Bash script to move Jenkins apps to "quietmode" for a specific time passed as parameter before draining node of your CI k8s cluster

quietShutDownBeforeDrain.sh

#!/bin/bash

set -euo pipefail
shopt -s inherit_errexit nullglob compat"${BASH_COMPAT=42}"

#Parameters
JENKINS_USER_ID=example.user
JENKINS_API_TOKEN=******
JENKINS_NS_LIST=("ns-example-1" "ns-example-2")
SLEEP_SEC=3600

quietDownJenkinsApps(){
   for ns in "${JENKINS_NS_LIST[@]}"; do
       mapfile -t podsPerNsList < <(kubectl get pods -n "$ns" | awk '{print $1}' | sed "1d")
       if [ ${#podsPerNsList[@]} -gt 0 ]; then
           for pod in "${podsPerNsList[@]}"; do
               isJenkinsApp=$(kubectl exec "$pod" -n "$ns" -- sh -c "[ -d /var/jenkins_home ] && echo \"true\" || echo \"false\"" )
               if [ "$isJenkinsApp" = "true" ]; then
                   jenkinsUrl=$(kubectl exec "$pod" -n "$ns" -- cat /var/jenkins_home/jenkins.model.JenkinsLocationConfiguration.xml | grep "<jenkinsUrl>" | sed -n 's:.*<jenkinsUrl>\(.*\)</jenkinsUrl>.*:\1:p')
                   # https://support.cloudbees.com/hc/en-us/articles/216118748
                   action="quietDown"
                   response=$(curl --write-out "%{http_code}\n" --user "${JENKINS_USER_ID}:${JENKINS_API_TOKEN}" -XPOST "${jenkinsUrl}/${action}" --silent)
                   # https://developer.mozilla.org/en-US/docs/Web/HTTP/Status
                   if [ "$response" -lt "400" ]; then
                       echo "[INFO] Moving $jenkinsUrl to $action ..."
                   fi
               fi
           done
       fi
   done
}

siestaTime(){
   echo "[INFO] Enter in siesta mode for $SLEEP_SEC sec..."
   sleep $SLEEP_SEC
}

drainNodes(){
   mapfile -t allNodesList < <(kubectl get nodes | awk '{print $1}' | sed "1d")
   if [ ${#allNodesList[@]} -gt 0 ]; then
       for node in "${allNodesList[@]}"; do
           kubectl drain "$node" --ignore-daemonsets --delete-emptydir-data
       done
   fi
}

quietDownJenkinsApps
siestaTime
drainNodes