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SONiC

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Configuration

Currently tested on the April 2021 release.

Manual

All configuration change done with sudo config need at some point a sudo config save to make them permanent (eg. device reboot)

Hostname

sudo config hostname dell-spine1

Management

SONiC supports having the management interface in a dedicated VRF, so the default management route (to mr1) doesn't risk impacting production traffic.

sudo config vrf add mgmt

sudo config interface ip add eth0 10.x.x.x/16 10.x.0.1

show management_interface address

https://github.com/Azure/SONiC/blob/master/doc/mgmt/sonic_stretch_management_vrf_design.md

https://github.com/Azure/sonic-utilities/blob/master/doc/Command-Reference.md#configuring-management-interface

SNMP

Have SNMP listen on its mgmt IP

sudo config snmpagentaddress add 10.x.x.x -v mgmt -p 161

In the tested release, sudo config snmp is not a valid configuration keyword.

Workaround to set the SNMP community:

sudo vim /etc/sonic/snmp.yml

sudo systemctl restart snmp

https://github.com/Azure/SONiC/wiki/How-to-Check-SNMP-Configuration

NTP

sudo config ntp add <server IP>

Some commands

show ip interface

Interface    Master    IPv4 address/mask    Admin/Oper    BGP Neighbor    Neighbor IP
-----------  --------  -------------------  ------------  --------------  -------------
Ethernet4              10.0.0.2/31          up/up         ARISTA02T2      10.0.0.3
Ethernet8              10.0.0.4/31          up/up         ARISTA03T2      10.0.0.5
Ethernet12             10.0.0.6/31          up/up         ARISTA04T2      10.0.0.7
Ethernet16             10.0.0.8/31          up/up         ARISTA05T2      10.0.0.9

sudo config interface shutdown Ethernet8

Interface    Master    IPv4 address/mask    Admin/Oper    BGP Neighbor    Neighbor IP
-----------  --------  -------------------  ------------  --------------  -------------
Ethernet4              10.0.0.2/31          up/up         ARISTA02T2      10.0.0.3
Ethernet8              10.0.0.4/31          down/down     ARISTA03T2      10.0.0.5
Ethernet12             10.0.0.6/31          up/up         ARISTA04T2      10.0.0.7

sudo config interface startup Ethernet8

Leaf/spine configuration

We are going to use the diagram below to setup the leaf/spine. Each lead switch has 1 connection to each spine switch. There is no connection between the spines. The first setup is to identify the interfaces on each switch.

400px

Interface mapping

show interfaces description

on S5232F-ON (Spine)

 Interface    Oper    Admin            Alias    Description
 -----------  ------  -------  ---------------  -------------
 Ethernet0    down       up   hundredGigE1/1            N/A
 Ethernet4    down       up   hundredGigE1/2            N/A
 Ethernet8    down       up   hundredGigE1/3            N/A
 -
 -
 Ethernet120    up       up  hundredGigE1/31            N/A
 Ethernet124    up       up  hundredGigE1/32            N/A
 Ethernet128  down       up      tenGigE1/33            N/A
 Ethernet129  down       up      tenGigE1/34            N/A
 

on both spines switches, we will use interfaces Ethernet120 on Sonic side which is interface E1/31 on Dell switch and Ethernet124 which is E1/32

On S5248F-ON (leaf)

leaf1# show interface description

 Interface    Oper    Admin                 Alias    Description
 -----------  ------  -------  --------------------  -------------
 Ethernet0    down       up   twentyfiveGigE1/1/1            N/A
 Ethernet1    down       up   twentyfiveGigE1/1/2            N/A
 Ethernet2    down       up   twentyfiveGigE1/1/3            N/A
 -
 -
 Ethernet54     up       up       hundredGigE1/55            N/A
 Ethernet55     up       up       hundredGigE1/56            N/A

On the leaf's we will use interfaces Ethernet54 and Ethernet55 which are E1/55 and E1/56 on the Dell switch

Now that we have the interface mapping from Sonic to Dell it is time to setup IP address on each of those interfaces. Below is the diagram showing the IP's and network that we will use for the leaf/spine setup.

