Overview

Use this repository to submit Charts for Helm. All of them are used into APSL organitzation to deploy our Django applications over GKE.

Dependencies

Helm & Tiller

First of all you need to install the Helm client following the next instructions:

curl https://raw.githubusercontent.com/kubernetes/helm/master/scripts/get > get_helm.sh
chmod 700 get_helm.sh
./get_helm.sh

For deploys is also needed the server portion of Helm, Tiller (it talks to a remote Kubernetes cluster). To install it into the cluster, simply runs:

helm init

For more information take a look at: Install Helm

Packages

To use this repository as a k8s charts repository for deploy your apps you have to configure helm adding it:

helm repo add apsl https://raw.githubusercontent.com/APSL/kubernetes-charts/master/packages/

Check that it has been added.

helm repo list

NAME     	URL
stable   	https://kubernetes-charts.storage.googleapis.com
incubator	https://kubernetes-charts-incubator.storage.googleapis.com/
local    	http://127.0.0.1:8879/charts
apsl     	https://raw.githubusercontent.com/APSL/kubernetes-charts/master/packages/

Structure of repository

kubernetes-charts/    
├── packages/                           # Reult folder where construct temporaly packages before be installed.
|    ...
|    ├── index.yaml                     # Contains the configuration for a django app deployment.
|    ├── django-nginx-uwsgi-0.1.1.tgz   # Django package. It includes nginx, uwsgi, redis, varnish packages.
|    ├── uwsgi-0.1.1.tgz                # Uwsgi package.
|    └── varnish-0.1.0.tgz              # Varnish package.
...
├── django/                             # Contains the configuration for a django app deployment.
|    ├── .helmignore                    # List of patterns to ignore when build the package.
|    ├── Chart.yaml                     # A YAML file containing information about the chart.
|    ├── requirements.yaml              # List of required charts and their overriden configuration.
|    ├── values.yaml                    # The default configuration values for this chart
|    ├── charts/                        # Include all dependency packages
|    |                                  # IMPORTANT: No commit packages into.
|    └── templates/                     # A directory of templates that, when combined with values.
|        └── _helpers.tpl               # Difinition of template variables.
|                                       # Note that not require templates because this chart only encapsulate
|                                       # dependencies.
...
└── uwsgi/                              # Contains the configuration for a uwsgi deployment.
     ├── charts/                        # Folder that contains built packages for the dependecies of this chart.
     |                                  # IMPORTANT: No commit packages into, will be auto-generated.
     ├── .helmignore                    # List of patterns to ignore when build the package.
     ├── Chart.yaml                     # A YAML file containing information about the chart.
     ├── requirements.yaml              # List of required charts and their overriden configuration.
     ├── values.yaml                    # The default configuration values for this chart
     └── templates/                     # A directory of templates that, when combined with values.
         ├── NOTES.txt                  # A plain text file containing short usage notes (rendered with Go Template engine)
         ├── _helpers.tpl               # Definition of template variables.
         ├── deployment.yaml            # Structure of deployment for this chart.
         ├── secrets.yaml               # Base secrets for the chart.
         └── service.yaml               # Structure of service for this chart.

Take a look to The Chart File Structure to get acquainted to chart structure.

How to

This section will try to explain you how to use this repository to deploy your applications.

How to deploy a chart over Kubernetes?

Will show you the procedure to deploy a Django application using this charts.

This example we'll deploy an app called demo, suposing you satisfy all dependencies.

Deploy the Django application.

helm install PACKAGE --version VERSION --namespace NAMESPACE --name RELEASE_NAME -f VALUES

PACKAGE → The path to stored package.
VERSION → The exact version of the package to install. If it is not set the last version will be deployed.
NAMESPACE → The namespace that will be create on Google Cloud Platform and will be user with in the deployment.
RELEASE_NAME → It must has a different value to namespace. It is used in the deployment and dependencies deployments.
VALUES → Path to the file where are all values that overrides the Helm chart, for example SECRET_KEY or DATABASE_PASSWORD, etc.

helm install apsl/django-nginx-uwsgi --version 0.1.1 --namespace demo --name r-demo -f your_demo_app_values.yaml

How to test your deployment before apply it on your K8s cluster?

Helm Template is a plugin used to render the resultant deployment of your chart.

Install:

helm plugin install https://github.com/technosophos/helm-template

Use it:

helm template -n NAMESPACE -r RELEASE_NAME -f VALUES --notes CHART > output.yaml

NAMESPACE → The namespace used with in deployment.
RELEASE_NAME → The release name used with in deployment.
VALUES → Override specific values for application.
CHART → Location path to the chart.

helm template -n demo -r r-demo -f your_demo_app_values.yaml --notes . > ~/k8s-deployment.yaml

Structure example of data values

This section show you how structure the values to deploy a single application using django-nginx-uwsgi chart.

# your_demo_app_values.yaml
global:
  image:
    uwsgi: eu.gcr.io/project/my-app-uwsgi
    nginx: eu.gcr.io/project/my-app-nginx

  dataConfigMap:
    - name: REDIS_HOST
      value: "10.0.0.1"
    - name: DEFAULT_FROM_EMAIL
      key: django.emailDefaultFromEmail
      value: Hotel Morito <bookmorito@hotelmorito.es>
    - name: AWS_STORAGE_BUCKET_NAME
      value: my-app-prod
    - name: AWS_ACCESS_KEY_ID
      value: aws-key-id

  dataSecrets:
    - name: AWS_SECRET_ACCESS_KEY
      value: secret-aws-access-ley

app:
  deployment:
    probes:
      livenessEnabled: true
      liveness:
        enabled: false

  replicaCount: 1

  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
    type: RollingUpdate

  secrets:
    secretKey: django-secret-key-value
    passwordDB: django-passwd-db-value
    sentryDSN: sentry-dsn-value

  configMap:
    enableSentry: "True"
    databaseHost: 127.0.0.1
    databaseName: myappdb
    databasePort: "5432"
    databaseUser: usrmyapp
    enableBasicAuth: "False"
    enableHttpsRedirect: "True"
    enable3wRedirect: "True"

varnish:
  enabled: true

crons:
  enabled: false

redis:
  enabled: false

Contributors

Developing new Helm charts

There are some notes and some command line instructions that can be useful as a guide how to develop new charts.

To create a new chart:

helm create CHART

CART → Full path to destination chart.

helm create django-nginx-uwsgi

After develop your template chart, you can validate if your chart is valid running a lint.

helm lint django-nginx-uwsgi

Building package

If you contribute creating new Charts or improving the existent you should do this:

Serve your packages locally
Resolve repository dependencies (local repository)
Update dependent locally repositories your Chart
Generate your package
Regenerate index-yaml

To simplify all this tasks, you only have to execute this:

make helm-up & \
make helm-packages && \
helm repo index packages

NOTE: Its possible see some non-liveness message using make command to build packages. If the message is like "No requirements found in ~/kubernetes-charts/nginx-uwsgi/charts" ignore it. It is because the commnand script try to get dependencies of all packages even if it has not charts (the dependency folder).

Use case:

We will generate a new chart packagedemo_:

Create the chart

helm create packagedemo

Serve built local packages:

cd packages
helm serve

Build all dependent packages:

helm package -u -d packages uwsgi
helm package -u -d packages nginx
helm package -u -d packages packagedemo

or use the Makefile commands:

make helm-packages

Generate index

helm repo index packages