custom SecurityContextConstraint to run sig-storage/local-volume-provisioner in a DaemonSet?

[jonasbartho]

Hi,

Is there any documentation on which custom SecurityContextConstraint that can be used to run registry.k8s.io/sig-storage/local-volume-provisioner in a daemonset without having "privileged=true" enabled? This is not allowed anymore in OKD/Openshift.

Proper documentation around this would be very useful. (using an operator is not possible here btw)

[jonasbartho]

I am using the following scc which looks to be working for now but the volume gets a "permission denied":

scc.yaml:

allowHostDirVolumePlugin: true
allowHostIPC: false
allowHostNetwork: false
allowHostPID: false
allowHostPorts: false
allowPrivilegeEscalation: false
allowPrivilegedContainer: false
allowedCapabilities:
  - CHOWN
  - FSETID
  - SETGID
  - SETUID
  - NET_BIND_SERVICE
apiVersion: security.openshift.io/v1
defaultAddCapabilities: null
fsGroup:
  type: RunAsAny
groups: []
kind: SecurityContextConstraints
metadata:
  name: scc-local-provisioner
priority: null
readOnlyRootFilesystem: false
requiredDropCapabilities:
  - KILL
  - DAC_OVERRIDE
  - FOWNER
  - SETPCAP
runAsUser:
  type: RunAsAny
seLinuxContext:
  type: RunAsAny
seccompProfiles:
- runtime/default
supplementalGroups:
  type: RunAsAny
volumes:
  - configMap
  - downwardAPI
  - emptyDir
  - hostPath
  - projected
  - secret

clusterrole.yaml:

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: system:openshift:scc:scc-local-provisioner
rules:
- apiGroups:
  - security.openshift.io
  resourceNames:
  - scc-local-provisioner
  resources:
  - securitycontextconstraints
  verbs:
  - use

rolebinding_scc.yaml:

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: system:openshift:scc:scc-local-provisioner
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:openshift:scc:scc-local-provisioner
subjects:
  - kind: ServiceAccount
    name: local-static-provisioner
    namespace: kube-system

oc logs -f local-static-provisioner:

E0514 17:31:15.318990       1 discovery.go:221] Failed to discover local volumes: error reading directory: open /mnt/local-disks: permission denied

[niranjandarshann]

@jonasbartho What i noticed in scc.yaml your current SCC lacks certain capabilities that might be required. Specifically, the SYS_ADMIN capability is often needed for operations involving hostPath volumes.
So try using

allowedCapabilities:
  - CHOWN
  - FSETID
  - SETGID
  - SETUID
  - NET_BIND_SERVICE
  - SYS_ADMIN 

and check whether it run fine or not.

[niranjandarshann]

Here One more thing what i want to ask is Had you given the appropriate permission to the directory /mnt/local-disks So that the container can access it?

[niranjandarshann]

If you forget and hadnt given appropriate permission to the directory /mnt/local-disks You can use
sudo chmod -R 777 /mnt/local-disks
Command to give permission to the container to access it.

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