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UPSMON.CONF(5) NUT Manual UPSMON.CONF(5) NAME upsmon.conf - Configuration for Network UPS Tools upsmon client DESCRIPTION This file's primary job is to define the systems that upsmon(8) will moni- tor, and to tell it how to shut down the system when necessary. It will contain passwords, so keep it secure. Ideally, only the upsmon process should be able to read it. A minimal configuration should include at least one MONITOR instruction, MINSUPPLIES (may be 0 if this system is only monitoring other NUT servers), and a POWERDOWNFLAG if this machine is a "primary" system connected to the UPS and drives its late-shutdown power-off command in case of an emergency. Additionally, other optional configuration values can be set in this file. IMPORTANT NOTES * Contents of this file should be pure ASCII (character codes not in range would be ignored with a warning message). * Balance the run-time user permissions to access the file (and perhaps the directory it is in) for only upsmon to be able to read it; write access is not needed. It is common to use chown root:nut and chmod 640 to set up acceptable file permissions. * Packages (and build recipes) typically prepare one set of user and group accounts for NUT. Custom builds with minimal configuration might even use nobody:nogroup or similar, which is inherently inse- cure. * On systems with extra security concerns, NUT drivers, data server, and any other monitoring, logging, etc. clients, should run as sep- arate user accounts. This would need some daemons to use customized user, group, RUN_AS_USER and/or RUN_AS_GROUP settings to override the single built-in value. * Keep in mind the security of also any backup copies of this file, e.g. the archive files it might end up in. CONFIGURATION DIRECTIVES DEADTIME seconds upsmon allows a UPS to go missing for this many seconds before declar- ing it "dead". The default is 15 seconds. upsmon requires a UPS to provide status information every few seconds (see POLLFREQ and POLLFREQALERT) to keep things updated. If the status fetch fails, the UPS is marked stale. If it stays stale for more than DEADTIME seconds, the UPS is marked dead. A dead UPS that was last known to be on battery is assumed to have changed to a low battery condition. This may force a shutdown if it is providing a critical amount of power to your system. This seems disrup- tive, but the alternative is barreling ahead into oblivion and crashing when you run out of power. Note: DEADTIME should be a multiple of POLLFREQ and POLLFREQALERT. Oth- erwise, you'll have "dead" UPSes simply because upsmon isn't polling them quickly enough. Rule of thumb: take the larger of the two POLLFREQ values, and multiply by 3. FINALDELAY seconds When handling a forced shutdown (FSD) due to a critical UPS state or explicit user signal, upsmon waits this long after sending the NO- TIFY_SHUTDOWN message to warn the users. After the timer elapses, it then runs your SHUTDOWNCMD. By default this is set to 5 seconds. If you need to let your users (or the NOTIFYCMD script) do something in between those events, increase this number. Remember, at this point your UPS battery is almost depleted, so don't make this too big. Alternatively, you can set this very low so you don't wait around when it's time to shut down. Some UPSes don't give much warning for low bat- tery and will require a value of 0 here for a safe shutdown. Note If FINALDELAY on the secondary is greater than HOSTSYNC on the pri- mary, the primary will give up waiting for that secondary upsmon to disconnect. HOSTSYNC seconds upsmon will wait up to this many seconds in primary mode for the secon- daries to disconnect during a shutdown situation. By default, this is 15 seconds. When a UPS goes critical (on battery + low battery, or "FSD": forced shutdown), the secondary systems are supposed to disconnect and shut down right away. The HOSTSYNC timer keeps the primary upsmon from sit- ting there forever if one of the secondaries gets stuck. This value is also used to keep secondary systems from getting stuck if the primary fails to respond in time. After a UPS becomes critical, the secondary will wait up to HOSTSYNC seconds for the primary to set the FSD flag. If that timer expires, the secondary upsmon will assume that the primary (or communications path to it) is broken and will shut down anyway. This keeps the secondaries from shutting down during a short-lived sta- tus change to "OB LB" and back that the secondaries see but the primary misses. MINSUPPLIES num Set the number of power supplies that must be receiving power to keep this system running. Normal computers have just one power supply, so the default value of 1 is