Kubernetes Cluster On-Prem: Infrastructure Requirements

Updated 1 month 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.

Port Mapping for gRPC Traffic

You also need to open port 9879 on the Load Balancer and map it to port 9879 on the Ingress controller. This is to support gRPC traffic.

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.

You can use self-signed certs for TLS connections between the MongoDB that ships with Harness and the Harness microservices. See Enable TLS/SSL between MongoDB and Harness Components.

Install Harness On-Prem

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

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