README.md

<!--- Deploy --->

# Deploy helm chart

## Introduction

This chart installs a deployment on a [Kubernetes](https://kubernetes.io) cluster using [Helm](https://helm.sh) package manager.

## Prerequisites

The code was tested on **Kubernetes cluster** (v1.21.11) with **Istio** (1.12.6)
> It is possible to use other versions, but it hasn't been tested

### Operation system

The code works in Debian-based Linux (Debian 10 and Ubuntu 20.04) and Windows WSL 2. Also, it works but is not guaranteed in Google Cloud Shell. All other operating systems, including macOS, are not verified and supported.

### Packages

Packages are only needed for installation from a local computer.

* **HELM** (version: v3.7.1 or higher) [helm](https://helm.sh/docs/intro/install/)
* **Kubectl** (version: v1.21.0 or higher) [kubectl](https://kubernetes.io/docs/tasks/tools/#kubectl)

## Installation

First you need to set variables in **values.yaml** file using any code editor. Some of the values are prefilled, but you need to specify some values as well. You can find more information about them below.

### Global variables

| Name | Description | Type | Default |Required |
|------|-------------|------|---------|---------|
**global.domain** | your domain for the external endpoint, ex `example.com` | string | - | yes
**global.limitsEnabled** | whether CPU and memory limits are enabled | boolean | `true` | yes
**global.logLevel** | severity of logging level | string | `ERROR` | yes
**global.tier** | Only PROD must be used to enable autoscaling | string | - | no
**global.autoscaling** | enables horizontal pod autoscaling, when tier=PROD | boolean | `true` | yes

### Configmap variables

| Name | Description | Type | Default |Required |
|------|-------------|------|---------|---------|
**data.logLevel** | logging severity level for this service only  | string | - | yes, only if differs from the `global.logLevel`
**data.dataPartitionId** | data partition id | string | - | yes
**data.entitlementsHost** | entitlements host | string | `http://entitlements` | yes
**data.javaOptions** | java options | string | `-Xms512M -Xmx1024M -XX:+UseG1GC -XX:+UseStringDeduplication -XX:InitiatingHeapOccupancyPercent=45` | yes
**data.partitionHost** | partition host | string | `http://partition` | yes
**data.schemaTopicName** | topic for schema changes events | string | `schema-changed` | yes

### Deployment variables

| Name | Description | Type | Default |Required |
|------|-------------|------|---------|---------|
**data.requestsCpu** | amount of requested CPU | string | `220m` | yes
**data.requestsMemory** | amount of requested memory| string | `1.7G` | yes
**data.limitsCpu** | CPU limit | string | `1` | only if `global.limitsEnabled` is true
**data.limitsMemory** | memory limit | string | `1.5G` | only if `global.limitsEnabled` is true
**data.bootstrapImage** | bootstrap image | string | - | yes
**data.bootstrapServiceAccountName** | bootstrap service account name | string | - | yes
**data.image** | service image | string | - | yes
**data.imagePullPolicy** | when to pull image | string | `IfNotPresent` | yes
**data.serviceAccountName** | name of your service account | string | `schema` | yes

### Configuration variables

| Name | Description | Type | Default |Required |
|------|-------------|------|---------|---------|
**conf.appName** | name of the app | string | `schema` | yes
**conf.configmap** | configmap to be used | string | `schema-config` | yes

### Datastore cleanup and bootstrap schemas variables

> Datastore cleanup is used for cleaning Datastore Schema Entities if they are not present in Schema bucket

| Name | Description | Type | Default |Required |
|------|-------------|------|---------|---------|
**data.datastoreKind** | Datastore Kind for Schema | string | `system_schema_osm` | yes
**data.datastoreNamespace** | Datastore Namespace for Schema | string | `dataecosystem` | yes
**data.enableCleanup** | whether cleanup is enabled | boolean | `false` | yes
**data.schemaBucket** | name of the bucket with schemas | string | - | yes
**data.schemaHost** | schema host | string | `http://schema` | yes

