Presentation Patterns

This year I decided to make the slides a bit mode modern as I read the Pressentation Patterns book by Neal Ford, Matthew McCullough, and Nate Schutta. It is truly an impressive book and a must read by anyone who wants to make presentations.

I describes a series of patterns on how to make good presentations or as I would say modern presentations.

I was a bit scared as it is a big transition from my old routine so I did a bit of a hybrid where I tried to minimize the number of bullets and talk more. I normally essentially have a bullet for each sentence which I have justified by saying it is my cheat sheet so I wont forget. So for me taking the plunge to a presentation where I cant read my way to what I shall say was scary but in the end it worked out so this is definitely the future.

I also went the way of adding a bling by making nifty(?) animations and having a lot of advanced hand animated transitions in PowerPoint which means I almost had to re create my slides to be able to make them available for paper.

So now I shall return to explain the demos a bit and then allow you to sit back and read the slides to your hearts content.

Demo 1: Using NSClient++ 0.4.x

The essence of this section and demo was to introduce the command line interface and convince people the settings generation stuff can really help them.

So I first had a deck presenting the command line syntax and various ways to get help. For that section I refer to the slides since it is explained there.

Then removed the configuration file and showed you I was not cheating:

rm nsclient.ini
ls nsclient.ini
# ls: cannot access nsclient.ini: No such file or directory

Next up I added a module using the command line syntax:

./nscp settings --activate-module NRPEServer --add-defaults

Which gives as a configuration that looks like this:

 ; A list of modules.
 [/modules]

; NRPE server - A simple server that listens for incoming NRPE connection and handles them.
 NRPEServer = enabled

; Section for NRPE (NRPEServer.dll) (check\_nrpe) protocol options.
 [/settings/NRPE/server]

; COMMAND ARGUMENT PROCESSING - This option determines whether or not the we will allow clients to specify arguments to commands that are executed.
 allow arguments = false

; COMMAND ALLOW NASTY META CHARS - This option determines whether or not the we will allow clients to specify nasty (as in \|\`&><'"\\[]{}) characters in arguments.
 allow nasty characters = false

; PORT NUMBER - Port to use for NRPE.
 port = 5666

; ... removed large chunk here ...

[/settings/default]

; ALLOWED CIPHERS - A better value is: ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH
 allowed ciphers = ADH

; ALLOWED HOSTS - A comaseparated list of allowed hosts. You can use netmasks (/ syntax) or \* to create ranges.
 allowed hosts = 127.0.0.1

; CACHE ALLOWED HOSTS - If hostnames should be cached, improves speed and security somewhat but wont allow you to have dynamic IPs for your nagios server.
 cache allowed hosts = true

; SSL CERTIFICATE -
 certificate =

; TIMEOUT - Timeout when reading packets on incoming sockets. If the data has not arrived within this time we will bail out.
 timeout = 30

; ENABLE SSL ENCRYPTION - This option controls if SSL should be
  enabled.
 use ssl = true

; VERIFY MODE -
 verify mode = none

If we now first change the port to 1234 and run the following command to remove all our default values we end up with the following snippet which is essentially the keys we have actually configured.

 ; A list of modules.
 [/modules]

; NRPE server - A simple server that listens for incoming NRPE connection and handles them.
 NRPEServer = enabled

; Section for NRPE (NRPEServer.dll) (check\_nrpe) protocol options.
 [/settings/NRPE/server]

; PORT NUMBER - Port to use for NRPE.
 port = 1234

Demo 2: Real-time monitoring

Next up was a crash course in real-time monitoring as well as introducing several new modules.

• CheckLogFile Listens for file system changes (events, not polling by the way) and performs pattern matching and sends events based on patterns
• SimpleFileWriter Writes events to files (a bit like NSCA does when it sends events to Nagios via the command file).
• NSCAClient Sends events to remote NSCA server.

I wont go through the command lines I used to create the configuration (since that is not really useful apart from show casing it can be done).

 [/modules]
 CheckLogFile = enabled
 SimpleFileWriter = enabled

[/settings/logfile/real-time/checks/sample]
 file = ./test.txt
 filter = column1 like 'hello'
 destination = FILE
 warning = column2 like 'warn'
 critical = column2 like 'crit'

[/settings/logfile/real-time]
 enabled = true

What we do here is in essence enable the CheckLogFile module and the SimpleFileWriter module as well as define a file we want to listen for changes from.

The most interesting part is the …/sample section. Where we have:

• file The file we want to listen to changes from. Here we assume it is a tab delimited file if it is we can reconfigure it to have other line and column separators. The file should (in some way) be a tabular file.
• filter The lines we are interested in should have the first column contain “hello”.
• destination To which target we want to send events.
• warning Lines matching this will become a warning (think Nagios).
• critical Lines matching this will become a critical (think Nagios).

To test this I first create the various files and then run tail on the “output.txt” file (which is the default filename on the SimpleFileWriter module.

Then I add data to the file using the echo command.

touch test.txt
touch output.txt
# In other window:
tail -f output.txt
# In yet another window:
nscp test
# In yet another window
echo -e "hello\\tworld"
echo -e "hello\\tcrit"

The result is two lines added to the output.txt file one “ok” and one “critical” like so:

sample OK ./test.txt: 1 (hello, world, )
sample CRITICAL ./test.txt: 1 (hello, crit, )

Next up we extend this by first adding the NSCAClient module and then changing destination to include *both FILE and NSCA* which gives us the following configuration:

 [/modules]
 CheckLogFile = enabled
 SimpleFileWriter = enabled
 NSCAClient = enabled

[/settings/logfile/real-time/checks/sample]
 file = ./test.txt
 filter = column1 like 'hello'
 destination = FILE,NSCA
 warning = column2 like 'warn'
 critical = column2 like 'crit'

[/settings/logfile/real-time]
 enabled = true

[/settings/NSCA/client/targets/default]
 address = 127.0.0.1
 encryption = xor
 password = secret

The result from repeating the above commands are now we in addition to get lines in output.txt also gets events sent to our NSCA server.

Demo 3: Passive real-time checks via NRPE

This module introduced yet another new module called SimpleCache which stores events for checking via NRPE. This module requires very little configuration (out of the box) so we merely enabled it but also changed the destination to send to FILE, NSCA and no also CACHE:

 [/modules]
 CheckLogFile = enabled
 SimpleFileWriter = enabled
 NSCAClient = enabled
 SimpleCache = enabled

[/settings/logfile/real-time/checks/sample]
 file = ./test.txt
 filter = column1 like 'hello'
 destination = FILE,NSCA,CACHE
 warning = column2 like 'warn'
 critical = column2 like 'crit'

[/settings/logfile/real-time]
 enabled = true

[/settings/NSCA/client/targets/default]
 address = 127.0.0.1
 encryption = xor
 password = secret

What we did now was again run the sample commands to add lines to our file and NSCA. After which we did an active check from the command line (in the NSClient++ window).

nscp test
...
check_cache index=sample
OK:./test.txt: 1 (hello, world, )

And that was pretty much it really… Now all that’s left, if you have not done so already, is to browse through the slides and hopefully you will then be ready to go with NSClient++ 0.4.1.

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