acceptable. Large/expensive server type systems usually have more, and can run with a few missing. The HP NetServer LH4 can run with 2 out of 4, for exam- ple, so you'd set it to 2. The idea is to keep the box running as long as possible, right? Obviously you have to put the redundant supplies on different UPS cir- cuits for this to make sense! See big-servers.txt in the docs subdirec- tory for more information and ideas on how to use this feature. Also see the section on "power values" in upsmon(8). MONITOR system powervalue username password type Each UPS that you need to be monitor should have a MONITOR line. Not all of these need supply power to the system that is running upsmon. You may monitor other systems if you want to be able to send notifica- tions about status changes on them. You must have at least one MONITOR directive in upsmon.conf. * system is a UPS identifier. It is in this form: <upsname>[@<hostname>[:<port>]] The default hostname is "localhost". Some examples: * "su700@mybox" means a UPS called "su700" on a system called "mybox". This is the normal form. * "fenton@bigbox:5678" is a UPS called "fenton" on a system called "bigbox" which runs upsd(8) on port "5678". * powervalue is an integer representing the number of power supplies that the UPS feeds on this system. Most normal computers have one power supply, and the UPS feeds it, so this value will be 1. You need a very large or special system to have anything higher here. You can set the powervalue to 0 if you want to monitor a UPS that doesn't actually supply power to this system. This is useful when you want to have upsmon do notifications about status changes on a UPS without shutting down when it goes critical. * The username and password on this line must match an entry in the upsd server system's upsd.users(5) file. If your username is "observer" and your password is "abcd", the MONITOR line might look like this (likely on a remote secondary system): MONITOR myups@bigserver 1 observer abcd secondary Meanwhile, the upsd.users on bigserver would look like this: [observer] password = abcd upsmon secondary [upswired] password = blah upsmon primary And the copy of upsmon on that bigserver would run with the primary configuration: MONITOR myups@bigserver 1 upswired blah primary * The type refers to the relationship with upsd(8). It can be either "primary" or "secondary". See upsmon(8) for more information on the meaning of these modes. The mode you pick here also goes in the upsd.users file, as seen in the example above. NOCOMMWARNTIME seconds upsmon will trigger a NOTIFY_NOCOMM after this many seconds if it can't reach any of the UPS entries in this configuration file. It keeps warn- ing you until the situation is fixed. By default this is 300 seconds. POLLFAIL_LOG_THROTTLE_MAX count upsmon normally reports polling failures for each device that are in place for each POLLFREQ loop (e.g. "Data stale" or "Driver not con- nected") to system log as configured. If your devices are expected to be AWOL for an extended timeframe, you can use this throttle to reduce the stress on syslog traffic and storage, by posting these messages only once in every several loop cycles, and when the error condition has changed or cleared. A negative value means standard behavior (log on every loop, effec- tively same as when max=1), and a zero value means to never repeat the message (log only on start and end/change of the failure state). Note that this throttle only applies to one latest-active error state per monitored device. NOTIFYCMD command upsmon calls this to send messages when things happen. This command is called with the full text of the message as one argu- ment. The environment string NOTIFYTYPE will contain the type string of whatever caused this event to happen. If you need to use upssched(8), then you must make it your NOTIFYCMD by listing it here. Note that this is only called for NOTIFY events that have EXEC set with NOTIFYFLAG. See NOTIFYFLAG below for more details. Making this some sort of shell script might not be a bad idea. For more information and ideas, see docs/scheduling.txt Remember, this command also needs to be one element in the configura- tion file, so if your command has spaces, then wrap it in quotes. NOTIFYCMD "/path/to/script --foo --bar" This script is run in the background--that is, upsmon forks before it calls out to start it. This means that your NOTIFYCMD may have multiple instances running simultaneously if a lot of stuff happens all at once. Keep this in mind when designing complicated notifiers. NOTIFYMSG type message upsmon comes with a set of stock messages for various events. You can change them if you like. NOTIFYMSG ONLINE "UPS %s is getting line power" NOTIFYMSG ONBATT "Someone