Restructure and fix and improve docs and manpages.

This commit is contained in:
Darko Poljak 2016-06-17 21:28:16 +02:00
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cdist-best-practice(7)
======================
NAME
----
cdist-best-practice - Practices used in real environments
Nico Schottelius <nico-cdist--@--schottelius.org>
PASSWORDLESS CONNECTIONS
------------------------
It is recommended to run cdist with public key authentication.
This requires a private/public key pair and the entry
"PermitRootLogin without-password" in the sshd server.
See sshd_config(5) and ssh-keygen(1).
SPEEDING UP SSH CONNECTIONS
---------------------------
When connecting to a new host, the initial delay with ssh connections
is pretty big. You can work around this by
"sharing of multiple sessions over a single network connection"
(quote from ssh_config(5)). The following code is suitable for
inclusion into your ~/.ssh/config::
Host *
ControlPath ~/.ssh/master-%l-%r@%h:%p
ControlMaster auto
ControlPersist 10
SPEEDING UP SHELL EXECUTION
----------------------------
On the source host, ensure that /bin/sh is *not* bash: bash is quite slow for
script execution. Instead, you could use dash after installing it::
ln -sf /bin/dash /bin/sh
MULTI MASTER OR ENVIRONMENT SETUPS
----------------------------------
If you plan to distribute cdist among servers or use different
environments, you can do so easily with the included version
control git. For instance if you plan to use the typical three
environments production, integration and development, you can
realise this with git branches::
# Go to cdist checkout
cd /path/to/cdist
# Create branches
git branch development
git branch integration
git branch production
# Make use of a branch, for instance production
git checkout production
Similar if you want to have cdist checked out at multiple machines,
you can clone it multiple times::
machine-a % git clone git://your-git-server/cdist
machine-b % git clone git://your-git-server/cdist
SEPERATING WORK BY GROUPS
-------------------------
If you are working with different groups on one cdist-configuration,
you can delegate to other manifests and have the groups edit only
their manifests. You can use the following snippet in
**conf/manifests/init**::
# Include other groups
sh -e "$__manifest/systems"
sh -e "$__manifest/cbrg"
MAINTAINING MULTIPLE CONFIGURATIONS
-----------------------------------
When you need to manage multiple sites with cdist, like company_a, company_b
and private for instance, you can easily use git for this purpose.
Including a possible common base that is reused across the different sites::
# create branches
git branch company_a company_b common private
# make stuff for company a
git checkout company_a
# work, commit, etc.
# make stuff for company b
git checkout company_b
# work, commit, etc.
# make stuff relevant for all sites
git checkout common
# work, commit, etc.
# change to private and include latest common stuff
git checkout private
git merge common
The following **.git/config** is taken from a a real world scenario::
# Track upstream, merge from time to time
[remote "upstream"]
url = git://git.schottelius.org/cdist
fetch = +refs/heads/*:refs/remotes/upstream/*
# Same as upstream, but works when being offline
[remote "local"]
fetch = +refs/heads/*:refs/remotes/local/*
url = /home/users/nico/p/cdist
# Remote containing various ETH internal branches
[remote "eth"]
url = sans.ethz.ch:/home/services/sans/git/cdist-eth
fetch = +refs/heads/*:refs/remotes/eth/*
# Public remote that contains my private changes to cdist upstream
[remote "nico"]
url = git.schottelius.org:/home/services/git/cdist-nico
fetch = +refs/heads/*:refs/remotes/nico/*
# The "nico" branch will be synced with the remote nico, branch master
[branch "nico"]
remote = nico
merge = refs/heads/master
# ETH stable contains rock solid configurations used in various places
[branch "eth-stable"]
remote = eth
merge = refs/heads/stable
Have a look at git-remote(1) to adjust the remote configuration, which allows
MULTIPLE DEVELOPERS WITH DIFFERENT TRUST
----------------------------------------
If you are working in an environment that requires different people to
work on the same configuration, but having different privileges, you can
implement this scenario with a gateway host and sudo:
- Create a dedicated user (for instance **cdist**)
- Setup the ssh-pubkey for this user that has the right to configure all hosts
- Create a wrapper to update the cdist configuration in ~cdist/cdist
- Allow every developer to execute this script via sudo as the user cdist
- Allow run of cdist as user cdist on specific hosts on a per user/group base
- f.i. nico ALL=(ALL) NOPASSWD: /home/cdist/bin/cdist config hostabc
For more details consult sudoers(5)
TEMPLATING
----------
* create directory files/ in your type (convention)
* create the template as an executable file like files/basic.conf.sh, it will output text using shell variables for the values
.. code-block:: sh
#!/bin/sh
# in the template, use cat << eof (here document) to output the text
# and use standard shell variables in the template
# output everything in the template script to stdout
cat << EOF
server {
listen 80;
server_name $SERVERNAME;
root $ROOT;
access_log /var/log/nginx/$SERVERNAME_access.log
error_log /var/log/nginx/$SERVERNAME_error.log
}
EOF
* in the manifest, export the relevant variables and add the following lines in your manifest:
.. code-block:: console
# export variables needed for the template
export SERVERNAME='test"
export ROOT='/var/www/test'
# render the template
mkdir -p "$__object/files"
"$__type/files/basic.conf.sh" > "$__object/files/basic.conf"
# send the rendered template
__file /etc/nginx/sites-available/test.conf \
--state present
--source "$__object/files/basic.conf"
TESTING A NEW TYPE
------------------
If you want to test a new type on a node, you can tell cdist to only use an
object of this type: Use the '--initial-manifest' parameter
with - (stdin) as argument and feed object into stdin
of cdist:
.. code-block:: sh
# Singleton type without parameter
echo __ungleich_munin_server | cdist --initial-manifest - munin.panter.ch
# Singleton type with parameter
echo __ungleich_munin_node --allow 1.2.3.4 | \
cdist --initial-manifest - rails-19.panter.ch
# Normal type
echo __file /tmp/stdintest --mode 0644 | \
cdist --initial-manifest - cdist-dev-01.ungleich.ch
OTHER CONTENT IN CDIST REPOSITORY
---------------------------------
Usually the cdist repository contains all configuration
items. Sometimes you may have additional resources that
you would like to store in your central configuration
repositiory (like password files from KeepassX,
Libreoffice diagrams, etc.).
