbler sync can automatically restart those services to apply changes. The exception for this is if using ISC for DHCP, then OMAPI eliminates the need for a restart. omapi, however, is experimental and not recommended for most configurations. If DHCP and DNS are going to be managed, but hosted on a box that is not on this server, disable restarts here and write some other script to ensure that the config files get copied/rsynced to the destination box. This can be done by modifying the restart services trigger. Note that if manage_dhcp and manage_dns are disabled, the respective parameter will have no effect. Most users should not need to change this.


restart_dns: true
restart_dhcp: true

5.2.76. run_install_triggers

Install triggers are scripts in /var/lib/cobbler/triggers/install that are triggered in autoinstall pre and post sections. Any executable script in those directories is run. They can be used to send email or perform other actions. They are currently run as root so if you do not need this functionality you can disable it, though this will also disable cobbler status which uses a logging trigger to audit install progress.

default: true

5.2.77. scm_track_*

enables a trigger which version controls all changes to /var/lib/cobbler when add, edit, or sync events are performed. This can be used to revert to previous database versions, generate RSS feeds, or for other auditing or backup purposes. Git and Mercurial are currently supported, but Git is the recommend SCM for use with this feature.


scm_track_enabled: false
scm_track_mode: "git"
scm_track_author: "cobbler <cobbler@localhost>"
scm_push_script: "/bin/true"

5.2.78. serializer_pretty_json

Sort and indent JSON output to make it more human-readable.

default: False

5.2.79. server

This is the address of the Cobbler server – as it is used by systems during the install process, it must be the address or hostname of the system as those systems can see the server. if you have a server that appears differently to different subnets (dual homed, etc), you need to read the --server-override section of the manpage for how that works.


5.2.80. sign_puppet_certs_automatically

When puppet starts on a system after installation it needs to have its certificate signed by the puppet master server. Enabling the following feature will ensure that the puppet server signs the certificate after installation if the puppet master server is running on the same machine as Cobbler. This requires puppet_auto_setup above to be enabled.

default: false

5.2.81. signature_path

The cobbler import workflow is powered by this file. Its location can be set with this config option.

default: /var/lib/cobbler/distro_signatures.json

5.2.82. signature_url

Updates to the signatures may happen more often then we have releases. To enable you to import new version we provide the most up to date signatures we offer on this like. You may host this file for yourself and adjust it for your needs.

default: https://cobbler.github.io/signatures/3.0.x/latest.json

5.2.83. tftpboot_location

This variable contains the location of the tftpboot directory. If this directory is not present Cobbler does not start.

Default: /srv/tftpboot

5.2.84. virt_auto_boot

Should new profiles for virtual machines default to auto booting with the physical host when the physical host reboots? This can be overridden on each profile or system object.

default: true

5.2.85. webdir

Cobbler’s web directory. Don’t change this setting – see the Wiki on “relocating your Cobbler install” if your /var partition is not large enough.

default: @@webroot@@/cobbler

5.2.86. webdir_whitelist

Directories that will not get wiped and recreated on a cobbler sync.


  - misc
  - web
  - webui
  - localmirror
  - repo_mirror
  - distro_mirror
  - images
  - links
  - pub
  - repo_profile
  - repo_system
  - svc
  - rendered
  - .link_cache

5.2.87. xmlrpc_port

Cobbler’s public XML-RPC listens on this port. Change this only if absolutely needed, as you’ll have to start supplying a new port option to Koan if it is not the default.

default: 25151

5.2.88. yum_distro_priority

The default yum priority for all the distros. This is only used if yum-priorities plugin is used. 1 is the maximum value. Tweak with caution.

default: true

5.2.89. yum_post_install_mirror

cobbler repo add commands set Cobbler up with repository information that can be used during autoinstall and is automatically set up in the Cobbler autoinstall templates. By default, these are only available at install time. To make these repositories usable on installed systems (since Cobbler makes a very convenient mirror) set this to True. Most users can safely set this to True. Users who have a dual homed Cobbler server, or are installing laptops that will not always have access to the Cobbler server may wish to leave this as False. In that case, the Cobbler mirrored yum repos are still accessible at http://cobbler.example.org/cblr/repo_mirror and YUM configuration can still be done manually. This is just a shortcut.

default: True

5.2.90. yumdownloader_flags

Flags to use for yumdownloader. Not all versions may support --resolve.

default: "--resolve"

5.3. modules.conf

If you have own custom modules which are not shipped with Cobbler directly you may have additional sections here.

5.3.1. authentication

What users can log into the WebUI and Read-Write XML-RPC?


  • authn_denyall – no one (default)
  • authn_configfile – use /etc/cobbler/users.digest (for basic setups)
  • authn_passthru – ask Apache to handle it (used for kerberos)
  • authn_ldap – authenticate against LDAP
  • authn_spacewalk – ask Spacewalk/Satellite (experimental)
  • authn_pam – use PAM facilities
  • authn_testing – username/password is always testing/testing (debug)
  • (user supplied) – you may write your own module

WARNING: this is a security setting, do not choose an option blindly.

For more information:

default: authn_configfile

5.3.2. authorization

Once a user has been cleared by the WebUI/XML-RPC, what can they do?


  • authz_allowall – full access for all authenticated users (default)
  • authz_ownership – use users.conf, but add object ownership semantics
  • (user supplied) – you may write your own module

WARNING: this is a security setting, do not choose an option blindly. If you want to further restrict Cobbler with ACLs for various groups, pick authz_ownership. authz_allowall does not support ACLs. Configuration file does but does not support object ownership which is useful as an additional layer of control.

For more information:

default: authz_allowall

5.3.3. dns

Chooses the DNS management engine if manage_dns is enabled in /etc/cobbler/settings.yaml, which is off by default.


  • manage_bind – default, uses BIND/named
  • manage_dnsmasq – uses dnsmasq, also must select dnsmasq for DHCP below
  • manage_ndjbdns – uses ndjbdns

NOTE: More configuration is still required in /etc/cobbler

For more information see DNS configuration management.

default: manage_bind

5.3.4. dhcp

Chooses the DHCP management engine if manage_dhcp is enabled in /etc/cobbler/settings.yaml, which is off by default.


  • manage_isc – default, uses ISC dhcpd
  • manage_dnsmasq – uses dnsmasq, also must select dnsmasq for DNS above

NOTE: More configuration is still required in /etc/cobbler

For more information see DHCP Management.

default: manage_isc

5.3.5. tftpd

Chooses the TFTP management engine if manage_tftpd is enabled in /etc/cobbler/settings.yaml, which is on by default.


  • manage_in_tftpd – default, uses the system’s TFTP server
  • manage_tftpd_py – uses Cobbler’s TFTP server

default: manage_in_tftpd