pulled the plug on %s" Note that %s is replaced with the identifier of the UPS in question. The message must be one element in the configuration file, so if it contains spaces, you must wrap it in quotes. NOTIFYMSG NOCOMM "Someone stole UPS %s" Possible values for type: ONLINE UPS is back online ONBATT UPS is on battery LOWBATT UPS is on battery and has a low battery (is critical) FSD UPS is being shutdown by the primary (FSD = "Forced Shutdown") COMMOK Communications established with the UPS COMMBAD Communications lost to the UPS SHUTDOWN The system is being shutdown SHUTDOWN_HOSTSYNC This primary system began the shutdown, and is waiting for secon- daries REPLBATT The UPS battery is bad and needs to be replaced NOCOMM A UPS is unavailable (can't be contacted for monitoring) NOPARENT upsmon parent process died - shutdown impossible CAL UPS calibration in progress NOTCAL UPS calibration finished OFF UPS administratively OFF or asleep NOTOFF UPS no longer administratively OFF or asleep BYPASS UPS on bypass (powered, not protecting) NOTBYPASS UPS no longer on bypass ECO UPS in ECO or similar mode (as defined and named by vendor); for more details see upsmon(8). NOTECO UPS no longer in ECO mode (see above) ALARM UPS has one or more active alarms (check ups.alarm); for this noti- fication, the message can contain a second %s placeholder to sub- stitute the current value of ups.alarm. NOTALARM UPS is no longer in an alarm state (no active alarms) OVER UPS is overloaded NOTOVER UPS is no longer overloaded TRIM UPS is trimming incoming voltage NOTTRIM UPS is no longer trimming incoming voltage BOOST UPS is boosting incoming voltage NOTBOOST UPS is no longer boosting incoming voltage OTHER UPS has at least one unclassified ups.status token; for this noti- fication, the message can contain a second %s placeholder to sub- stitute the current collection of such tokens. NOTOTHER UPS has no unclassified status tokens anymore SUSPEND_STARTING OS is entering sleep/suspend/hibernate mode SUSPEND_FINISHED OS just finished sleep/suspend/hibernate mode, de-activating obso- lete UPS readings to avoid an unfortunate shutdown NOTIFYFLAG type flag[+flag]... By default, upsmon sends walls global messages to all logged in users) via /bin/wall and writes to the syslog when things happen. Except for Windows where upsmon only writes to the Event Log by default. You can change this. Examples: NOTIFYFLAG ONLINE SYSLOG NOTIFYFLAG ONBATT SYSLOG+WALL+EXEC Possible values for the flags: SYSLOG Write the message to the syslog WALL Write the message to all users with /bin/wall EXEC Execute NOTIFYCMD (see above) with the message IGNORE Don't do anything If you use IGNORE, don't use any other flags on the same line. POLLFREQ seconds Normally upsmon polls the upsd(8) server every 5 seconds. If this is flooding your network with activity, you can make it higher. You can also make it lower to get faster updates in some cases. There are some catches. First, if you set the POLLFREQ too high, you may miss short-lived power events entirely. You also risk triggering the DEADTIME (see above) if you use a very large number. Second, there is a point of diminishing returns if you set it too low. While upsd normally has all of the data available to it instantly, most drivers only refresh the UPS status once every 2 seconds. Polling any more than that usually doesn't get you the information any faster. Note This setting is different from a pollfreq supported by some of the NUT driver programs, such as usbhid-ups(8) (about how often the driver polls a particular device). POLLFREQALERT seconds This is the interval that upsmon waits between polls if any of its UP- Ses are on battery. You can use this along with POLLFREQ above to slow down polls during normal behavior, but get quicker updates when some- thing bad happens. This should always be equal to or lower than the POLLFREQ value. By de- fault it is also set 5 seconds. The warnings from the POLLFREQ entry about too-high and too-low values also apply here. POWERDOWNFLAG filename upsmon creates this file when running in primary mode when the UPS needs to be powered off. You should check for this file in your late shutdown scripts and call upsdrvctl shutdown if it exists; note that upsmon -K may be called for this effect, if NUT configuration files re- main readable at that point (file systems mostly unmounted or changed to read-only). Historically it was often /etc/killpower but nowadays you may want it in a temporary filesystem (e.g. under (/var)/run or even a dedicated (/var)/run/nut location). Note that double backslashes must be used for Windows paths, e.g. C:\\Temp\\killpower (modern Windows may also accept forward slashes like C:/Temp/killpower but YMMV). This