It is recommended to use a subfolder named "non-cdist"
in the repository for such content: It allows you to
easily distinguish what is used by cdist and what not
and also to store all important files in one
repository.
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-tutorial(7) <cdist-tutorial.html>`_
COPYING
-------
Copyright \(C) 2011-2013 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-bootstrap(7)
==================
NAME
----
cdist-bootstrap - Setup cdist environment
Nico Schottelius <nico-cdist--@--schottelius.org>
INTRODUCTION
------------
This document describes the usual steps recommended for a new
cdist setup. It is recommended that you have read and understood
cdist-quickstart(7) before digging into this.
LOCATION
---------
First of all, you should think about where to store your configuration
database and who will be accessing or changing it. Secondly you have to
think about where to configure your hosts from, which may be a different
location.
For starters, having cdist (which includes the configuration database) on
your notebook should be fine.
Additionally an external copy of the git repository the configuration
relies on is recommended, for use as backup as well as to allow easy collaboration
with others.
For more sophisticated setups developing cdist configurations with multiple
people, have a look at cdist-best-practice(7).
SETUP WORKING DIRECTORY AND BRANCH
----------------------------------
I assume you have a fresh copy of the cdist tree in ~/cdist, cloned from
one of the official urls (see cdist-quickstart(7) if you don't).
Entering the command "git branch" should show you "* master", which indicates
you are on the **master** branch.
The master branch reflects the latest development of cdist. As this is the
development branch, it may or may not work. There are also version branches
available, which are kept in a stable state. Let's use **git branch -r**
to list all branches::
cdist% git branch -r
origin/1.0
origin/1.1
origin/1.2
origin/1.3
origin/1.4
origin/1.5
origin/1.6
origin/1.7
origin/2.0
origin/HEAD -> origin/master
origin/archive_shell_function_approach
origin/master
So **2.0** is the latest version branch in this example.
All versions (2.0.x) within one version branch (2.0) are compatible to each
other and won't break your configuration when updating.
It's up to you to decide which branch you want to base your own work on:
master contains more recent changes, newer types, but may also break.
The version branches are stable, but may lack the latest features.
Your decision can be changed later on, but may result in merge conflicts,
which you will need to solve.
Let's assume you want latest stuff and select the master branch as base for
your own work. Now it's time to create your branch, which contains your
local changes. I usually name it by the company/area I am working for:
ethz-systems, localch, customerX, ... But this is pretty much up to you.
In this tutorial I use the branch **mycompany**::
cdist% git checkout -b mycompany origin/master
Branch mycompany set up to track remote branch master from origin.
Switched to a new branch 'mycompany'
cdist-user% git branch
master
* mycompany
From now on, you can use git as usual to commit your changes in your own branch.
PUBLISHING THE CONFIGURATION
----------------------------
Usually a development machine like a notebook should be considered
temporary only. For this reason and to enable shareability, the configuration
should be published to another device as early as possible. The following
example shows how to publish the configuration to another host that is
reachable via ssh and has git installed::
# Create bare git repository on the host named "loch"
cdist% ssh loch "GIT_DIR=/home/nutzer/cdist git init"
Initialized empty Git repository in /home/nutzer/cdist/
# Add remote git repo to git config
cdist% git remote add loch loch:/home/nutzer/cdist
# Configure the mycompany branch to push to loch
cdist% git config branch.mycompany.remote loch
# Configure mycompany branch to push into remote master branch
cdist% git config branch.mycompany.merge refs/heads/master
# Push mycompany branch to remote branch master initially
cdist% git push loch mycompany:refs/heads/master
Now you have setup the git repository to synchronise the **mycompany**
branch with the **master** branch on the host **loch**. Thus you can commit
as usual in your branch and push out changes by entering **git push**.
UPDATING FROM ORIGIN
--------------------
Whenever you want to update your cdist installation, you can use git to do so::
# Update git repository with latest changes from origin
cdist% git fetch origin
# Update current branch with master branch from origin
cdist% git merge origin/master
# Alternative: Update current branch with 2.0 branch from origin
cdist% git merge origin/2.0
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-tutorial(7) <cdist-tutorial.html>`_
COPYING
-------
Copyright \(C) 2012 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-explorer(7)
=================
NAME
----
cdist-explorer - Explore the target systems
Nico Schottelius <nico-cdist--@--schottelius.org>
DESCRIPTION
-----------
Explorer are small shell scripts, which will be executed on the target
host. The aim of the explorer is to give hints to types on how to act on the
target system. An explorer outputs the result to stdout, which is usually
a one liner, but may be empty or multi line especially in the case of
type explorers.
