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k8s-metacollector

⚠️ The repository is still a work in progress ⚠️

The k8s-metacollector is a self-contained module that can be deployed within a Kubernetes cluster to perform the task of gathering metadata from various Kubernetes resources and subsequently transmitting this collected metadata to designated subscribers.

Description

Falco enriches events coming from syscall event source with metadata coming from other sources, for example Kubernetes API server. Historically, each instance of Falco running in a Kubernetes cluster would connect to the Kubernetes API server in order to fetch the metadata for a subset of Kubernetes resources. This approach works well in small Kubernetes cluster but does not scale in large environments. The following issue describes the problems that were affecting the old Kubernetes client: https://github.com/falcosecurity/libs/issues/987.

The aim of k8s-metacollector is to propose a novel approach to k8s metadata enrichment in Falco by moving the fetching logic of the metadata to a centralized component. The Falco instances would connect to this component and receive the metadata without the need to connect to the Kubernetes API server. The following image shows the deployment of k8s-metacollector and Falco in a kubernetes cluster.

Having a centralized component that connects to the API server and pushes metadata to the Falco instances reduces the load on the Kubernetes API server. Keep in mind that Falco is deployed as a DaemonSet, one Falco instance on each node. It also reduces the number of events sent to the Falco instances by filtering the metadata by the node. A given Falco instance running in a given node will receive metadata only for the resources that are related to that node:

• pods running on the node;
• namespaces that contain a pod running on the node;
• deployment, replicaset, replicationcontrollers associated with a pod running on the node;
• services serving a pod running on the node.

The filtering done by k8s-metacollector reduces significantly the number of events sent to the Falco instances. The metadata received by the subscribers is ready to be used without the need for further processing on the subscribers side.

Functional Guarantees:

The k8s-metacollector assures that:

• subscribers (Falco instances) at subscribe time will receive all the metadata for the resources related to the subscriber(node for which the subscriber wants to receive the metadata);
• a message of type Create is sent to the subscribers when a new resource is discovered; for it;
• a message of type Update is sent to the subscriber when an already sent resource has some fields modified;
• a message of type Delete is sent to the subscriber when an already sent resource is not anymore relevant for the subscriber;
• only metadata for resources related to a subscriber are sent;

Getting Started

You’ll need a Kubernetes cluster to run against. You can use KIND to get a local cluster for testing, or run against a remote cluster.

Running on the cluster

Manifests

It's as easy as running:

kubectl apply -f manifests/meta-collector.yaml

If you want to scrape the metrics exposed by k8s-metacollector using prometheus then deploy the provided ServiceMonitor. Make sure to add the appropriate label to the manifest file in order to be discovered and scraped by your prometheus instance.

kubectl apply -f manifests/monitor.yaml

Helm Chart

Before installing the chart, add the falcosecurity charts repository:

helm repo add falcosecurity https://falcosecurity.github.io/charts
helm repo update

To install the chart with default values and release name k8s-metacollector run:

helm install k8s-metacollector falcosecurity/k8s-metacollector \
    --namespace metacollector \
    --create-namespace

After a few seconds, k8s-metacollector should be running in the metacollector namespace.

Enabling ServiceMonitor

Assuming that Prometheus scrapes only the ServiceMonitors that present a release label the following command will install and label the ServiceMonitor:

helm install k8s-metacollector falcosecurity/k8s-metacollector \
    --namespace metacollector \
    --create-namespace \
    --set serviceMonitor.create=true \
    --set serviceMonitor.labels.release="kube-prometheus-stack"

There is also a default grafana dashboard ready to be used under grafana folder.

License

This project is licensed to you under the Apache 2.0 license.