Kubernetes Cluster Health Monitoring with AWS Node Problem Detector

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Pulumi · Accepted Answer

To monitor the health of a Kubernetes cluster using AWS with Node Problem Detector, you can deploy the Node Problem Detector as a DaemonSet in your Kubernetes cluster. The Node Problem Detector is a project developed by Kubernetes that aims to surface node problems that either affect node conditions, or are visible to the kernel. It is designed to work with a variety of log monitors and tools and can be extended with custom plugins.

In this program, we will use Pulumi to deploy a Node Problem Detector DaemonSet into an Amazon Elastic Kubernetes Service (EKS) cluster. Here's how you can accomplish this:

1. **Set up an EKS cluster**: Use the `aws.eks.Cluster` class to create an EKS cluster. This serves as the environment where your Kubernetes resources will run.
2. **Define the Node Problem Detector DaemonSet**: Kubernetes resources such as DaemonSets can be defined using `pulumi_kubernetes.apps.v1.DaemonSet`. The Node Problem Detector will run as a DaemonSet, meaning it will run on every node in the cluster.
3. **Deploy the Node Problem Detector DaemonSet**: Use Pulumi's deployment capabilities to deploy the Node Problem Detector to your EKS cluster.

The following program deploys an EKS cluster and the Node Problem Detector DaemonSet:

```python
import pulumi
import pulumi_aws as aws
import pulumi_kubernetes as kubernetes
from pulumi_aws import eks

# Step 1: Create an EKS cluster
eks_cluster = eks.Cluster("eksCluster",
    region="us-west-2",
    instance_type="t2.medium")

# Step 2: Use the EKS cluster's kubeconfig to interact with the cluster
kubeconfig = eks_cluster.kubeconfig.apply(lambda kc: kc)

# Step 3: Create a Kubernetes provider to deploy the Node Problem Detector
k8s_provider = kubernetes.Provider("k8sProvider", kubeconfig=kubeconfig)

# Step 4: Define the Node Problem Detector DaemonSet
node_problem_detector_daemonset = kubernetes.apps.v1.DaemonSet("nodeProblemDetector",
    metadata=kubernetes.meta.v1.ObjectMetaArgs(
        name="node-problem-detector",
        namespace="kube-system", # Node Problem Detector is typically deployed in the kube-system namespace
    ),
    spec=kubernetes.apps.v1.DaemonSetSpecArgs(
        selector=kubernetes.meta.v1.LabelSelectorArgs(
            match_labels={"name": "node-problem-detector"}
        ),
        template=kubernetes.core.v1.PodTemplateSpecArgs(
            metadata=kubernetes.meta.v1.ObjectMetaArgs(
                labels={"name": "node-problem-detector"}
            ),
            spec=kubernetes.core.v1.PodSpecArgs(
                containers=[kubernetes.core.v1.ContainerArgs(
                    name="node-problem-detector",
                    image="k8s.gcr.io/node-problem-detector/node-problem-detector:v0.8.8",
                    resources=kubernetes.core.v1.ResourceRequirementsArgs(
                        limits={"cpu": "200m", "memory": "100Mi"},
                        requests={"cpu": "200m", "memory": "100Mi"}
                    ),
                )],
            ),
        ),
    ),
    opts=pulumi.ResourceOptions(provider=k8s_provider))

# Step 5: Export the cluster name and kubeconfig
pulumi.export("cluster_name", eks_cluster.name)
pulumi.export("kubeconfig", eks_cluster.kubeconfig)
```

This program does the following:
- Defines an EKS cluster called `eksCluster` which will be created in the `us-west-2` region using `t2.medium` instance types.
- Creates a `Provider` called `k8sProvider` which allows Pulumi to communicate with the Kubernetes cluster using the `kubeconfig`.
- Specifies a `DaemonSet` for the Node Problem Detector to ensure it runs on all nodes within the cluster.
- Assigns the `node-problem-detector` DaemonSet to the `kube-system` namespace.
- Uses the `node-problem-detector` container image from the official Google Container Registry.
- Exports the `cluster_name` and `kubeconfig` as outputs for you to access your cluster outside of Pulumi.

Make sure to [follow the directions](https://www.pulumi.com/docs/get-started/kubernetes/deploy-app/) to install Pulumi CLI, set up your AWS credentials, and install kubectl if you haven't done that already. To deploy this program, save it as a Python file, and run `pulumi up` from within the directory containing your file. Pulumi will provision the necessary resources and deploy the Node Problem Detector DaemonSet to your EKS cluster.