Difference between revisions of "Configuring Nexus as a Helm repo"

Revision as of 09:51, 22 October 2018

What we will do:

– create a private (hosted) repository for our own package

– create a proxy repository pointing to stable helm repo server (https://kubernetes-charts.storage.googleapis.com) for 'kubernetes'or other private repo.

I suggest you create a new blob store for each new repo you want to create. That way, the data for every repo will be in a different folder in /nexus-data.

But this is not mandatory for it to work.

private repo

A repository for Helm repo that your team creates.

Create a new Helm (hosted) repository and configure it like:

proxy repo

A repository that proxies everything you download from the official repository, Kubeapps Hub. Next time you download the same dependency, it will be cached in your Nexus.

Create a new Helm (proxy) repository and configure it like:

Configuring Helm for private repository

Configuring Helm to use Nexus Repository is fairly easy! Once you have Helm up and running you'll want to run a command similar to the following:

​$ helm repo add nexusrepo http://localhost:8081/repository/helm-proxy/

​$ helm install nexusrepo/mongodb

Create a package

What is a helm chart? It is basically a set of templates and a file containing variables used to fill these templates. Let’s have a look at an example. I assume that you already have Helm installed and configured at this point.

To start working on a chart, Helm uses a simple command create:

​$ helm create my-app

After that Helm creates a directory with the following layout:​\

my-app/
├── charts
├── Chart.yaml
├── templates
│     ├── deployment.yaml
│     ├── _helpers.tpl
│     ├── ingress.yaml
│     ├── NOTES.txt
│     └── service.yaml
└── values.yaml
2 directories, 7 files

It has charts directory with chart dependencies, but we don’t need it at the moment. Next comes Chart.yaml containing global variables for the chart such as version and description:

​$ cat my-app/Chart.yaml
apiVersion: v1
appVersion: "1.0"
description: A Helm chart for Kubernetes
name: my-app
version: 0.1.0

Then comes templates directory – there you put all the *.yaml files for Kubernetes. Helm uses Go template markup language to customize these files. Helm creates three default file types: deployment, service, and ingress. All the files in this directory are ‘skeletons’ which are filled with the variables from values.yaml when you deploy your Helm chart. File _helpers.tpl contains your custom helper functions for variable calculation. By default, helm creates an nginx deployment. Let’s customize it a bit. Add new ConfigMap to the templates directory:

​$ cat << HELM &gt; my-app/templates/cm.yaml
apiVersion: v1
data:
nginx.conf: |
  events {
    worker_connections 1024;
  }
  http {
    server {
      listen 80;
      location / {
        return 200 "===============================\n\n &nbsp;&nbsp;This is your helm deploy! \n\n===============================\n";
      }
    }
  }
kind: ConfigMap
metadata:
name: nginx-config
HELM

Point our nginx Deployment to that ConfigMap. Add the following lines to the deployment.yaml:

volumes: 
- name: config
  configMap:
    name: nginx-config

and:

volumeMounts:
- name: config
  mountPath: /etc/nginx/nginx.conf
  subPath: nginx.conf

That’s it! Let’s check if we are doing the right thing: helm template my-app This will generate all templates with variables and show the output. Now that we know everything is OK, we can deploy the chart:

helm install my-app --name=my-app-name

Then check that Service and Deploy have been created and curl our Service:

$ kubectl get svc
NAME                         TYPE CLUSTER-IP EXTERNAL-IP  PORT(S) AGE
my-app-name-my-app      ClusterIP 10.100.56.254 <none>     80/TCP 44m

$ curl 10.100.56.254
====== =================== ======
 This is your helm deploy!
====== =================== ======

Congratulations! We have created and deployed our first Helm chart.

Additionally, you can create a package:

$ helm package my-app

This command creates an archive like my-app-0.1.0.tgz — now you can share your chart with others. For instance, you can upload this file to Helm repository, which we are going to do now.