uptime

Time since boot of a Linux host, by SNMP

Returns the time since the system booted, in hours. One watch is offered: a recent reboot.

How it works

The collector reads hrSystemUptime (HOST-RESOURCES-MIB), the system's time since boot in hundredths of a second, and not sysUpTime, the SNMP agent's own, which restarts each time snmpd does.

• A reboot shows as a time since boot shorter than the threshold of "Recent reboot".

Prerequisites

• snmpd (net-snmp) running on the host, listening on an address the poller reaches (UDP 161), with the firewall open to the poller only.
• The view granted to the poller includes hrSystem (.1.3.6.1.2.1.25.1), which most default configurations already allow.
• Read-only access, SNMPv2c or SNMPv3, set on the host or one of its folders (protocol:snmp:* variables).

# /etc/snmp/snmpd.conf
agentaddress udp:161
view   banshee included .1.3.6.1.2.1.25.1
rocommunity <community> 192.0.2.10 -V banshee
# or: rouser <user> priv -V banshee

Outputs

Watches

Limits

• hrSystemUptime counts hundredths of a second on 32 bits: it wraps every 497 days, which the watch takes for a reboot.
• A reboot shorter than the probe's interval is seen only if the threshold is longer than that interval.