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mgmt-documentation.pdf
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#mgmt
|
||||
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||||
<!--
|
||||
Mgmt
|
||||
Copyright (C) 2013-2016+ James Shubin and the project contributors
|
||||
Written by James Shubin <james@shubin.ca> and the project contributors
|
||||
|
||||
This program is free software: you can redistribute it and/or modify
|
||||
it under the terms of the GNU Affero General Public License as published by
|
||||
the Free Software Foundation, either version 3 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU Affero General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Affero General Public License
|
||||
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
-->
|
||||
|
||||
##mgmt by [James](https://ttboj.wordpress.com/)
|
||||
####Available from:
|
||||
####[https://github.com/purpleidea/mgmt/](https://github.com/purpleidea/mgmt/)
|
||||
|
||||
####This documentation is available in: [Markdown](https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md) or [PDF](https://pdfdoc-purpleidea.rhcloud.com/pdf/https://github.com/purpleidea/mgmt/blob/master/docs/documentation.md) format.
|
||||
|
||||
####Table of Contents
|
||||
|
||||
1. [Overview](#overview)
|
||||
2. [Project description - What the project does](#project-description)
|
||||
3. [Setup - Getting started with mgmt](#setup)
|
||||
4. [Features - All things mgmt can do](#features)
|
||||
* [Autoedges - Automatic resource relationships](#autoedges)
|
||||
* [Autogrouping - Automatic resource grouping](#autogrouping)
|
||||
* [Automatic clustering - Automatic cluster management](#automatic-clustering)
|
||||
* [Remote mode - Remote "agent-less" execution](#remote-agent-less-mode)
|
||||
* [Puppet support - write manifest code for mgmt](#puppet-support)
|
||||
5. [Resources - All built-in primitives](#resources)
|
||||
6. [Usage/FAQ - Notes on usage and frequently asked questions](#usage-and-frequently-asked-questions)
|
||||
7. [Reference - Detailed reference](#reference)
|
||||
* [Meta parameters](#meta-parameters)
|
||||
* [Graph definition file](#graph-definition-file)
|
||||
* [Command line](#command-line)
|
||||
8. [Examples - Example configurations](#examples)
|
||||
9. [Development - Background on module development and reporting bugs](#development)
|
||||
10. [Authors - Authors and contact information](#authors)
|
||||
|
||||
##Overview
|
||||
|
||||
The `mgmt` tool is a next generation config management prototype. It's not yet
|
||||
ready for production, but we hope to get there soon. Get involved today!
|
||||
|
||||
##Project Description
|
||||
|
||||
The mgmt tool is a distributed, event driven, config management tool, that
|
||||
supports parallel execution, and librarification to be used as the management
|
||||
foundation in and for, new and existing software.
|
||||
|
||||
For more information, you may like to read some blog posts from the author:
|
||||
|
||||
* [Next generation config mgmt](https://ttboj.wordpress.com/2016/01/18/next-generation-configuration-mgmt/)
|
||||
* [Automatic edges in mgmt](https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/)
|
||||
* [Automatic grouping in mgmt](https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/)
|
||||
* [Automatic clustering in mgmt](https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/)
|
||||
|
||||
There is also an [introductory video](http://meetings-archive.debian.net/pub/debian-meetings/2016/debconf16/Next_Generation_Config_Mgmt.webm) available.
|
||||
Older videos and other material [is available](https://github.com/purpleidea/mgmt/#on-the-web).
|
||||
|
||||
##Setup
|
||||
|
||||
During this prototype phase, the tool can be run out of the source directory.
|
||||
You'll probably want to use ```./run.sh run --yaml examples/graph1.yaml``` to
|
||||
get started. Beware that this _can_ cause data loss. Understand what you're
|
||||
doing first, or perform these actions in a virtual environment such as the one
|
||||
provided by [Oh-My-Vagrant](https://github.com/purpleidea/oh-my-vagrant).
|
||||
|
||||
##Features
|
||||
|
||||
This section details the numerous features of mgmt and some caveats you might
|
||||
need to be aware of.
|
||||
|
||||
###Autoedges
|
||||
|
||||
Automatic edges, or AutoEdges, is the mechanism in mgmt by which it will
|
||||
automatically create dependencies for you between resources. For example,
|
||||
since mgmt can discover which files are installed by a package it will
|
||||
automatically ensure that any file resource you declare that matches a
|
||||
file installed by your package resource will only be processed after the
|
||||
package is installed.