There are general explorers, which are run in an early stage, and
type explorers. Both work almost exactly the same way, with the difference
that the values of the general explorers are stored in a general location and
the type specific below the object.
Explorers can reuse other explorers on the target system by calling
::
$__explorer/<explorer_name> (general and type explorer)
or
::
$__type_explorer/<explorer name> (type explorer).
In case of significant errors, the explorer may exit non-zero and return an
error message on stderr, which will cause cdist to abort.
You can also use stderr for debugging purposes while developing a new
explorer.
EXAMPLES
--------
A very simple explorer may look like this::
hostname
Which is in practise the **hostname** explorer.
A type explorer, which could check for the status of a package may look like this:
.. code-block:: sh
if [ -f "$__object/parameter/name" ]; then
name="$(cat "$__object/parameter/name")"
else
name="$__object_id"
fi
# Expect dpkg failing, if package is not known / installed
dpkg -s "$name" 2>/dev/null || exit 0
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-reference(7) <cdist-reference.html>`_
- `cdist-stages(7) <cdist-stages.html>`_
COPYING
-------
Copyright \(C) 2010-2014 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-hacker(7)
===============
NAME
----
cdist-hacker - How to get (stuff) into cdist
Nico Schottelius <nico-cdist--@--schottelius.org>
WELCOME
-------
Welcome dear hacker! I invite you to a tour of pointers to
get into the usable configuration mangament system, cdist.
The first thing to know is probably that cdist is brought to
you by people who care about how code looks like and who think
twice before merging or implementing a feature: Less features
with good usability are far better than the opposite.
REPORTING BUGS
--------------
If you believe you've found a bug and verified that it is
in the latest version, drop a mail to the cdist mailing list,
subject prefixed with "[BUG] " or create an issue on github.
CODING CONVENTIONS (EVERYWHERE)
-------------------------------
If something should be better done or needs to fixed, add the word FIXME
nearby, so grepping for FIXME gives all positions that need to be fixed.
Indention is 4 spaces (welcome to the python world).
HOW TO SUBMIT STUFF FOR INCLUSION INTO UPSTREAM CDIST
-----------------------------------------------------
If you did some cool changes to cdist, which you value as a benefit for
everybody using cdist, you're welcome to propose inclusion into upstream.
There are though some requirements to ensure your changes don't break others
work nor kill the authors brain:
- All files should contain the usual header (Author, Copying, etc.)
- Code submission must be done via git
- Do not add cdist/conf/manifest/init - This file should only be touched in your
private branch!
- Code to be included should be branched of the upstream "master" branch
- Exception: Bugfixes to a version branch
- On a merge request, always name the branch I should pull from
- Always ensure **all** manpages build. Use **./build man** to test.
- If you developed more than **one** feature, consider submitting them in
separate branches. This way one feature can already be included, even if
the other needs to be improved.
As soon as your work meets these requirements, write a mail
for inclusion to the mailinglist **cdist at cdist -- at -- l.schottelius.org**
or open a pull request at http://github.com/telmich/cdist.
HOW TO SUBMIT A NEW TYPE
------------------------
For detailled information about types, see cdist-type(7).
Submitting a type works as described above, with the additional requirement
that a corresponding manpage named man.text in asciidoc format with
the manpage-name "cdist-type__NAME" is included in the type directory
AND asciidoc is able to compile it (i.e. do NOT have to many "=" in the second
line).
Warning: Submitting "exec" or "run" types that simply echo their parameter in
**gencode** will not be accepted, because they are of no use. Every type can output
code and thus such a type introduces redundant functionality that is given by
core cdist already.
EXAMPLE GIT WORKFLOW
---------------------
The following workflow works fine for most developers::
# get latest upstream master branch
git clone https://github.com/telmich/cdist.git
# update if already existing
cd cdist; git fetch -v; git merge origin/master
# create a new branch for your feature/bugfix
cd cdist # if you haven't done before
git checkout -b documentation_cleanup
# *hack*
*hack*
# clone the cdist repository on github if you haven't done so
# configure your repo to know about your clone (only once)
git remote add github git@github.com:YOURUSERNAME/cdist.git
# push the new branch to github
git push github documentation_cleanup
# (or everything)
git push --mirror github
# create a pull request at github (use a browser)
# *fixthingsbecausequalityassurancefoundissuesinourpatch*
*hack*
# push code to github again
git push ... # like above
# add comment that everything should be green now (use a browser)
# go back to master branch
git checkout master
# update master branch that includes your changes now
git fetch -v origin
git diff master..origin/master
git merge origin/master
If at any point you want to go back to the original master branch, you can
use **git stash** to stash your changes away::
# assume you are on documentation_cleanup
git stash
# change to master and update to most recent upstream version
git checkout master
git fetch -v origin
git merge origin/master
Similar when you want to develop another new feature, you go back
to the master branch and create another branch based on it::
# change to master and update to most recent upstream version
git checkout master
git fetch -v origin
git merge origin/master
git checkout -b another_feature
(you can repeat the code above for as many features as you want to develop
in parallel)
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- git(1)
- git-checkout(1)
- git-stash(1)
COPYING
-------
Copyright \(C) 2011-2013 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-manifest(7)
=================
NAME
----
cdist-manifest - (Re-)Use types
Nico Schottelius <nico-cdist--@--schottelius.org>
DESCRIPTION
-----------
Manifests are used to define which objects to create.
Objects are instances of **types**, like in object oriented programming languages.
