Kubernetes Cluster Health Monitoring with Prometheus

Question

Pulumi · Accepted Answer

To set up Kubernetes cluster health monitoring with Prometheus using Pulumi, you need to deploy a few key components:

1. **Prometheus:** The core monitoring service that uses a time-series database to record real-time metrics.
2. **Node Exporter:** A Prometheus exporter that measures various machine metrics such as CPU, disk, and memory usage.
3. **KubeStateMetrics:** A service that listens to the Kubernetes API server and generates metrics about the state of the objects.
4. **AlertManager:** Handles alerts sent by client applications such as the Prometheus server.

The following Pulumi program will demonstrate how to create a Kubernetes cluster and set up basic monitoring with Prometheus:

- First, we will create a managed Kubernetes cluster using Amazon EKS (you can adapt this for other cloud providers).
- Then, we will deploy Prometheus to the cluster.
- We will also deploy Node Exporter and KubeStateMetrics as necessary exporters to gather the metrics.

Here's how you can do this with Pulumi in Python:

```python
import pulumi
import pulumi_aws as aws
import pulumi_kubernetes as k8s

# Create an AWS EKS cluster. This will house our Prometheus setup.
eks_cluster = aws.eks.Cluster("eksCluster", 
    role_arn=eks_service_role.arn,
    vpc_config=aws.eks.ClusterVpcConfigArgs(
        public_access_cidrs=["0.0.0.0/0"],
        subnet_ids=public_subnet_ids,
    )
)

# We need a Kubernetes provider that uses the kubeconfig from our newly created cluster.
k8s_provider = k8s.Provider("k8sProvider", kubeconfig=eks_cluster.kubeconfig.apply(lambda c: c))

# Setting up a Prometheus instance in our cluster, including various components like
# Node Exporter and Kube State Metrics for monitoring node and cluster-wide metrics.
prometheus_chart = k8s.helm.v3.Chart(
    "prometheus",
    k8s.helm.v3.ChartOpts(
        chart="prometheus",
        version="11.0.3",
        namespace="monitoring",
        fetch_opts=k8s.helm.v3.FetchOpts(
            repo="https://prometheus-community.github.io/helm-charts",
        ),
        values={
            "alertmanager": {"enabled": True},
            "kubeStateMetrics": {"enabled": True},
            "nodeExporter": {"enabled": True},
            "server": {
                "persistentVolume": {
                    "enabled": True,
                    "size": "50Gi"
                }
            },
        },
    ),
    opts=pulumi.ResourceOptions(provider=k8s_provider)
)

# To get alerts out of Prometheus when thresholds are breached,
# we need to set up AlertManager with appropriate alerting rules and receivers.
# Let's assume we have an AlertManager config file at `alertmanager-config.yaml`.

alertmanager_config = k8s.core.v1.ConfigMap(
    "alertmanager-config",
    metadata=k8s.meta.v1.ObjectMetaArgs(
        namespace="monitoring",
        name="alertmanager-config",
    ),
    data={
        "config.yml": pulumi.AssetArchive({
            "alertmanager.yml": pulumi.FileAsset("alertmanager-config.yaml")
        }),
    },
    opts=pulumi.ResourceOptions(provider=k8s_provider)
)

# Export the cluster name and kubeconfig
pulumi.export('cluster_name', eks_cluster.name)
pulumi.export('kubeconfig', eks_cluster.kubeconfig)
```

Explanation:

1. We create a new EKS cluster (`eks_cluster`) hosted on AWS which will be our Kubernetes environment.
2. A Pulumi Kubernetes Provider (`k8s_provider`) is created to interact with our EKS cluster.
3. We deploy Prometheus to our Kubernetes cluster using the `prometheus_chart` resource. The Prometheus Helm chart includes various components like AlertManager, Node Exporter, and Kube State Metrics, which we enable in the `values` of `ChartOpts`.
4. We create a `ConfigMap` for the AlertManager config using `alertmanager_config`, assuming there's a configuration file at `alertmanager-config.yaml`.
5. Finally, we export the `cluster_name` and `kubeconfig` which might be useful for interacting with the cluster outside of Pulumi.

This program sets up a basic monitoring infrastructure within your Kubernetes cluster. You will use the kubeconfig to interact with your cluster and view the Prometheus UI once the pods are running. The AlertManager configuration should include your alerting rules and destinations such as email, Slack, or other notification channels.

Remember to create your `alertmanager-config.yaml` file with your configuration for AlertManager. This isn't a monitored dashboard solution, but Prometheus does have an expression browser and a basic UI to explore metrics and to check the state of alerts and scrape targets. For a full dashboard solution, you might consider deploying Grafana and integrating it with Prometheus.