reproducer.sh

cat <<EOF | oc apply -f -
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfigPool
metadata:
  name: reproducer
spec:
  machineConfigSelector:
    matchExpressions:
    - key: machineconfiguration.openshift.io/role
      operator: In
      values:
      - worker
      - reproducer
  nodeSelector:
    matchLabels:
      node-role.kubernetes.io/reproducer: ""
EOF
WORKER=$(oc get nodes --selector node-role.kubernetes.io/worker= --output jsonpath="{.items[0].metadata.name}")
oc label nodes "$WORKER" node-role.kubernetes.io/reproducer=
MCD=$(oc get pods -n openshift-machine-config-operator --field-selector spec.nodeName="$WORKER" --output jsonpath="{.items[0].metadata.name}")
oc exec -n openshift-machine-config-operator -c machine-config-daemon pod/"$MCD" -- bash -c "chroot /rootfs echo 1 > /proc/sys/kernel/sysrq"

cat <<EOF | oc apply -f -
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  name: reproducer
  labels:
    machineconfiguration.openshift.io/role: reproducer
spec:
  kernelType: realtime
EOF

export MCD
expect -c '
spawn oc logs -f -n openshift-machine-config-operator -c machine-config-daemon pod/$env(MCD)
expect "Initiating switch from kernel default to realtime"
'

oc exec -n openshift-machine-config-operator -c machine-config-daemon pod/"$MCD" -- bash -c "chroot /rootfs echo b > /proc/sysrq-trigger"

while ! oc exec -n openshift-machine-config-operator -c machine-config-daemon pod/"$MCD" -- chroot /rootfs uname -r; do : ; done

# cleanup
oc delete mc/reproducer
oc delete mcp/reproducer
oc label nodes "$WORKER" node-role.kubernetes.io/reproducer-