Overview of the Major Components of NMIS9
The NMIS9 daemon bin/nmisd
In NMIS9 almost all work is controlled, scheduled and executed by the nmis daemon and its worker child processes.
The nmis daemon is controllable using the typical service
interface with the service name being "nmis9d"; e.g. sudo service nmis9d restart
.
The daemon should be running by the end of the initial NMIS9 installation.
The primary CLI took bin/nmis-cli
The nmis-cli tool is your primary tool to interact NMIS on the command line; e.g. for querying the status of the nmis daemons, for scheduling new operations and for scheduling outages.
Besides these administrative duties the cli tool is currently the only entity that can create saved reports (which is scheduled using a minimal NMIS 9 cron job).
The Node administration CLI tool admin/node_admin.pl
Like with NMIS8, in NMIS9 nodes can be administered using the GUI or with the node_admin cli tool. NMIS9's version has a few extra features over NMIS8's but otherwise doesn't differ excessively.
The node admin tool is described in more detail on the Node Administration Tools page.
Because of its reliance on a database NMIS9 is more strict about identifying objects, which means that nodes for example are identified exclusively by UUIDs. Node names are of course still present, but as informal properties only. The relationship between these is queried most easily by the node_admin tool using the act=list_uuid
operation.
The GUI
The adminstrative capabilities of the NMIS9 GUI are almost identical to how NMIS8 worked; the only major exception being that "Edit and Update Node" cannot display any logs of the Node Update operation as that's scheduled asynchronously. The NMIS9 GUI plays a slightly more passive and and limited role, i.e. only schedules certain operations for the nmis daemon to pick up - different from NMIS8 where some of these were executed directly by GUI components.
The Database
NMIS9 makes extensive use of MongoDB behind the scenes; most of the time that should be invisible to you past the initial installation stage, where you will have to interact with setup_mongodb.pl
to prime the environment.
NMIS9 is much more powerful than NMIS8 when it comes to clustering; amongst other things that also means that each NMIS9 installation has to be uniquely identified by what we call its cluster_id
configuration setting (which is automatically generated for you during the initial installation).
Interacting with the daemon directly
The NMIS9 daemon only accepts a small number of command line arguments, which are shown when you run it with -h
or --help
:
./bin/nmisd -? Usage: nmisd [option=value...] [act=command] act=version: print version of this daemon and exit act=stop: shut down running daemon and workers act=abort: terminate all workers and kill running daemon if no act argument is present: daemon starts option foreground=1: stay in the foreground, don't daemonize option max_workers=N: overrides the configuration option debug=0/1: print extra debug information option confdir=path: path to configuration files
The most commonly used ones would be act=stop
and act=abort
:
- With
stop
you're instructing a running nmis daemon and all its workers to terminate gracefully, i.e. when any operations that were in progress are completed. - With
abort
a running nmis daemon and its workers are stopped immediately and without regard to operations that are in progress.
In both of these cases no new nmis daemon is started.
Interacting with the daemon using nmis-cli
Just like all other NMIS9 command line tools nmis-cli shows an overview of its arguments and capabilities when you run it with -h
or --help
(or without any arguments whatsoever):
./bin/nmis-cli Usage: nmis-cli [option=value...] <act=command> act=fixperms act=config-backup act=noderefresh act=daemon-status (or act=status) act=schedule [at=time] <job.type=activity> [job.priority=0..1] [job.X=....] act=schedule-help for more detailed help act=list-schedules [verbose=t/f] [only=active|queued] [job.X=...] act=delete-schedule id=<schedule_id|ALL> [job.X=...] act=abort id=<schedule_id> act=purge [simulate=t/f] [info=t/f] act=dbcleanup [simulate=t/f] [info=t/f] act=run-reports period=<day|week|month> type=<all|times|health|top10|outage|response|avail|port> act=list-outages [filter=X...] act=create-outage [outage.A=B... outage.X.Y=Z...] act=update-outage id=<outid> [outage.A=B... outage.X.Y=Z...] act={delete-outage|show-outage} id=<outid> act=check-outages [node=X|uuid=Y] [time=T] act=outage-help for more detailed help
Process Status
Queue Status
Queue Status Details
Scheduling of jobs
aborting jobs, automatic aborts
Logging and Verbosity
Standard Log Files
logs/fping.log
: the fping worker process (managed by the nmis daemon) logs all its operations to this log file.logs/auth.log
: contains all authentication-related logging that the NMIS9 GUI produces, in the same format that NMIS8 used.logs/event.log
: contains all nmis node events in a machine-consumable format, identical to NMIS8.logs/nmis.log
: all log data that isn't directed elsewhere goes into this log file.
Please note that in NMIS9 all logs are written to in buffered form: information may arrive on disk a few seconds delayed, but at much less performance cost that NMIS8 incurred.
Log files are now also kept open permanently, until the nmis daemon is instructed to reopen them (by sending a SIGHUP
signal the the nmis daemon process).
The format of the log files fping.log
and nmis.log
has changed:
[Thu Jul 25 10:38:09 2019] [info] nmisd[1325] Found 7 nodes due for services operation
Now all log messages are prefixed by time tag, severity level and the process name/role and process identifier of the process in question. In the example above the supervisor component of the nmis daemon has logged this informational announcement.
What gets logged?
NMIS9 is able to log a bit more detail than NMIS8, but much more controllable in terms of what to include when.
There are 13 verbosity levels (in increasing order of noisiness): fatal
, error
, warn
, info
, debug
(or debug1
), debug2
, debug3
and so on to debug9
.
All messages with severities debug1
to debug9
are logged with the tag "[debug]
".
When you set a particular verbosity level then all messages of higher verbosity are suppressed; e.g. at level info
messages of severity fatal
, error
, warn
and info
are logged but messages belonging to severities debug1
to debug9
are suppressed.
- By default the configuration property
log_level
controls all logging. The default value for this isinfo
. - If you start the nmis daemon with a
debug=<level
> command line argument, then that will be used for this daemon and its workers. - For node-admin and nmis-cli invocations the same
debug=<level>
command line argument is available. - A manually scheduled daemon job can have a custom
verbosity
property, which applies to the processing of this job only. - All NMIS daemon instances can be instructed to change their verbosity levels on the fly while the processes remain running, by sending particular UNIX signals to those processes.
Adjusting verbosity levels on the fly
All NMIS daemon processes listen for two particular UNIX signals:
- When a daemon process instance receives the
SIGUSR1
signal, it increments its verbosity by one level, e.g. fromwarn
toinfo
, or fromdebug2
todebug3
. - When a daemon receives the
SIGUSR2
signal, it decrements its verbosity by one level.
In both cases a message is logged at the new verbosity level, e.g.:
[Thu Jul 25 12:05:06 2019] [debug] nmisd[1325] received SIGUSR1, incremented verbosity level to debug, debug to 2 [Thu Jul 25 12:05:34 2019] [info] nmisd[1325] received SIGUSR2, decremented verbosity level to info, debug to 0
How to determine which process to signal?
- use
nmis-cli act=status
to see the list of active daemon processes and usekill
with the correct process id, - or use a smarter
kill
-replacement likepkill
and select by full daemon command line,
e.g.pkill -ef -USR2 "nmisd fping"