An object is represented by the combination of
**type + slash + object name**: **\__file/etc/cdist-configured** is an
object of the type **__file** with the name **etc/cdist-configured**.
All available types can be found in the **cdist/conf/type/** directory,
use **ls cdist/conf/type** to get the list of available types. If you have
setup the MANPATH correctly, you can use **man cdist-reference** to access
the reference with pointers to the manpages.
Types in manifests are used like normal command line tools. Let's have a look
at an example::
# Create object of type __package with the parameter state = absent
__package apache2 --state absent
# Same with the __directory type
__directory /tmp/cdist --state present
These two lines create objects, which will later be used to realise the
configuration on the target host.
Manifests are executed locally as a shell script using **/bin/sh -e**.
The resulting objects are stored in an internal database.
The same object can be redefined in multiple different manifests as long as
the parameters are exactly the same.
In general, manifests are used to define which types are used depending
on given conditions.
INITIAL AND TYPE MANIFESTS
--------------------------
Cdist knows about two types of manifests: The initial manifest and type
manifests. The initial manifest is used to define, which configurations
to apply to which hosts. The type manifests are used to create objects
from types. More about manifests in types can be found in cdist-type(7).
DEFINE STATE IN THE INITIAL MANIFEST
------------------------------------
The **initial manifest** is the entry point for cdist to find out, which
**objects** to configure on the selected host.
Cdist expects the initial manifest at **cdist/conf/manifest/init**.
Within this initial manifest you define, which objects should be
created on which host. To distinguish between hosts, you can use the
environment variable **__target_host**. Let's have a look at a simple
example::
__cdistmarker
case "$__target_host" in
localhost)
__directory /home/services/kvm-vm --parents yes
;;
esac
This manifest says: Independent of the host, always use the type
**__cdistmarker**, which creates the file **/etc/cdist-configured**,
with the timestamp as content.
The directory **/home/services/kvm-vm**, including all parent directories,
is only created on the host **localhost**.
As you can see, there is no magic involved, the manifest is simple shell code that
utilises cdist types. Every available type can be executed like a normal
command.
SPLITTING UP THE INITIAL MANIFEST
---------------------------------
If you want to split up your initial manifest, you can create other shell
scripts in **cdist/conf/manifest/** and include them in **cdist/conf/manifest/init**.
Cdist provides the environment variable **__manifest** to reference
the directory containing the initial manifest (see cdist-reference(7)).
The following example would include every file with a **.sh** suffix::
# Include *.sh
for manifest in $__manifest/*.sh; do
# And source scripts into our shell environment
. "$manifest"
done
DEPENDENCIES
------------
If you want to describe that something requires something else, just
setup the variable "require" to contain the requirements. Multiple
requirements can be added white space separated.
::
1 # No dependency
2 __file /etc/cdist-configured
3
4 # Require above object
5 require="__file/etc/cdist-configured" __link /tmp/cdist-testfile \
6 --source /etc/cdist-configured --type symbolic
7
8 # Require two objects
9 require="__file/etc/cdist-configured __link/tmp/cdist-testfile" \
10 __file /tmp/cdist-another-testfile
Above the "require" variable is only set for the command that is
immediately following it. Dependencies should always be declared that way.
On line 4 you can see that the instantion of a type "\__link" object needs
the object "__file/etc/cdist-configured" to be present, before it can proceed.
This also means that the "\__link" command must make sure, that either
"\__file/etc/cdist-configured" allready is present, or, if it's not, it needs
to be created. The task of cdist is to make sure, that the dependency will be
resolved appropriately and thus "\__file/etc/cdist-configured" be created
if necessary before "__link" proceeds (or to abort execution with an error).
If you really need to make all types depend on a common dependency, you can
export the "require" variable as well. But then, if you need to add extra
dependencies to a specific type, you have to make sure that you append these
to the globally already defined one.
::
# First of all, update the package index
__package_update_index
# Upgrade all the installed packages afterwards
require="__package_update_index" __package_upgrade_all
# Create a common dependency for all the next types so that they get to
# be executed only after the package upgrade has finished
export require="__package_upgrade_all"
# Ensure that lighttpd is installed after we have upgraded all the packages
__package lighttpd --state present
# Ensure that munin is installed after lighttpd is present and after all
# the packages are upgraded
require="$require __package/lighttpd" __package munin --state present
All objects that are created in a type manifest are automatically required
from the type that is calling them. This is called "autorequirement" in
cdist jargon.
You can find an more in depth description of the flow execution of manifests
in cdist-stages(7) and of how types work in cdist-type(7).
CREATE DEPENDENCIES FROM EXECUTION ORDER
-----------------------------------------
You can tell cdist to execute all types in the order in which they are created
in the manifest by setting up the variable CDIST_ORDER_DEPENDENCY.
When cdist sees that this variable is setup, the current created object
automatically depends on the previously created object.
It essentially helps you to build up blocks of code that build upon each other
(like first creating the directory xyz than the file below the directory).
OVERRIDES
---------
In some special cases, you would like to create an already defined object
with different parameters. In normal situations this leads to an error in cdist.
If you wish, you can setup the environment variable CDIST_OVERRIDE
(any value or even empty is ok) to tell cdist, that this object override is
wanted and should be accepted.
ATTENTION: Only use this feature if you are 100% sure in which order
cdist encounters the affected objects, otherwise this results
in an undefined situation.
