How to activate SSL/HTTPS on Jenkins

For CentOS or RPM based:
Go to /etc/sysconfig/jenkins, set the JENKINS_HTTPS_PORT="8443"

Then restart Jenkins.

If you want to generate ssh key:
openssl genrsa -out key.pem  # creates key.pem

openssl req -new -key key.pem -out csr.pem
# you need to put the dns name of your website, testweb.local
# for the 'Common Name' question
# other questions, you can just accept defaults
# actually, you can accept defaults for all, will work ok too

openssl x509 -req -days 9999 -in csr.pem -signkey key.pem -out cert.pem
rm csr.pem
start jenkins
if you want both https and http:
java -jar jenkins.war --httpsPort=8443 --httpsCertificate=cert.pem --httpsPrivateKey=key.pem
if you want https only, dont open http port:
java -jar jenkins.war --httpsPort=8443 --httpsCertificate=cert.pem --httpsPrivateKey=key.pem --httpPort=-1
starting a slave
Convert the cert.pem to cert.der:
 openssl x509 -outform der -in cert.pem -out cert.der
create keystore, containing this cert:
keytool -import -alias testweb.local -keystore cacerts -file cert.der
# reply trust certificate=yes
# put keystore password of 'changeit', or make your own password
transfer this file to the slave computer somehow (eg via /var/www/html, and download from slave)
launch slave
as for normal slave launch, but add `-Djavax.net.trustStore=cacerts
java -Djavax.net.ssl.trustStore=cacerts -jar slave.jar -jnlpUrl https://jenkins.myweb.com:8443/computer/testnode/slave-agent.jnlp