This article explains how to prevent or mitigate an HTTP compression issue with SAS Studio on SAS Viya when using the Contour ingress controller.
In November 2025, the Kubernetes community announced that it would retire ingress-nginx in March 2026. With the retirement of ingress-nginx, SAS recommends that customers adopt the Contour ingress controller. For more details, see SAS Help Center: Virtual Infrastructure Requirements.
If you encounter this issue, SAS Studio might be unable to save updates to existing content (either on SAS Server or SAS Content).
The error message varies depending on the item that is being updated.
For example, replacing an existing flow might fail with the following error pop-up message: "The flow 'flow_name' could not be saved":
Updating a SAS Program file might return an error message similar to the following: "The file 'program_name.sas' has been changed by another user. Do you want to replace the other user's content?"
Replacing a job definition, an error message similar to the following might appear in the bottom right corner of the screen:" The job definition 'job_definition_name' could not be saved":
This issue occurs because Contour compression can strip the required request headers.
Depending on the object that is being overwritten, these HTTP errors might appear in the HAR file at the time of the failure:
To verify whether the environment is using Contour, do the following:
HTTP/2.0 428 Precondition Required
content-length: 746
content-security-policy: default-src 'self'; object-src 'none'; frame-ancestors 'self'; form-action 'self';
content-type: application/vnd.sas.error+json;charset=utf-8;version=2
date: Tue, 31 Mar 2026 12:57:24 GMT
sas-service-response-flag: true
server: envoy
vary: Origin
...
For compatibility with the SAS Viya platform, the compression setting for the Contour ingress controller must be disabled.
If you encounter the symptoms described and your environment is using Contour, ensure that compression is disabled by completing the steps described in the Contour Ingress Controller Errors section of the SAS® Viya® Platform Operations guide.
If you must keep compression enabled because other applications depend on it, complete these steps:
Set the environment variable SAS_STUDIO_CONVERT_ETAGS=true on the sas-studio deployment:
kubectl -n viya set env deployment sas-studio SAS_STUDIO_CONVERT_ETAGS=true
Install all available patches if you run any of the following SAS Studio versions: