If it helps to fix the problem in an official build. I have managed to adjust everything so that a SNMPv3 context can also be stored for the system description OID and it works. However, there are probably still optimization and improvement possibilities.
I changed the following things
/omd/sites/[site]/lib/python3/cmk/fetchers/_snmpscan.py
_prefetch_description_object
get_single_oid(
oid,
single_oid_cache=snmp_cache.single_oid_cache(),
backend=backend,
)
to
get_single_oid(
oid,
single_oid_cache=snmp_cache.single_oid_cache(),
section_name=SectionName(“sys_descr”),
backend=backend,
)
/omd/sites/[site]/lib/python3/cmk/base/automations/check_mk.py
_execute_snmp
data = get_snmp_table(
section_name=None,
tree=BackendSNMPTree(
base=“.1.3.6.1.2.1.1”,
oids=[BackendOIDSpec(c, “string”, False) for c in “1456”],
),
walk_cache={},
backend=make_snmp_backend(snmp_config, log.logger),
)
to
data = get_snmp_table(
section_name=SectionName(“sys_descr”),
tree=BackendSNMPTree(
base=“.1.3.6.1.2.1.1”,
oids=[BackendOIDSpec(c, “string”, False) for c in “1456”],
),
walk_cache={},
backend=make_snmp_backend(snmp_config, log.logger),
)
/omd/sites/[site]/lib/python3/cmk/gui/wato/_check_mk_configuration.py
_valuespec_snmpv3_contexts
choices=lambda: [(None, _(“All SNMP sections”))] + get_snmp_section_names()
to
choices=lambda: [(None, _(“All SNMP sections”))] + [(“sys_descr”, _(“System Description OID”))] + get_snmp_section_names()
/omd/sites/[site]/lib/python3/cmk/snmplib/_typedefs.py
snmpv3_contexts_of
inserted additional variable
var_sysoid_section=SectionName(“sys_descr”)
and changed
if ctx.section is None or ctx.section == section_name:
to
if (ctx.section is None and section_name != var_sysoid_section) or (ctx.section is not None and ctx.section == section_name):
I tried to change the condition in snmpv3_contexts_of in a way, that will not break the old behavior of the context rules that use “All SNMP Sections”. This way a context for the system description oid will only be used if a rule for that section is present like this:
These changes have no effect on SNMPv1 or SNMPv2 since they dont use context. And for SNMP3 it only adds the option to define a context for the system description but the rest should still work the same way. At least on my system i can not find any problems with the systems that use snmpv3 without a context.
In order for the HP printers to monitor reliably with snmpv3, I had to create the rules from this answer
https://forum.checkmk.com/t/bug-snmp-v3-with-hp-printer-any-update-or-even-better-a-solution/20372/12