Kubernetes Cluster On-Prem: Infrastructure Requirements

Updated 2 months ago by Michael Cretzman

This document lists the infrastructure requirements for installing Harness Kubernetes Cluster On-Prem in an existing Kubernetes cluster.

For requirements when installing the Kubernetes On-Prem cluster on VMs, see Virtual Machine On-Prem: Infrastructure Requirements.

In this topic:

Production Installation

Here are the requirements for each microservice.

Microservice

Pods

CPU / Pod

Memory / Pod

Total CPU

Total Memory

Manager

2

2

4

4

8

Verification

2

1

3

2

6

Machine Learning Engine

1

8

2

8

2

UI

2

0.25

0.25

0.5

0.5

MongoDB

3

4

8

12

24

Proxy

1

0.5

0.5

0.5

0.5

Ingress

2

0.25

0.25

0.5

0.5

TimescaleDB

3

2

8

6

24

KOTS Admin Pods

 

 

 

4

8

Total

 

 

 

37.5

73.5

The KOTS Admin Pods requirements are for a full stack. In an existing cluster, they will likely be lower.

Dev Installation

Here are the requirements for each microservice.

Microservice

Pods

CPU / Pod

Memory / Pod

Total CPU

Total Memory

Manager

1

2

4

2

4

Verification

1

1

3

1

3

Machine Learning Engine

1

3

2

3

2

UI

1

0.25

0.25

0.25

0.25

MongoDB

3

2

4

6

12

Proxy

1

0.5

0.5

0.5

0.5

Ingress

1

0.25

0.25

0.25

0.25

TimescaleDB

1

2

8

2

8

Kots Admin Pods

 

 

 

4

8

Total

 

 

 

19

38

Node Specifications: 8 cores vCPU, greater than 12 GB memory.

Storage Requirements

You should have a Kubernetes Storage Class attached to the Kubernetes cluster.

You need to provide the StorageClass name during installation.

Harness uses a total 1000 GB of space distributed as:

  • MongoDB - 3 pods * 200 GB each = 600 GB
  • Timescale DB - 3 pods * 120 GB each = 360 GB
  • Redis: 40 GB total
  • Note: For POC installation, total requirement will be: 200 GB total
  • MongoDB - 3 pods * 50 GB each = 150 GB
  • Timescale DB - 1 pods * 20 GB each = 20 GB
  • Redis: 30 GB total

Whitelist and Outbound Access Requirements

Whitelist the following URLs:

  • kots.io — Kots pulls the latest versions of the kubectl plugin and Kots admin console.
  • app.replicated.com — Kots admin console connects to check for the availability of releases according to your license
  • proxy.replicated.com — Proxy your registry to pull your private images.

Outbound access to the following URLs:

  • proxy.replicated.com​
  • replicated.app
  • k8s.kurl.sh​
  • app.replicated.com
The outbound access is required for a connected install only. If you have opted for Airgap mode, this is not required.

If your cluster does not have direct outbound connectivity and needs a proxy for outbound connections, use these instructions: https://docs.docker.com/network/proxy to set up a proxy on the node machines.

Cluster and Network Architecture

The following diagram illustrates the simple cluster and networking architecture for an On-Prem Kubernetes Cluster setup.

The following sections go into greater detail.

Namespace Requirements

In the examples in all Harness On-Prem documentation, we use namespace named harness.

If can use a different namespace, ensure that you update any spec samples provided by Harness.

Load Balancer

You need to set up a Load Balancer before installing Harness On-Prem.

During installation, you will provide the Load Balancer URL in the KOTS admin console.

After On-Prem is installed, the load balancer is used to access the Harness Manager UI using a web browser.

Follow the steps on creating the load balancer as part of the process described in Kubernetes Cluster On-Prem: Kubernetes Cluster Setup.

Trusted Certificate Requirement for Harness On-Prem

All connections to the Harness Manager can be secure or unencrypted according to the URL scheme you use when you configure the Load Balancer URL during installation (https:// or http://):

For secure connections from any integration into the Harness Manager (Github Webhooks, etc), including the Harness Delegate, you must use a publicly trusted certificate.

Harness does not support self-signed certificates for connections to the Harness Manager.

For connections from the Harness Manager outbound to an integration, you can use a self-signed certificate. In this case, you must import the self-signed certificate into Harness Delegate's JRE keystore manually or using a Harness Delegate Profile.

See Add Self-Signed Certificates for Delegate Connections.

Install Harness On-Prem

Now that you have set up the requirements, proceed with installation in Kubernetes Cluster On-Prem: Kubernetes Cluster Setup.

How did we do?