Configuring Istio Ingress

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UDS Core leverages Istio for ingress into the service mesh. This document provides an overview and examples of the Istio resources that UDS Core deploys to handle ingress.

Gateways

UDS Core provides a few Istio Gateway resources to allow ingress into the service mesh. Each one serves a different purpose and can be used to route traffic to different services.

1. (Required) Tenant Gateway - This gateway provides ingress to typical end-user applications. By default, UDS Core deploys a few services on this gateway, such as the Keycloak SSO portal. This gateway is typically exposed to end users of the applications deployed on top of UDS Core.
2. (Required) Admin Gateway - This gateway provides ingress to admin-related applications that are not for use by the default end user. By default, UDS Core deploys a few services on this gateway, such as the Admin Keycloak interface. This gateway is typically accessible to admins of the applications deployed on top of UDS Core. Since the Admin and Tenant Gateways are logically separated, it is possible to have different security controls on each gateway.
3. (Optional) Passthrough Gateway - This gateway allows mesh ingress without TLS termination performed by Istio. This could be useful for applications that need to (or currently) handle their own TLS termination. This gateway used to be a default component of UDS Core but is no longer deployed by default. To deploy this gateway, you must specify istio-passthrough-gateway as an optionalComponent in your UDS Bundle configuration.

Enable Passthrough Gateway

In order to enable the Passthrough Gateway, you must specify istio-passthrough-gateway as an optionalComponent in your UDS Bundle configuration. Here is an example of how to do this:

kind: UDSBundle
metadata:
  name: core-with-passthrough
  description: A UDS example bundle for packaging UDS core with the passthrough gateway enabled
  version: "0.0.1"

packages:
  - name: core
    repository: oci://ghcr.io/defenseunicorns/packages/uds/core
    ref: 0.23.0-upstream
    # You must specify the istio-passthrough-gateway as an optionalComponent or else it will not be deployed
    optionalComponents:
      - istio-passthrough-gateway

Configure Domain Name and TLS for Istio Gateways

By default, the UDS Core Istio Gateways are set up to use the uds.dev domain and have a valid TLS certificate packaged. You will want to change the domain name for your environment and provide a valid TLS certificate for this domain.

You can set the TLS certs via overrides in a UDS Bundle (see below). UDS Core Istio Gateways default to only supporting TLS v1.3, but this can also be overridden per gateway if clients use TLS 1.2 (as seen in the tenant gateway example value below).

kind: UDSBundle
metadata:
  name: core-with-cert-override
  description: A UDS example bundle for packaging UDS core with a custom TLS certificate
  version: "0.0.1"
  
packages:
  - name: core
    repository: oci://ghcr.io/defenseunicorns/packages/uds/core
    ref: 0.23.0-upstream
    overrides:
      istio-admin-gateway:
        uds-istio-config:
          variables:
            - name: ADMIN_TLS_CERT
              description: "The TLS cert for the admin gateway (must be base64 encoded)"
              path: tls.cert
            - name: ADMIN_TLS_KEY
              description: "The TLS key for the admin gateway (must be base64 encoded)"
              path: tls.key
      istio-tenant-gateway:
        uds-istio-config:
          values:
            - path: tls.supportTLSV1_2
              value: true # Add support for TLS 1.2 on this gateway, can be specified via variables if needed at deploy time
          variables:
            - name: TENANT_TLS_CERT
              description: "The TLS cert for the tenant gateway (must be base64 encoded)"
              path: tls.cert
            - name: TENANT_TLS_KEY
              description: "The TLS key for the tenant gateway (must be base64 encoded)"
              path: tls.key

You can then either use environment variables (UDS_ADMIN_TLS_CERT, UDS_ADMIN_TLS_KEY, UDS_TENANT_TLS_CERT, and UDS_TENANT_TLS_KEY) or a config file to configure the certs for each gateway. These values should be base64 encoded strings of the TLS certificate and key for the admin and tenant gateways respectively.

Domain should be set via your uds-config file using the shared key to override the Zarf Domain Variable (see example uds-config.yaml below).

shared:
  domain: yourawesomedomain.com # shared across all packages in a bundle

# TLS Certs/Keys if not provided via environment variables
variables: 
  core:
    admin_tls_cert: # base64 encoded admin cert here
    admin_tls_key: # base64 encoded admin key here
    tenant_tls_cert: # base64 encoded tenant cert here
    tenant_tls_key: # base64 encoded tenant key here