When browsing to "Installing 3scale --> Chapter 4. Deploying APIcast on the Docker containerized environment":

$ sudo docker pull registry.redhat.io/3scale-amp2/apicast-gateway-rhel7:3scale2.9

$ sudo docker run --name apicast --rm -p 8080:8080 -e THREESCALE_PORTAL_ENDPOINT=https://<access_token>@<domain>-admin.3scale.net registry.redhat.io/3scale-amp2/apicast-gateway-rhel7:3scale2.9

Source: https://access.redhat.com/documentation/en-us/red_hat_3scale_api_management/2.9/html/installing_3scale/deploying-apicast-on-the-docker-containerized-environment

However when checking the Red Hat Container Catalog [1], the image should be located actually on rhel8 instead of rhel7:

$ sudo docker pull registry.redhat.io/3scale-amp2/apicast-gateway-rhel8:3scale2.9

$ sudo docker run --name apicast --rm -p 8080:8080 -e THREESCALE_PORTAL_ENDPOINT=https://<access_token>@<domain>-admin.3scale.net registry.redhat.io/3scale-amp2/apicast-gateway-rhel8:3scale2.9

[1] https://catalog.redhat.com/software/containers/3scale-amp2/apicast-gateway-rhel8/5df398c85a13466876712703?tag=3scale2.9&container-tabs=gti