Ep. 42: Working with the Local DNS plugin in Checkmk

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[0:00:00] Make sure your local DNS resolution works with the local DNS plugin for Checkmk.
[0:00:16] Welcome to the Checkmk Channel. In modern networking, DNS is a service that has to work reliably and stable.
[0:00:25] Name resolution is something both applications and operating systems rely on. And if that doesn't work, you get the most interesting effects in your application and operating system.
[0:00:37] With the Checkmk plugin for local DNS resolution you can be sure that your Linux systems are always able to resolve DNS names.
[0:00:47] The plugin works in a way that it resolves a URL whatever you want to provide there. And as long as this resolution works, the service will be okay.
[0:00:59] In case the resolution doesn't work for any reason at all, you will be aware of that.
[0:01:03] So, now let's take a look at how to configure that plugin and how to get the service.
[0:01:11] First, let's head to the Setup menu and search for local DNS. There we find the agent rule Local DNS resolving. There we create a rule, and there we can see we need to provide it with Hostnames to resolve.
[0:01:29] In this example, I'm just going to use checkmk.com. And this is used by the plugin to look up whether the resolution still works.
[0:01:40] Of course, you can add additional names here. For example, let's go with tribe29.com. We also want to be sure that that is available.
[0:01:51] So, that's really all there is to do to configure the plugin. And with that I'm going to save that rule, activate changes, and bake the agents.
[0:02:10] And after baking the automatic updates, we'll take care of updating the agent. And then it takes a few moments for the DNS resolution to actually be carried out and to produce the first check result. 
[0:02:21] So, it can take a few seconds for that to actually occur. I'm just going to give the agent updater here a little nudge, just to speed up the process.
[0:02:35] And then we can go to our host. So, let's take a look at the service configuration.
[0:02:48] And as said, this might take a few moments until we see the service here. So, here's our two services. We can see both domain names were resolved into IP addresses, the resolution works. We would be aware if one of those doesn't work.
[0:03:13] So, as a first step, you now can detect issues in the local DNS resolution on your Linux system. 
[0:03:23] But you could also use this service to be sure that a certain domain name is still resolvable by the local DNS resolver of your Linux system. 
[0:03:34] So, let's add these services. And then we are done. Normal DNS failures without our knowledge.
[0:03:45] So, that concludes today's video. Thank you guys so much for watching. Be sure to subscribe to never miss another video and I will see you around.

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