is done to forcibly reset the secondary systems, so they don't get stuck at the "halted" stage even if the power returns during the shut- down process. This usually does not work well on contact-closure UPSes that use the genericups driver. Warning The upsmon binary program does not have a built-in default, so this setting MUST be specified in the configuration, in order for the late shutdown integration to work on the particular primary-mode system! See the config-notes.txt file in the docs subdirectory for more infor- mation. Refer to the section: "Configuring automatic shutdowns for low battery events", or refer to the online version. OFFDURATION seconds NUT supports an "administrative OFF" for power devices which can be managed to turn off their application workload, while the UPS or ePDU remains accessible for monitoring and management. This toggle allows to delay propagation of such state into a known loss of a feed (possibly triggering FSD on upsmon clients which MONITOR the device and are in fact still alive -- e.g. with multiple power sources or because they as the load are not really turned off), because when some devices begin battery calibration, they report "OFF" for a few seconds and only then they might report "CAL" after switching all the power relays -- thus causing false-positives for upsmon FSD trigger. A negative value means to disable decreasing the counter of working power supplies in such cases, and a zero makes the effect of detected "OFF" state immediate. Built-in default value is 30 (seconds), to put an "OFF" state into effect (decrease known-fed supplies count) if it persists for this many seconds. Note So far we support the device reporting an "OFF" state which usually means completely un-powering the load; a bug-tracker issue was logged to design similar support for just some manageable outlets or outlet groups. OVERDURATION seconds This setting handles how a UPS that is overloaded should be treated in situations when it is not fully communicating. Because such a UPS may be in a potentially severe state, some users may want their systems to be shutdown either immediately or after a set timeout has elapsed. The OVERDURATION setting defines this timeout (in seconds), after which an overloaded UPS that is not communicating will be considered critical. A negative value means an overloaded UPS will never be considered crit- ical (at least not because of the overload itself). A value of zero means the UPS will instantly be considered critical when overloaded and not communicating. Built-in default value is -1 (seconds). Note This setting only affects the behavior when a UPS is both over- loaded and not communicating. When the UPS is communicating nor- mally, an overload condition may raise notifications but won't trigger a system shutdown on its own. OBLBDURATION seconds NUT normally raises alarms for immediate shutdown (FSD) for consumers of an UPS known to be on battery ("OB") and achieving the low battery status ("LB"), if that is their last remaining power source to satisfy their MINSUPPLIES setting. In some special cases, users may want to de- lay raising the alarm (using the OBLBDURATION option) at their discre- tion and risk of an ungraceful shutdown. A positive value puts "OB LB" state into effect only if it persists for this many seconds. A non-positive value makes the FSD effect of de- tected "OB LB" state immediate. Built-in default value is 0 (seconds). Note If both OBLBDURATION and HOSTSYNC options are set on the same (sec- ondary) upsmon client system, and HOSTSYNC is shorter, it would be effectively ignored: upsmon would wait for up to OBLBDURATION sec- onds for the "OB LB" state to clear, and then the secondary client logic would fall through to immediate shutdown. If the primary sys- tem issues an FSD on this UPS, that would take an even higher-pri- ority effect as soon as seen. RBWARNTIME seconds When a UPS says that it needs to have its battery replaced, upsmon will generate a NOTIFY_REPLBATT event. By default, this happens every 43200 seconds (12 hours). If you need another value, set it here. ALARMCRITICAL 0 | 1 NUT normally considers UPS with active alarms as volatile, meaning they are observed more closely and may be considered critical/dead earlier than in other regular UPS statuses. This is especially true for no-com- munication situations, where UPS in an ALARM status will be considered lost and system shutdowns may be triggered as a product. As there is no common standard for what constitutes an alarm, such alarm states may in fact be mundane in nature and the behavior above unwanted due to possibly resulting in unwarranted system shutdowns. When this setting is disabled, upsmon will consider a UPS in an alarm