Change cache modes

This page provides instructions for changing cache modes with Cloud CDN. Cache modes let you configure how Cloud CDN caches your content.

Before you begin

  • Read about cache modes and static content.

  • Ensure that Cloud CDN is enabled; for instructions, see Using Cloud CDN.

  • If necessary, update to the latest version of the Google Cloud CLI:

    gcloud components update

Setting the cache mode

To configure cache modes for a Cloud CDN-enabled backend, do the following:

Console

  1. In the Google Cloud console, go to the Load Balancing page.

    Go to the Load balancing page

  2. Click the name of your external Application Load Balancer.
  3. Click Edit .
  4. In Backend configuration, select a backend and click Edit .
  5. Make sure that Enable Cloud CDN is selected.
  6. Under Cache mode, select one of the following options:
    • Cache static content (recommended): Static content is web assets that don't change for each user. Static content is based on the Content-Type in the response. For more information, see static content.
    • Use origin settings based on Cache-Control headers: Cache responses with valid cache directives in the response headers.
    • Force cache all content: Cache all successful content served by the origin, ignoring any private or no-store directives.
  7. Click Save.

gcloud

For backend services, use the gcloud compute backend-services create or gcloud compute backend-services update command with the --cache-mode flag.

For backend buckets, use the gcloud compute backend-buckets create or gcloud compute backend-buckets update command with the --cache-mode flag.

gcloud compute backend-services (create | update) BACKEND_SERVICE_NAME
    --cache-mode=CACHE_MODE

gcloud compute backend-buckets (create | update) BACKEND_BUCKET_NAME
    --cache-mode=CACHE_MODE

Replace CACHE_MODE with one of the following:

  • CACHE_ALL_STATIC (default): Automatically caches static content. Responses that are marked as uncacheable (private or no-store directives in Cache-Control response headers) aren't cached. To cache dynamic content, the content must have valid caching headers.

  • USE_ORIGIN_HEADERS: Requires the origin to set valid caching headers to cache content. Responses without these headers aren't cached at Google's edge and require a full trip to the origin on every request, potentially impacting performance and increasing load on the origin server.

  • FORCE_CACHE_ALL: Caches all content (that is, successful responses), ignoring any private or no-store directives in Cache-Control response headers. This might result in caching of private, per-user (user identifiable) content. Only enable this on backends that are not serving private or dynamic content, such as Cloud Storage buckets. Don't enable this on backends that are serving private or dynamic content.

API

For backend buckets, use the Method: backendBuckets.insert or Method: backendBuckets.update API call.

For backend services, use the Method: backendServices.insert or Method: backendServices.update API call.

Use one of the following API calls:

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/global/backendBuckets
PUT https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/global/backendBuckets/BACKEND_BUCKET
POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/global/backendServices
PUT https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/global/backendServices/BACKEND_SERVICE

Add the following snippet to the JSON request body:

"cdnPolicy": {
  "cacheMode": (CACHE_ALL_STATIC | USE_ORIGIN_HEADERS | FORCE_CACHE_ALL)

Replace CACHE_MODE with one of the following:

  • CACHE_ALL_STATIC (default): Automatically caches static content if the origin does not set valid caching headers. Responses that are marked as uncacheable (private or no-store directives in Cache-Control response headers) aren't cached. To cache dynamic content, the content must have valid caching headers.

  • USE_ORIGIN_HEADERS: Requires the origin to set valid caching headers to cache content. Responses without these headers aren't cached at Google's edge and require a full trip to the origin on every request, potentially impacting performance and increasing load on the origin server.

  • FORCE_CACHE_ALL: Caches all content (that is, successful responses), ignoring any private or no-store directives in Cache-Control response headers. This might result in caching of private, per-user (user identifiable) content. You should only enable this on backends that are not serving private or dynamic content, such as Cloud Storage buckets.