### Istio variables

| Name | Description | Type | Default |Required |
|------|-------------|------|---------|---------|
**istio.proxyCPU** | CPU request for Envoy sidecars | string | `90m` | yes
**istio.proxyCPULimit** | CPU limit for Envoy sidecars | string | `500m` | yes
**istio.proxyMemory** | memory request for Envoy sidecars | string | `100Mi` | yes
**istio.proxyMemoryLimit** | memory limit for Envoy sidecars | string | `512Mi` | yes
**istio.bootstrapProxyCPU** | CPU request for Envoy sidecars | string | `10m` | yes
**istio.bootstrapProxyCPULimit** | CPU limit for Envoy sidecars | string | `100m` | yes

### Horizontal Pod Autoscaling (HPA) variables (works only if tier=PROD and autoscaling=true)

| Name                                                | Description                                                                   | Type    | Default          | Required                                                       |
|-----------------------------------------------------|-------------------------------------------------------------------------------|---------|------------------|----------------------------------------------------------------|
| **hpa.minReplicas**                                 | minimum number of replicas                                                    | integer | `6`              | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.maxReplicas**                                 | maximum number of replicas                                                    | integer | `15`             | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.targetType**                                  | type of measurements: AverageValue or Value                                   | string  | `"AverageValue"` | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.targetValue**                                 | threshold value to trigger the scaling up                                     | integer | `100`            | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.behaviorScaleUpStabilizationWindowSeconds**   | time to start implementing the scale up when it is triggered                  | integer | `10`             | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.behaviorScaleUpPoliciesValue**                | the maximum number of new replicas to create (in percents from current state) | integer | `50`             | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.behaviorScaleUpPoliciesPeriodSeconds**        | pause for every new scale up decision                                         | integer | `15`             | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.behaviorScaleDownStabilizationWindowSeconds** | time to start implementing the scale down when it is triggered                | integer | `60`             | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.behaviorScaleDownPoliciesValue**              | the maximum number of replicas to destroy (in percents from current state)    | integer | `25`             | only if `global.autoscaling` is true and `global.tier` is PROD |
| **hpa.behaviorScaleDownPoliciesPeriodSeconds**      | pause for every new scale down decision                                       | integer | `60`             | only if `global.autoscaling` is true and `global.tier` is PROD |

### Limits variables

| Name                     | Description                                     | Type    | Default | Required                                                       |
|--------------------------|-------------------------------------------------|---------|---------|----------------------------------------------------------------|
| **limits.maxTokens**     | maximum number of requests per fillInterval     | integer | `100`   | only if `global.autoscaling` is true and `global.tier` is PROD |
| **limits.tokensPerFill** | number of new tokens allowed every fillInterval | integer | `100`   | only if `global.autoscaling` is true and `global.tier` is PROD |
| **limits.fillInterval**  | time interval                                   | string  | `"1s"`  | only if `global.autoscaling` is true and `global.tier` is PROD |

### Methodology for Parameter Calculation variables: **hpa.targetValue**, **limits.maxTokens** and **limits.tokensPerFill**

The parameters **hpa.targetValue**, **limits.maxTokens** and **limits.tokensPerFill** were determined through empirical testing during load testing. These tests were conducted using the N2D machine series, which can run on either AMD EPYC Milan or AMD EPYC Rome processors. The values were fine-tuned to ensure optimal performance under typical workloads.

### Recommendations for New Instance Types

When changing the instance type to a newer generation, such as the C3D series, it is essential to conduct new load testing. This ensures the parameters are recalibrated to match the performance characteristics of the new processor architecture, optimizing resource utilization and maintaining application stability.

### Install the helm chart

Run this command from within this directory:

```console
helm install gc-schema-deploy .
```

## Uninstalling the Chart

To uninstall the helm deployment:

```console
helm uninstall gc-schema-deploy
```

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