This document discusses managing Nagios monitoring with Puppet. It explains why Puppet is useful for Nagios configuration, highlighting key Puppet features like exported resources, Hiera, templates and Facter. It provides examples of using these features with Nagios and discusses integrating different configuration sources. Overall, the document shows how Puppet can be used to automate and simplify Nagios monitoring in a consistent, reusable way.

1. The
Art
and
Zen
of
Managing
Nagios
with
Puppet
Michael
Merideth
-­‐
VictorOps

2. Why
Manage
Nagios
with
Puppet?
• Mind
the
gaps
• Keep
the
config
readable
• Good
intro
to
key
Puppet
features

3. Key
Puppet
Features
• Exported
Resources
• Hiera
• Inline
Templates
• Facter
• Nagios
Resource
Types
• Puppet
Forge

4. Key
Puppet
Features
Exported
Resources:
• Resources
get
defined
on
one
host,
and
“collected”
on
another
• Requires
the
use
of
PuppetDB
• Saves
having
to
use
shared
storage
or
insecure
file
transfers
• Keeps
the
number
of
config
files
low
@@nagios_host
{
$::fqdn:
alias
=>
$nag_alias,
address
=>
$::ipaddress_eth1
use
=>
"${::vo_env}-­‐host",
hostgroups
=>
$::my_hostgroups,
tag
=>
"${::vo_env}-­‐host",
target
=>
"${cfg_tmpdir}/hosts.cfg",
owner
=>
'nagios',
group
=>
'nagios',
mode
=>
'0644',
}

5. Key
Puppet
Features
Hiera:
• Separate
code
from
data
• Set
defaults
and
provide
overrides
• Encrypted
back-­‐ends
allow
for
security,
even
if
your
source
code
is
stolen

6. Key
Puppet
Features
Inline
Templates:
• Not
just
for
file
content
• Allows
the
use
of
native
Ruby
code
within
Puppet
policy
inline_template(
'<%=
Hash[scope.to_hash.select{
|k,v|
k
=~
/nag_gr_/
&&
v
}].keys.join(",")
%>'
)

7. Key
Puppet
Features
Facter:
• Variable
values
defined
at
run-­‐time,
on
the
client
• Easily
extensible

8. Key
Puppet
Features
Nagios
Resource
Types:
• Makes
creating
Nagios
configs
simple
• Enforces
correct
syntax
• Not
suitable
for
every
config
in
every
file

9. Key
Puppet
Features
Puppet
Forge:
• A
public
repository
of
Puppet
modules
• Modules
can
be
libraries,
defined
resource
types,
or
classes
• Quality
Score
and
Community
Rating
help
you
choose
safe,
well-­‐maintained
modules
• You
should
still
review
third-­‐party
modules
carefully

10. Why
Not
Use
an
Existing
Module?
There
are
several
user-­‐submitted
Nagios
modules
in
the
Forge,
but
I
wanted
one
that
would:
• Automatically
add
new
hosts
• Provision
some
services
within
other
modules
• Automatically
remove
decommissioned
hosts
• Make
use
of
host
and
service
groups

11. Putting
It
All
Together
Hiera
and
Facter
define
the
variables
• Sane
defaults
for
most
values
• Environment-­‐specific
overrides
(dev,
stage,
prod)
• Site-­‐specific
overrides
for
different
datacenters

12. Putting
It
All
Together
Monitored
hosts
build
their
own
config
• Hostgroup
membership
is
determined
in
the
client
context
• Other
facts
integrate
into
the
host
definition
• NRPE
config
built
from
a
common
template
• Client
puppet
run
exports
resources

13. Putting
It
All
Together
Some
service
definitions
get
embedded
in
the
manifest
for
that
service
• A
change
to
a
service
may
mean
a
change
to
how
you
monitor
it
• Manage
that
all
in
one
place
• profile::vo_webserver
provides
an
example

14. Putting
It
All
Together
Some
service
definitions
are
done
with
templates
• Not
everything
needs
to
get
built
dynamically
• Some
services
are
monitored
on
all
hosts
• Less
dynamic
config
means
shorter
catalog
compilation
• Templates
can
be
easier
to
debug

15. Ugly
Hack
Alert
Dynamic
files
built
every
run,
installed
if
there’s
a
diff
• Allows
keeping
backup
directories
with
previous
versions
of
the
configs
• Allows
automatic
removal
of
decommissioned
hosts
• Prevents
excessive
Nagios
restarts

16. Vagrant
• AWESOME
way
to
test
Puppet
code
as
you
develop
Github
repository
• Contains
Vagrantfile
and
complete
Puppet
policy
• github.com/victorops/puppet-­‐nagios
The
Demo
Environment

17. Demo
Time!
Running low on slides, so it must be…

18. The
Demo
Environment
github.com/victorops/puppet-­‐nagios
• Check
it
out!
• Contribute!
• Or
fork
it!
• Help
work
towards
a
Puppet
Forge
module:
• Parameterize
the
class
• More
types
of
config
resources
• Cross
platform
support
• Documentation