Downgrade to frr-7.5.1

[majst01]

This tries to solve #186 and FRRouting/frr#10298

TODO:

• try to reproduce with frr-9.0 as well

The Issue can be reproduced with the following steps:

On one of the connected leaves take the switch port where the firewall is connected to down like so:

From a machine in the cluster try to reach all of the machines in the storage network, for example with curl https://

# f4f8b200-deef-11e9-8000-3cecef22f910 is the machineid of the firewall
net show lldp | grep f4f8b200-deef-11e9-8000-3cecef22f910
swp7s1     25G    Default    f4f8b200-deef-11e9-8000-3cecef22f910  lan0
# take this switchport down
sudo ip link set dev swp7s1 down

# Wait a while until frr reached steady state again
# take switch up again
sudo ip link set dev swp7s1 up

Try again to reach all storage servers

[Gerrit91]

On SONiC, also with FRR 7.5.1, after a leaf going offline the firewall will loose internet connection until FRR is restarted.

Reproducer:

• Have a firewall in the same rack as the leaf
• Shutdown spine uplink on a single leaf switch

@mwindower

[majst01]

Tested with frr 9.1 without any downtime