|
||||
|
||||
####Controlling autoedges
|
||||
|
||||
Though autoedges is likely to be very helpful and avoid you having to declare
|
||||
all dependencies explicitly, there are cases where this behaviour is
|
||||
undesirable.
|
||||
|
||||
Some distributions allow package installations to automatically start the
|
||||
service they ship. This can be problematic in the case of packages like MySQL
|
||||
as there are configuration options that need to be set before MySQL is ever
|
||||
started for the first time (or you'll need to wipe the data directory). In
|
||||
order to handle this situation you can disable autoedges per resource and
|
||||
explicitly declare that you want `my.cnf` to be written to disk before the
|
||||
installation of the `mysql-server` package.
|
||||
|
||||
You can disable autoedges for a resource by setting the `autoedge` key on
|
||||
the meta attributes of that resource to `false`.
|
||||
|
||||
####Blog post
|
||||
|
||||
You can read the introductory blog post about this topic here:
|
||||
[https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/](https://ttboj.wordpress.com/2016/03/14/automatic-edges-in-mgmt/)
|
||||
|
||||
###Autogrouping
|
||||
|
||||
Automatic grouping or AutoGroup is the mechanism in mgmt by which it will
|
||||
automatically group multiple resource vertices into a single one. This is
|
||||
particularly useful for grouping multiple package resources into a single
|
||||
resource, since the multiple installations can happen together in a single
|
||||
transaction, which saves a lot of time because package resources typically have
|
||||
a large fixed cost to running (downloading and verifying the package repo) and
|
||||
if they are grouped they share this fixed cost. This grouping feature can be
|
||||
used for other use cases too.
|
||||
|
||||
You can disable autogrouping for a resource by setting the `autogroup` key on
|
||||
the meta attributes of that resource to `false`.
|
||||
|
||||
####Blog post
|
||||
|
||||
You can read the introductory blog post about this topic here:
|
||||
[https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/](https://ttboj.wordpress.com/2016/03/30/automatic-grouping-in-mgmt/)
|
||||
|
||||
###Automatic clustering
|
||||
|
||||
Automatic clustering is a feature by which mgmt automatically builds, scales,
|
||||
and manages the embedded etcd cluster which is compiled into mgmt itself. It is
|
||||
quite helpful for rapidly bootstrapping clusters and avoiding the extra work to
|
||||
setup etcd.
|
||||
|
||||
If you prefer to avoid this feature. you can always opt to use an existing etcd
|
||||
cluster that is managed separately from mgmt by pointing your mgmt agents at it
|
||||
with the `--seeds` variable.
|
||||
|
||||
####Blog post
|
||||
|
||||
You can read the introductory blog post about this topic here:
|
||||
[https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/](https://ttboj.wordpress.com/2016/06/20/automatic-clustering-in-mgmt/)
|
||||
|
||||
###Remote ("agent-less") mode
|
||||
|
||||
Remote mode is a special mode that lets you kick off mgmt runs on one or more
|
||||
remote machines which are only accessible via SSH. In this mode the initiating
|
||||
host connects over SSH, copies over the `mgmt` binary, opens an SSH tunnel, and
|
||||
runs the remote program while simultaneously passing the etcd traffic back
|
||||
through the tunnel so that the initiators etcd cluster can be used to exchange
|
||||
resource data.
|
||||
|
||||
The interesting benefit of this architecture is that multiple hosts which can't
|
||||
connect directly use the initiator to pass the important traffic through to each
|
||||
other. Once the cluster has converged all the remote programs can shutdown
|
||||
leaving no residual agent.
|
||||
|
||||
This mode can also be useful for bootstrapping a new host where you'd like to
|
||||
have the service run continuously and as part of an mgmt cluster normally.
|
||||
|
||||
In particular, when combined with the `--converged-timeout` parameter, the
|
||||
entire set of running mgmt agents will need to all simultaneously converge for
|
||||
the group to exit. This is particularly useful for bootstrapping new clusters
|
||||
which need to exchange information that is only available at run time.
|
||||
|
||||
####Blog post
|
||||
|
||||
You can read the introductory blog post about this topic here:
|
||||
[https://ttboj.wordpress.com/2016/10/07/remote-execution-in-mgmt/](https://ttboj.wordpress.com/2016/10/07/remote-execution-in-mgmt/)
|
||||
|
||||
###Puppet support
|
||||
|
||||
You can supply a Puppet manifest instead of creating the (YAML) graph manually.
