JAILS-MIB

All MIBs › JAILS-MIB

Organization: Stef Walter

Last Updated: 2009-03-01

Category: Domain: Server/Host Monitoring, Net-SNMP and Linux

Description: Defines managed objects for monitoring FreeBSD jail containers, providing status, resource usage, and configuration information for each active jail.

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What Is JAILS-MIB?

JAILS-MIB is the MIB for the bsnmp-jail module, providing management objects for monitoring FreeBSD jail containers (lightweight OS-level virtualization instances) on a FreeBSD host. It exposes a count of active jails and a per-jail table giving each jail's identifying host name/index along with network traffic and resource-usage figures. Explicitly for monitoring software status of a system, it reports per-jail process and thread counts and CPU time consumed, alongside inbound/outbound octet and packet counters, letting an administrator see which jail is consuming excessive CPU or generating unusual network load. It is tied specifically to the FreeBSD jail subsystem and the bsnmp agent framework rather than a general IETF MIB. The JAILS-MIB monitor is typically deployed on FreeBSD servers hosting multiple jailed application environments where operators need per-container visibility via SNMP.

IPNetwork Monitor allows you to monitor SNMP objects defined in JAILS-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

FreeBSD server running jail containers

Monitoring Examples

An administrator would poll jailCount to see how many jails are currently active, then walk jailTable/jailEntry (indexed by jailIndex) to read jailHost, jailProcesses, jailThreads, and jailCpuTime for each jail. A jail with jailCpuTime climbing much faster than its peers, or jailProcesses/jailThreads far above baseline, would indicate a runaway process inside that container. jailInOctets/jailOutOctets and jailInPackets/jailOutPackets reveal which jail is driving unexpected network traffic.

What Can Be Monitored

active jail count
per-jail CPU time
per-jail process and thread counts
per-jail inbound/outbound traffic (octets and packets)

Imported Objects

From BEGEMOT-MIB

begemot

MODULE-IDENTITY

From SNMPv2-SMI

Counter64
Integer32
MODULE-IDENTITY
OBJECT-TYPE
TimeTicks
Unsigned32

How to Use in IPNetwork Monitor

Example using jailInOctets OID:

Select a FreeBSD server running jail container (bsnmp-jail) as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type jailInOctets into the Find box to locate it in the OID tree, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. It reports the number of octets received by this jail. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is a Counter64-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases sharply between polls relative to its normal baseline, since an unexpected spike often reflects a real change in traffic or activity. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
jails	1.3.6.1.4.1.12325.1.1111			The MIB for the bsnmp-jail module.
I32 jailCount	1.3.6.1.4.1.12325.1.1111.1	Integer32	read-only	The number jails running on the system.
jailTable	1.3.6.1.4.1.12325.1.1111.2		not-accessible	A list of entries representing jails running on the system. The number of entries is given by the value of jailCount.
jailEntry	1.3.6.1.4.1.12325.1.1111.2.1		not-accessible	An entry containing information about a running jail.
I32 jailIndex	1.3.6.1.4.1.12325.1.1111.2.1.0	Integer32	read-only	Index of this jailEntry.
OCT jailHost	1.3.6.1.4.1.12325.1.1111.2.1.1	OCTET STRING	read-only	The host name of this jail.
C64 jailInOctetsEx	1.3.6.1.4.1.12325.1.1111.2.1.10	Counter64	read-only	Number of octets received by this jail.
C64 jailInPackets	1.3.6.1.4.1.12325.1.1111.2.1.11	Counter64	read-only	Number of packets received by this jail.
C64 jailOutOctets	1.3.6.1.4.1.12325.1.1111.2.1.12	Counter64	read-only	Number of octets sent by this jail.
C64 jailOutPackets	1.3.6.1.4.1.12325.1.1111.2.1.13	Counter64	read-only	Number of packets sent by this jail.
I32 jailProcesses	1.3.6.1.4.1.12325.1.1111.2.1.20	Integer32	read-only	Number of processes running in this jail.
I32 jailThreads	1.3.6.1.4.1.12325.1.1111.2.1.21	Integer32	read-only	Number of threads running in this jail.
TIK jailCpuTime	1.3.6.1.4.1.12325.1.1111.2.1.25	TimeTicks	read-only	Amount of CPU time taken by this jail.
C64 jailDiskSpace	1.3.6.1.4.1.12325.1.1111.2.1.30	Counter64	read-only	Amount of disk space taken by this jail. Zero means unknown.
C64 jailDiskFiles	1.3.6.1.4.1.12325.1.1111.2.1.31	Counter64	read-only	Number of files (inodes) in this jail. Zero means unknown.

RFC description

Monitors jail instances with CPU, memory, disk, and network statistics on FreeBSD systems.

Start monitoring FreeBSD server running jail containers (bsnmp-jail) with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download JAILS-MIB