Dynamically update the Horizontal Pod Autoscaler for a given Openshift deployment.

run-hpa-update.sh

#!/bin/sh
set -o nounset -o errexit

## Dynamically update the Horizontal Pod Autoscaler for a given Openshift deployment.
## Usage: ./run-hpa-update.sh 3 5 my-app production

MIN_REPLICAS=${1:-1}
MAX_REPLICAS=${2:-1}
APP=${3:-my-app-name}
ENVIRONMENT=${4:-staging}

# workaround for https://github.com/kubernetes/kubernetes/issues/34413
if oc get hpa/${APP}-${ENVIRONMENT} > /dev/null 2>&1
then
  oc delete hpa/${APP}-${ENVIRONMENT}
fi

HPA='{
  "apiVersion": "autoscaling/v1",
  "kind": "HorizontalPodAutoscaler",
  "metadata": {
    "name": "'${APP}'-'${ENVIRONMENT}'",
    "labels": {
      "app": "'${APP}'"
    }
  },
  "spec": {
    "maxReplicas": '${MAX_REPLICAS}',
    "minReplicas": '${MIN_REPLICAS}',
    "scaleTargetRef": {
      "apiVersion": "v1",
      "kind": "DeploymentConfig",
      "name": "'${APP}'-'${ENVIRONMENT}'"
     },
     "targetCPUUtilizationPercentage": 80
  }
}'

echo $HPA | oc create --dry-run -o yaml -f - | oc apply -f -