|
||||
Puppet must be installed and in `mgmt`'s search path. You also need the
|
||||
[ffrank-mgmtgraph Puppet module](https://forge.puppet.com/ffrank/mgmtgraph).
|
||||
|
||||
Invoke `mgmt` with the `--puppet` switch, which supports 3 variants:
|
||||
|
||||
1. Request the configuration from the Puppet Master (like `puppet agent` does)
|
||||
|
||||
mgmt run --puppet agent
|
||||
|
||||
2. Compile a local manifest file (like `puppet apply`)
|
||||
|
||||
mgmt run --puppet /path/to/my/manifest.pp
|
||||
|
||||
3. Compile an ad hoc manifest from the commandline (like `puppet apply -e`)
|
||||
|
||||
mgmt run --puppet 'file { "/etc/ntp.conf": ensure => file }'
|
||||
|
||||
For more details and caveats see [Puppet.md](Puppet.md).
|
||||
|
||||
####Blog post
|
||||
|
||||
An introductory post on the Puppet support is on
|
||||
[Felix's blog](http://ffrank.github.io/features/2016/06/19/puppet-powered-mgmt/).
|
||||
|
||||
##Resources
|
||||
|
||||
This section lists all the built-in resources and their properties. The
|
||||
resource primitives in `mgmt` are typically more powerful than resources in
|
||||
other configuration management systems because they can be event based which
|
||||
lets them respond in real-time to converge to the desired state. This property
|
||||
allows you to build more complex resources that you probably hadn't considered
|
||||
in the past.
|
||||
|
||||
In addition to the resource specific properties, there are resource properties
|
||||
(otherwise known as parameters) which can apply to every resource. These are
|
||||
called [meta parameters](#meta-parameters) and are listed separately. Certain
|
||||
meta parameters aren't very useful when combined with certain resources, but
|
||||
in general, it should be fairly obvious, such as when combining the `noop` meta
|
||||
parameter with the [Noop](#Noop) resource.
|
||||
|
||||
* [Exec](#Exec): Execute shell commands on the system.
|
||||
* [File](#File): Manage files and directories.
|
||||
* [Hostname](#Hostname): Manages the hostname on the system.
|
||||
* [Msg](#Msg): Send log messages.
|
||||
* [Noop](#Noop): A simple resource that does nothing.
|
||||
* [Nspawn](#Nspawn): Manage systemd-machined nspawn containers.
|
||||
* [Password](#Password): Create random password strings.
|
||||
* [Pkg](#Pkg): Manage system packages with PackageKit.
|
||||
* [Svc](#Svc): Manage system systemd services.
|
||||
* [Timer](#Timer): Manage system systemd services.
|
||||
* [Virt](#Virt): Manage virtual machines with libvirt.
|
||||
|
||||
###Exec
|
||||
|
||||
The exec resource can execute commands on your system.
|
||||
|
||||
###File
|
||||
|
||||
The file resource manages files and directories. In `mgmt`, directories are
|
||||
identified by a trailing slash in their path name. File have no such slash.
|
||||
|
||||
####Path
|
||||
|
||||
The path property specifies the file or directory that we are managing.
|
||||
|
||||
####Content
|
||||
|
||||
The content property is a string that specifies the desired file contents.
|
||||
|
||||
####Source
|
||||
|
||||
The source property points to a source file or directory path that we wish to
|
||||
copy over and use as the desired contents for our resource.
|
||||
|
||||
####State
|
||||
|
||||
The state property describes the action we'd like to apply for the resource. The
|
||||
possible values are: `exists` and `absent`.
|
||||
|
||||
####Recurse
|
||||
|
||||
The recurse property limits whether file resource operations should recurse into
|
||||
and monitor directory contents with a depth greater than one.
|
||||
|
||||
####Force
|
||||
|
||||
The force property is required if we want the file resource to be able to change
|
||||
a file into a directory or vice-versa. If such a change is needed, but the force
|
||||
property is not set to `true`, then this file resource will error.
|
||||
|
||||
###Hostname
|
||||
|
||||
The hostname resource manages static, transient/dynamic and pretty hostnames
|
||||
on the system and watches them for changes.
|
||||
|
||||
#### static_hostname
|
||||
The static hostname is the one configured in /etc/hostname or a similar
|
||||
file.
