Resolving the "Request Entity Too Large" Error in Helm Deployments: Effective Strategies and Solutions

When deploying an application using Helm, you might encounter the error:

Error: INSTALLATION FAILED: create: failed to create: Request entity too large: limit is 3145728

This error occurs when the size of the Helm chart or the generated Kubernetes resources exceeds the default size limit set by the Kubernetes API server or ingress controllers. This blog provides a comprehensive guide to resolving the issue, including an approach to split an umbrella Helm chart into multiple smaller charts.

Problem Overview

What does the error mean?

The error indicates that the payload size of your Helm installation request is larger than the allowed size limit (3 MB by default).

Common causes include:

• Large ConfigMaps or Secrets.
• Oversized values.yaml files.
• Complex umbrella charts generating large manifests.

Solution: Splitting an Umbrella Chart

Splitting an umbrella chart into smaller, more manageable charts is an effective way to address this error. Here’s how to do it:

1. Analyze and Group Components

Identify logical groupings within your current umbrella chart. For example:

• Core Services: Redis, PostgreSQL, RabbitMQ.
• Application Modules: Microservices or feature-specific components.
• Auxiliary Tools: Monitoring (e.g., Prometheus), logging (e.g., Fluentd), and alerting (e.g., Alertmanager).

2. Create Smaller Umbrella Charts

For each logical grouping, create a new Helm chart with its own dependencies:

Folder Structure Example

umbrella-chart-core/
├── Chart.yaml
├── values.yaml
├── charts/
│   ├── redis/
│   ├── postgres/
│   └── rabbitmq/

umbrella-chart-app/
├── Chart.yaml
├── values.yaml
├── charts/
│   ├── service-a/
│   ├── service-b/
│   └── service-c/

3. Update Dependencies

• Define the dependencies in each new chart's Chart.yaml.

• Example Chart.yaml for umbrella-chart-core:
  

apiVersion: v2
name: umbrella-chart-core
dependencies:
  - name: redis
    version: "6.0.8"
    repository: "https://charts.bitnami.com/bitnami"
  - name: postgres
    version: "12.9.0"
    repository: "https://charts.bitnami.com/bitnami"

• Run the following command to update dependencies:

  helm dependency update

4. Externalize Shared Values

Move shared configurations to an external location to avoid duplication:

• Use Kubernetes ConfigMaps or Secrets for shared settings.

• Example values.yaml:
  

  global:
    database:
      host: "db.example.com"
      username: "user"
      password: "password"`
  

5. Deploy Charts Independently

Deploy each smaller umbrella chart individually:

helm install core-services umbrella-chart-core/
helm install app-services umbrella-chart-app/

Best Practices

• Keep Charts Modular: Avoid bloated umbrella charts.
• Use External Storage: Store large files (e.g., certificates) outside Kubernetes.

• Test Chart Output: Use helm template to verify the size of generated manifests:

  helm template my-release my-chart > output.yaml