Zabbix Availability & Inventory

Server

zabbix-mcp — vendored third-party, read-only, three tools. See zabbix-metrics-history for the shared cautions.

⚠ The wording rule — this is the whole skill

> ### "Zabbix cannot reach it" is not "the device is down."

An NMS reports what one poller saw, from one vantage point, at one polling interval. That is evidence, not a verdict.

A device can be unreachable from Zabbix and completely healthy: a firewall rule, a management-VRF problem, a dead SNMP daemon on an otherwise forwarding router, or a poller that has simply not tried recently.

Never write "the device is down." Write:

> "Zabbix has been unable to reach rtr-01 since 14:02 UTC. That is the monitoring system's view from its > own vantage point — it is not confirmation the device is down. `pyats` or `multivendor-cli` can check the > device directly."

This is the same discipline globalping-external-checks applies to probes, and it matters more here, because an NMS feels authoritative in a way a probe network does not.

Four states, not two

| State | available | Say | |---|---|---| | Reachable | 1 | "Zabbix reached it at \<time>" | | Unreachable | 2 | "Zabbix cannot reach it as of \<time>" — never "it is down" | | Unknown | 0 | "Zabbix has not yet established reachability" — not the same as unreachable | | Not monitored | host absent | "this device is not monitored by Zabbix" — not the same as unreachable, and by far the most common cause of surprise |

jsonc
zabbix_api("host.get", {
  "output": ["hostid","host","name","status"],
  "selectInterfaces": ["interfaceid","ip","dns","port","available","error","errors_from"],
  "selectTags": "extend"
})

Always carry the time

Availability without a timestamp is a claim about the present that may be minutes or hours stale. Every answer states when that state was last observed. errors_from gives you when the failure began.

Down vs flapping — different problems

"It has been down for 40 minutes" and "it has bounced nine times in 40 minutes" lead to completely different investigations. Get the transitions, not just the current state — event.get against the unreachability trigger gives you the history.

Report the count of transitions as well as the current state whenever the window contains more than one.

Inventory — what is the NMS actually watching?

jsonc
zabbix_api("host.get",      {"output":["hostid","host","status"], "selectInterfaces":"extend",
                             "selectParentTemplates":["name"], "selectHostGroups":["name"]})
zabbix_api("hostgroup.get", {"output":"extend"})
zabbix_api("item.get",      {"hostids":["<id>"],
                             "output":["itemid","name","key_","value_type","units","history","trends","lastclock"]})

Two rules:

• A disabled host (status: 1) is shown as disabled, never omitted. A device nobody is watching is a

finding, not an absence — it is usually how a gap in monitoring is discovered.

• List items with their units and retention (history, trends). This lets an engineer see how far

back a question can be answered before they ask it, which is far better than asking and getting nothing.

An item whose lastclock is empty is monitored but has never returned a value — a broken poll, and a real finding. Do not report it as "no data".

Boundaries

| Want to… | Use | |---|---| | Metric values over time | zabbix-metrics-history | | Problems and alerts | zabbix-problem-review | | Unsolicited traps | snmptrap-mcp — push, not poll | | Flows | ipfix-mcp | | Instrumented metrics | prometheus, grafana | | SaaS monitoring | auvik, thousandeyes, datadog | | Confirm whether a device is actually down | pyats, multivendor-cli, fortinet — go ask the device. This skill only reports what the poller saw | | Add, enable or disable a host | nothing here. Read-only; NMS configuration is out of scope entirely |

Rules

1. Never say "the device is down." Say what Zabbix observed, and when.
2. Always timestamp the observation.
3. Not monitored ≠ unreachable. Check before you conclude.
4. Report flap counts, not just current state.
5. Show disabled hosts. Omitting them hides the gap.
6. Read-only.