|
||||
It is chosen by the local user. It is not always in sync with the current
|
||||
host name as returned by the gethostname() system call.
|
||||
|
||||
#### transient_hostname
|
||||
The transient / dynamic hostname is the one configured via the kernel's
|
||||
sethostbyname().
|
||||
It can be different from the static hostname in case DHCP or mDNS have been
|
||||
configured to change the name based on network information.
|
||||
|
||||
#### pretty_hostname
|
||||
The pretty hostname is a free-form UTF8 host name for presentation to the user.
|
||||
|
||||
#### hostname
|
||||
Hostname is the fallback value for all 3 fields above, if only `hostname` is
|
||||
specified, it will set all 3 fields to this value.
|
||||
|
||||
###Msg
|
||||
|
||||
The msg resource sends messages to the main log, or an external service such
|
||||
as systemd's journal.
|
||||
|
||||
###Noop
|
||||
|
||||
The noop resource does absolutely nothing. It does have some utility in testing
|
||||
`mgmt` and also as a placeholder in the resource graph.
|
||||
|
||||
###Nspawn
|
||||
|
||||
The nspawn resource is used to manage systemd-machined style containers.
|
||||
|
||||
###Password
|
||||
|
||||
The password resource can generate a random string to be used as a password. It
|
||||
will re-generate the password if it receives a refresh notification.
|
||||
|
||||
###Pkg
|
||||
|
||||
The pkg resource is used to manage system packages. This resource works on many
|
||||
different distributions because it uses the underlying packagekit facility which
|
||||
supports different backends for different environments. This ensures that we
|
||||
have great Debian (deb/dpkg) and Fedora (rpm/dnf) support simultaneously.
|
||||
|
||||
###Svc
|
||||
|
||||
The service resource is still very WIP. Please help us my improving it!
|
||||
|
||||
###Timer
|
||||
|
||||
This resource needs better documentation. Please help us my improving it!
|
||||
|
||||
###Virt
|
||||
|
||||
The virt resource can manage virtual machines via libvirt.
|
||||
|
||||
##Usage and frequently asked questions
|
||||
(Send your questions as a patch to this FAQ! I'll review it, merge it, and
|
||||
respond by commit with the answer.)
|
||||
|
||||
###Why did you start this project?
|
||||
|
||||
I wanted a next generation config management solution that didn't have all of
|
||||
the design flaws or limitations that the current generation of tools do, and no
|
||||
tool existed!
|
||||
|
||||
###Why did you use etcd? What about consul?
|
||||
|
||||
Etcd and consul are both written in golang, which made them the top two
|
||||
contenders for my prototype. Ultimately a choice had to be made, and etcd was
|
||||
chosen, but it was also somewhat arbitrary. If there is available interest,
|
||||
good reasoning, *and* patches, then we would consider either switching or
|
||||
supporting both, but this is not a high priority at this time.
|
||||
|
||||
###Can I use an existing etcd cluster instead of the automatic embedded servers?
|
||||
|
||||
Yes, it's possible to use an existing etcd cluster instead of the automatic,
|
||||
elastic embedded etcd servers. To do so, simply point to the cluster with the
|
||||
`--seeds` variable, the same way you would if you were seeding a new member to
|
||||
an existing mgmt cluster.
|
||||
|
||||
The downside to this approach is that you won't benefit from the automatic
|
||||
elastic nature of the embedded etcd servers, and that you're responsible if you
|
||||
accidentally break your etcd cluster, or if you use an unsupported version.
|
||||
|
||||
###What does the error message about an inconsistent dataDir mean?
|
||||
|
||||
If you get an error message similar to:
|
||||
|
||||
```
|
||||
Etcd: Connect: CtxError...
|
||||
Etcd: CtxError: Reason: CtxDelayErr(5s): No endpoints available yet!
|
||||
Etcd: Connect: Endpoints: []
|
||||
Etcd: The dataDir (/var/lib/mgmt/etcd) might be inconsistent or corrupt.
|
||||
```
|
||||
|
||||
This happens when there are a series of fatal connect errors in a row. This can
|
||||
happen when you start `mgmt` using a dataDir that doesn't correspond to the
|
||||
current cluster view. As a result, the embedded etcd server never finishes
|
||||
starting up, and as a result, a default endpoint never gets added. The solution
|
||||
is to either reconcile the mistake, and if there is no important data saved, you
|
||||
can remove the etcd dataDir. This is typically `/var/lib/mgmt/etcd/member/`.
