T5702: SNMP add interface-mib max-interfaces-number and prefix

- Allow to configure only required interface prefixes

  set service snmp mib interface 'eth'
  set service snmp mib interface 'bond'

 include_ifmib_iface_prefix eth bond

Sets the interface name prefixes to include in the IF-MIB data collection.
For servers with a large number of interfaces (ppp, dummy, bridge, etc)
the IF-MIB processing will take a large chunk of CPU for ioctl calls.
A set of space separated interface name prefixes will reduce the CPU
load for IF-MIB processing. For example, configuring
"include_ifmib_iface_prefix eth dummy lo" will include only interfaces
with these prefixes and ignore all others for IF-MIB processing.

- Allow to configure maximum interface number

  set service snmp mib interface-max '100'

  ifmib_max_num_ifaces NUM

Sets the maximum number of interfaces included in IF-MIB data collection.
For servers with a large number of interfaces (ppp, dummy, bridge, etc)
the IF-MIB processing will take a large chunk of CPU for ioctl calls
(on Linux). Setting a reasonable maximum for the CPU used will
reduce the CPU load for IF-MIB processing.  For example, configuring
"ifmib_max_num_ifaces 500" will include only the first 500 interfaces
based on ifindex and ignore all others for IF-MIB processing.

1 files changed, 10 insertions, 0 deletions

diff --git a/data/templates/snmp/etc.snmpd.conf.j2 b/data/templates/snmp/etc.snmpd.conf.j2
index 9d78d479a..3db8c4d7b 100644
--- a/data/templates/snmp/etc.snmpd.conf.j2
+++ b/data/templates/snmp/etc.snmpd.conf.j2
@@ -56,6 +56,16 @@ SysDescr {{ description }}
 {% endif %}
 agentaddress unix:/run/snmpd.socket{{ ',' ~ options | join(',') if options is vyos_defined }}
 
+{% if mib is vyos_defined %}
+# Interface MIB limits
+{%     if mib.interface_max is vyos_defined %}
+ifmib_max_num_ifaces {{ mib.interface_max }}
+{%     endif %}
+{%     if mib.interface is vyos_defined %}
+include_ifmib_iface_prefix {{ mib.interface | join(' ') }}
+{%     endif %}
+{% endif %}
+
 # SNMP communities
 {% if community is vyos_defined %}
 {%     for comm, comm_config in community.items() %}