When deploying an application, specifically on Kubernetes, it is required to define and manage several Kubernetes resources such as pods, services, deployments, and replicasets. These hooks all live in a YAML based file. Let’s hop in.

What is Helm?

Helm is a package manager for Kubernetes. It allows you to easily configure, add, remove things, and deploy applications and services on Kubernetes clusters.

Usage

Let’s grab Helm from Katakoda:

curl -L https://git.io/get_helm.sh | bash

Let’s build the Helm package:

helm package tomcat

Let’s now define the repo index:

helm repo index .

Let’s add a new repository to the Helm client, it’s a lot like adding a project to a GitHub repository:

helm init
helm repo add (img name) (repo link)
helm repo update
helm install (repo name) --name tomcat
helm status tomcat
helm delete tomcat

Starting with Travis CI

Let’s get a vaild .travis.yml going:

language: minimal
if: branch = master

before_install:
  - curl -L https://git.io/get_helm.sh | bash
  - helm init --client-only

script:
  - mkdir files-to-gh-pages
  - echo $(pwd)
  - helm package charts/tomcat-prod -d files-to-gh-pages
  - helm package charts/tomcat -d files-to-gh-pages
  - cp README.md files-to-gh-pages
  - cd files-to-gh-pages
  - helm repo index .
  - ls -ltr 
  
deploy:
  provider: pages  
  github_token: $GITHUB_TOKEN
  local_dir: files-to-gh-pages
  target_branch: gh-pages
  verbose: true
  skip_cleanup: true
  keep_history: true
  on:
    branch: master

As you can see we are going to push this to a gh-pages, via the hook provider: pages. Now let’s make a folder in our project entitled charts then inside of charts let’s make one called tomcat. I made a .helmignore file, and I’ll share it below:

 # Negation (prefixed with !). Only one pattern per line.
.DS_Store
.git/
.gitignore
.bzr/
.bzrignore
.hg/
.hgignore
.svn/
*.swp
*.bak
*.tmp
*~
.project
.idea/
*.tmproj
.vscode/

In your tomcat directory let’s make a file called Chart.yaml:

apiVersion: v1
appVersion: "9.0.26"
description: A Helm chart for Tomcat 9 (with Oracle openjdk13)
name: tomcat
version: 0.1.2

Now we need to make another yaml file, as I said in. the beginning - Helm’s method of action is getting configuration settings from yaml files. Let’s call this file values.yaml:

replicaCount: 3

image:
  repository: tomcat
  tag: 9.0.26-jdk13-openjdk-oracle
  pullPolicy: IfNotPresent

imagePullSecrets: []
nameOverride: ""
fullnameOverride: ""

service:
  type: ClusterIP
  port: 8080
  targetPort: 8080

ingress:
  enabled: true
  annotations:
    kubernetes.io/ingress.class: "tomcat"
    # kubernetes.io/tls-acme: "true"
  hosts:
    - host: (your host)
      paths: []

  tls: []

resources: {}

nodeSelector: {}

tolerations: []

affinity: {}

Travis will now deploy Helm and in turn, Helm will now use the newly built image to deploy Helm Charts. You can repeat this process say if you had another directory entitled tomcat-prod, but just redoing the following steps above:

Conclusion

So there you have it, you now know what Helm is all about, and why not give it a shot? See how Travis makes an easier process even easier.

Happy building!

If you have any questions please email me at montana@travis-ci.org.