Icinga icon   Icinga – How to configure passive checks made easy (2)



In the previous post I explained what is the difference between Icinga active and passive checks, why can be interesting to use passive checks, what is the result format Icinga is expecting when processing those checks and the way I use to send those results (instead of using snmp traps).

Now it is time to show how to configure it … Read more

Icinga icon   Icinga – How to configure passive checks made easy (1)



As I posted long time ago for Nagios (Nagios – Using passive checks without agent), it is time to show an easy way to configure Icinga to perform passive checks (without using SNMP traps).

This is the first of two posts. In this I only want to make some theoretical explanations and then in the second I will … Read more

Windows   Windows – Configure scheduled task every minute



This time a simple as well as important post. Have you tried to run a scheduled task every minute?

When editing the trigger of a task schedule, there is a section in which the “Repeat task every” parameter can be set, and you have probably noticed that by default only the values “5 minutes, 10 minutes, 15 minutes, 30 … Read more

Hardware icon   HW – Upgrade laptop with an SSD drive



One of the biggest bottlenecks regarding the performance of a laptop is disk access. Therefore, installing an SSD (Solid State Drive) is a fantastic way to speed it up. It is a great feeling to see how fast Windows or any program starts after installing it. The only disadvantage is the price of this type of disks, but currently, … Read more

Windows   Windows – VMware machines offline due to Microsoft patches



Today, just when starting the working day we have realized that there were somes servers offline (still powered on but without network connection). It seemed that the network adapters were incorrectly configured without the static IPs.

After some research, a job partner discovered that some days ago (March 13th) Microsoft released some security updates that generates issues to Windows 2008 Read more

F5 BIG-IP icon   F5 BIGIP – Upgrade an active/standby cluster



Step by step procedure to upgrade an active/standby BIGIP cluster. In this example, I needed to upgrade from BIG IP v13.0.0.0 to v13.1.0.2

Download

Login to https://downloads.f5.com/, search and download the ISO image of the version you want to upgrade to.
F5 BIGIP - Upgrade an activestandby cluster - Download BIGIP upgrade

F5 BIGIP - Upgrade an activestandby cluster - Download BIGIP upgrade

Export configuration

As a good sysadmin practice, it is better to export the configuration of both nodes … Read more

F5 BIG-IP icon   F5 BIGIP – LTM Policy GUI incorrectly shows conditions with datagroups



The last F5 BIGIP version 13.1.0.2 (I upgraded from v13.0.0 some days ago – 2018 February) seems to generate a bug with the LTM policies.

Symptoms

Fortunately, the issue is only at the Presentation layer. The LTM policy show the rules conditions always with datagroups. This affects all rules and policies.

Better explained with an example:
If this is a … Read more

F5 BIG-IP icon   F5 BIGIP – HTTP header count exceeded maximum allowed count



Last week we published a new application on our web servers (which are balanced by the F5 BIGIP)
Accessing directly to the servers produced no problem, but when the connection was through the virtual balancing IP of the F5, the application did not work correctly.

Error message

Fortunately, monitoring the LTM module logs of the F5 (/var/log/ltm) while the problem … Read more

Security   Security – Create self signed SAN certificate with OpenSSL



This post explains how to generate self signed certificates with SAN – Subject Alternative Names using openssl. It is a common but not very funny task, only a minute is needed when using this method.

The example below generates a certificate with two SubAltNames: mydomain.com and www.mydomain.com

Create openssl configuration file

Create configuration file for openssh (In a Linux … Read more