My impression about Merlin and Ninja
Mathieu Gagné
mgagne at iweb.com
Sat Jul 18 01:35:00 CEST 2009
Hi all,
Some of us are under the impression that Merlin and Ninja will be the
new default GUI and NEB module used in Nagios.
I therefore gave a try to both of them this week and I would like to
share my impression and opinion about those.
Lets start with Merlin.
1) Lack of documentation
There's a serious lack of documentation about the project making it
difficult for anyone to join and test Merlin.
1.1. We should be explained the terminology used by Merlin
What is a NOC, Poller and Peer? What are they in the big picture and how
do they interact with each others?
1.2) We should be provided examples of setup
How can Merlin be configured and used? Clear working examples should be
provided, including schema and network information (hostname/ip).
Over the years, I tend to be more and more a visual person. The backend
illustration is nice (http://www.op5.org/community/projects/merlin) but
not enough for me to understand how can multiple Merlin enabled Nagios
can interact with each others and what I should be expecting from them.
1.3) Configuration propagation
- How is it propagated? Do I have to rsync them? Is it propagated or
just imported to the database for status aggregation purpose?
- How does Merlin deal with name collisions? Does it assume "localhost"
from "nagios1" is the same as the one on "nagios2"?
All those questions would probably be answered if real life examples
were provided.
1.4) Nagios instance
Was the NDOutils concept of "nagios instance" dropped? I can see this in
object_importer.inc.php:
$obj['instance_id'] = 0;
$obj['instance_name'] = 'Local Nagios/Merlin instance';
2) Installation process to be improved
The installation process isn't trouble free.
I installed a MySQL server on a remote host. There's unfortunately no
way to tell the install script to use a remote MySQL server. It assumes
MySQL is installed on the local host and can authenticate using the
password-less root account. We should be given a choice and asked
authentication informations. (host,port,user,pass)
3) Using PHP for shell scripts
I used to program PHP for several years in the past. PHP is nice and
easy to learn. However having to install PHP on a monitoring server just
so a single shell script can import a Nagios configuration isn't really
cool. I would prefer Perl or Python which are usually already installed
on the server.
And now with Ninja.
1) Installation process
The installation process isn't trouble free with Ninja neither.
1.1. I installed a MySQL server on a remote host. I can't specify a host
on which I want to configure the database. I had to execute each part of
the installation process separately.
1.2. Error reporting isn't user friendly. I was prompted with this error
during the installation process:
sh: -c: line 0: syntax error near unexpected token `newline'
sh: -c: line 0: `/usr/bin/php /usr/local/ninja/index.php
cli/insert_user_data <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> '
An error occurred and this script will terminate. Too bad...
It is in fact the first line of a huge backtrace from Kohana telling it
can't connect to MySQL.
2) Interface
2.1) At first glance, the interface is nice. The dashboard and the use
of widgets is a good idea.
However the interface is very pale and seriously lacking colors/contrast.
Your answer would be: "Ninja supports themes so improve it yourself".
While it's a valid answer, it certainly won't satisfy anybody as it
requires time and expertise which most of us don't have. And I would
personally consider this answer as a loophole so you don't have to
review/change the theme to answer most people concerns and needs.
To justify my opinion, let me give you an example. With the current CGI
interface, when a server is marked as DOWN, we get a WHOLE red line to
draw our attention. This is great because I know in seconds where to
look and what is asking my attention.
However, with Ninja, we only get a 16x16 icon which doesn't draw any
attention. It's even worst when you are showing the interface on a big
screen in a NOC. Small icons simply don't do the job compared to an
awesome huge red line.
IMO, state should use background colors instead of icons and commands
should use icons. (pretty much like Nagios does today)
2.2) State Information and Commands
Both sections are overlapping and some state information are hidden
because of that.
2.3) Typos
I saw some typos here and there.
- "Notification enabled" instead of "Notification disabled"
- Icon filenames: nofity-disabled.png => notify-disabled.png
- Etc.
2.4) Errors
Anyone got them so far?
session_start() [function.session-start]: ps_files_cleanup_dir:
opendir(/var/lib/php5) failed: Permission denied (13)
Invalid argument supplied for foreach()
application/controllers/status.php [675]:
Status_Controller->group_summary( service, all )
Status_Controller->servicegroup_summary( )
3) Documentation
It should be clearly stated that Nagios needs to be running on the same
host as Ninja to be able to use commands. Otherwise you will be getting
those errors:
fopen(/usr/local/nagios/var/rw/nagios.cmd) [function.fopen]: failed to
open stream: No such file or directory
-------------
I hope my message won't discourage you. I guess most of us are curious
about Merlin and Ninja and have big hopes for them.
I just wanted to give my first impression. :)
--
Mathieu
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