Using kubernetes apm.k8s.elastic.co with upgrade.cattle.io

Question

Pulumi · Accepted Answer

In Kubernetes, `apm.k8s.elastic.co` generally refers to the Elastic APM (Application Performance Monitoring) resources provided by Elastic for monitoring application performance. Meanwhile, `upgrade.cattle.io` likely refers to resources for managing application or system upgrades within a Kubernetes cluster. This could potentially be related to the Rancher's system-upgrade-controller, which manages the upgrade of system services and applications.

In Pulumi, to work with Kubernetes resources we use the `@pulumi/kubernetes` package. This package allows us to declare Kubernetes resources in a programmatic way using TypeScript (or other supported languages).

To illustrate, I'll show you a simple Pulumi TypeScript example where we deploy an Elastic APM Server instance on Kubernetes. Keep in mind that for a real-world application, you would need to cater to more specifics such as storage, networking policies, and secure configuration management.

Here's a basic Pulumi program that will deploy an Elastic APM instance:

```typescript
import * as k8s from "@pulumi/kubernetes";

const ns = new k8s.core.v1.Namespace("apm-namespace", {
    metadata: { name: "elastic-apm" },
});

const apmServerDeployment = new k8s.apps.v1.Deployment("apm-server-deployment", {
    metadata: {
        namespace: ns.metadata.name,
        labels: { app: "apm-server" },
    },
    spec: {
        replicas: 1,
        selector: { matchLabels: { app: "apm-server" } },
        template: {
            metadata: { labels: { app: "apm-server" } },
            spec: {
                containers: [{
                    name: "apm-server",
                    image: "docker.elastic.co/apm/apm-server:7.6.0",
                    ports: [{ containerPort: 8200 }],
                }],
            },
        },
    },
});

new k8s.core.v1.Service("apm-server-service", {
    metadata: {
        namespace: ns.metadata.name,
        labels: apmServerDeployment.metadata.labels,
    },
    spec: {
        type: "NodePort",
        ports: [{ port: 8200, targetPort: 8200, protocol: "TCP" }],
        selector: apmServerDeployment.spec.template.metadata.labels,
    },
});
```

In this code:

- We import the `@pulumi/kubernetes` package to work with Kubernetes resources.
- We create a dedicated namespace for Elastic APM by instantiating `k8s.core.v1.Namespace`.
- We define a `Deployment` resource for the APM server using `k8s.apps.v1.Deployment`. We set the container to use an Elastic APM server image from Elastic's Docker Registry.
- Additionally, we expose the APM service on a `NodePort` for accessibility using `k8s.core.v1.Service`.

Please note that this example does not include setting up Elasticsearch for data storage, which is required by APM Server for operation. Also, the security considerations (e.g., credentials, network policies) are not addressed here and would need to be in a production setup. The configuration specifics would depend on your cluster setup and Elastic's best practice recommendations.

This code is a starting point and does not include upgrading functionality as that is more complex and requires understanding the specifics of the environment, existing configurations, and the desired upgrade strategy.

If you want to perform rolling updates to your deployment in the future, you would update the relevant parts of your deployment spec, and Kubernetes would handle the rolling update of the pods for you. Pulumi would similarly be used to change the desired state of the system, and then Kubernetes would converge the actual state to the desired state.

For managing more complex updates, with custom pipelines or fine-grained control, you might want to look into using tools like Rancher or ArgoCD in addition to Pulumi for more sophisticated deployment and update orchestration.

To run the Pulumi program, you simply execute `pulumi up` after setting up the project with Pulumi CLI and configuring your access to a Kubernetes cluster.

Remember, leveraging Kubernetes and Pulumi for infrastructure as code will require some learning and experience with both technologies, so I'd encourage investing time into understanding the fundamental concepts and practices.