fixes hpa issue while deployment is triggered

hpa_fix.sh

#!/bin/bash

set -e

# STEPS
# 1. Set the HPA max to current replicas
# 2. Set image
# 2.1 wait for deployment to be completed or 15 mins
# 3. Set max hpa to original number

export KUBECONFIG=/var/lib/jenkins/.kube/config ## Export your file


## variables | Change these variables as per your requirements
service_name="my-service"
image_with_tag="image_registry/image_repo:$BUILD_NUMBER"
wait_for=15 #in mins

let iterations="(${wait_for}*60)/10"

## 1. Set the HPA max to current replicas
# Get the hpa config
random=$(LC_CTYPE=C tr -d -c '[:alnum:]' </dev/urandom | head -c 8)
filename="hpa-config-$random.yaml"
rm -f $filename
kubectl get hpa $service_name -o yaml > $filename

parse_yaml() {
   local prefix=$2
   local s='[[:space:]]*' w='[a-zA-Z0-9_]*' fs=$(echo @|tr @ '\034')
   sed -ne "s|^\($s\)\($w\)$s:$s\"\(.*\)\"$s\$|\1$fs\2$fs\3|p" \
        -e "s|^\($s\)\($w\)$s:$s\(.*\)$s\$|\1$fs\2$fs\3|p"  $1 |
   awk -F$fs '{
      indent = length($1)/2;
      vname[indent] = $2;
      for (i in vname) {if (i > indent) {delete vname[i]}}
      if (length($3) > 0) {
         vn=""; for (i=0; i<indent; i++) {vn=(vn)(vname[i])("_")}
         printf("%s%s%s=\"%s\"\n", "'$prefix'",vn, $2, $3);
      }
   }'
}

# read yaml file
eval $(parse_yaml $filename "config_")

# access yaml content
echo $config_status_currentReplicas
currentReplicas="$config_status_currentReplicas"

newMaxValue="  maxReplicas: $currentReplicas"
echo "#$newMaxValue"

oldMaxValue="$(grep "  maxReplicas:" $filename)"
echo "#$oldMaxValue"


perl -i -ne "print unless /resourceVersion:/" $filename
echo $?

sleep 1

perl -pi -e "s/$oldMaxValue/$newMaxValue/g" $filename
echo $?

grep "maxReplicas" $filename

# apply hpa config
kubectl apply -f $filename


## 2. Set image

kubectl set image deployment/$service_name $service_name=$image_with_tag

## 2.1 Sleep till deployment is finished
expected_output="deployment \"$service_name\" successfully rolled out"
count=0
while :
do
   ((count=count+1))
   echo "$count : waiting for deployment to be completed..."
   sleep 10
   output=$(kubectl rollout status deploy/${service_name} --watch=false)
   if [[ "$output" == "$expected_output"  ]]
   then
     echo "[Success] ::: YO ::: deployment completed ::: YO :::"
	 echo "resetting hpa value"
     break
   elif [[ $count -eq $iterations ]]
   then
   	 echo "enough time($wait_for) waited for deployment to be completed"
     echo "$count : $output"
	 echo "resetting hpa value"
     break
   else
     echo "[INFO] : $output"
   fi
done


## 3. Set max hpa to original number
perl -i -ne "print unless /resourceVersion:/" $filename
echo $?

sleep 1

perl -pi -e "s/$newMaxValue/$oldMaxValue/g" $filename
echo $?

grep "maxReplicas" $filename

# apply hpa config
kubectl apply -f $filename

echo "SUCCESS"