If CDIST_OVERRIDE and CDIST_ORDER_DEPENDENCY are set for an object,
CDIST_ORDER_DEPENDENCY will be ignored, because adding a dependency in case of
overrides would result in circular dependencies, which is an error.
EXAMPLES
--------
The initial manifest may for instance contain the following code:
.. code-block:: sh
# Always create this file, so other sysadmins know cdist is used.
__file /etc/cdist-configured
case "$__target_host" in
my.server.name)
__directory /root/bin/
__file /etc/issue.net --source "$__manifest/issue.net
;;
esac
The manifest of the type "nologin" may look like this:
.. code-block:: sh
__file /etc/nologin --source "$__type/files/default.nologin"
This example makes use of dependencies:
.. code-block:: sh
# Ensure that lighttpd is installed
__package lighttpd --state present
# Ensure that munin makes use of lighttpd instead of the default webserver
# package as decided by the package manager
require="__package/lighttpd" __package munin --state present
How to override objects:
.. code-block:: sh
# for example in the inital manifest
# create user account foobar with some hash for password
__user foobar --password 'some_fancy_hash' --home /home/foobarexample
# ... many statements and includes in the manifest later ...
# somewhere in a conditionally sourced manifest
# (e.g. for example only sourced if a special application is on the target host)
# this leads to an error ...
__user foobar --password 'some_other_hash'
# this tells cdist, that you know that this is an override and should be accepted
CDIST_OVERRIDE=yes __user foobar --password 'some_other_hash'
# it's only an override, means the parameter --home is not touched
# and stays at the original value of /home/foobarexample
Dependencies defined by execution order work as following:
.. code-block:: sh
# Tells cdist to execute all types in the order in which they are created ...
export CDIST_ORDER_DEPENDENCY=on
__sample_type 1
require="__some_type_somewhere/id" __sample_type 2
__example_type 23
# Now this types are executed in the creation order until the variable is unset
unset CDIST_ORDER_DEPENDENCY
# all now following types cdist makes the order ..
__not_in_order_type 42
# how it works :
# this lines above are translated to:
__sample_type 1
require="__some_type_somewhere/id __sample_type/1" __sample_type 2
require="__sample_type/2" __example_type 23
__not_in_order_type 42
SEE ALSO
--------
- `cdist-tutorial(7) <cdist-tutorial.html>`_
- `cdist-type(7) <cdist-type.html>`_
COPYING
-------
Copyright \(C) 2010-2014 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-messaging(7)
==================
NAME
----
cdist-messaging - How the initial manifest and types can communication
Nico Schottelius <nico-cdist--@--schottelius.org>
DESCRIPTION
-----------
cdist has a simple but powerful way of allowing communication between
the initial manifest and types as well as types and types.
Whenever execution is passed from cdist to one of the
scripts described below, cdist generate 2 new temporary files
and exports the environment variables **__messages_in** and
**__messages_out** to point to them.
Before handing over the control, the content of the global message
file is copied into the file referenced by **$__messages_in**.
After cdist gained control back, the content of the file referenced
by **$__messages_out** is appended to the global message file.
This way overwriting any of the two files by accident does not
interfere with other types.
The order of execution is not defined unless you create dependencies
between the different objects (see cdist-manifest(7)) and thus you
can only react reliably on messages by objects that you depend on.
AVAILABILITY
------------
Messaging is possible between all **local** scripts:
- initial manifest
- type/manifest
- type/gencode-local
- type/gencode-remote
EXAMPLES
--------
When you want to emit a message use:
.. code-block:: sh
echo "something" >> "$__messages_out"
When you want to react on a message use:
.. code-block:: sh
if grep -q "^__your_type/object/id:something" "$__messages_in"; then
echo "I do something else"
fi
Some real life examples:
.. code-block:: sh
# Reacting on changes from block for keepalive
if grep -q "^__block/keepalive-vrrp" "$__messages_in"; then
echo /etc/init.d/keepalived restart
fi
# Reacting on changes of configuration files
if grep -q "^__file/etc/one" $__messages_in; then
echo 'for init in /etc/init.d/opennebula*; do $init restart; done'
fi
Restart sshd on changes
.. code-block:: sh
os="$(cat "$__global/explorer/os")"
case "$os" in
centos|redhat|suse)
restart="/etc/init.d/sshd restart"
;;
debian|ubuntu)
restart="/etc/init.d/ssh restart"
;;
*)
cat << eof >&2
Unsupported os $os.
If you would like to have this type running on $os,
you can either develop the changes and send a pull
request or ask for a quote at www.ungleich.ch
eof
exit 1
;;
esac
if grep -q "^__key_value/PermitRootLogin" "$__messages_in"; then
echo $restart
fi
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-manifest(7) <cdist-manifest.html>`_
- `cdist-reference(7) <cdist-reference.html>`_
- `cdist-type(7) <cdist-type.html>`_
COPYING
-------
Copyright \(C) 2013 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-quickstart(7)
===================
NAME
----
cdist-quickstart - Jump in and enjoy cdist
Nico Schottelius <nico-cdist--@--schottelius.org>
INTRODUCTION
------------
This tutorial is aimed at people learning cdist and shows
typical approaches as well as gives an easy start into
the world of configuration management.
This tutorial assumes you are configuring **localhost**, because
it is always available. Just replace **localhost** with your target
host for real life usage.
QUICK START - GET YOUR HANDS DIRTY NOW
--------------------------------------
For those who just want to configure a system with the
cdist configuration management and do not need (or want)
to understand everything.
