Editing restricted SCC is not recommended.
In case adding hostpath to restricted SCC, and then rebooting OS, critical pods such as "apiserver [namespace: kube-servivce-catalogue]" and "kube-state-metrics [namespace: openshift-monitoring]" won't be able to run anymore.
So workaround is creating new SCC to allow hostpath as I modified.
Editing restricted SCC is not recommended. In case adding hostpath to restricted SCC, and then rebooting OS, critical pods such as "apiserver [namespace: kube-servivce-catalogue]" and "kube-state-metrics [namespace: openshift-monitoring]" won't be able to run anymore. So workaround is creating new SCC to allow hostpath as I modified.