Objects of type
PodSecurityPolicy govern the ability
to make requests on a pod that affect the
SecurityContext that will be
applied to a pod and container.
See PodSecurityPolicy proposal for more information.
A Pod Security Policy is a cluster-level resource that controls the
actions that a pod can perform and what it has the ability to access. The
PodSecurityPolicy objects define a set of conditions that a pod must
run with in order to be accepted into the system. They allow an
administrator to control the following:
|Control Aspect||Field Name|
|Running of privileged containers||
|Default set of capabilities that will be added to a container||
|Capabilities that will be dropped from a container||
|Capabilities a container can request to be added||
|Controlling the usage of volume types||
|The use of host networking||
|The use of host ports||
|The use of host’s PID namespace||
|The use of host’s IPC namespace||
|The use of host paths||
|The SELinux context of the container||
|The user ID||
|Configuring allowable supplemental groups||
|Allocating an FSGroup that owns the pod’s volumes||
|Requiring the use of a read only root file system||
Pod Security Policies are comprised of settings and strategies that control the security features a pod has access to. These settings fall into three categories:
rangeto be configured. Uses the first value of the range as the default. Validates against the configured range.
runAsUseror have the
USERdirective defined in the image. No default provided.
runAsUserto be specified.
seLinuxOptionsto be configured if not using pre-allocated values. Uses
seLinuxOptionsas the default. Validates against
seLinuxOptionsto be specified.
supplementalGroupsto be specified.
fsGroupID to be specified.
The usage of specific volume types can be controlled by setting the volumes field of the PSP. The allowable values of this field correspond to the volume sources that are defined when creating a volume:
The recommended minimum set of allowed volumes for new PSPs are configMap, downwardAPI, emptyDir, persistentVolumeClaim, secret, and projected.
empty. List of
HostPortRange, defined by
max(inclusive), which define the allowed host ports.
Admission control with
PodSecurityPolicy allows for control over the
creation and modification of resources based on the capabilities allowed in the cluster.
Admission uses the following approach to create the final security context for the pod:
If a matching policy is found, then the pod is accepted. If the request cannot be matched to a PSP, the pod is rejected.
A pod must validate every field against the PSP.
Here is an example Pod Security Policy. It has permissive settings for all fields
Create the policy by downloading the example file and then running this command:
$ kubectl create -f ./psp.yaml podsecuritypolicy "permissive" created
To get a list of existing policies, use
$ kubectl get psp NAME PRIV CAPS SELINUX RUNASUSER FSGROUP SUPGROUP READONLYROOTFS VOLUMES permissive false  RunAsAny RunAsAny RunAsAny RunAsAny false [*] privileged true  RunAsAny RunAsAny RunAsAny RunAsAny false [*] restricted false  RunAsAny MustRunAsNonRoot RunAsAny RunAsAny false [emptyDir secret downwardAPI configMap persistentVolumeClaim projected]
To modify policy interactively, use
$ kubectl edit psp permissive
This command will open a default text editor where you will be able to modify policy.
Once you don’t need a policy anymore, simply delete it with
$ kubectl delete psp permissive podsecuritypolicy "permissive" deleted
In order to use Pod Security Policies in your cluster you must ensure the following
extensions/v1beta1/podsecuritypolicy(only for versions prior 1.6)
In Kubernetes 1.5 and newer, you can use PodSecurityPolicy to control access to privileged containers based on user role and groups. Access to different PodSecurityPolicy objects can be controlled via authorization. To limit access to PodSecurityPolicy objects for pods created via a Deployment, ReplicaSet, etc, the Controller Manager must be run against the secured API port, and must not have superuser permissions.
PodSecurityPolicy authorization uses the union of all policies available to the user creating the pod and the service account specified on the pod. When pods are created via a Deployment, ReplicaSet, etc, it is Controller Manager that creates the pod, so if it is running against the unsecured API port, all PodSecurityPolicy objects would be allowed, and you could not effectively subdivide access. Access to given PSP policies for a user will be effective only when deploying Pods directly. For more details, see the PodSecurityPolicy RBAC example of applying PodSecurityPolicy to control access to privileged containers based on role and groups when deploying Pods directly.Create an Issue Edit this Page