Table of Contents
OS Agent - Monitor
The Monitor tab lists every host that pushes metrics to this Collector, with their status and last activity. It is also where you can link a host to a System, deactivate it, or remove it.
Host list
Each row shows:
| Column | Meaning |
| Hostname | The host's network name as reported in the host tag of the push. Case-insensitive, used as the unique identifier inside the Collector. |
| System | The linked System short name, or - if the host is standalone. |
| Status | OK / ERROR / OFF. See below. |
| OS | linux, windows, or empty when not detected. |
| Last Push | Time of the last received push. Never if the host has been registered but never pushed. |
| Active | ON (accepts pushes) or OFF (rejects pushes with 403). |
Click a row to expand the detail for the host.
Status values
OK(green) - the host is active and has pushed within the last 5 minutesERROR(red) - the host is active but has not pushed in the last 5 minutesOFF(grey) - the host is set inactive in the Collector - all incoming pushes for this host are rejected
The 5-minute threshold is fixed in the Collector. Telegraf default flush interval is 15 seconds, so a missed push of more than 20 cycles is a real problem (network down, Telegraf crashed, host shut down).
Host detail (expanded)
When you click a host row, the panel below shows the last received values:
Top metrics grid
Four big cards: CPU, Memory, Swap, Load Average. Each shows the latest known value (used percent for CPU/Mem/Swap, 1-minute load with 5m/15m below).
Disk Usage
A table with one row per mount point (Linux) or drive letter (Windows), with the used percent. Color codes:
- < 75% → green
- 75-90% → orange
- > 90% → red
Top Processes
A table with the top processes ranked by CPU, Memory, or Disk I/O (button toggles at the top right of the panel). Up to 20 processes are listed.
- CPU % - per-process CPU usage as reported by Telegraf
- Memory - resident set size (RSS) - actual physical memory used
- Disk I/O - read and write bytes since the process started
If you do not see any process, the most likely causes are:
- The process input is not enabled in the Configuration tab → enable it and redeploy the agent
- The agent has not pushed yet → wait 30 seconds (procstat sends every 30s by default)
- On Linux Docker without
SYS_PTRACE, the process list works but read/write bytes will be zero (see the process monitoring section)
Bottom info row
- Processes - total / running / zombies (from the
processesinput - Linux only) - Network - bytes sent (↑) and received (↓) per interface, in human-readable units
- First Seen - when the host was first auto-discovered
Actions per host
Remap to a System
Use the Remap to System dropdown to link the host to a System (or set it back to Standalone).
- When a host is linked to a System, its metrics get the System tags automatically (sid, system name, etc.) - dashboards by System include them
- When standalone, metrics are stored with only the host tag - they still go through the pipeline but they are not associated to any System
Click Save to apply the link.
Activate / Deactivate
The Activate / Deactivate button (pause icon when ON, play when OFF) toggles the Active flag on the host:
- OFF rejects every incoming push from this host with 403 Forbidden
- ON accepts pushes again
Useful when you want to silence a host temporarily without uninstalling Telegraf.
Delete
Removes the host from the database. The next push from this host will re-create it as a new entry (with Standalone link, so you will need to re-map it).
Use this to clean up old hosts that no longer exist.
Refresh
A Refresh button at the top of the panel reloads the host list and detail. The list does not auto-refresh - click Refresh after waiting a few seconds to see the new values.
Auto-discovery
Hosts appear automatically the first time they push successfully:
- The Collector parses the
hosttag from the first metric line - It checks the in-memory map and the database
- If unknown, tries to resolve a System by matching the hostname (case-insensitive) against the existing connectors
- If it matches a connector, the host is auto-linked to that System
- Otherwise the host is standalone
You do not need to pre-register hosts. Just install Telegraf and they show up.
