How to override deployment variable at Kubernetes Horizontal Pod Auto scalar - kubernetes

Question

I have a deployment script like below, which implement a single pod Redis server. At this Reids dockerfile I have a startup.sh which basically perform some start up task if environment variable's DB_TASK value is 1
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: redis-server
labels:
app: redis-server
spec:
replicas: 1
selector:
matchLabels:
app: redis-server
template:
metadata:
labels:
app: redis-server
spec:
containers:
- name: redis-server
image: secretregistry.azurecr.io/redis-server:__imgTag__
env:
- name: DB_TASK
value: 1
args:
- --requirepass
- __RedisSecret__
resources:
requests:
memory: "4Gi"
cpu: "1"
limits:
memory: "4Gi"
cpu: "1"
ports:
- containerPort: 6379
Now I have a HPA which basically scale up and Down this server based on CPU usage
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
name: redis-server-hpa
spec:
maxReplicas: 2 # define max replica count
minReplicas: 1 # define min replica count
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: redis-server
targetCPUUtilizationPercentage: 51 # target CPU utilization
Now the problem is when load goes beyond 51% it scale up 2nd Redis server with DB_TASK value is 1 how I can provision this HPA in way that I can tell it when you scale up scale up override DB_TASK value with 0 so it does not perform startup work once more.