Configuration and Authentication File Security

To harden your SUSE Virtualization cluster, you must verify and enforce strict file ownership and permission controls across all nodes. System configuration files govern storage, networking, and security secrets, while authentication files (such as keys, certificates, and tokens) establish cluster identity. Restricting access to these critical files prevents non-privileged users or compromised processes from altering system settings, exposing sensitive data, or causing cluster instability.

Test all recommended ownership and mode settings in a non-production environment before production deployment. Enforcing incorrect permissions can disrupt critical cluster services.

Auditing file permissions

Verify the permissions of the files and directories listed in the table using the following commands:

cd <PATH>
ls -l

For example, to verify the permissions of the primary RKE2 (server and agent) configuration files and cluster kubeconfig files, run the following commands:

cd var/lib/rancher/rke2
ls -l
Path Object Recommended Ownership Recommended Mode

/etc/passwd

Files

root:root

0644

/etc/rancher/rke2

Files

root:root (0:0)

0600

/etc/shadow

Files

root:root or root:shadow

0000 or 0400

/etc/sysctl.d

File

root:root

0600 or 0400

/root/

Home directory

root:root

0700

Varies

User home directories

owner:group

0700

/var/lib/rancher/rke2/agent

Subdirectories and files

root:root (0:0)

See RKE2 agent permissions.

/var/lib/rancher/rke2/bin

Files

root:root (0:0)

0750

/var/lib/rancher/rke2/data

Directory and files

root:root (0:0)

0750

/var/lib/rancher/rke2/server

Subdirectories and files

root:root (0:0)

See RKE2 server permissions.

You must also verify that the RKE2 server configuration file on each node contains the following text:

(cat /etc/rancher/rke2/config.yaml)
write-kubeconfig-mode: "0600"

RKE2 agent permissions

The following table lists the recommended modes for objects in /var/lib/rancher/rke2/agent.

Object Name Recommended Mode

Subdirectories

pod-manifests, etc

0700

Certificate files

client-ca.crt, client-kubelet.crt, client-kube-proxy.crt, client-rke2-controller.crt, server-ca.crt, serving-kubelet.crt

0600

Key file

client-kubelet.key, client-kube-proxy.key, client-rke2-controller.key, serving-kubelet.key

0600

Kubeconfig files

rke2controller.kubeconfig, kubelet.kubeconfig, kubeproxy.kubeconfig

At least 0640

RKE2 server permissions

The following table lists the recommended modes for objects in /var/lib/rancher/rke2/server.

Object Name Recommended Mode

Subdirectories

cred, db, tls

0700

Subdirectories

logs, manifests

0750

Token file

token

0600

Management node configuration files

You can find the configuration files for management (control plane) nodes in the following locations:

Path File Description Recommended Ownership

/var/lib/rancher/rke2/agent/pod-manifests/kube-apiserver.yaml

API server pod specification file

root:root

/var/lib/rancher/rke2/agent/pod-manifests/kube-controller-manager.yaml

Controller manager pod specification file

root:root

/var/lib/rancher/rke2/agent/pod-manifests/kube-scheduler.yaml

Scheduler pod specification file

root:root

/var/lib/rancher/rke2/agent/pod-manifests/etcd.yaml

etcd pod specification file

root:root

Varies (example: /var/lib/cni/networks/<filename>)

Container Network Interface file

root:root

/var/lib/rancher/rke2/server/cred/admin.kubeconfig

Admin configuration file

root:root

/var/lib/rancher/rke2/server/cred/scheduler.kubeconfig

Scheduler configuration file

root:root

/var/lib/rancher/rke2/server/cred/controller.kubeconfig

Controller manager configuration file

root:root

/var/lib/rancher/rke2/server/db/etcd

etcd data directory

etcd:etcd

/var/lib/rancher/rke2/server/tls

Kubernetes PKI directory

root:root

/var/lib/rancher/rke2/server/tls/*.crt

Kubernetes PKI certificate file

root:root

/var/lib/rancher/rke2/server/tls/*.key

Kubernetes PKI key file

root:root

Worker node configuration files

You can find the configuration files for worker nodes in the following locations:

Path File Description Recommended Ownership

/var/lib/rancher/rke2/agent/kubeproxy.kubeconfig

Proxy kubeconfig file

root:root

/var/lib/rancher/rke2/agent/kubelet.kubeconfig

kubelet kubeconfig file

root:root

/var/lib/rancher/rke2/agent/client-ca.crt

Certificate authorities file

root:root

Mitigating insecure file system permissions

  1. Set the correct permissions for insecure files and directories.

    • Files in /etc/rancher/rke2

      cd /etc/rancher/rke2
chmod -R 0600 ./*
chown -R root:root ./*
ls -l

    • Files in /var/lib/rancher/rke2

      cd /var/lib/rancher/rke2
chown root:root ./*
ls -l

    • Subdirectories and files in /var/lib/rancher/rke2/agent

      cd /var/lib/rancher/rke2/agent
chown root:root ./*
chmod 0700 pod-manifests
chmod 0700 etc
find . -maxdepth 1 -type f -name "*.kubeconfig" -exec chmod 0640 {} \;
find . -maxdepth 1 -type f -name "*.crt" -exec chmod 0600 {} \;
find . -maxdepth 1 -type f -name "*.key" -exec chmod 0600 {} \;
ls -l

    • Files in /var/lib/rancher/rke2/bin

      cd /var/lib/rancher/rke2/bin
chown root:root ./*
chmod 0750 ./*
ls -l

    • /var/lib/rancher/rke2/data directory

      cd /var/lib/rancher/rke2
chown root:root data
chmod 0750 data
ls -l

    • Files in /var/lib/rancher/rke2/data

      cd /var/lib/rancher/rke2/data
chown root:root ./*
chmod 0750 ./*
ls -l

    • Files and subdirectories in /var/lib/rancher/rke2/server

      cd /var/lib/rancher/rke2/server
chown root:root ./*
chmod 0700 cred
chmod 0700 db
chmod 0700 tls
chmod 0750 manifests
chmod 0750 logs
chmod 0600 token
ls -l

  2. Edit the RKE2 server configuration file (/etc/rancher/rke2/config.yaml) on all nodes and add the following:

    write-kubeconfig-mode: "0600"

    After updating the configuration file, restart the RKE2 server.

    systemctl restart rke2-server

  3. Set the correct permission for the Container Network Interface file.

    Example:

    cd /var/lib/cni/networks
chmod -R 600 *
ls -l