7.9.2. Namespaced and node-level sysctls

In a OpenShift Container Platform cluster, you can use namespaced sysctls, which apply to specific pods on a node, or node-level sysctls, which affect an entire node.

Some sysctls are namespaced in the Linux kernels. This means that you can set them independently for each pod on a node. Being namespaced is a requirement for sysctls to be accessible in a pod context within Kubernetes.

The following sysctls are known to be namespaced:

Additionally, most of the sysctls in the net.* group are known to be namespaced. Their namespace adoption differs based on the kernel version and distributor.

Node-level sysctls are not namespaced and must be set manually by a cluster administrator, either by using of the underlying Linux distribution of the nodes, such as by modifying the /etc/sysctls.conf file, or by using a daemon set with privileged containers. You can also use the Node Tuning Operator to set node-level sysctls.