# WEKA installation on GCP

## WEKA on GCP overview

Leveraging GCP's advantages, WEKA offers a customizable **terraform-gcp-weka** module for deploying the WEKA cluster on GCP. In GCP, WEKA operates on instances, each capable of using up to eight partitions of drives on the connected physical server (without direct drive usage). These drives can be shared among partitions for other clients on the same server.

WEKA requires either four or seven VPC networks, depending on which instance type is being used for the WEKA backends. This configuration aligns with the four key WEKA processes: Management, Drive, Compute and optionally Frontend, with each process requiring a dedicated network interface as follows:

* eth0: Management vpc-0
* eth1: Drive vpc-1
* eth2: Compute vpc-2
* eth3: Frontend vpc-3

For a WEKA instance using seven NICs, the alignment is as follows:

* eth0: Management vpc-0
* eth1: Drive vpc-1
* eth2: Compute vpc-2
* eth3: Compute vpc-3
* eth4: Compute vpc-4
* eth5: Compute vpc-5
* eth6: Frontend vpc-6

If the frontend container is not deployed, then its core is instead used by the compute process. 

VPC peering facilitates communication between the WEKA processes, each using its NIC. The maximum allowable number of peers within a VPC is limited to 25 by GCP (you can request GCP to increase the quota, but it depends on the GCP resources availability).

<figure><img src="https://content.gitbook.com/content/VJsIYq2tJgf6IfttPZ6j/blobs/erQYX8ZjSMvLRxW4QfTR/GCP_overview.png" alt=""><figcaption><p>Server infrastructure in GCP</p></figcaption></figure>

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<summary>Terraform overview</summary>

Terraform is an open-source project from Hashicorp. It creates and manages resources on cloud platforms and on-premises clouds. Unlike AWS CloudFormation, it works with many APIs from multiple platforms and services.

The GCP Console is already installed with Terraform by default. It is the primary tool for deploying WEKA on GCP. Terraform can be used outside of GCP or independent of GCP Console.

<img src="https://content.gitbook.com/content/VJsIYq2tJgf6IfttPZ6j/blobs/N1ARIDrKbNWus8kpTNCx/Terraform_overview.png" alt="" data-size="original">

### How does Terraform work?

A deployment with Terraform involves three phases:

* **Write:** Define the infrastructure in configuration files and customize the project variables provided in the Terraform package.
* **Plan**: Review the changes Terraform will make to your infrastructure.
* **Apply:** Terraform provisions the infrastructure, including the VMs and instances, installs the WEKA software, and creates the cluster. Once completed, the WEKA cluster runs on GCP.

<img src="https://content.gitbook.com/content/VJsIYq2tJgf6IfttPZ6j/blobs/PUByiacACpflKK7vU5IL/Terraform_how.png" alt="Terraform phases" data-size="original">

**Related information**

[Terraform Tutorials](https://learn.hashicorp.com/terraform?track=gcp)

[Terraform Installation](https://learn.hashicorp.com/tutorials/terraform/install-cli)

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