Running different Jenkins for different environments leads to use case where Jenkins jobs are imported from one environment to another. And since jenkins slaves might have different labels/names in different environments, we need to ensure lables are correct for each job

jenkins-slave-label-check.sh

#!/bin/bash
#
# Author:   Abhinav Kumar
# About:    Script to check 
#           - if Jenkins is using valid and allowed slave labels only. 
#           - if jobs are configured to run on slaves with labels which are node names.


# change IFS for the course of this script
OLDIFS=$IFS
IFS=$'\n'

# make sure /usr/bin is in PATH.
PATH="$PATH:/usr/bin"

predefined_node_name_array=('build' 'mobile' 'docker' 'node' 'perl')

jenkins_user='some-user'
jenkins_pass='some-token'

# find all nodes in jenkins
jenkins_allnodes_details_json="`curl -f --silent http://${jenkins_user}:${jenkins_pass}@localhost:8080/jenkins/computer/api/json`"
if [ "$?" -ne '0' ]; then echo "unable to get node details from Jenkins"; exit 1; fi


# if there is only one node for this jenkins setup, no need to proceed further, even if the jobs are labeled with wrong node name.
#  The node names will not even come into picture until there are multiple nodes in jenkins cluster.
# in this case, just print everything is good and exit with zero status code. Me happy, BASH happy and System happy :)
if [ "`echo $jenkins_allnodes_details_json | jq '.computer | length'`" -eq '1' ]; then echo 'All Good!!' && exit 0; fi


# find all jobs in jenkins
jenkins_alljobs_details_json="`curl -f --silent http://${jenkins_user}:${jenkins_pass}@localhost:8080/jenkins/api/json`"
if [ "$?" -ne '0' ]; then echo "unable to get all job details. Exiting."; exit 1; fi


# clean the previous garbage just in case and create a placeholder temp file for later use.
rm -f /tmp/jenkins-nc.*.list
tmp_file="`mktemp /tmp/jenkins-nc.XXXXXXXXXX.list`"
if [ "$?" -ne '0' ]; then echo "Unable to create new file in /tmp directory"; exit 1; fi

# get where the job is running
for job_name in `echo $jenkins_alljobs_details_json | jq -r .jobs[].name`; do
    sed -n "s/.*<assignedNode>\(.*\)<.*/\1/p" /mnt1/jenkins/jobs/$job_name/config.xml | tr ' ' '\n' | sed "s/\$/ $job_name/g" >> $tmp_file
done

check_variable1='0'
for node_name in `echo $jenkins_allnodes_details_json | jq -r .computer[].displayName | grep -v master`; do
    IFS=$OLDIFS
    while read node_n job_n; do
        if [ ! -z "${node_n}" ]; then echo "job : ${job_n}, node: ${node_n}" && check_variable1='1'; fi
    done <<< "$(awk -v n_name="$node_name" '$1 == n_name {print}' $tmp_file)"
    IFS=$'\n'
done
rm -f $tmp_file

# now check if all the node labels that are present are subset of `predefined_node_name_array`
check_variable2='0'
for label_name in `comm -23 <(sed -n 's/.*<label>\(.\+\)<\/label>/\1/p' /mnt1/jenkins/nodes/*/config.xml | tr ' ' '\n' | sort | uniq) <(printf '%s\n' "${predefined_node_name_array[@]}" | sort)`; do
    if [ ! -z "$label_name" ]; then
        for node_name in `curl --silent http://${jenkins_user}:${jenkins_pass}@localhost:8080/jenkins/label/${label_name}/api/json| jq -r .nodes[].nodeName`; do
            echo "${node_name} assigned unknown label: ${label_name}" && check_variable2='1'
        done
    fi
done
IFS=$OLDIFS

check_variable="$(( check_variable1 + check_variable2 ))"

if [ "$check_variable" -eq "0" ]; then echo 'All Good!!'; fi

exit $check_variable