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CFEngine 3 masterfiles

CFEngine 3 is a popular open source configuration management system. Its primary function is to provide automated configuration and maintenance of large-scale computer systems.

This repository is intended to provide a stable base policy for installations and upgrades, and is used by CFEngine 3.6 and newer.

Installation

The contents of this repository are intended to live in /var/cfengine/masterfiles or wherever $(sys.masterdir) points.

Use the convenience install target:

make install

to install only what's needed (without tests, only policies). By default it installs in /var/cfengine/masterfiles but you can override that easily:

make install DESTDIR=/my/other/install/directory

Setting up

First, review update.cf and def.cf. Most settings you need to change will live here.

update.cf

Synchronizing clients with the policy server happens here, in update.cf. Its main job is to copy all the files on the policy server (usually the hub) under $(sys.masterdir) (usually /var/cfengine/masterfiles) to the local host into $(sys.inputdir) (usually /var/cfengine/inputs).

This is a standalone policy file. You can actually run it with cf-agent -KI -f ./update.cf but if you don't understand what that command does, please hold off until you've gone through the CFEngine documentation. The contents of update.cf duplicate other things under lib sometimes, in order to be completely standalone.

When update.cf is broken, things go bonkers. CFEngine will try to run a backup failsafe.cf you can find at https://github.com/cfengine/core/blob/master/libpromises/failsafe.cf (that .cf file is written into the C code and can't be modified). If things get to that point, you probably have to look at why corrupted policies made it into production.

As is typical for CFEngine, the policy and the configuration are mixed. In update.cf you'll find some very useful settings. Keep referring to https://github.com/cfengine/masterfiles/blob/master/update.cf as you read this. We are skipping the nonessential ones.

How it works

There are 4 stages in update.cf. See the bundlesequence: after loading the configuration from update_def, we take these steps in order.

cfe_internal_dc_workflow

This step implements the auto-deployment of policies. See https://docs.cfengine.com/docs/master/guide-enterprise-cfengine-guide-version-control-policy.html and cfengine_internal_masterfiles_update below for details.

cfe_internal_update_policy

This step updates the policy files themselves. See https://github.com/cfengine/masterfiles/blob/master/update/update_policy.cf for the implementation details. Basically it's a check step that looks at $(sys.inputdir)/cf_promises_validated and compares it with the policy server's $(sys.masterdir)/cf_promises_validated. Then there's the actual copy, which happens only if the cf_promises_validated file was updated in the check step.

cfe_internal_update_processes

This step manages the running processes, ensuring cf-execd and cf-serverd and cf-monitord are running and doing some other tasks.

cfe_internal_update_bins

This step does a self-update of CFEngine. See the Enterprise documentation for details; this functionality is unsupported in CFEngine Community.

update.cf configuration

input_name_patterns

Change this variable to add more file extensions to the list copied from the policy server. By default this is a pretty sparse list.

masterfiles_perms_mode

Usually you want to leave this at 0600 meaning the inputs will be readable only by their owner.

cfengine_internal_masterfiles_update

Off by default.

Turn this on (set to any) to auto-deploy policies on the policy server, it has no effect on clients. See https://docs.cfengine.com/docs/master/guide-enterprise-cfengine-guide-version-control-policy.html for details on how to use it.

This may result in DATA LOSS.

cfengine_internal_encrypt_transfers

Off by default.

Turn this on (set to any) to encrypt your policy transfers.

Note it has a duplicate in def.cf, see below. If they are not synchronized, you will get unexpected behavior.

cfengine_internal_purge_policies

Off by default.

Turn this on (set to any) to delete any files in your $(sys.inputdir) that are not in the policy server's masterfiles.

This may result in DATA LOSS.

Note it has a duplicate in def.cf, see below. If they are not synchronized, you will get unexpected behavior.

def.cf

After update.cf is configured, you can configure the main def.cf policy.

This file is included by the main promises.cf and you can run that with cf-agent -KI -f ./promises.cf but as before, make sure you understand what this command does before using it.

Keep referring to https://github.com/cfengine/masterfiles/blob/master/def.cf as you read this.

How it works

def.cf has some crucial settings used by the rest of CFEngine. It's expected that users will edit it but won't normally change the rest of the masterfiles except in services or if they know it's necessary.

This is a simple CFEngine policy, so read on for configuring it.

def.cf configuration

domain

Set your domain to the right value. By default it's used for mail and to deduce your file access ACLs.

acl

The acl is crucial. This is used by every host, not just the policy server. Make sure you only allow hosts you want to allow.

trustkeysfrom

trustkeysfrom tells the policy server what hosts to trust for bootstrapping. As the comments say, empty it after your hosts have been bootstrapped to avoid unpleasant surprises.

services_autorun

Off by default.

