Helm Chart for Frappe/ERPNext based applications

This project provides a helm chart for deploying a Frappe/ERPnext based application onto Kubernetes using 'helm' packaging tool.

Pre-requisites

1. Working installation of Helm components - Tiller installed and configured (for RBAC) on target Kubernetes cluster and 'helm' client machine. For more details please refer to Helm documentation.
2. Storage provisioned using either azure-file or azure-disk (for AKS deployments). This involves creation of a storage account and a file-share, if using azure-file based persistent storage. For azure-disk based persistence, it setting up of dynamic provisioning is recommended. The disk can be provisioned using steps provided Here. Once provisioned, create a blank apps.txt and currentsite.txt in the shared drive created for the application. Note that, without this, the application will fail to deploy.
3. Docker image created and available (i.e. docker pushed) in a shared repository.
4. Namespace where the components are to be deployed. This should be provided as targetNamespace in values.yaml.

Installation Steps

1. git clone this chart (until a helm chart repository is setup) to any location locally.
2. Use one of the sample values.yaml or create your own with same structure as the sample file. Update the values in the file as appropriate for your application.
3. Change to the directory where this chart has been cloned and deploy the application using helm command as follows -

helm install --name  -f  .

For example -

helm install --name cas -f /workspace/matrix/values-matrix.yaml .

4. Chart can also be installed from any location, by providing path to the local chart directory instead of '.' (current directory) in the command above.

Key Terms

• Release Name - Name provided in above command after --name parameter.

What the chart does

The helm chart creates following kubernetes resources for the application -

• RBAC Configuration - Chart creates a binding for role cluster-admin to the default service account in target namespace for the deployment.

• Configuration Files - Configuration required for redis components and frappe components are created with following naming convention -

  • Server configurations - <release-name>-server-config: Contains configuration for

    • Kafka
    • DB Host
    • DB Name to be used for the site to be setup in frappe
    • Gunicorn Connections per Worker
    • Number of gunicorn workers to start

  • Fluentd Configuration - <release-name>-fluentd-config: Contains configuration for fluentd sidecar container that polls the log files generated in logs folder of the bench installation and publishes them to an elasticsearch host. Destination Elastic search host is configured through etchosts group in values.yaml.

  • Redis Configuration - <release-name>-redis-config: Contains configuration files for redis instances for cache, queue and socketio, used by the frappe installation. Persistence can be enabled for each of the redis servers, if required. (Not tested yet).

• Storage Components have following naming convention -

  • Storage class - <release-name>-sites-sc
  • Persistent Volume - <release-name>-sites-pv
  • Persistent Volume Claim - <release-name>-sites-pvc Storage capacity requested is picked up from the values.yaml file provided from the key persistence.capacityInGi. Other parameters that are specific to the Azure persistance provisioned, are also picked up from persistence group of values in values.yaml.
  • Secrets are created with name <release-name>-secrets - This contains the authentication information required to connect to Azure's File shares created using storage account.

• Deployment of Redis and Frappe components

  • StatefulSet that runs 2 containers in a pod - one with Frappe and related applications and another sidecar that runs fluentd log collector. Number of replicas for the stateful set can be defined in the values.yaml.
  • Stateful set for Redis cache instance with configuration provided from configuration created above. This will be named as <release-name>-redis-cache
  • Stateful set for Redis queue instance with configuration provided from configuration created above. This will be named as <release-name>-redis-queue
  • Stateful set for Redis socketio instance with configuration provided from configuration created above. This will be named as <release-name>-redis-socketio

• Services expose the applications deployed in the cluster. Following services are created -

  • Service with same name as the stateful set for frappe application is created that exposes the NGinx port (8000) in the frappe container
  • External Database is made available to the frappe application as an external name service which is used by the frappe application. The actual IP Address of the database is looked up using the entries in etchosts. The branch name provided in the values.yaml is used as prefix to -db.ntex.com and used as hostname for the database. This entry must be present in the etchosts group for frappe application to connect to the database. Application will then create/re-create database with name site.dbname value. Note that if the database exists while site is being initialized, it will be deleted and recreated - any data from the old database will be lost.
  • Redis cache setup is made available to the frappe application through a service named er-frappe-redis-cache and connects back to the deployment of redis cache created above. This service is exposed on port 13000.
  • Redis queue setup is made available to the frappe application through a service named er-frappe-redis-queue and connects back to the deployment of redis queue created above. This service is exposed on port 11000.
  • Redis socketio setup is made available to the frappe application through a service named er-frappe-redis-socketio and connects back to the deployment of redis socketio created above. This service is exposed on port 12000.

Configuration

Besides the above resources created, chart can be customized through the configuration parameters listed below.

Parameter	Description	Default
replicaCount	Number of replicas to be created for the frappe application	1
targetNamespace	Target namespace to which the application and related components should be deployed	default
TODO	TODO	TODO