The customer was on code 19.2 and upgraded to 21.4 JUNOS. After the upgrade they started seeing the below alarms:

Major alarms: Power Budget: Insufficient Power

Check for the below command in the RSI collected by the customer before and after the upgrade.

#show chassis power

You will see a spike in the allocated power.

Allocated power in 19.2 code:

Model: ptx10016
Junos: 19.2X3.2
System:
 Zone 0:
     Capacity:         22000 W (maximum 22000 W) ===== (10 PSMs each 2200W, total 22000W)
     Allocated power:  19380 W (2620 W remaining)
     Actual usage:     11568 W
     Total system capacity: 22000 W (maximum 22000 W)
     Total remaining power: 2620 W ===== (Remaining power is >2200W, thus n+1 redundancy is there, n is the total number of PSMs in the system)

Allocated power in 21.4 code:
Model: ptx10016
Junos: 21.4X10.6
System:
 Zone 0:
     Capacity:         22000 W (maximum 22000 W) ===== (10 PSMs each 2200W, total 22000W)
     Allocated power:  20850 W (1150 W remaining)
     Actual usage:     11412 W
    Total system capacity: 22000 W (maximum 22000 W)
    Total remaining power: 1150 W ===== (Remaining power is <2200W, thus n+1 redundancy is not there, n is the total number of PSMs in the system) === This will raise the alarm, power redundancy issues.

Based on the chassis ambient temperature, the allocated power for the FRUs varies. On a PTX10016 model, there are 3 settings for the chassis ambient temperature: 25C, 40C, and 55C.

After the upgrade, when the device for checked for this setting:

root@router> show chassis ambient-temperature
Ambient Temperature: 40C

When checking the RSI, there was no configuration for this setting.
On 19.2 code, this setting is set by default to 25C.
On 21.4 code, this setting is set by default to 40C.

Allocated power increases when the chassis ambient temperature is set to 40C.

Upon checking with the customer, it was confirmed that 25C was enough for the environment. On the new code, 25C setting had to be set manually via cli config using the below command:

root@router-re0# set chassis ambient-temperature 25C

Once this setting was pushed, allocated power dropped back, and the alarms were cleared.