How to delete offline (slave/nodes) from Jenkins in SWARM mode - jenkins

Question

How do I delete a node from Jenkins?
Jenkins operates in Docker Swarm mode.
When I am trying to remove the offline container, swarm keeps generating new containers

Answer 1

You can try:
Using Jenkins Pipeline:
node("master") {
println "Cleaning up offline slaves..."
hudson.model.Hudson.instance.slaves.each {
if(it.getComputer().isOffline()) {
println "Deleting ${it.name}"
it.getComputer().doDoDelete()
}
}
println "Done."
}
Using SH
#!/bin/bash
# This script should be run on the Jenkins master. We set up a job in Jenkins to run this once a week on master.
function jenkins-cli {
java -jar /var/cache/jenkins/war/WEB-INF/jenkins-cli.jar -s http://localhost:8080 "$#"
}
for slave in slavename1 slavename2 slavename3; do
if [[ `curl -s "http://localhost:8080/computer/${slave}/api/xml?xpath=*/offline/text()"` = "true" ]]; then
echo "$slave is already offline. Skipping cleanup"
else
echo "Cleaning up docker on $slave"
echo "Taking $slave offline"
jenkins-cli offline-node $slave -m "Scheduled docker cleanup is running" && \
echo "Waiting on $slave to go offline" && \
jenkins-cli wait-node-offline $slave && \
while [[ `curl -s "http://localhost:8080/computer/${slave}/api/xml?xpath=*/idle/text()"` != "true" ]]; do echo "Waiting on $slave to be idle" && sleep 5; done && \
echo "Running cleanup_docker on $slave" && \
ssh -o "StrictHostKeyChecking no" $slave -i /var/lib/jenkins/.ssh/id_rsa "sudo /usr/local/bin/cleanup_docker"
echo "Bringing $slave back online"
jenkins-cli online-node $slave
fi

Answer 2

There are a lot of snippets with which one can list existing nodes in Python. Removing slave nodes works like this:
request = urllib.request.Request("https://insert_jenkins_url/computer/insert_node_name/doDelete", data=bytes("", "ascii"))
#according to https://stackoverflow.com/a/28052583/4609258 the following is ugly
context = ssl._create_unverified_context()
base64string = base64.b64encode(bytes('%s:%s' % ('insert_user_name', 'insert_api_token_with_roughly_35_characters'),'ascii'))
request.add_header("Authorization", "Basic %s" % base64string.decode('utf-8'))
with urllib.request.urlopen(request, context=context) as url:
print(str(url.read().decode()))