Merge pull request #25986 from Random-Liu/enable-node-problem-detector

Automatic merge from submit-queue

Add node problem detector as an addon pod.

```release-note
Introduce a new add-on pod NodeProblemDetector.

NodeProblemDetector is a DaemonSet running on each node, monitoring node health and reporting
node problems as NodeCondition and Event. Currently it already supports kernel log monitoring, and
will support more problem detection in the future. It is enabled by default on gce now.
```

This PR enables NodeProblemDetector as an add-on pod.

/cc @mikedanese @kubernetes/sig-node 

[![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/.github/PULL_REQUEST_TEMPLATE.md?pixel)]()

cluster/gce/config-default.sh

@@ -104,6 +104,9 @@ CLUSTER_REGISTRY_DISK_TYPE_GCE="${CLUSTER_REGISTRY_DISK_TYPE_GCE:-pd-standard}"
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"
 
+# Optional: Install node problem detector.
+ENABLE_NODE_PROBLEM_DETECTOR="${KUBE_ENABLE_NODE_PROBLEM_DETECTOR:-true}"
+
 # Optional: Create autoscaler for cluster's nodes.
 ENABLE_NODE_AUTOSCALER="${KUBE_ENABLE_NODE_AUTOSCALER:-false}"
 if [[ "${ENABLE_NODE_AUTOSCALER}" == "true" ]]; then
@@ -126,6 +129,5 @@ OPENCONTRAIL_PUBLIC_SUBNET="${OPENCONTRAIL_PUBLIC_SUBNET:-10.1.0.0/16}"
 
 # How should the kubelet configure hairpin mode?
 HAIRPIN_MODE="${HAIRPIN_MODE:-promiscuous-bridge}" # promiscuous-bridge, hairpin-veth, none
-
 # Optional: if set to true, kube-up will configure the cluster to run e2e tests.
 E2E_STORAGE_TEST_ENVIRONMENT=${KUBE_E2E_STORAGE_TEST_ENVIRONMENT:-false}