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---
title: Apply Pod Security Standards at the Cluster Level
content_type: tutorial
weight: 10
---
{{% alert title="Note" %}}
This tutorial applies only for new clusters.
{{% /alert %}}
Pod Security admission (PSA) is enabled by default in v1.23 and later, as it has
[graduated to beta](/blog/2021/12/09/pod-security-admission-beta/).
Pod Security
is an admission controller that carries out checks against the Kubernetes
[Pod Security Standards](/docs/concepts/security/pod-security-standards/) when new pods are
created. This tutorial shows you how to enforce the `baseline` Pod Security
Standard at the cluster level which applies a standard configuration
to all namespaces in a cluster.
To apply Pod Security Standards to specific namespaces, refer to
[Apply Pod Security Standards at the namespace level](/docs/tutorials/security/ns-level-pss).
If you are running a version of Kubernetes other than v{{< skew currentVersion >}},
check the documentation for that version.
## {{% heading "prerequisites" %}}
Install the following on your workstation:
- [KinD](https://kind.sigs.k8s.io/docs/user/quick-start/#installation)
- [kubectl](/docs/tasks/tools/)
This tutorial demonstrates what you can configure for a Kubernetes cluster that you fully
control. If you are learning how to configure Pod Security Admission for a managed cluster
where you are not able to configure the control plane, read
[Apply Pod Security Standards at the namespace level](/docs/tutorials/security/ns-level-pss).
## Choose the right Pod Security Standard to apply
[Pod Security Admission](/docs/concepts/security/pod-security-admission/)
lets you apply built-in [Pod Security Standards](/docs/concepts/security/pod-security-standards/)
with the following modes: `enforce`, `audit`, and `warn`.
To gather information that helps you to choose the Pod Security Standards
that are most appropriate for your configuration, do the following:
1. Create a cluster with no Pod Security Standards applied:
```shell
kind create cluster --name psa-wo-cluster-pss
```
The output is similar to:
```
Creating cluster "psa-wo-cluster-pss" ...
✓ Ensuring node image (kindest/node:v{{< skew currentVersion >}}.0) 🖼
✓ Preparing nodes 📦
✓ Writing configuration 📜
✓ Starting control-plane 🕹️
✓ Installing CNI 🔌
✓ Installing StorageClass 💾
Set kubectl context to "kind-psa-wo-cluster-pss"
You can now use your cluster with:
kubectl cluster-info --context kind-psa-wo-cluster-pss
Thanks for using kind! 😊
```
1. Set the kubectl context to the new cluster:
```shell
kubectl cluster-info --context kind-psa-wo-cluster-pss
```
The output is similar to this:
```
Kubernetes control plane is running at https://127.0.0.1:61350
CoreDNS is running at https://127.0.0.1:61350/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
```
1. Get a list of namespaces in the cluster:
```shell
kubectl get ns
```
The output is similar to this:
```
NAME STATUS AGE
default Active 9m30s
kube-node-lease Active 9m32s
kube-public Active 9m32s
kube-system Active 9m32s
local-path-storage Active 9m26s
```
1. Use `--dry-run=server` to understand what happens when different Pod Security Standards
are applied:
1. Privileged
```shell
kubectl label --dry-run=server --overwrite ns --all \
pod-security.kubernetes.io/enforce=privileged
```
The output is similar to:
```
namespace/default labeled
namespace/kube-node-lease labeled
namespace/kube-public labeled
namespace/kube-system labeled
namespace/local-path-storage labeled
```
2. Baseline
```shell
kubectl label --dry-run=server --overwrite ns --all \
pod-security.kubernetes.io/enforce=baseline
```
The output is similar to:
```
namespace/default labeled
namespace/kube-node-lease labeled
namespace/kube-public labeled
Warning: existing pods in namespace "kube-system" violate the new PodSecurity enforce level "baseline:latest"