400px

Interface configuration

By default the Sonic OS comes with all the interfaces already preconfigured with some IP's.You can check that by looking at the "config_db.json"

admin@dell-spine1:/etc/sonic$ vi config_db.json

"Ethernet120|10.0.0.60/31": {},
"Ethernet124|10.0.0.62/31": {},
"Ethernet128|10.0.0.64/31": {},
"Ethernet129|10.0.0.66/31": {},
"Ethernet12|10.0.0.6/31": {},
"Ethernet16|10.0.0.8/31": {},

We see the two(2) interfaces Ethernet120 and 124 that we are going to use have already an IP address. When setting up the interface IP we need to delete as well the existing IP address.

spine1

sudo config interface ip add  Ethernet120 172.16.0.9/30
sudo config interface ip remove  Ethernet120 10.0.0.60/31
sudo config interface ip add  Ethernet124 172.16.0.1/30
sudo config interface ip remove  Ethernet120 10.0.0.62/31
Sudo config save -y

spine2

sudo config interface ip add Ethernet124 172.16.0.5/30
sudo config interface ip add Ethernet120 172.16.0.13/30
sudo config interface ip remove Ethernet120 10.0.0.60/30
sudo config interface ip remove Ethernet124 10.0.0.62/30        
Sudo config save -y 

leaf1

sudo config interface ip add  Ethernet54 172.16.0.6/30
sudo config interface ip remove  Ethernet54 10.0.0.108/31
sudo config interface ip add  Ethernet55 172.16.0.2/30
sudo config interface ip remove  Ethernet55 10.0.0.110/31
Sudo config save -y
leaf2
sudo config interface ip add  Ethernet54 172.16.0.14/30
sudo config interface ip remove  Ethernet54 10.0.0.108/31
sudo config interface ip add  Ethernet55 172.16.0.10/30
sudo config interface ip remove  Ethernet55 10.0.0.110/31
Sudo config save -y

Check connectivity between spine1 and leaf1

admin@dell-spine1:/etc/sonic$ ping 172.16.0.2
PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data.
64 bytes from 172.16.0.2: icmp_seq=1 ttl=64 time=0.246 ms
64 bytes from 172.16.0.2: icmp_seq=2 ttl=64 time=0.235 ms
admin@leaf1:/etc/sonic$ ping 172.16.0.1
PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data.
64 bytes from 172.16.0.1: icmp_seq=1 ttl=64 time=0.268 ms
64 bytes from 172.16.0.1: icmp_seq=2 ttl=64 time=0.241 ms

Check connectivity between spine2/leaf1/leaf2

admin@dell-spine2:~$ ping 172.16.0.14
PING 172.16.0.14 (172.16.0.14) 56(84) bytes of data.
64 bytes from 172.16.0.14: icmp_seq=1 ttl=64 time=0.429 ms
64 bytes from 172.16.0.14: icmp_seq=2 ttl=64 time=0.248 ms

admin@dell-spine2:~$ ping 172.16.0.6
PING 172.16.0.6 (172.16.0.6) 56(84) bytes of data.
bytes from 172.16.0.6: icmp_seq=1 ttl=64 time=0.264 ms

Now that we have connectivity, the next step is to setup BGP

BGP configuration

There are two(2) ways to configure BGP

- using command line (shell for FRR daemons). I am still testing this method

sudo vtysh

- Make the changes directly from the config_db.json file. If you make the changes from this file you need to run

sudo config reload -y to save the changes to the Database.

Sonic comes with some BGP neighbor's settings preconfigured. We have the option to delete those settings and add new once or just add new once. Note: The preconfigured settings are not active.See below

"BGP_NEIGHBOR": {
    "10.0.0.1": {
       "asn": "65200",
       "holdtime": "180",
       "keepalive": "60",
       "local_addr": "10.0.0.0",
       "name": "ARISTA01T2",
       "nhopself": "0",
       "rrclient": "0"
    },
    "10.0.0.3": {
    "asn": "65200",
    "holdtime": "180",
    "keepalive": "60",
    "local_addr": "10.0.0.2",
    "name": "ARISTA02T2",
    "nhopself": "0",
    "rrclient": "0"

