1.1.12 Ensure that the admission control policy is set to AlwaysPullImages


Always pull images.


Setting admission control policy to `AlwaysPullImages` forces every new pod to pull the required images every time. In a multitenant cluster users can be assured that their private images can only be used by those who have the credentials to pull them. Without this admisssion control policy, once an image has been pulled to a node, any pod from any user can use it simply by knowing the image's name, without any authorization check against the image ownership. When this plug-in is enabled, images are always pulled prior to starting containers, which means valid credentials are required.


Edit the `/etc/kubernetes/apiserver` file on the master node and set the `KUBE_ADMISSION_CONTROL` parameter to `'--admission-control=...,AlwaysPullImages,...'`: `KUBE_ADMISSION_CONTROL='--admission-control=...,AlwaysPullImages,...'`

Based on your system, restart the `kube-apiserver` service. For example: `systemctl restart kube-apiserver.service`


Credentials would be required to pull the private images every time. Also, in trusted environments, this might increases load on network, registry, and decreases speed.

See Also


Item Details


References: 800-53|AC-6, CSCv6|14.4

Plugin: Unix

Control ID: ac6dd3710010852c951cc00beb105ed319c8c8898707f533ab849a23430da406