[config] Add snmp-community command to set SNMP community string

[samaity]

Signed-off-by: Sangita Maity sangitamaity0211@gmail.com

- What I did
added a new command called snmp-community to set SNMP community string or add to snmp_rocommunities.

- How I did it

followed the below doc.
Set SNMP community string

- How to verify it

before this feature is implemented, there was no snmp-community command under config CLI.

There's only one SNMP community string named public

admin@lnos-x1-a-fab01:~$ sudo cat /etc/sonic/snmp.yml
snmp_location: public
snmp_rocommunity : public




admin@lnos-x1-a-fab01:~$ sudo docker exec -it snmp snmpwalk -v2c -c public 127.0.0.1 iso.3.6.1.2.1.1.1.0

iso.3.6.1.2.1.1.1.0 = STRING: "SONiC Software Version: SONiC.lnos_v2.0.0 - HwSku: Seastone-DX010-10-50 - Distribution: Debian 9.11 - Kernel: 4.9.0-9-amd64"

There is no SNMP community string named new_public. so, snmpwalk got failed.

admin@lnos-x1-a-fab01:~$ sudo docker exec -it snmp snmpwalk -v2c -c new_public 127.0.0.1 iso.3.6.1.2.1.1.1.0

Timeout: No Response from 127.0.0.1
admin@lnos-x1-a-fab01:~$

After this feature is implemented

admin@lnos-x1-a-fab01:~$ sudo config snmp-community new_public
Restarting SNMP service...

so a new SNMP community string named new_public has been added.

admin@lnos-x1-a-fab01:~$ cat /etc/sonic/snmp.yml
snmp_location: public
snmp_rocommunities:
- public
- new_public

Both the community strings are working fine with snmpwalk.

admin@lnos-x1-a-fab01:~$ sudo docker exec -it snmp snmpwalk -v2c -c public 127.0.0.1 iso.3.6.1.2.1.1.1.0
iso.3.6.1.2.1.1.1.0 = STRING: "SONiC Software Version: SONiC.lnos_v2.0.0 - HwSku: Seastone-DX010-10-50 - Distribution: Debian 9.11 - Kernel: 4.9.0-9-amd64"

admin@lnos-x1-a-fab01:~$ sudo docker exec -it snmp snmpwalk -v2c -c new_public 127.0.0.1 iso.3.6.1.2.1.1.1.0
iso.3.6.1.2.1.1.1.0 = STRING: "SONiC Software Version: SONiC.lnos_v2.0.0 - HwSku: Seastone-DX010-10-50 - Distribution: Debian 9.11 - Kernel: 4.9.0-9-amd64"

[samaity]

@jleveque, kindly review this PR.

[jleveque]

Looks good to me. @qiluo-msft to review, as well.

[samaity]

Looks good to me. @qiluo-msft to review, as well.

Thank you @jleveque for this quick review!!! 👍

[qiluo-msft]

As comments

[qiluo-msft]

New comments added.

[qiluo-msft]

New comments added.

[qiluo-msft]

As comment

[qiluo-msft]

minor format issues

[jleveque]

Retest this please

[samaity]

@jleveque, do you have any idea when it can be merged? I can see three test case failures which is not related to my changes, I believe. Is there something I can do from my end?

[samaity]

retest this please