What I did:
Following changes done for packet based chassis:-
1> Run arp_update on LC's to resolve static route nexthops over backend
port-channel interfaces.
2> On Supervisor make sure arp_update exit gracefully
Fix#7968
Issue is detected on SONiC.20201231.11
In test_static_route.py::test_static_route_ecmp static routes are configured, but neighbors are not resolved after config reload even after 10 minutes.
It looks like the arp_update script is starting to ping when Vlan1000 is not fully configured.
When issue is reproduced, stuck ping6 process is observed in swss container :
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 180 0.1 0.0 6296 1272 pts/0 S 17:03 0:03 ping6 -I Vlan1000 -n -q -i 0 -c 1 -W 0 ff02::1
And when arp_update script successfully resolves neighbors, we observe sleep 300 instead of ping process
#### Why I did it
* `arp_update` fails to ping those neighbors over vlan sub interfaces.
#### How I did it
* modify `arp_update_vars.j2` to get vlan sub interfaces with ipv6 addresses assigned.
* modify `arp_update` to send ipv6 pings over those retrieved vlan sub interfaces.
Signed-off-by: Longxiang Lyu <lolv@microsoft.com>
This PR limited the number of calls to sonic-cfggen to one call
per iteration instead of current 3 calls per iteration.
The PR also installs jq on host for future scripts if needed.
signed-off-by: Tamer Ahmed <tamer.ahmed@microsoft.com>
* Fix potential blackholing/looping traffic and refresh ipv6 neighbor to avoid CPU hit
In case ipv6 global addresses were configured on L3 interfaces and used for peering,
and routing protocol was using link-local addresses on the same interfaces as prefered nexthops,
the link-local addresses could be aged out after a while due to no activities towards the link-local
addresses themselves. And when we receive new routes with the link-local nexthops, SONiC won't insert
them to the HW, and thus cause looping or blackholing traffic.
Global ipv6 addresses on L3 interfaces between switches are refreshed by BGP keeplive and other messages.
On server facing side, traffic may hit fowarding plane only, and no refresh for the ipv6 neighbor entries regularly.
This could age-out the linux kernel ipv6 neighbor entries, and HW neighbor table entries could be removed,
and thus traffic going to those neighbors would hit CPU, and cause traffic drop and temperary CPU high load.
Also, if link-local addresses were not learned, we may not get them at all later.
It is intended to fix all above issues.
Changes:
Add ndisc6 package in swss docker and use it for ipv6 ndp ping to update the neighbors' state on Vlan interfaces
Change the default ipv6 neighbor reachable timer to 30mins
Add periodical ipv6 multicast ping to ff02::11 to get/refresh link-local neighbor info.
* Fix review comments:
Add PORTCHANNEL_INTERFACE interface for ipv6 multicast ping
format issue
* Combine regular L3 interface and portchannel interface for looping
* Add ndisc6 package to vs docker