Cdist uses **ssh** for communication and transportation
and usually logs into the **target host** as the
**root** user. So you need to configure the **ssh server**
of the target host to allow root logins: Edit
the file **/etc/ssh/sshd_config** and add one of the following
lines::
# Allow login only via public key
PermitRootLogin without-password
# Allow login via password and public key
PermitRootLogin yes
As cdist uses ssh intensively, it is recommended to setup authentication
with public keys::
# Generate pubkey pair as a normal user
ssh-keygen
# Copy pubkey over to target host
ssh-copy-id root@localhost
Have a look at ssh-agent(1) and ssh-add(1) on how to cache the password for
your public key. Usually it looks like this::
# Start agent and export variables
eval `ssh-agent`
# Add keys (requires password for every identity file)
ssh-add
At this point you should be able to **ssh root@localhost** without
re-entering the password. If something failed until here, ensure that
all steps went successfully and you have read and understood the
documentation.
As soon as you are able to login without password to localhost,
we can use cdist to configure it. You can copy and paste the following
code into your shell to get started and configure localhost::
# Get cdist
# Mirrors can be found on
# http://www.nico.schottelius.org/software/cdist/install/#index2h4
git clone git://git.schottelius.org/cdist
# Create manifest (maps configuration to host(s)
cd cdist
echo '__file /etc/cdist-configured' > cdist/conf/manifest/init
# Configure localhost in verbose mode
./bin/cdist config -v localhost
# Find out that cdist created /etc/cdist-configured
ls -l /etc/cdist-configured
That's it, you've successfully used cdist to configure your first host!
Continue reading the next sections, to understand what you did and how
to create a more sophisticated configuration.
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-tutorial(7) <cdist-tutorial.html>`_
COPYING
-------
Copyright \(C) 2011-2012 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-remote-exec-copy(7)
=========================
NAME
----
cdist-remote-exec-copy - How to use remote exec and copy
Nico Schottelius <nico-cdist--@--schottelius.org>
INTRO
-----
Cdist interacts with the target host in two ways:
- it executes code (__remote_exec)
- and it copies files (__remote_copy)
By default this is accomplished with ssh and scp respectively.
The default implementations used by cdist are::
__remote_exec: ssh -o User=root -q
__remote_copy: scp -o User=root -q
The user can override these defaults by providing custom implementations and
passing them to cdist with the --remote-exec and/or --remote-copy arguments.
For __remote_exec, the custom implementation must behave as if it where ssh.
For __remote_copy, it must behave like scp.
With this simple interface the user can take total control of how cdist
interacts with the target when required, while the default implementation
remains as simple as possible.
EXAMPLES
--------
See cdist/other/examples/remote/ for some example implementations.
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
COPYING
-------
Copyright \(C) 2011-2012 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-stages(7)
===============
NAME
----
cdist-stages - Stages used during configuration deployment
Nico Schottelius <nico-cdist--@--schottelius.org>
DESCRIPTION
-----------
Starting the execution of deployment with cdist, cdist passes
through different stages.
STAGE 1: TARGET INFORMATION RETRIEVAL
-------------------------------------
In this stage information is collected about the target host using so called
explorers. Every existing explorer is run on the target and the output of all
explorers are copied back into the local cache. The results can be used by
manifests and types.
STAGE 2: RUN THE INITIAL MANIFEST
---------------------------------
The initial manifest, which should be used for mappings of hosts to types,
is executed. This stage creates objects in a cconfig database that contains
the objects as defined in the manifest for the specific host. In this stage,
no conflicts may occur, i.e. no object of the same type with the same id may
be created, if it has different parameters.
STAGE 3: OBJECT INFORMATION RETRIEVAL
-------------------------------------
Every object is checked whether its type has explorers and if so, these are
executed on the target host. The results are transferred back
and can be used in the following stages to decide what changes need to be made
on the target to implement the desired state.
STAGE 4: RUN THE OBJECT MANIFEST
--------------------------------
Every object is checked whether its type has a executable manifest. The
manifest script may generate and change the created objects. In other words,
one type can reuse other types.
For instance the object __apache/www.example.org is of type __apache, which may
contain a manifest script, which creates new objects of type __file.
The newly created objects are merged back into the existing tree. No conflicts
may occur during the merge. A conflict would mean that two different objects
try to create the same object, which indicates a broken configuration.
STAGE 5: CODE GENERATION
------------------------
In this stage for every created object its type is checked for executable
gencode scripts. The gencode scripts generate the code to be executed on the
target on stdout. If the gencode executables fail, they must print diagnostic
messages on stderr and exit non-zero.
STAGE 6: CODE EXECUTION
-----------------------
For every object the resulting code from the previous stage is transferred to
the target host and executed there to apply the configuration changes.
STAGE 7: CACHE
--------------
The cache stores the information from the current run for later use.
SUMMARY
-------
If, and only if, all the stages complete without an errors, the configuration
will be applied to the target.
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-reference(7) <cdist-reference.html>`_
COPYING
-------
Copyright \(C) 2010-2012 Nico Schottelius, Steven Armstrong. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-troubleshooting(7)
========================
NAME
----
cdist-troubleshooting - Common problems and their solutions
Nico Schottelius <nico-cdist--@--schottelius.org>
ERROR IN MANIFEST IS NOT CONSIDERED AN ERROR BY CDIST
-----------------------------------------------------
Situation: You are executing other scripts from a manifest.