Warning: etcd-psa-wo-cluster-pss-control-plane (and 3 other pods): host namespaces, hostPath volumes
Warning: kindnet-vzj42: non-default capabilities, host namespaces, hostPath volumes
Warning: kube-proxy-m6hwf: host namespaces, hostPath volumes, privileged
namespace/kube-system labeled
namespace/local-path-storage labeled
```
3. Restricted
```shell
kubectl label --dry-run=server --overwrite ns --all \
pod-security.kubernetes.io/enforce=restricted
```
The output is similar to:
```
namespace/default labeled
namespace/kube-node-lease labeled
namespace/kube-public labeled
Warning: existing pods in namespace "kube-system" violate the new PodSecurity enforce level "restricted:latest"
Warning: coredns-7bb9c7b568-hsptc (and 1 other pod): unrestricted capabilities, runAsNonRoot != true, seccompProfile
Warning: etcd-psa-wo-cluster-pss-control-plane (and 3 other pods): host namespaces, hostPath volumes, allowPrivilegeEscalation != false, unrestricted capabilities, restricted volume types, runAsNonRoot != true
Warning: kindnet-vzj42: non-default capabilities, host namespaces, hostPath volumes, allowPrivilegeEscalation != false, unrestricted capabilities, restricted volume types, runAsNonRoot != true, seccompProfile
Warning: kube-proxy-m6hwf: host namespaces, hostPath volumes, privileged, allowPrivilegeEscalation != false, unrestricted capabilities, restricted volume types, runAsNonRoot != true, seccompProfile
namespace/kube-system labeled
Warning: existing pods in namespace "local-path-storage" violate the new PodSecurity enforce level "restricted:latest"
Warning: local-path-provisioner-d6d9f7ffc-lw9lh: allowPrivilegeEscalation != false, unrestricted capabilities, runAsNonRoot != true, seccompProfile
namespace/local-path-storage labeled
```
From the previous output, you'll notice that applying the `privileged` Pod Security Standard shows no warnings
for any namespaces. However, `baseline` and `restricted` standards both have
warnings, specifically in the `kube-system` namespace.
## Set modes, versions and standards
In this section, you apply the following Pod Security Standards to the `latest` version:
* `baseline` standard in `enforce` mode.
* `restricted` standard in `warn` and `audit` mode.
The `baseline` Pod Security Standard provides a convenient
middle ground that allows keeping the exemption list short and prevents known
privilege escalations.
Additionally, to prevent pods from failing in `kube-system`, you'll exempt the namespace
from having Pod Security Standards applied.
When you implement Pod Security Admission in your own environment, consider the
following:
1. Based on the risk posture applied to a cluster, a stricter Pod Security
Standard like `restricted` might be a better choice.
1. Exempting the `kube-system` namespace allows pods to run as
`privileged` in this namespace. For real world use, the Kubernetes project
strongly recommends that you apply strict RBAC
policies that limit access to `kube-system`, following the principle of least
privilege.
To implement the preceding standards, do the following:
1. Create a configuration file that can be consumed by the Pod Security
Admission Controller to implement these Pod Security Standards:
```
mkdir -p /tmp/pss
cat <<EOF > /tmp/pss/cluster-level-pss.yaml
apiVersion: apiserver.config.k8s.io/v1
kind: AdmissionConfiguration
plugins:
- name: PodSecurity
configuration:
apiVersion: pod-security.admission.config.k8s.io/v1
kind: PodSecurityConfiguration
defaults:
enforce: "baseline"
enforce-version: "latest"
audit: "restricted"
audit-version: "latest"
warn: "restricted"
warn-version: "latest"
exemptions:
usernames: []
runtimeClasses: []
namespaces: [kube-system]
EOF
```
{{< note >}}
`pod-security.admission.config.k8s.io/v1` configuration requires v1.25+.
For v1.23 and v1.24, use [v1beta1](https://v1-24.docs.kubernetes.io/docs/tasks/configure-pod-container/enforce-standards-admission-controller/).
