Cálculo de ruido audible para condiciones de conductor húmedo

A host can be considered as a basic grouping unit in Zabbix's configuration. As you might remember, hosts are used to group items, which in turn are basic data acquiring structures. Each host can have any number of items assigned spanning all item types—Zabbix agents, simple checks, SNMP, IPMI, and so on. An item can't exist on its own, so hosts are mandatory.

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Zabbix does not allow a host to be "left alone", that is, not belonging to any group, since version 1.8. Let's look at what host groups we have currently defined—in the frontend, open Configuration | Host groups.

The first thing that catches the eye is that group Templates seems to have a large number of templates already. These are provided as examples, so that you can later quickly reference them for some hints on items. We'll ignore these for now. We can also see an empty Windows servers group, and the Zabbix Servers group which contains a single example host. The interesting part is at the top of the table—we can see both groups we created along the way with all the corresponding members. Note, you might be missing IPMI Host if you set up IPMI for one of the existing hosts. This table is fairly simple with just a group name, a count of the number of group members (individually denoting hosts and templates contained in the group), and individual members being listed.

As can be seen, individual members are color coded. Black: Normal, enabled host

Red: Normal, disabled host Grey: Host template •

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Let's create another host group and assign some hosts to it. Click the Create Group

button. Enter Test Group in the Group name field, then select Linux servers in the Group dropdown above the Other Hosts list box. In the filtered list, select our custom created hosts—A Test Host, Another Host, and IPMI Host (if applicable). You can use the Ctrl and Shift keys to select multiple entries. When you have these hosts selected, click the << button.

Now select SNMP Devices in the Group dropdown and select SNMP Device, then click on the << button again.

This form allows easy selection of any number of hosts to be added when a new group is created. You can freely move hosts from one box to another until you are satisfied with the result. When you are done, click Save.

A new group now appears in the list. As we can see, it contains the four hosts we just added.

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But wait, the two first groups have 3 and 2 hosts correspondingly.

Right, we forgot to add the snmptraps host. Move your mouse cursor over it—notice how this (and every other host on this page) is a link. Clicking it will take you to host details, so do that now. As we can see on the host editing form, it is already in one group, SNMP Devices. Click on Test Group in the Other Groups list box, then click the << button.

When you are done, click Save.

You have probably guessed by now that a host can belong to any number of groups. That allows you to choose grouping based on any arbitrary decisions, like having a single host in groups "Linux servers", "Europe servers", and "DB servers".

Now you are back in the host list, so return to host group list by navigating to

Configuration | Host groups. Test Group contains five hosts, as it should. Let's say you would like to disable a whole group of hosts, or even several host groups. Maybe you have a group of hosts that are retired, but that you don't want to delete just yet, or maybe you want to disable hosts created for testing when creating an actual production configuration on the Zabbix server. The group listing provides an easy way to do that. Mark the checkboxes next to Linux servers and SNMP Devices

entries, then choose Disable selected hosts action in the dropdown at the bottom of the list, then click the Go button and confirm the pop up.

After this operation, all black hosts should be gone—they should be red now, indicating they are in the disabled state.

This time you could also have marked checkbox next to Test Group only as Linux servers and SNMP Devices are subsets of Test Group, the final effect would be the same. After doing this, we remember that snmptraps is a generic SNMP trap receiving host which probably should be left enabled. Again, click on it to open the host editing details page.

While we have the host details page open, we can take a quick look at DNS name and IP address fields. As you can see, only a single IP and DNS field is available, and Connect to controls which is used for server-side initiated checks. This means that Zabbix currently does not natively support multihomed hosts, with the only exception being the ability to query IPMI on another IP address

It is a common practice to use a separate network for management interface access so that application caused problems on the network do not impact access to the management interfaces. If that is the case, Zabbix server will need access to the management network, and the host operating system should provide correct routing.

Change Status dropdown to Monitored and click Save.

You should now see a host list with one disabled host (indicated by red text saying

Not monitored in the Status column), and one enabled host (indicated by green text

Monitored in the Status column). Let's enable back the SNMP Device—click on the

Not monitored text next to it. That leaves us with two enabled devices on the list. Select Linux servers in the Group dropdown and mark checkboxes next to the still disabled ones (if you have three of them, you can use range select feature again by holding down Ctrl, clicking first entry, then last entry in the list that you want to see selected) and choose Activate selected in the dropdown at the bottom of the list, then click the Go button. Click on OK in the confirmation dialog. Finally, we are back to having all hosts enabled again. We used four methods to change host state here:

Changing state for whole groups in Configuration | Host groups area Changing state for a single host by changing the Status dropdown value in that host's properties page

Changing state for a single host by using controls for each host in the Status column in host configuration list

Changing state for a single host or multiple hosts by marking the relevant checkboxes in the host configuration list and using the controls at the bottom of the list

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We created the last host group by going through the group configuration screen. As you might remember, another way is to use the New group field when creating or editing the host—this created the group and simultaneously added the host to that group.

The host list in the configuration screen also is useful in another way. It provides a quite nice and quick way to see which hosts are down. While monitoring section gives quite extensive information on state of specific services and conditions on each device, sometimes you will want a quick peek at device status—for example, determining availability for all devices in a particular group such as printers, routers, or switches. Configuration divulges this information in a list that contains almost no other information to distract you. If we would now select all in the Group

dropdown, we would see all the hosts this installation has:

This time we are interested in two columns—Status and Availability. As can be seen, we have one host that is not monitored, and this information is easily

noticeable—printed in red, it stands out from the usual green entries. The availability column shows the internal state, as determined by Zabbix, for each host and for each polled item type. If Zabbix tries to get data from a host but fails, the availability of that host for this specific type of information is determined to be unavailable, as has happened here with Another Host. Both the availability status and error message are displayed and preserved for three separate types of items polled by the Zabbix server:

Zabbix agent (passive) SNMP

IPMI

On the other hand, the availability of the snmptraps host is unknown for all polled item types, as Zabbix has never tried to retrieve any data from it (that is, there are no items configured for it that Zabbix server polls). Again, both unknown and unavailability visually differ from the available hosts, providing a quick overview. That about wraps it up for host and host group management in Zabbix. Host group usefulness extends a bit past frontend management, though—we'll see how exactly in the next section.

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Users, user groups, and permissions