This script fails, but cdist does not recognise the error.
An example script would be something like this:
.. code-block:: sh
% cat ~/.cdist/manifest/init
"$__manifest/special"
% cat ~/.cdist/manifest/special
#!/bin/sh
echo "Here is an unclean exiting script"
somecommandthatdoesnotexist
echo "I continue here although previous command failed"
We can clearly see that **somecommandthatdoesnotexist**
will fail in ~/.cdist/manifest/special. But as the custom
script is not called with the -e flag (exit on failure) of shell,
it does not lead to an error. And thus cdist sees the exit 0
code of the last echo line instead of the failing command.
All scripts executed by cdist carry the -e flag.
To prevent the above from happening, there are three solutions available,
two of which can be used in the calling script:
.. code-block:: sh
# Execute as before, but abort on failure
sh -e "$__manifest/special"
# Source the script in our namespace, runs in a set -e environment:
. "$__manifest/special"
The third solution is to include a shebang header in every script
you write to use the -e flag:
.. code-block:: sh
% cat ~/.cdist/manifest/special
#!/bin/sh -e
...
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-tutorial(7) <cdist-tutorial.html>`_
COPYING
-------
Copyright \(C) 2013 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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cdist-tutorial(7)
=================
NAME
----
cdist-tutorial - A guided introduction into cdist
Nico Schottelius <nico-cdist--@--schottelius.org>
INTRODUCTION
------------
This document gives you a pointer on what to read in
which order and is thus a "guide to the right locations".
So in case you are just starting, just "begin at the beginning"
(Brave New World). You can see the target audience in [] brackets
after the description.
cdist-quickstart
New to cdist? Want to get your hands dirty? Read this. [beginner]
cdist-bootstrap
The comprehensive guide to your first cdist installation [beginner]
cdist-manifest
Learn how to define which hosts get which configurations [beginner]
cdist-type
Understand how types are working and created [intermediate]
cdist-best-practice
Hints from real life experience to help you to organise cdist [intermediate]
cdist-reference
The type, explorers and environment variables reference [intermediate]
cdist-explorer
Interested in getting more information about the target system? [intermediate]
cdist-stages
Understand the internal workflow of cdist. [advanced]
cdist-hacker
README, if you want to extend or modify cdist. [hacker]
SEE ALSO
--------
- `cdist(1) <../man1/cdist.html>`_
- `cdist-type(7) <cdist-type.html>`_
- `cdist-best-practice(7) <cdist-best-practice.html>`_
- `cdist-stages(7) <cdist-stages.html>`_
- Brave New World by Aldous Huxley
COPYING
-------
Copyright \(C) 2011-2012 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).

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@ -1,317 +0,0 @@
cdist-type(7)
=============
NAME
----
cdist-type - Functionality bundled
Nico Schottelius <nico-cdist--@--schottelius.org>
SYNOPSIS
--------
::
__TYPE ID --parameter value [--parameter value ...]
__TYPE --parameter value [--parameter value ...] (for singletons)
DESCRIPTION
-----------
Types are the main component of cdist and define functionality. If you
use cdist, you'll write a type for every functionality you would like
to use.
HOW TO USE A TYPE
-----------------
You can use types from the initial manifest or the type manifest like a
normal shell command:
.. code-block:: sh
# Creates empty file /etc/cdist-configured
__file /etc/cdist-configured --type file
# Ensure tree is installed
__package tree --state installed
A list of supported types can be found in the cdist-reference(7) manpage.
SINGLETON TYPES
---------------
If a type is flagged as a singleton, it may be used only
once per host. This is useful for types which can be used only once on a
system. Singleton types do not take an object name as argument.
Example:
.. code-block:: sh
# __issue type manages /etc/issue
__issue
# Probably your own type - singletons may use parameters
__myfancysingleton --colour green
HOW TO WRITE A NEW TYPE
-----------------------
A type consists of
- parameter (optional)
- manifest (optional)
- singleton (optional)
- explorer (optional)
- gencode (optional)
Types are stored below cdist/conf/type/. Their name should always be prefixed with
two underscores (__) to prevent collisions with other executables in $PATH.
To implement a new type, create the directory **cdist/conf/type/__NAME**.
DEFINING PARAMETERS
-------------------
Every type consists of required, optional and boolean parameters, which must
each be declared in a newline separated file in **parameter/required**,
**parameter/required_multiple**, **parameter/optional**,
**parameter/optional_multiple** and **parameter/boolean**.
Parameters which are allowed multiple times should be listed in
required_multiple or optional_multiple respectively. All other parameters
follow the standard unix behaviour "the last given wins".
If either is missing, the type will have no required, no optional, no boolean
or no parameters at all.