For v1.22, use [v1alpha1](https://v1-22.docs.kubernetes.io/docs/tasks/configure-pod-container/enforce-standards-admission-controller/).
{{< /note >}}
1. Configure the API server to consume this file during cluster creation:
```
cat <<EOF > /tmp/pss/cluster-config.yaml
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
kubeadmConfigPatches:
- |
kind: ClusterConfiguration
apiServer:
extraArgs:
admission-control-config-file: /etc/config/cluster-level-pss.yaml
extraVolumes:
- name: accf
hostPath: /etc/config
mountPath: /etc/config
readOnly: false
pathType: "DirectoryOrCreate"
extraMounts:
- hostPath: /tmp/pss
containerPath: /etc/config
# optional: if set, the mount is read-only.
# default false
readOnly: false
# optional: if set, the mount needs SELinux relabeling.
# default false
selinuxRelabel: false
# optional: set propagation mode (None, HostToContainer or Bidirectional)
# see https://kubernetes.io/docs/concepts/storage/volumes/#mount-propagation
# default None
propagation: None
EOF
```
{{<note>}}
If you use Docker Desktop with KinD on macOS, you can
add `/tmp` as a Shared Directory under the menu item
**Preferences > Resources > File Sharing**.
{{</note>}}
1. Create a cluster that uses Pod Security Admission to apply
these Pod Security Standards:
```shell
kind create cluster --name psa-with-cluster-pss --config /tmp/pss/cluster-config.yaml
```
The output is similar to this:
```
Creating cluster "psa-with-cluster-pss" ...
✓ Ensuring node image (kindest/node:v{{< skew currentVersion >}}.0) 🖼
✓ Preparing nodes 📦
✓ Writing configuration 📜
✓ Starting control-plane 🕹️
✓ Installing CNI 🔌
✓ Installing StorageClass 💾
Set kubectl context to "kind-psa-with-cluster-pss"
You can now use your cluster with:
kubectl cluster-info --context kind-psa-with-cluster-pss
Have a question, bug, or feature request? Let us know! https://kind.sigs.k8s.io/#community 🙂
```
1. Point kubectl to the cluster:
```shell
kubectl cluster-info --context kind-psa-with-cluster-pss
```
The output is similar to this:
```
Kubernetes control plane is running at https://127.0.0.1:63855
CoreDNS is running at https://127.0.0.1:63855/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
```
1. Create a Pod in the default namespace:
```shell
kubectl apply -f https://k8s.io/examples/security/example-baseline-pod.yaml
```
The pod is started normally, but the output includes a warning:
```
Warning: would violate PodSecurity "restricted:latest": allowPrivilegeEscalation != false (container "nginx" must set securityContext.allowPrivilegeEscalation=false), unrestricted capabilities (container "nginx" must set securityContext.capabilities.drop=["ALL"]), runAsNonRoot != true (pod or container "nginx" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container "nginx" must set securityContext.seccompProfile.type to "RuntimeDefault" or "Localhost")
pod/nginx created
```
## Clean up
Now delete the clusters which you created above by running the following command:
```shell
kind delete cluster --name psa-with-cluster-pss
```
```shell
kind delete cluster --name psa-wo-cluster-pss
```
## {{% heading "whatsnext" %}}
- Run a
[shell script](/examples/security/kind-with-cluster-level-baseline-pod-security.sh)
to perform all the preceding steps at once:
1. Create a Pod Security Standards based cluster level Configuration
2. Create a file to let API server consume this configuration
3. Create a cluster that creates an API server with this configuration
4. Set kubectl context to this new cluster
5. Create a minimal pod yaml file
6. Apply this file to create a Pod in the new cluster
- [Pod Security Admission](/docs/concepts/security/pod-security-admission/)
- [Pod Security Standards](/docs/concepts/security/pod-security-standards/)
- [Apply Pod Security Standards at the namespace level](/docs/tutorials/security/ns-level-pss/)