Host groups

As the name suggests, a host group is nothing more than a container that holds various hosts. This makes it possible to have all your database systems visible as status objects from one view, or to have multiple database host groups depending on the type of database. Base your host groups on what your organization needs.

Host groups can be created by going to settings | Groups | Host Groups .

The following screenshot shows the default host group of Monitoring Servers, which contains the Opsview host:

So let's create our own host group by clicking on the add icon (as shown in Chapter 1, Opsview Core Basics), then enter a name (test group 1 for instance), and submit the changes. Repeat this to create a couple of host groups (we will use them later on). We should now see two (or more) host groups, one containing the Opsview host and the other containing no hosts.

Deleting host groups is possible only when it contains no hosts; if you wish to remove a host group, first move all the hosts to another group. Try to keep the naming of your host groups logical so that others can easily navigate through the various groups.

Host group hierarchy

Once we have created a couple of host groups, we might want to group some of them together to create a tree-based view or a hierarchical view. Using the host group hierarchy, we can add host groups with similar systems together, or even group them based on departments, or order by relevance.

For this, we use the host group hierarchy view by going to settings | Groups | Host Group.

We can also use this view to move host groups from one group to another by simply dragging-and-dropping them. If you have made the test groups, try moving them around.

Setting up a good structure for your host groups is very important. So, make sure to fit it to your organization's needs as it will make traversing the host group view, under monitoring | Status Summary | Host Groups, a lot easier.

A good structure will also help in setting up your roles (status objects) making sure everyone sees the information they need to access (or need to be able to configure).

Shown here is an example of a host group hierarchy divided into smaller groups depending on the application or database, with databases split into MySQL and Oracle, applications split into Finance or HR, and so on.

Hosts

Now that we have a basic layout of host groups and our hierarchy, it is time to add our hosts to the system. For this, we go to settings | Basic | Hosts. The screen will currently have only the Opsview host defined. Just add a host by clicking on the add icon or by cloning. Cloning is a great way of adding similar hosts in a fast and efficient way.

When we add a new host, there are some options we can fill out or choose from. For now, we will stick to the defaults for most values and focus on the most important parts (but do take some time to look at the various options available on this screen).

The following screenshot shows a small portion of the New Host page:

There are two required fields in the host screen, Primary Hostname / IP (which is either an IP address or a Fully Qualified Domain Name) and Host Title (which is how the host will be displayed within Opsview).

There is a very important distinction between the two fields and how they are applied within service checks and within Opsview in terms of information management.

Imagine that we have a host named hostX with Primary Hostname as hostx.example.com, but we need to migrate it to hostx.second.example.com. By simply changing the primary hostname, all the data collected for hostX is preserved (all the data is collected under the Host Title).

Now let's create a test host so we can see the process involved in adding a new host.

Set the primary hostname and input a host title, select an appropriate host group (and icon if you want) and click on Next, which will take us to the notification screen, as shown in the following screenshot:

Select any settings you want, after which we can Submit our changes and then we will have added a new host to our system.

There are a number of tabs available within the host edit screen, each responsible for various settings. Take some time to look around in these tabs, but don't worry though as all these tabs will be discussed in this chapter and the following chapter.

Now that we have created our first host, let's make another one; but instead of using the add icon let's use the clone function. Simply click on the clone icon in front of our first host and we will go to the edit screen of our new host. Make any adjustments that are required (like host title) and needed (like primary hostname) and submit.

Using the clone function makes adding new hosts a lot easier and faster. So, when you are adding new hosts in Opsview, always look for a similar host already there, or maybe even create some example hosts that contain just the basics.

Host templates

While adding the host, you might have noticed the host template section at the bottom of the edit screen. Much like a host group is a group of hosts, a host template is a set of service checks grouped together for a specific purpose.

By default, Opsview comes with a vast amount of readymade templates containing checks for the most common applications. To find out what a template does, select it from the right-hand side column and click on Template details.

You can create your own templates by going to settings | Basic | Host Templates and clicking on the add icon.

As shown in the following screenshot, our new host template contains a number of tabs:

Enter the name of your template and a clear description of its intended purpose in the Host Template tab.

From the Monitors tab, which we have in the host edit screen too, you can select any service check that you wish to include in the template. Service checks are grouped by service group, both of which we will discuss soon.

In the Management URL section, you can add references to online documentation or internal wikis. These URLs will then be made available in the contextual menu when the host is viewed in the monitoring view.

You can use multiple host templates within a single host, where any duplicate settings (or service checks) in the template are handled based on the order in which the templates are applied, with the first template taking precedence.

Any check directly assigned to a host, through the Monitors tab in the host edit screen, will take precedence over any duplicate checks assigned through a host template. To assign a template to a host, simply edit the host, select the template, and click on the arrow pointing to the left. You can use the up and down arrows to reorder your templates. The Opsview host with multiple templates assigned is shown here:

You can also edit the host template and add the host to the template. Remember that the order of the templates does matter, so doing this from the host gives more priority to that template.