CI/CD Pipeline using Node.js and Jenkins - 6: Creating and Destroying Droplets
After getting my CI/CD pipeline up and running, I needed an easier way to create droplets from snapshots so that process wasn’t so time-consuming.
Parameterising the Node-App IP Address:
With my current setup, if I take a snapshot and destroy the Node-App server, when I re-create the server from the snapshot in another droplet it will have a different IP address. The IP address is hard-coded into the deploy script so each time I create it, I would need to commit new code to be able to deploy.
To get over this hurdle, I parameterised the deploy script to accept the IP address as a command line argument, so the IP address could be configured in the Jenkins config, instead of within the code itself.
#!/bin/sh
ssh twulz@$1 <<EOF
cd ~/node-app
git pull
npm install -—production
pm2 restart all
exit
EOF
So now the Build Execute Shell script reads:
whoami
npm install
./script/test
./script/deploy 157.245.55.163 #IP address of node-app server.
So each time the Node-App server address changes, just need to update that parameter to the new IP on the Jenkins server, without needing a new commit to git.
To spin up a new Jenkins droplet:
- Use the previous droplet snapshot.
- Wait for it to be live, then copy the new IP address
- Update the webhook in Github
- Done! Any new commits will automatically deploy to the Node-App server.
To spin up a new Node-App droplet:
- Create the droplet from the snapshot
- Wait for it to be live, then copy the new IP address
- Update the IP address in the jenkins config: http://jenkins-ip-address:8080/job/node-app/configure
- ssh into the jenkins droplet (may need to login as root or twulz then
su - jenkins) - ssh from jenkins droplet into node-app droplet once
ssh twulz@node-ip-address, answer “yes”, this adds it to a known hosts file. - in the node-app server, start pm2:
pm2 start index.js - Now if you hit “Build now” in Jenkins, it should build and deploy: http://jenkins-ip-address:8080/