Requirements and Build Information

The following sections describe the requirements and prerequisites for the Azure reference platform.

Prerequisites

Before starting the deployment, ensure you have the following tools and access:

  • Terraform 1.0+: Terraform is the infrastructure as code tool used to manage the deployment.

  • kubectl 1.28+: kubectl is the command-line tool for interacting with the Kubernetes cluster.

  • Azure Command Line 2.68.0+: The Azure Command Line (az cli) enables you to interact with Azure services from the command line.

  • Owner Access to Azure Subscription: For full architecture deployment, owner access is expected to the target Azure subscription.

It is additionally recommended, but not required, to install Helm 3.17.0 or later, for troubleshooting Helm-based Kubernetes deployments.

Azure Access Requirements

The account running this Terraform needs to be assigned the Owner role for the target subscription due to the assignment of roles to the managed identity used by the kubernetes control plane. Role assignment for the Kubernetes cluster is as follows:

  • Reader - scoped to the Disk Encryption Set created during this process. Allows identity to read the disk encryption set used for node disk encryption.

  • Network Contributor - scoped to the resource group created by this terraform. Allows identity to bind a managed load balancer to a public IP created during the Terraform run for environment access.

  • Key Vault Crypto User - scoped to the Azure Key Vault created during this process. Allows the disk set encryption managed identity the ability to use the key vault for disk encryption.

IP-based Access Restrictions

There are five variables that control public access to the environment. You set these in your Terraform configuration file, terraform.tfvars.

IP range variables:

ini
ip_ranges_allowed_to_kubeapi            = ["192.168.3.32/32", "192.168.4.1/32"]
ip_ranges_allowed_https                 = ["192.168.1.0/24"]
ip_ranges_allowed_kv_access             = ["192.168.3.32/32", "192.168.4.1/32"]

Network access control variables:

ini
kubernetes_private_cluster_enabled      = true   # Optional: Make k8s API private-only
logscale_lb_internal_only              = true   # Optional: Make LogScale internal-only
Type Description
ip_ranges_allowed_to_kubeapi The Kubernetes API is publicly available by default. This variable limits access to the API and impacts the ability to run Kubernetes API commands.
ip_ranges_allowed_https The ingress endpoint for UI Access to LogScale and Ingestion to logscale is publicly available. This limits access.
ip_ranges_allowed_kv_access Access to the Azure Key Vault is limited to ranges defined here.
kubernetes_private_cluster_enabled When true, the Kubernetes API is only accessible from within the Azure VNet (requires VPN/ExpressRoute for external access). Overrides ip_ranges_allowed_to_kubeapi restrictions.
logscale_lb_internal_only When true, LogScale uses an internal load balancer with no public IP (requires VPN/ExpressRoute for external access). Overrides ip_ranges_allowed_https restrictions.

Note

ip_ranges_allowed_kv_access and ip_ranges_allowed_to_kubeapi must be set correctly for Terraform to operate as expected. For enterprise deployments, consider enabling kubernetes_private_cluster_enabled and logscale_lb_internal_only for enhanced security.

Cluster Size Configuration

The cluster_size.tpl file specifies the available parameters for different sizes of LogScale clusters. This template defines various cluster sizes, for example xsmall, small, medium and their associated configurations, including node counts, instance types, disk sizes, and resource limits. The Terraform configuration uses this template to dynamically configure the LogScale deployment based on the selected cluster size.

The data from cluster_size.tpl is retrieved and rendered by the locals.tf file. The locals.tf file uses the jsondecode function to parse the template and select the appropriate cluster size configuration based on the logscale_cluster_size variable.

Example:

ini
# Local Variables
  locals {
    # Render a template of available cluster sizes
    cluster_size_template = jsondecode(templatefile("${path.module}/cluster_size.tpl", {}))
    cluster_size_rendered = {
      for key in keys(local.cluster_size_template) :
      key => local.cluster_size_template[key]
    }
    cluster_size_selected = local.cluster_size_rendered[var.logscale_cluster_size]
  }