|
||||
|
||||
###Why do resources have both a `Compare` method and an `IFF` (on the UID) method?
|
||||
|
||||
The `Compare()` methods are for determining if two resources are effectively the
|
||||
same, which is used to make graph change delta's efficient. This is when we want
|
||||
to change from the current running graph to a new graph, but preserve the common
|
||||
vertices. Since we want to make this process efficient, we only update the parts
|
||||
that are different, and leave everything else alone. This `Compare()` method can
|
||||
tell us if two resources are the same.
|
||||
|
||||
The `IFF()` method is part of the whole UID system, which is for discerning if a
|
||||
resource meets the requirements another expects for an automatic edge. This is
|
||||
because the automatic edge system assumes a unified UID pattern to test for
|
||||
equality. In the future it might be helpful or sane to merge the two similar
|
||||
comparison functions although for now they are separate because they are
|
||||
actually answer different questions.
|
||||
|
||||
###Did you know that there is a band named `MGMT`?
|
||||
|
||||
I didn't realize this when naming the project, and it is accidental. After much
|
||||
anguishing, I chose the name because it was short and I thought it was
|
||||
appropriately descriptive. If you need a less ambiguous search term or phrase,
|
||||
you can try using `mgmtconfig` or `mgmt config`.
|
||||
|
||||
###You didn't answer my question, or I have a question!
|
||||
|
||||
It's best to ask on [IRC](https://webchat.freenode.net/?channels=#mgmtconfig)
|
||||
to see if someone can help you. Once we get a big enough community going, we'll
|
||||
add a mailing list. If you don't get any response from the above, you can
|
||||
contact me through my [technical blog](https://ttboj.wordpress.com/contact/)
|
||||
and I'll do my best to help. If you have a good question, please add it as a
|
||||
patch to this documentation. I'll merge your question, and add a patch with the
|
||||
answer!
|
||||
|
||||
##Reference
|
||||
Please note that there are a number of undocumented options. For more
|
||||
information on these options, please view the source at:
|
||||
[https://github.com/purpleidea/mgmt/](https://github.com/purpleidea/mgmt/).
|
||||
If you feel that a well used option needs documenting here, please patch it!
|
||||
|
||||
###Overview of reference
|
||||
* [Meta parameters](#meta-parameters): List of available resource meta parameters.
|
||||
* [Graph definition file](#graph-definition-file): Main graph definition file.
|
||||
* [Command line](#command-line): Command line parameters.
|
||||
|
||||
###Meta parameters
|
||||
These meta parameters are special parameters (or properties) which can apply to
|
||||
any resource. The usefulness of doing so will depend on the particular meta
|
||||
parameter and resource combination.
|
||||
|
||||
####AutoEdge
|
||||
Boolean. Should we generate auto edges for this resource?
|
||||
|
||||
####AutoGroup
|
||||
Boolean. Should we attempt to automatically group this resource with others?
|
||||
|
||||
####Noop
|
||||
Boolean. Should the Apply portion of the CheckApply method of the resource
|
||||
make any changes? Noop is a concatenation of no-operation.
|
||||
|
||||
####Retry
|
||||
Integer. The number of times to retry running the resource on error. Use -1 for
|
||||
infinite. This currently applies for both the Watch operation (which can fail)
|
||||
and for the CheckApply operation. While they could have separate values, I've
|
||||
decided to use the same ones for both until there's a proper reason to want to
|
||||
do something differently for the Watch errors.
|
||||
|
||||
####Delay
|
||||
Integer. Number of milliseconds to wait between retries. The same value is
|
||||
shared between the Watch and CheckApply retries. This currently applies for both
|
||||
the Watch operation (which can fail) and for the CheckApply operation. While
|
||||
they could have separate values, I've decided to use the same ones for both
|
||||
until there's a proper reason to want to do something differently for the Watch
|
||||
errors.
|
||||
|
||||
###Graph definition file
|
||||
graph.yaml is the compiled graph definition file. The format is currently
|
||||
undocumented, but by looking through the [examples/](https://github.com/purpleidea/mgmt/tree/master/examples)
|
||||
you can probably figure out most of it, as it's fairly intuitive.
|
||||
|
||||
###Command line
|
||||
The main interface to the `mgmt` tool is the command line. For the most recent
|
||||
documentation, please run `mgmt --help`.