For our testing, we are going to replace the first two(2) preconfigured neighbors with our settings. First we need to setup the Loopback0 interface IP since we will use this in the BGP configuration for the router identifier (router-id). like for the Ethernetx configuration, the Loopback0 interface also comes with a default IP address of 10.1.0.1/32

sudo config interface ip add Loopback0 10.0.1.13/32 (spine1)
sudo config interface ip remove Loopback0 10.1.0.1/32
sudo config save -y
sudo config interface ip add Loopback0 10.0.1.14/32 (spine2)
sudo config interface ip remove Loopback0 10.1.0.1/32
sudo config save -y
sudo config interface ip add Loopback0 10.0.1.24/32 (leaf1)
sudo config interface ip remove Loopback0 10.1.0.1/32
sudo config save -y
sudo config interface ip add Loopback0 10.0.1.25/32 (leaf2)
sudo config interface ip remove Loopback0 10.1.0.1/32
sudo config save -y

spine1

"BGP_NEIGHBOR": {
    "172.16.0.2": {
       "asn": "65032",
       "holdtime": "180",
       "keepalive": "60",
       "local_addr": "10.0.1.13",
       "name": "leaf1",
       "nhopself": "0",
       "rrclient": "0"
    },
    "172.16.0.10": {
    "asn": "65033",
    "holdtime": "180",
    "keepalive": "60",
    "local_addr": "10.0.1.13",
    "name": "leaf2",
    "nhopself": "0",
    "rrclient": "0"

Under "DEVICE_METADATA" change "bgp_asn": "65100" to spine1 asn number

"DEVICE_METADATA": {
    "localhost": {
    "bgp_asn": "65030",

Close the file and run sudo config reload -y

Repeat the same steps for spine2, leaf1 and leaf2 by replacing the "IP addresses" and "asn"

verification

show ip bgp summary

spine1

Neighbhor      V     AS    MsgRcvd    MsgSent    TblVer    InQ    OutQ  Up/Down      State/PfxRcd  NeighborName
-----------  ---  -----  ---------  ---------  --------  -----  ------  ---------  --------------  --------------
172.16.0.2     4  65032       1566       1569         0      0       0  1d01h57m                3  leaf1
172.16.0.10    4  65033       1534       1543         0      0       0  1d01h27m                2  leaf2
Total number of neighbors 2

spine2

Neighbhor      V     AS    MsgRcvd    MsgSent    TblVer    InQ    OutQ  Up/Down      State/PfxRcd  NeighborName
-----------  ---  -----  ---------  ---------  --------  -----  ------  ---------  --------------  --------------
172.16.0.6     4  65032       1548       1548         0      0       0  1d01h40m                2  leaf1
172.16.0.14    4  65033       1543       1544         0      0       0  1d01h28m                3  leaf2
Total number of neighbors 2

leaf1

Neighbhor      V     AS    MsgRcvd    MsgSent    TblVer    InQ    OutQ  Up/Down      State/PfxRcd  NeighborName
-----------  ---  -----  ---------  ---------  --------  -----  ------  ---------  --------------  --------------
172.16.0.1     4  65030       1562       1561         0      0       0  1d01h53m                2  Spine1
172.16.0.5     4  65031       1543       1647         0      0       0  1d01h35m                2  spine2
Total number of neighbors 2

leaf2

Neighbhor      V     AS    MsgRcvd    MsgSent    TblVer    InQ    OutQ  Up/Down      State/PfxRcd  NeighborName
-----------  ---  -----  ---------  ---------  --------  -----  ------  ---------  --------------  --------------
172.16.0.9     4  65030       1539       1537         0      0       0  1d01h30m   3               spine1
172.16.0.13    4  65031       1538       1537         0      0       0  1d01h30m   3               spine2

Known limitations

  • It is not possible to configure a DNS resolver, all configuration needs to be done using IPs
  • It is not possible to change the syslog facility
  • cgexec -g l3mdev:mgmt is supposed to run commands from the mgmt VRF, but fails with "cgroup change of group failed"