Backup and Restore default configuration (/etc/sonic/config_db.json)

Example: 

Reference model:

• Switch model name: AS7726-32X
• Edgecore SONiC version: SONiC.Edgecore-SONiC_20200827_110345_ec201911_2020-aug_enhanced_178

Known issue: In SONiC.Edgecore-SONiC_20200827_110345_ec201911_2020-aug_enhanced_178 version, dynamic port breakout fails after using default configuration file generated by sonic-cfggen (method 2) and restore.sh (method 3) below.

Procedure :

Method 1: Backup and Restore default configuration manually

Backup default configuration "config_db.json" after SONiC installation

 admin@sonic:~$ sudo cp /etc/sonic/config_db.json /etc/sonic/config_db.json.bk

Restore default configuration

Step 1. Replace current config_db.json by backup config

admin@sonic:~$ sudo cp /etc/sonic/config_db.json.bk /etc/sonic/config_db.json

Step 2. config reload or power cycle the switch

admin@sonic:~$sudo config reload -y

Method 2: Use sonic-cfggen command to generate default configuration which is identical to the file generated after ONIE installation:

sudo sonic-cfggen -H -p /usr/share/sonic/device/$Platform/$HwSKU/port_config.ini --preset t1 -k $HwSKU > ~/default.log

Caution: You can get the values of $Platform and $HwSKU from "show platform" or "show version"

admin@sonic:~$ show platform summary
Platform: x86_64-accton_as7816_64x-r0
HwSKU: Accton-AS7816-64X
ASIC: broadcom

Step 1: Generate the default config_db.json to the home directory.

admin@sonic:~$ sudo sonic-cfggen -H -p /usr/share/sonic/device/x86_64-accton_as7816_64x-r0/Accton-AS7816-64X/port_config.ini --preset t1 -k Accton-AS7816-64X > ~/default.log

Step 2: Move the "default.log" to the correct position.

admin@sonic:~$ sudo cp default.log /etc/sonic/config_db.json

Step 3. config reload or power cycle the switch

admin@sonic:~$sudo config reload -y

Known issue: In SONiC.Edgecore-SONiC_20200827_110345_ec201911_2020-aug_enhanced_178 version, dynamic port breakout fails after using default configuration file generated by sonic-cfggen and restore.sh.

Method 3: Upload and Execute the script restore.sh on the SONiC 

The script generates default configuration config_db.json automatically.  Reboot the switch to take effect.

Step 1: Set the management IP

admin@sonic:~$ sudo ip address add 188.188.98.21/16 dev eth0

Step 2: Upload the Script to the SONiC

admin@sonic:~$ sudo scp root@188.188.36.36:/root/restore.sh ~/  

Step 3: Change permission of script.

admin@sonic:~$ chmod +x restore.sh

Step 4: Running the script.

admin@sonic:~$ ./restore.sh

Step 5. config reload or power cycle the switch

admin@sonic:~$sudo config reload -y

Example:

admin@sonic:~$ ./restore.sh
Get HwSKU and Platfrom from the database
/etc/sonic/config_db.json is restored to default

admin@sonic:~$ sudo config reload -y

Known issue: In SONiC.Edgecore-SONiC_20200827_110345_ec201911_2020-aug_enhanced_178 version, dynamic port breakout fails after using default configuration file generated by sonic-cfggen and restore.sh.