istio.io/istio@v0.0.0-20240520182934-d79c90f27776/releasenotes/notes/sni-dnat-default.yaml (about)

     1  apiVersion: release-notes/v2
     2  kind: feature
     3  area: networking
     4  issue:
     5  - 27749
     6  releaseNotes:
     7  - |
     8    **Updated** the default installation of gateways to not configure clusters for `AUTO_PASSTHROUGH`, reducing memory costs.
     9  
    10  upgradeNotes:
    11  - title: "`AUTO_PASSTHROUGH` Gateway mode"
    12    content: |
    13      Previously, gateways were configured with multiple Envoy `cluster` configurations for each Service in the cluster, even those
    14      not referenced by any Gateway or VirtualService. This was added to support the `AUTO_PASSTHROUGH` mode on Gateway, generally used for exposing Services across networks.
    15  
    16      However, this came at an increased CPU and memory cost in the gateway and Istiod. As a result, we have disabled these by default
    17      on the `istio-ingressgateway` and `istio-egressgateway`.
    18  
    19      If you are relying on this feature for multi-network support, please ensure you apply one of the following changes:
    20  
    21      1. Follow our new [Multicluster Installation](/docs/setup/install/multicluster/) documentation.
    22  
    23         This documentation will guide you through running a dedicate gateway deployment for this type of traffic (generally referred to as the `eastwest-gateway`).
    24         This `eastwest-gateway` will automatically be configured to support `AUTO_PASSTHROUGH`.
    25  
    26      1. Modify your installation of the gateway deployment to include this configuration. This is controlled by the `ISTIO_META_ROUTER_MODE` environment variable. Setting this to `sni-dnat` enables these clusters, while `standard` (the new default) disables them.
    27  
    28        {{< text yaml >}}
    29        ingressGateways:
    30         - name: istio-ingressgateway
    31           enabled: true
    32           k8s:
    33             env:
    34               - name: ISTIO_META_ROUTER_MODE
    35                 value: "sni-dnat"
    36         {{< /text >}}