Default values for optional parameters can be predefined in
**parameter/default/<name>**.
Example:
.. code-block:: sh
echo servername >> cdist/conf/type/__nginx_vhost/parameter/required
echo logdirectory >> cdist/conf/type/__nginx_vhost/parameter/optional
echo loglevel >> cdist/conf/type/__nginx_vhost/parameter/optional
mkdir cdist/conf/type/__nginx_vhost/parameter/default
echo warning > cdist/conf/type/__nginx_vhost/parameter/default/loglevel
echo server_alias >> cdist/conf/type/__nginx_vhost/parameter/optional_multiple
echo use_ssl >> cdist/conf/type/__nginx_vhost/parameter/boolean
USING PARAMETERS
----------------
The parameters given to a type can be accessed and used in all type scripts
(e.g manifest, gencode, explorer). Note that boolean parameters are
represented by file existence. File exists -> True,
file does not exist -> False
Example: (e.g. in cdist/conf/type/__nginx_vhost/manifest)
.. code-block:: sh
# required parameter
servername="$(cat "$__object/parameter/servername")"
# optional parameter
if [ -f "$__object/parameter/logdirectory" ]; then
logdirectory="$(cat "$__object/parameter/logdirectory")"
fi
# optional parameter with predefined default
loglevel="$(cat "$__object/parameter/loglevel")"
# boolean parameter
if [ -f "$__object/parameter/use_ssl" ]; then
# file exists -> True
# do some fancy ssl stuff
fi
# parameter with multiple values
if [ -f "$__object/parameter/server_alias" ]; then
for alias in $(cat "$__object/parameter/server_alias"); do
echo $alias > /some/where/usefull
done
fi
INPUT FROM STDIN
----------------
Every type can access what has been written on stdin when it has been called.
The result is saved into the **stdin** file in the object directory.
Example use of a type: (e.g. in cdist/conf/type/__archlinux_hostname)
.. code-block:: sh
__file /etc/rc.conf --source - << eof
...
HOSTNAME="$__target_host"
...
eof
If you have not seen this syntax (<< eof) before, it may help you to read
about "here documents".
In the __file type, stdin is used as source for the file, if - is used for source:
.. code-block:: sh
if [ -f "$__object/parameter/source" ]; then
source="$(cat "$__object/parameter/source")"
if [ "$source" = "-" ]; then
source="$__object/stdin"
fi
....
WRITING THE MANIFEST
--------------------
In the manifest of a type you can use other types, so your type extends
their functionality. A good example is the __package type, which in
a shortened version looks like this:
.. code-block:: sh
os="$(cat "$__global/explorer/os")"
case "$os" in
archlinux) type="pacman" ;;
debian|ubuntu) type="apt" ;;
gentoo) type="emerge" ;;
*)
echo "Don't know how to manage packages on: $os" >&2
exit 1
;;
esac
__package_$type "$@"
As you can see, the type can reference different environment variables,
which are documented in cdist-reference(7).
Always ensure the manifest is executable, otherwise cdist will not be able
to execute it. For more information about manifests see cdist-manifest(7).
SINGLETON - ONE INSTANCE ONLY
-----------------------------
If you want to ensure that a type can only be used once per target, you can
mark it as a singleton: Just create the (empty) file "singleton" in your type
directory:
.. code-block:: sh
touch cdist/conf/type/__NAME/singleton
This will also change the way your type must be called:
.. code-block:: sh
__YOURTYPE --parameter value
As you can see, the object ID is omitted, because it does not make any sense,
if your type can be used only once.
THE TYPE EXPLORERS
------------------
If a type needs to explore specific details, it can provide type specific
explorers, which will be executed on the target for every created object.
The explorers are stored under the "explorer" directory below the type.
It could for instance contain code to check the md5sum of a file on the
client, like this (shortened version from the type __file):
.. code-block:: sh
if [ -f "$__object/parameter/destination" ]; then
destination="$(cat "$__object/parameter/destination")"
else
destination="/$__object_id"
fi
if [ -e "$destination" ]; then
md5sum < "$destination"
fi
WRITING THE GENCODE SCRIPT
--------------------------
There are two gencode scripts: **gencode-local** and **gencode-remote**.
The output of gencode-local is executed locally, whereas
the output of gencode-remote is executed on the target.
The gencode scripts can make use of the parameters, the global explorers
and the type specific explorers.
If the gencode scripts encounters an error, it should print diagnostic
messages to stderr and exit non-zero. If you need to debug the gencode
script, you can write to stderr:
.. code-block:: sh
# Debug output to stderr
echo "My fancy debug line" >&2
# Output to be saved by cdist for execution on the target
echo "touch /etc/cdist-configured"
VARIABLE ACCESS FROM THE GENERATED SCRIPTS
------------------------------------------
In the generated scripts, you have access to the following cdist variables
- __object
- __object_id
but only for read operations, means there is no back copy of this
files after the script execution.
So when you generate a script with the following content, it will work:
.. code-block:: sh
if [ -f "$__object/parameter/name" ]; then
name="$(cat "$__object/parameter/name")"
else
name="$__object_id"
fi
HINTS FOR TYPEWRITERS
----------------------
It must be assumed that the target is pretty dumb and thus does not have high
level tools like ruby installed. If a type requires specific tools to be present
on the target, there must be another type that provides this tool and the first
type should create an object of the specific type.
If your type wants to save temporary data, that may be used by other types
later on (for instance \__file), you can save them in the subdirectory
"files" below $__object (but you must create it yourself).
cdist will not touch this directory.
If your type contains static files, it's also recommended to place them in
a folder named "files" within the type (again, because cdist guarantees to
never ever touch this folder).
HOW TO INCLUDE A TYPE INTO UPSTREAM CDIST
-----------------------------------------
If you think your type may be useful for others, ensure it works with the
current master branch of cdist and have a look at cdist-hacker(7) on
how to submit it.
SEE ALSO
--------
- `cdist-explorer(7) <cdist-explorer.html>`_
- `cdist-hacker(7) <cdist-hacker.html>`_
- `cdist-stages(7) <cdist-stages.html>`_
- `cdist-tutorial(7) <cdist-tutorial.html>`_
COPYING
-------
Copyright \(C) 2011-2012 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).