Mac OS X – The recovery server could not be contacted.

I believe some of your guys may experience the following error when trying to reinstall Mac OS X in recovery mode.

There are two possible reason cause above error.

Reason 1:- Wi-Fi connection is not stable and keeps disconnecting.

Reason 2:- System time on your Mac is incorrect.
To fix system time issue in recovery mode

  1. Open up a Terminal from the utilities menu
  2. Enter the following command
ntpdate -u
  1. Try to install your Mac OS X again. It should work as expected.

Basic Server Load Balancing Concept

1) User enters in their browser. Hostname sent to DNS for resolution

2) DNS resolves to the Virtual IP address (VIP) of

3) Client sends request to VIP.

4) Array proxies request to selected real service.

5) Further requests from the client may be sent to the same or a different real service, depending on persistency configuration.

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NagiosXI – How to reset nagiosadmin password

I have a NagiosXI server which i already 2 year never login. Recently one of the System Admin leaving the company and i have to take over back the NagiosXI server management. But i already forgot what is nagiosadmin password.

Lucky NagiosXI come with a lot of useful scripts which located at /usr/local/nagiosxi/scripts/

Here i going to show your guys how i reset the nagiosadmin password using NagiosXI script.

To do that, you have to ssh in to NagiosXI server and execute following command to reset nagiosadmin password

/usr/local/nagiosxi/scripts/reset_nagiosadmin_password.php --password=newpassword

If you wish to use any special  characters in your password, you should escape them with “\”. For example, if you want to set your new password to be “p@ssw0rd#”, then you can run:

/usr/local/nagiosxi/scripts/reset_nagiosadmin_password.php --password=p\@ssw0rd\#

After reset, you should able to login to your NagiosXI with your new password.