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SSL and Java

2018-11-26 Ronny Trommer
Running applications with a current Java is not a big deal thanks Let’s Encrypt. This article describes what happens if you want to authenticate your OpenNMS against LDAP using SSL with a self-certified certificate. First of all I assume you have confiured verything so you can authenticate against LDAP in plaintext and you got a role mapping as you wanted it. If not you can have a look here. Continue reading

Send notifications with Signal

2018-11-01 Ronny Trommer
In some cases it is nice to have notifications from OpenNMS in a separate channel on a smartphone and you don’t want to pay for SMS. Here is a tutorial where I use Signal using the signal-cli. This Howto will describe how to download the latest signal-cli tool, link it to your existing Signal account and how to configure OpenNMS to use it as a notification target. You should have already an OpenNMS Horizon or Meridian running and you need a Signal account with the Signal app installed and configured on your smartphone. Continue reading

Everyone can change it and why you shouldn't

2018-09-27 Ronny Trommer
Open Source software is great. If there is something you don’t like, you can at least - try to change it. A lot of Open Source software out there is not primarily used by private people. There are many companies who provide professional services around Open Source software. Some of them try to enhance the appearance with custom User Interfaces, their company logo to fit their own Corporate Identity. There are several motivations, mostly they want to be distinguished on the marked or need some easy to maintain little customization which allows their sales guys easier to sell a project and not using the software from the community projects website. Continue reading

Guidance to Survive Monitoring

2018-08-08 Ronny Trommer
While working in the monitoring field for a long time, here are some rules I try to follow when requirements go awry. Rule #1: Only create an alert when human interaction is required When you setup a monitoring, it tends to get noisy very quickly. The problem is, people want to know everything and want to monitor everything. You tend to build a system which sends you a lot of alarms and you will get alarm fatique. Continue reading

There are only two hard things in Computer Science: cache invalidation and naming things.

Phil Karlton

If you’re brave to say’ goodbye’, life will reward you with a new ‘hello’.

Paulo Coelho

He's dead, Jim

2018-07-30 Ronny Trommer
If you operate networks there is a big chance you had to deal with SNMP - the Simple Network Management Protocol. If you ever wondered where it came from, it started with a big bang. On October 27, 1980, there was an unusual occurrence on the ARPANET. For a period of several hours, the network appeared to be unusable, due to what was later diagnosed as a high priority software process running out of control. Continue reading

Monitoring Websites with OpenNMS

2018-07-27 Ronny Trommer
Monitoring websites is a common requirement. Using OpenNMS to monitor websites can be done by using the built in HTTP/HTTPS based monitors. While a “Node” can be pretty much everything in a network, the internal model to monitor something is pretty old-fashioned and static. Monitoring a service requires to assign a service to an IP address. This article describes a pattern how you can monitor web sites with low maintenance and without the need to maintain for each website a monitor which is cumbersome in maintenance. Continue reading

Authenticate OpenNMS Horizon with FreeRADIUS

2018-07-22 Ronny Trommer
Centralized authentication is a core service as soon you have a network with more than 3 computers. This article is about how to authenticate a OpenNMS Horizon 22.0.2 using RADIUS provided by a FreeRADIUS service. In this example the FreeRADIUS server is configured to provide 3 users. A dictionary is configured which returns 2 roles, ROLE_USER and ROLE_ADMIN which can be used to decide which security role is assigned in the OpenNMS Horizon Web UI. Continue reading

Authenticate OpenNMS Horizon with Active Directory on Windows Server 2016

2018-07-16 Ronny Trommer
Centralized authentication is a core service as soon you have a network with more than 3 computers. This article is about how to authenticate a OpenNMS Horizon 22.0.1 against an Active Directory provided on a Microsoft Windows Server 2016. I’ll focus here on the Active Directory and Spring configuration parts, securing the connection with LDAPS and using self-signed certificates in Java is another topic and not covered here. In this example the domain is called labmonkeys. Continue reading
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