Module: check_mk Branch: master Commit: 9823d40205f9321bd5977b36bfe64d078c8df597 URL: http://git.mathias-kettner.de/git/?p=check_mk.git;a=commit;h=9823d40205f932… Author: Mathias Kettner &lt;mk(a)mathias-kettner.de&gt; Date: Fri Feb 25 12:20:18 2011 +0100 h3c_lanswitch_cpu: make conform to new guidelines --- README.writing_checks | 45 +++++++++++++++++++++++++++++-- checks/h3c_lanswitch_cpu | 65 ++++++++++++++++++++++++++------------------- 2 files changed, 79 insertions(+), 31 deletions(-) diff --git a/README.writing_checks b/README.writing_checks index 308cb82..687720b 100644 --- a/README.writing_checks +++ b/README.writing_checks @@ -1,5 +1,7 @@ This file will help you to write *good* checks for Check_MK. +Naming + * Check file names should be named short and unique. They must consist only of lower case characters, digits and underscores and begin with a lower case character. @@ -16,10 +18,9 @@ This file will help you to write *good* checks for Check_MK. not be named after the vendor but after the MIB. An example are the hr_* checks. -In case of SNMP checks you might use the name of the MIB you fetch data from as - part of check name -Header notes: +Coding style + * If the check is contributed by a third party (like you), you must add your name and your email address. @@ -82,6 +83,44 @@ Header notes: You can use it to get nagios state string from nagios return codes. e.g.: nagios_state_names[0] gives you 'OK'. +SNMP Scan function: + +* Every SNMP check *must* have an SNMP scan function. That function + should as *minimal* as possible: It should only fire at those devices + that really can support the check. Reason: unneccessary SNMP walks + on devices not supporting that check must be avoied. + The scan function must on the other hand not be so strict that it + rules out devices where the check would work. If in conflict between + these two issues than rather make the scan function not too strict. + The scan function should avoid fetching non-standard-OIDs by any + means. It should rather try to use the basic SMIv2 OIDs as these will + already have been fetched and cached by the scan functions of other checks! + All scan functions of all checks together should fetch as few OIDs as + possible! + +Other issues: + +* Default values for check parameters (e.g. switch_cpu_default_levels) must be + chosen in a way that they make sense for *everybody*, not just for your special + case. In case you are not sure then rather choose too loose than too tight levels. + This helps avoid false alarms. + +* If the same configuration variable is used in multiple checks, *all* of them + must set a default value and all those values must be identical! + +* Your check should assume that the agent is always producing valid data. It + should *not* try to handle cases where the agent output is broken. This is + handled by Check_MK via Python exceptions. Otherwise you would make the code + uglier and also disable the debug handler. + +* int() vs. saveint(), float vs. savefloat(): int(s) will throw an exception if + if is not a valid number string (or empty). Then Check_MK will catch the exception + and make the check result "UNKNOWN" with an according error message. saveint(s) will + assume 0, if s is not valid. Important: use saveint() in all places, where you know + or suspect that some device does not supply valid data *but* the check can work + with the rest of the data and produce useful results. use int() in all other cases, + e.g. if the check does not make any sense if you have no valid data. + Manpages: * diff --git a/checks/h3c_lanswitch_cpu b/checks/h3c_lanswitch_cpu index 6b799bb..227411e 100644 --- a/checks/h3c_lanswitch_cpu +++ b/checks/h3c_lanswitch_cpu @@ -34,11 +34,38 @@ # SNMPv2-SMI::enterprises.43.45.1.6.1.1.1.3.13 = Gauge32: 16 # Reasonably low warning and crit levels -h3c_lanswitch_cpu_default_levels = (50, 75) +switch_cpu_default_levels = (50, 75) + + +# We do not want to use the end OID as item since. +# We prefer "Switch 1 CPU 1" over "65537"... +def h3c_lanswitch_cpu_genitem(item): + # decide switch class here (stacked or standalone/modular) + cpuid = int(item) + + # if we have a cpuid lower than (hopefully) 256 it is not hashed with a unit ID + if cpuid < 256: + switchid = 1 + cputype = "Slot" + cpunum = cpuid + + # othwise, if above 64k it is a known stackable switch + elif cpuid >= 65536: + switchid = cpuid / 65536 + cputype = "CPU" + cpunum = cpuid % 65536 + + # if we end up here 3com has added another hash method. + else: + switchid = 1 + cputype = "Unknown" + cpunum = cpuid + return ("Switch %d %s %d" % (switchid, cputype, cpunum)) def inventory_h3c_lanswitch_cpu(checkname, info): - return [ (h3c_lanswitch_cpu_genitem(line[0]), "h3c_lanswitch_cpu_default_levels") for line in info ] + return [ (h3c_lanswitch_cpu_genitem(line[0]), "switch_cpu_default_levels") for line in info ] + def check_h3c_lanswitch_cpu(item, params, info): warn, crit = params @@ -46,7 +73,7 @@ def check_h3c_lanswitch_cpu(item, params, info): if h3c_lanswitch_cpu_genitem(line[0]) == item: util = int(line[1]) infotext = (" - average usage was %d%% over last 5 minutes." % util) - perfdata = [ ( "Usage", util, warn, crit, 0) ] + perfdata = [ ( "usage", util, warn, crit, 0) ] if util > crit: return (2, "CRIT" + infotext, perfdata) @@ -54,38 +81,20 @@ def check_h3c_lanswitch_cpu(item, params, info): return (1, "WARN" + infotext, perfdata) else: return (0, "OK" + infotext, perfdata) - return (3, "UNKNOWN - Unit/CPU %s not found" % item) -# decide switch class here (stacked or standalone/modular) and make a check item for it. -def h3c_lanswitch_cpu_genitem(item): - cpuid = int(item) -# if we have a cpuid lower than 512 it is not hashed with a unit ID - if cpuid < 256: - switchid = 1 - cputype = "Slot" - cpunum = cpuid -# othwise, if above 64k it is a known stackable switch - elif cpuid >= 65536: - switchid = cpuid / 65536 - cputype = "CPU" - cpunum = cpuid % 65536 -# if we end up here 3com has added another hash method. - else: - switchid = 1 - cputype = "Unknown" - cpunum = cpuid - return ("Switch %d %s %d" % (switchid, cputype, cpunum)) + return (3, "UNKNOWN - %s not found" % item) + check_info["h3c_lanswitch_cpu"] = (check_h3c_lanswitch_cpu, "CPU Load %s", 1, inventory_h3c_lanswitch_cpu ) -# get only the 5-min average load. snmp_info["h3c_lanswitch_cpu"] = \ - ( "1.3.6.1.4.1.43.45.1.6.1.1.1", [ OID_END, "3" ] ) + ( "1.3.6.1.4.1.43.45.1.6.1.1.1", [ + OID_END, + "3" # 5-min average load. + ]) # just a rough match that will handle most devices. snmp_scan_functions["h3c_lanswitch_cpu"] = \ - lambda oid: oid (".1.3.6.1.2.1.1.1.0").lower().startswith('3com s') - - + lambda oid: oid(".1.3.6.1.2.1.1.1.0").lower().startswith('3com s')