Scaling jenkins with kubernetes
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This document discusses scaling Jenkins with Kubernetes. Previously, Jenkins was run on single EC2 instances with issues like underutilization and port collisions. The new approach runs Jenkins on Kubernetes, allowing on-demand PODs for each build with complete isolation. A modified Kubernetes plugin was created to support multiple containers and persistent volumes per POD. Builds now have isolated environments, persistent storage, and can scale across Kubernetes nodes. This saves costs by using spot instances for Kubernetes nodes managed by Spot Fleets.
Scaling jenkins with kubernetes
- 1. Scaling Jenkins with Kubernetes 1.2
- 2. About me Senior DevOps Engineer @ Glide rubygems.org/profiles/amimahloof Contribution to OpenSource via RubyGems and GitHub: github.com/innovia linkedin.com/in/amimahloof
- 3. Glide environment Multiple Redis Servers MySQL DynamoDB Multiple Background Queue Processors App Server Multiple Web Socket Servers CloudSearch
- 4. Previous Jenkins setup Single Jenkins Master machine for Server code builds Single Jenkins Master Machine for Android client builds Dedicated MySQL database per build Dedicated port per build service Each build environment encapsulated and managed by Eye - process monitoring https://github.com/kostya/eye
- 5. Previous Jenkins Issues Under-utilized instances running 24/7 (expensive!) Port collisions Out of memory issues - build failures Databases needed to be created and wiped per build Debugging failed tests was extremely hard Updating Jenkins ec2 image especially for Android was a challenge
- 6. NFS-SERVER POD EBS Volume Scaling Jenkins with Kubernetes Jenkins Master BackEnd RC Jenkins Master Android RC Backend POD Jenkins Ingress Controller POD nginx configmap Jenkins Slave POD With KubeCtl Backend Service (IP) single elb for both CI’s addresses
- 7. Current Jenkins Kubernetes Plugin https://github.com/jenkinsci/kubernetes-plugin Support single docker image (jenkins-slave docker image - it create’s a POD with that image) Does not support multiple containers in a POD Does not support Persistent Volumes
- 8. Modified Jenkins Kubernetes Plugin https://github.com/innovia/kubernetes-plugin Support reading and parsing a POD template file Support multiple containers in a POD Support Persistant Volumes, EBS, EmptyDir, HostPath Volum Does not support POD template per JOB (System global config)
- 9. Read POD Template Start Build Send POD Object Jenkins Slave POD download JNLP file from Jenkins Master Connect to Jenkins Master Slave Port Build Flow Part 1 Pull Request
- 10. Build Flow Part 2 Jenkins Master Jenkins Slave Start Job on Slave git fetch and merge server code create service JOB_NAME-BUILD_NUMBER create PV - PVC JOB_NAME-BUILD_NUMBER start tests teardown POD, SERVICE, PV, PVC clean-up temp location submit result to bitbucket create POD JOB_NAME-BUILD_NUMBER wait for setup complete file (check dependancies)
- 11. Advantages On Demand PODs Complete test isolation Source controlled by developers flexible POD template Jobs queued up in Kubernetes Scheduler until node resources are available (running builds finish) Scalable Kubernetes Nodes Plugin keeps track of POD - if POD dies in the middle it launches up a new slave for that job Persistant Storage (EBS via NFS) Spot instances using node selectors
- 12. Kubernetes on Spot Instances Save 70-90% over On Demand Managed by Spot Fleet to reduce downtime Different fleets for different types of Kubernetes Nodes, allowing dynamic pod allocation using Node Selector Until implemented in Kubernetes 1.3, we have to create our own Fleets eg. https://github.com/kubernetes/kubernetes/issues/24472#issuecommen t-211975112