diff --git a/modules/nodes-containers-sysctls-unsafe.adoc b/modules/nodes-containers-sysctls-unsafe.adoc index c3d00a8b17..1a649ac636 100644 --- a/modules/nodes-containers-sysctls-unsafe.adoc +++ b/modules/nodes-containers-sysctls-unsafe.adoc @@ -6,11 +6,16 @@ = Enabling unsafe sysctls A cluster administrator can allow certain unsafe sysctls for very special -situations such as high-performance or real-time application tuning. +situations such as high performance or real-time application tuning. If you want to use unsafe sysctls, a cluster administrator must enable them individually for a specific type of node. The sysctls must be namespaced. +You can further control which sysctls can be set in pods by specifying lists of sysctls or sysctl patterns in the `forbiddenSysctls` and `allowedUnsafeSysctls` fields of the Security Context Constraints. + +- The `forbiddenSysctls` option excludes specific sysctls. +- The `allowedUnsafeSysctls` option controls specific needs such as high performance or real-time application tuning. + [WARNING] ==== Due to their nature of being unsafe, the use of unsafe sysctls is @@ -20,7 +25,7 @@ containers, resource shortage, or breaking a node. .Procedure -. Add a label to the machine config pool where the containers where containers +. Add a label to the machine config pool where the containers where containers with the unsafe sysctls will run: + [source,terminal] @@ -59,7 +64,7 @@ spec: ---- <1> Specify the label from the machine config pool. <2> List the unsafe sysctls you want to allow. - + . Create the object: + [source,terminal] @@ -119,4 +124,3 @@ $ oc get machineconfig 99-worker-XXXXXX-XXXXX-XXXX-XXXXX-kubelet -o json | grep ---- + You can now add unsafe sysctls to pods as needed. -