|
||||
|
||||
####`--yaml <graph.yaml>`
|
||||
Point to a graph file to run.
|
||||
|
||||
####`--converged-timeout <seconds>`
|
||||
Exit if the machine has converged for approximately this many seconds.
|
||||
|
||||
####`--max-runtime <seconds>`
|
||||
Exit when the agent has run for approximately this many seconds. This is not
|
||||
generally recommended, but may be useful for users who know what they're doing.
|
||||
|
||||
####`--noop`
|
||||
Globally force all resources into no-op mode. This also disables the export to
|
||||
etcd functionality, but does not disable resource collection, however all
|
||||
resources that are collected will have their individual noop settings set.
|
||||
|
||||
####`--remote <graph.yaml>`
|
||||
Point to a graph file to run on the remote host specified within. This parameter
|
||||
can be used multiple times if you'd like to remotely run on multiple hosts in
|
||||
parallel.
|
||||
|
||||
####`--allow-interactive`
|
||||
Allow interactive prompting for SSH passwords if there is no authentication
|
||||
method that works.
|
||||
|
||||
####`--ssh-priv-id-rsa`
|
||||
Specify the path for finding SSH keys. This defaults to `~/.ssh/id_rsa`. To
|
||||
never use this method of authentication, set this to the empty string.
|
||||
|
||||
####`--cconns`
|
||||
The maximum number of concurrent remote ssh connections to run. This defaults
|
||||
to `0`, which means unlimited.
|
||||
|
||||
####`--no-caching`
|
||||
Don't allow remote caching of the remote execution binary. This will require
|
||||
the binary to be copied over for every remote execution, but it limits the
|
||||
likelihood that there is leftover information from the configuration process.
|
||||
|
||||
####`--prefix <path>`
|
||||
Specify a path to a custom working directory prefix. This directory will get
|
||||
created if it does not exist. This usually defaults to `/var/lib/mgmt/`. This
|
||||
can't be combined with the `--tmp-prefix` option. It can be combined with the
|
||||
`--allow-tmp-prefix` option.
|
||||
|
||||
####`--tmp-prefix`
|
||||
If this option is specified, a temporary prefix will be used instead of the
|
||||
default prefix. This can't be combined with the `--prefix` option.
|
||||
|
||||
####`--allow-tmp-prefix`
|
||||
If this option is specified, we will attempt to fall back to a temporary prefix
|
||||
if the primary prefix couldn't be created. This is useful for avoiding failures
|
||||
in environments where the primary prefix may or may not be available, but you'd
|
||||
like to try. The canonical example is when running `mgmt` with `--remote` there
|
||||
might be a cached copy of the binary in the primary prefix, but in case there's
|
||||
no binary available continue working in a temporary directory to avoid failure.
|
||||
|
||||
##Examples
|
||||
For example configurations, please consult the [examples/](https://github.com/purpleidea/mgmt/tree/master/examples) directory in the git
|
||||
source repository. It is available from:
|
||||
|
||||
[https://github.com/purpleidea/mgmt/tree/master/examples](https://github.com/purpleidea/mgmt/tree/master/examples)
|
||||
|
||||
### Systemd:
|
||||
See [`misc/mgmt.service`](misc/mgmt.service) for a sample systemd unit file.
|
||||
This unit file is part of the RPM.
|
||||
|
||||
To specify your custom options for `mgmt` on a systemd distro:
|
||||
|
||||
```bash
|
||||
sudo mkdir -p /etc/systemd/system/mgmt.service.d/
|
||||
|
||||
cat > /etc/systemd/system/mgmt.service.d/env.conf <<EOF
|
||||
# Environment variables:
|
||||
MGMT_SEEDS=http://127.0.0.1:2379
|
||||
MGMT_CONVERGED_TIMEOUT=-1
|
||||
MGMT_MAX_RUNTIME=0
|
||||
|
||||
# Other CLI options if necessary.
|
||||
#OPTS="--max-runtime=0"
|
||||
EOF
|
||||
|
||||
sudo systemctl daemon-reload
|
||||
```
|
||||
|
||||
##Development
|
||||
|
||||
This is a project that I started in my free time in 2013. Development is driven
|
||||
by all of our collective patches! Dive right in, and start hacking!
|
||||
Please contact me if you'd like to invite me to speak about this at your event.