state as not volatile and make it treat the ALARM status as any other. RUN_AS_USER username upsmon normally splits into two processes, keeping a small part which remains owned by root to initiate the system shutdown by calling SHUT- DOWNCMD when/if the time comes, and runs the bulk of the monitoring du- ties under another user ID after dropping root privileges. On most cus- tom-built systems this means it runs as "nobody", since that's the de- fault from compile-time; packages often deliver a "nut" or "ups" user to run NUT service daemons. The catch is that the system-default "nobody" can't read your up- smon.conf file, since by default it is installed so that only root can open it (because this file can contain sensitive data like remote NUT data server credentials). This means you won't be able to reload the configuration file, since it will be unavailable to the unprivileged part of the upsmon daemon. The solution is to create a new user just for upsmon, then make it run as that user. It may be the same account as that used for the NUT dri- vers or data server, but does not have to be. On systems with higher concerns about security and privilege separation we suggest "nutmon", but you can use anything that isn't already taken on your system. Just create a regular user with no special privileges and an impossible password. Then, tell upsmon to run as that user, and make upsmon.conf readable by it. Your reloads will work, and your config file will stay secure. This file should not be writable by the upsmon user, as it would be possible to exploit a hole, change the SHUTDOWNCMD to something mali- cious, then wait for upsmon to be restarted. So typically you would also create a group for NUT daemons (which the user would be a member of) and allow that group read-only access to root-owned configuration files. That said, other variants may be possible -- e.g. run all of upsmon as a single process initially started and owned by nut and call a shutdown script prefixed by sudo, pfexec or other RBAC tools. This however adds more "moving parts" and fragility (e.g. the sudoers settings may live in LDAP, and that server could be unavailable at shutdown when the rack is half powered off, at just the time you need it here), and is not available on all platforms -- so such setups are something users ex- plore on their own so far (we would welcome posts on NUT Wiki or links to blogs though). SHUTDOWNCMD command upsmon runs this command when the system needs to be brought down. If it is a secondary, it will do that immediately whenever the current overall power value drops below the MINSUPPLIES value above. When upsmon is a primary, it will allow any secondaries to log out be- fore starting the local shutdown procedure. Note that the command needs to be one element in the config file. If your shutdown command includes spaces, then put it in quotes to keep it together, i.e.: SHUTDOWNCMD "/sbin/shutdown -h +0" SHUTDOWNEXIT boolean|number After initiating shutdown, should this upsmon daemon itself exit? By doing so NUT secondary systems can tell the NUT primary that it can proceed with its own shutdown and eventually tell the UPS to cut power for the load. ("Yes" by default) Some "secondary" systems with workloads that take considerable time to stop (e.g. virtual machines or large databases) can benefit from re- porting (by virtue of logging off the data server) that they are ready for the "primary" system to begin its own shutdown and eventually to tell the UPS to cut the power -- not as soon as they have triggered their own shutdown, but at a later point (e.g. when the upsmon service is stopped AFTER the heavier workloads). Note that the actual ability to complete such shutdown depends on the remaining battery run-time at the moment when UPS power state becomes considered critical and the shutdowns begin. You may also have to tune HOSTSYNC on the NUT primary to be long enough for those secondaries to stop their services. In practice, it may be worthwhile to investigate ways to trigger shutdowns earlier on these systems, e.g. by setting up upssched integration, or dummy-ups driver with overrides for stricter battery.charge or battery.runtime triggers than used by the rest of your servers. This option supports Boolean-style strings (yes/on/true or no/off/false) or numbers to define a delay (in seconds) between calling SHUTDOWNCMD and exiting the daemon. Zero means immediate exit (de- fault), negative values mean never exiting on its own accord. CERTPATH certificate database When compiled with SSL support, you can enter the certificate database path here. With NSS: Certificates are stored in a dedicated database (data split in 3 files). Specify the path of the database directory. With