Turn this on (set to any) to auto-load files in services/autorun and run bundles found that are tagged autorun. See https://github.com/cfengine/masterfiles/blob/master/services/autorun/hello.cf for a simple example of such a bundle.

cfengine_internal_rotate_logs

On by default. Rotates CFEngine's own logs. For the details, see the cfe_internal_log_rotation bundle in https://github.com/cfengine/masterfiles/blob/master/cfe_internal/CFE_cfengine.cf

cfengine_internal_encrypt_transfers

Duplicate of the one in update.cf. They should be set in unison or you will get unexpected behavior.

cfengine_internal_purge_policies

Duplicate of the one in update.cf. They should be set in unison or you will get unexpected behavior.

cfengine_internal_sudoers_editing_enable

Off by default. Only used on the CFEngine Enterprise hub.

Turn this on (set to any) to allow the hub to edit sudoers in order for the Apache user to run passwordless sudo cf-runagent (part of Mission Portal troubleshooting).

def.cf inventory control

The inventory is a cool new feature in 3.6.0. You can disable pieces of it (inventory modules) or the whole thing if you wish.

disable_inventory

This class is off by default (meaning the inventory is on by default). Here's the master switch to disable all inventory modules.

disable_inventory_lsb

LSB is the Linux Standard Base, see https://wiki.linuxfoundation.org/en/LSB

By default, this class is turned off (and the module is on) if the LSB executable /usr/bin/lsb_release can be found. This inventory module will populate inventory reports and variables for you with LSB details. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/lsb.cf

disable_inventory_dmidecode

By default, this class is turned off (and the module is on) if the executable /usr/sbin/dmidecode can be found. This inventory module will populate inventory reports and variables for you. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/any.cf

disable_inventory_LLDP

LLDP is a protocol for Link Layer Discovery. See http://en.wikipedia.org/wiki/Link_Layer_Discovery_Protocol

By default, this class is turned off (and the module is on) if the executable /usr/bin/lldpctl can be found. This inventory module will populate variables for you. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/any.cf

disable_inventory_package_refresh

By default, this class is turned off (and the module is on). This inventory module will populate the installed packages for you. On CFEngine Enterprise, the available packages will also be populated. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/any.cf

disable_inventory_mtab

By default, this class is turned off (and the module is on) if /etc/mtab exists. This inventory module will populate variables for you based on the mounted filesystems. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/any.cf

disable_inventory_fstab

By default, this class is turned off (and the module is on) if $(sys.fstab) (usually /etc/fstab or /etc/vfstab) exists. This inventory module will populate variables for you based on the defined filesystems. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/any.cf

disable_inventory_proc

By default, this class is turned off (and the module is on) if /proc is a directory. This inventory module will populate variables for you from some of the contents of /proc. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/any.cf

disable_inventory_cmdb

By default, this class is turned on (and the module is off).

Turn this on (set to any) to allow each client to load a me.json file from the server and load its contents. For details, see https://github.com/cfengine/masterfiles/blob/master/inventory/any.cf

promises.cf

How it works

promises.cf is your main run file. Keep referring to https://github.com/cfengine/masterfiles/blob/master/promises.cf as you read this.

promises.cf configuration

bundlesequence

Edit the bundlesequence to add any bundles you with. Consider using the services_autorun facility so you don't have to edit this at all.

BEWARE THAT ONLY VALID (KNOWN) BUNDLES CAN BE ADDED.

By default, the inventory modules, then internal hub modules, then Design Center sketches, then the autorun services, and finally internal management bundles are in the bundlesequence.

inputs

In order to find bundles, CFEngine needs to know where to look. This list defines what files are needed. Note there are several dynamic entries here, coming from other bundles. CFEngine will keep evaluating the inputs and bundlesequence until all the bundles are found and resolved.

Make sure to add any of your own services files here if you don't use the services_autorun facility, to ensure the bundles in them are found.

Unexpected behavior

Note that in this document, the term "unexpected behavior" has been used, so a definition would help.

Last year, a CFEngine user got hit by a flying frisbee while walking backwards through a revolving door. This year, he won 4 track events in the winter Olympics. That's unexpected behavior.

Further structure

  • cfe_internal: internal CFEngine policies you shouldn't modify or you will get unexpected behavior
  • controls: configuration of components, e.g. the cf-agent or cf-serverd, beyond what def.cf can offer
  • def.cf: defaults you can and should configure, see above
  • inventory: inventory modules (loaded before anything else to discover facts about the system) live here; see above
  • lib: main library directory. You'll see 3.5 and 3.6 and 3.7 under it. These are the supported versions for masterfiles backwards compatibility.
  • promises.cf: main policy, you will need to configure this, see above
  • services: your site's policies go here
  • services_autorun: see above
  • sketches: Design Center installations use this; do not touch or you will get unexpected behavior
  • update and update.cf: functionality for updating inputs and CFEngine itself, see above. You shouldn't modify files under update or you will get unexpected behavior.

Contributing

Please see the CONTRIBUTING.md file.

The CFEngine masterfiles are under the MIT license, see https://github.com/cfengine/masterfiles/blob/master/LICENSE