|
||||
|
||||
You can follow along [on my technical blog](https://ttboj.wordpress.com/).
|
||||
|
||||
To report any bugs, please file a ticket at: [https://github.com/purpleidea/mgmt/issues](https://github.com/purpleidea/mgmt/issues).
|
||||
|
||||
##Authors
|
||||
|
||||
Copyright (C) 2013-2016+ James Shubin and the project contributors
|
||||
|
||||
Please see the
|
||||
[AUTHORS](https://github.com/purpleidea/mgmt/tree/master/AUTHORS) file
|
||||
for more information.
|
||||
|
||||
* [github](https://github.com/purpleidea/)
|
||||
* [@purpleidea](https://twitter.com/#!/purpleidea)
|
||||
* [https://ttboj.wordpress.com/](https://ttboj.wordpress.com/)
|
||||
163
docs/puppet.md
Normal file
163
docs/puppet.md
Normal file
@@ -0,0 +1,163 @@
|
||||
#mgmt Puppet support
|
||||
|
||||
1. [Prerequisites](#prerequisites)
|
||||
* [Testing the Puppet side](#testing-the-puppet-side)
|
||||
2. [Writing a suitable manifest](#writing-a-suitable-manifest)
|
||||
* [Unsupported attributes](#unsupported-attributes)
|
||||
* [Unsupported resources](#unsupported-resources)
|
||||
* [Avoiding common warnings](#avoiding-common-warnings)
|
||||
3. [Configuring Puppet](#configuring-puppet)
|
||||
4. [Caveats](#caveats)
|
||||
|
||||
`mgmt` can use Puppet as its source for the configuration graph.
|
||||
This document goes into detail on how this works, and lists
|
||||
some pitfalls and limitations.
|
||||
|
||||
For basic instructions on how to use the Puppet support, see
|
||||
the [main documentation](documentation.md#puppet-support).
|
||||
|
||||
##Prerequisites
|
||||
|
||||
You need Puppet installed in your system. It is not important how you
|
||||
get it. On the most common Linux distributions, you can use packages
|
||||
from the OS maintainer, or upstream Puppet repositories. An alternative
|
||||
that will also work on OSX is the `puppet` Ruby gem. It also has the
|
||||
advantage that you can install any desired version in your home directory
|
||||
or any other location.
|
||||
|
||||
Any release of Puppet's 3.x and 4.x series should be suitable for use with
|
||||
`mgmt`. Most importantly, make sure to install the `ffrank-mgmtgraph` Puppet
|
||||
module (referred to below as "the translator module").
|
||||
|
||||
puppet module install ffrank-mgmtgraph
|
||||
|
||||
Please note that the module is not required on your Puppet master (if you
|
||||
use a master/agent setup). It's needed on the machine that runs `mgmt`.
|
||||
You can install the module on the master anyway, so that it gets distributed
|
||||
to your agents through Puppet's `pluginsync` mechanism.
|
||||
|
||||
###Testing the Puppet side
|
||||
|
||||
The following command should run successfully and print a YAML hash on your
|
||||
terminal:
|
||||
|
||||
```puppet
|
||||
puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": ensure => present }'
|
||||
```
|
||||
|
||||
You can use this CLI to test any manifests before handing them straight
|
||||
to `mgmt`.
|
||||
|
||||
##Writing a suitable manifest
|
||||
|
||||
###Unsupported attributes
|
||||
|
||||
`mgmt` inherited its resource module from Puppet, so by and large, it's quite
|
||||
possible to express `mgmt` graphs in terms of Puppet manifests. However,
|
||||
there isn't (and likely never will be) full feature parity between the
|
||||
respective resource types. In consequence, a manifest can have semantics that
|
||||
cannot be transferred to `mgmt`.
|
||||
|
||||
For example, at the time of writing this, the `file` type in `mgmt` had no
|
||||
notion of permissions (the file `mode`) yet. This lead to the following
|
||||
warning (among others that will be discussed below):
|
||||
|
||||
$ puppet mgmtgraph print --code 'file { "/tmp/foo": mode => "0600" }'
|
||||
Warning: cannot translate: File[/tmp/foo] { mode => "600" } (attribute is ignored)
|
||||
|
||||
This is a heads-up for the user, because the resulting `mgmt` graph will
|
||||
in fact not pass this information to the `/tmp/foo` file resource, and
|
||||
`mgmt` will ignore this file's permissions. Including such attributes in
|
||||
manifests that are written expressly for `mgmt` is not sensible and should
|
||||
be avoided.