OpenSSL: Directory containing CA certificates in PEM format, used to verify the server certificate presented by the upsd server. The files each contain one CA certificate. The files are looked up by the CA sub- ject name hash value, which must hence be available. Alternatively, with OpenSSL the CERTPATH can specify a particular PEM file with a collection of multiple CA certificates, e.g. CERTPATH /etc/ssl/certs/ca-certificates.crt CERTFILE certificate file When compiled with SSL support with OpenSSL backend (since NUT v2.8.6), you can enter the client certificate file here. No-op in NSS builds which use CERTPATH for all purposes. The certificates must be in PEM format and must be sorted starting with the subject's certificate (server certificate), followed by intermedi- ate CA certificates (if applicable) and the highest level (root) CA. It should end with the server's private key corresponding to the certifi- cate. See docs/security.txt in NUT sources, or the Security chapter of the NUT User manual, for more information on the SSL support in NUT. CERTIDENT certificate name database password When compiled with SSL support, you can specify the certificate name to retrieve from the database, for the client to authenticate itself, and the password required to access the private key related to that cer- tificate. Up until NUT release v2.8.5 this was a no-op when built with OpenSSL. Now this feature is supported with both OpenSSL (fully with 1.1.0 or newer, just for private key password with older 1.0.2+ library and an empty "certificate name") and NSS backends. Note Be sure to enclose the "certificate name" in double-quotes if you are using a value with spaces in it. CERTHOST hostname certificate name certverify forcessl When compiled with SSL support, you can specify the security directive for each server you can contact. Each entry maps a server name with the expected certificate name and flags indicating if the server certificate must be "verified" (should the secure connection attempt be aborted upon mismatch or inability to verify?), and if the connection must be "secured" (should there be no fallback to plain-text?) Up until NUT release v2.8.5 this was a no-op when built with OpenSSL. Now this feature is supported with both OpenSSL >= 1.1.0 and NSS back- ends. Note Be sure to enclose "certificate name" in double-quotes if you are using a value with spaces in it. CERTVERIFY 0 | 1 When compiled with SSL support, make upsmon verify all connections with certificates. Without this, there is no guarantee that the upsd is the right host. Enabling this greatly reduces the risk of man-in-the-middle attacks. This effectively forces the use of SSL, so don't use this unless all of your upsd hosts are ready for SSL and have their certificates in order. When compiled with NSS support of SSL (also OpenSSL since NUT release v2.8.6), this can be overridden for certain hosts specified with a CERTHOST directive. FORCESSL 0 | 1 When compiled with SSL, specify that a secured connection must be used to communicate with upsd. If you don't use CERTVERIFY 1, then this will at least make sure that nobody can sniff your sessions without a large effort. Setting this will make upsmon drop connections if the remote upsd doesn't support SSL, so don't use it unless all of them have it running. When compiled with NSS support of SSL (also OpenSSL since NUT release v2.8.6), this can be overridden for certain hosts specified with a CERTHOST directive. DEBUG_MIN INTEGER Optionally specify a minimum debug level for upsmon daemon, e.g. for troubleshooting a deployment, without impacting foreground or back- ground running mode directly. Command-line option -D can only increase this verbosity level. Note If the running daemon receives a reload command, presence of the DEBUG_MIN NUMBER value in the configuration file can be used to tune debugging verbosity in the running service daemon (it is rec- ommended to comment it away or set the minimum to explicit zero when done, to avoid huge journals and I/O system abuse). Keep in mind that for this run-time tuning, the DEBUG_MIN value present in reloaded configuration files is applied instantly and overrides any previously set value, from file or CLI options, regardless of older logging level being higher or lower than the newly found number; a missing (or commented away) value however does not change the pre- viously active logging verbosity. SEE ALSO upsmon(8), upsd(8), nutupsdrv(8). Internet resources: The NUT (Network UPS Tools) home page: https://www.networkupstools.org/ Network UPS Tools 2.8.5. 08/04/2026 UPSMON.CONF(5)
NAME | DESCRIPTION | IMPORTANT NOTES | CONFIGURATION DIRECTIVES | SEE ALSO
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