* [dhcp-relay]: Add DHCP Relay Monitor (#3886)
DHCP relay MONitor (dhcpmon) keeps track of DORA messages. If DHCP Relay
is detected to be not forwarding DORA message, dhcpmon will log such event
to syslog. Under the hood dhcpmon keeps counts of clients DR messages,
forwarded DR messages, DHCP server OA messages, and forwarded OA messages.
dhcpmon will check every 12 sec (configurable) if counts are monotonically
increasing and record snapshot of those counters. dhcpmon will report
discrepancies when detected between current counters and snapshot counters.
pull-request: https://github.com/Azure/sonic-buildimage/pull/3886
signed-off-by: Tamer Ahmed <tamer.ahmed@microsoft.com>
* Eliminate dependency on libexplain
* Remove dependency on libexplain
* [DHCP Relay]: Support new <DhcpRelays> minigraph tag; support multiple VLANs
* Don't start dhcrelay in quiet mode so as to get startup output in syslog
* Update sonic-cfggen tests to support new '<DhcpRelays>' tag
* <DhcpRelays> tag is only present for VLANs which require a DHCP relay agent -- only parse if present
* Don't attempt to configure a DHCP relay agent for VLANs without specified DHCP servers
* Modify to work with Taoyu's minigraph/DB changes (#942)
* Reduce number of DHCP servers in sonic-cfggen unit tests from 4 to 2
* Remove isc-dhcp-relay sample output file from sonic-cfggen test, as we no longer generate that file
* Update Option 82 isc-dhcp-relay patch to load all interface name-alias maps into memory once at start instead of calling sonic-cfggen on each packet we relay
* Remove executable permission from Jinja2 template
* Set max hop count to 1 so that DHCP relay will only relay packets with a hop count of zero
* Replace tabs with spaces
* Modify overlooked sonic-cfggen call, use Config DB instead of minigraph
* Also ensure > 1 VLAN requires a DHCP relay agent before outputting to template
* Generate port name-alias map file using sonic-cfggen and parse that in lieu of parsing port_config.ini directly
* No longer drop packets with hop count > 0; Instead, drop packets which already contain agent info
Modify minigraph parser output format so it fit DB schema
Modify configuration templates to fit new schema
Systemd services dependencies are modified so database starts before any configuration consumer
- Consolidate config.sh and start.sh scripts into one script (start.sh)
- Solve issue #435 - All dockers now run supervisord as their ENTRYPOINT
- All stdout/stderr output from processes managed by supervisord is now sent to syslog instead of their own files
- Supervisord log messages are now also sent to syslog
- Removed unused smartmontools package from docker-platform-monitor