|
||||
|
||||
###Unsupported resources
|
||||
|
||||
Puppet has a fairly large number of
|
||||
[built-in types](https://docs.puppet.com/puppet/latest/reference/type.html),
|
||||
and countless more are available through
|
||||
[modules](https://forge.puppet.com/). It's unlikely that all of them will
|
||||
eventually receive native counterparts in `mgmt`.
|
||||
|
||||
When encountering an unknown resource, the translator module will replace
|
||||
it with an `exec` resource in its output. This resource will run the equivalent
|
||||
of a `puppet resource` command to make Puppet apply the original resource
|
||||
itself. This has quite abysmal performance, because processing such a
|
||||
resource requires the forking of at least one Puppet process (two if it
|
||||
is found to be out of sync). This comes with considerable overhead.
|
||||
On most systems, starting up any Puppet command takes several seconds.
|
||||
Compared to the split second that the actual work usually takes,
|
||||
this overhead can amount to several orders of magnitude.
|
||||
|
||||
Avoid Puppet types that `mgmt` does not implement (yet).
|
||||
|
||||
###Avoiding common warnings
|
||||
|
||||
Many resource parameters in Puppet take default values. For the most part,
|
||||
the translator module just ignores them. However, there are cases in which
|
||||
Puppet will default to convenient behavior that `mgmt` cannot quite replicate.
|
||||
For example, translating a plain `file` resource will lead to a warning message:
|
||||
|
||||
$ puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": }'
|
||||
Warning: File[/tmp/mgmt-test] uses the 'puppet' file bucket, which mgmt cannot do. There will be no backup copies!
|
||||
|
||||
The reason is that per default, Puppet assumes the following parameter value
|
||||
(among others)
|
||||
|
||||
```puppet
|
||||
file { "/tmp/mgmt-test":
|
||||
backup => 'puppet',
|
||||
}
|
||||
```
|
||||
|
||||
To avoid this, specify the parameter explicitly:
|
||||
|
||||
$ puppet mgmtgraph print --code 'file { "/tmp/mgmt-test": backup => false }'
|
||||
|
||||
This is tedious in a more complex manifest. A good simplification is the
|
||||
following [resource default](https://docs.puppet.com/puppet/latest/reference/lang_defaults.html)
|
||||
anywhere on the top scope of your manifest:
|
||||
|
||||
```puppet
|
||||
File { backup => false }
|
||||
```
|
||||
|
||||
If you encounter similar warnings from other types and/or parameters,
|
||||
use the same approach to silence them if possible.
|
||||
|
||||
##Configuring Puppet
|
||||
|
||||
Since `mgmt` uses an actual Puppet CLI behind the scenes, you might
|
||||
need to tweak some of Puppet's runtime options in order to make it
|
||||
do what you want. Reasons for this could be among the following:
|
||||
|
||||
* You use the `--puppet agent` variant and need to configure
|
||||
`servername`, `certname` and other master/agent-related options.
|
||||
* You don't want runtime information to end up in the `vardir`
|
||||
that is used by your regular `puppet agent`.
|
||||
* You install specific Puppet modules for `mgmt` in a non-standard
|
||||
location.
|
||||
|
||||
`mgmt` exposes only one Puppet option in order to allow you to
|
||||
control all of them, through its `--puppet-conf` option. It allows
|
||||
you to specify which `puppet.conf` file should be used during
|
||||
translation.
|
||||
|
||||
mgmt run --puppet /opt/my-manifest.pp --puppet-conf /etc/mgmt/puppet.conf
|
||||
|
||||
Within this file, you can just specify any needed options in the
|
||||
`[main]` section:
|
||||
|
||||
[main]
|
||||
server=mgmt-master.example.net
|
||||
vardir=/var/lib/mgmt/puppet
|
||||
|
||||
##Caveats
|
||||
|
||||
Please see the [README](https://github.com/ffrank/puppet-mgmtgraph/blob/master/README.md)
|
||||
of the translator module for the current state of supported and unsupported
|
||||
language features.
|
||||
|
||||
You should probably make sure to always use the latest release of
|
||||
both `ffrank-mgmtgraph` and `ffrank-yamlresource` (the latter is
|
||||
getting pulled in as a dependency of the former).
|
||||
Reference in New Issue
Block a user