Introduction to kdave - Kubernetes Deprecated API Versions Exporter

kdave is an open source tool that helps monitor and manage deprecated Kubernetes API versions in your clusters. As Kubernetes evolves, older API versions get deprecated and eventually removed. This can cause issues if you have workloads using those older APIs. kdave makes it easy to monitor and export metrics about deprecated API usage, so you can plan upgrades proactively.

How kdave Works

kdave is deployed as a pod inside your Kubernetes cluster. It queries the Kubernetes API server to detect deprecated API versions in use. It exports this usage data as Prometheus metrics. This allows dashboards and alerts to be created based on deprecated API usage.

The key features of kdave are:

• Detects deprecated API versions from all namespaces
• Exports Prometheus metrics for deprecated API version usage
• Easy to deploy as a pod in your cluster
• Configurable with annotations and labels
• Open source tool with permissive licensing

Deploying kdave

RBAC Permissions

kdave needs read access to query the Kubernetes API to detect deprecated versions. It uses the /apis and /api endpoints.

Create a ClusterRole:

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: kdave
rules:
- apiGroups:
  - ""
  resources:
  - pods
  - nodes
  - namespaces
  verbs:
  - get
  - list
  - watch        

This allows kdave to query core API resources like pods and nodes across all namespaces.

Next, create a ServiceAccount for kdave and bind the ClusterRole:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: kdave
  
---

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: kdave
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: kdave
subjects:
- kind: ServiceAccount
  name: kdave
  namespace: default        

With this ServiceAccount, kdave will have the necessary access.

Resource Limits

Set proper resource limits on the kdave pod to avoid it taking too many cluster resources:

?resources:
  requests:
    memory: "64Mi"
    cpu: "100m"
  limits:
    memory: "128Mi"
    cpu: "200m"        

Adjust as needed based on your cluster size and resources available.

Customizing Metrics

kdave allows customizing metrics through annotations. For example, to change the metric prefix:

template:
  metadata:
    annotations:
      kdave.sqshq.com/metrics.prefix: "custom_"        

Now metrics will be prefixed custom_ instead of kdave_.

There are other annotations to customize labels, timeout values, etc. Refer to the kdave GitHub repo for details.

Deployment Architecture

For high availability, run kdave as a Deployment with 2+ replicas. Scale as needed for large clusters.

kdave plays well with Prometheus operators. Create a ServiceMonitor to auto-discover kdave pods as a target.

Use Kubernetes concepts like nodeSelectors, affinity, and tolerations to control the nodes kdave is scheduled on.

Viewing kdave Metrics

Here are some additional details on viewing and using the metrics exported by kdave:

Metric Types

The main metrics exported by kdave are:

• kdave_deprecated_versions - Gauge showing the total count of deprecated API versions
• kdave_deprecated_resources - Gauge with the count of resources using deprecated APIs
• kdave_deprecations - Histogram metric with API deprecation lookups

These metrics give visibility into overall deprecated API usage in your cluster.

Querying Metrics

You can query the kdave metrics from Prometheus. For example:

kdave_deprecated_versions
kdave_deprecated_resources        

This will show the time series for those metrics over various time ranges.

Use Prometheus querying to aggregate, rate(), etc:

?sum(rate(kdave_deprecated_versions[5m]))        

Building Dashboards

?Dashboarding tools like Grafana can visualize the kdave metric data. Build charts showing:

• Total deprecated versions over time
• Deprecated resources by namespace
• API deprecation lookup latency
• Alerts on increased deprecated API usage

This gives a graphical view into API deprecation status.

Alerting Rules

Set alerting rules in Prometheus based on kdave metrics, like:

- alert: DeprecatedVersionIncrease
  expr: sum(kdave_deprecated_versions) > 10
  for: 5m        

Alert on increased usage of deprecated APIs over time. Integrate with platforms like Alertmanager.

Usage with CI/CD

Leverage kdave metrics in CI/CD pipelines for deployments. Fail builds if a new deployment suddenly starts using deprecated APIs. This prevents accidental use of older APIs.

Overall, the metrics from kdave can power comprehensive visibility and alerts around API deprecation.

Additional resources on kdave and monitoring deprecated Kubernetes APIs

kdave GitHub Repo

This contains the official code, documentation, examples, and issues list for kdave. The README provides a good overview and the docs have additional details.

Kubernetes Deprecation Policy

Kubernetes has a formal policy for deprecating and removing APIs. This doc explains the timeline and procedures around deprecation.

Exporters and Integrations

Prometheus documentation on exporters and integrations like kdave that expose metrics for monitoring.

Kube-state-metrics

Common metrics exporter for Kubernetes objects and resources. kdave provides additional focus on API deprecation.

Common Use Cases

Transitioning from older Kubernetes versions:? When upgrading from an older Kubernetes version like 1.x to modern versions, kdave can detect any workloads still relying on deprecated 1.x APIs. This allows you to migrate those workloads before decommissioning the older cluster.

Avoiding deprecated APIs in new deployments:? kdave can be part of CI/CD pipelines to fail builds if a new deployment begins using a deprecated API. This prevents accidental usage of older APIs during development.

Monitoring API deprecation during upgrades:? When incrementally upgrading Kubernetes versions like from 1.19 to 1.20, kdave can monitor if any new deprecations get introduced with each incremental upgrade.

Alerting on increased deprecated API usage:? kdave metrics can power alerts if usage of deprecated APIs suddenly increases. This may indicate something is wrong

Deprecated API usage across environments:? Run kdave in dev, staging, and prod environments to compare deprecated API usage. You can prioritize upgrading environments with higher usage first.

Tracking API deprecation status:? The time series metrics from kdave provide a history of API deprecation signals. This allows you to analyze trends and see the impact of upgrade activities.

Planning removal of deprecated APIs:? kdave metrics help understand the scope and impact of fully removing deprecated APIs. You can set TARGET_REMOVAL milestones based on measured deprecation usage.

Conclusion

kdave is a valuable open source tool for monitoring and managing deprecated Kubernetes APIs in your clusters.

The key takeaways are:

• kdave detects and exports metrics on deprecated API usage
• This gives visibility into usage of older APIs that may cause issues
• Metrics can power alerts, dashboards, and automation workflows
• Helps you proactively plan upgrades and removals of deprecated APIs
• Easy to deploy as a pod inside your Kubernetes cluster
• Integrates with Prometheus for scraping metrics

As Kubernetes evolves, deprecation of older APIs will continue. kdave provides the telemetry you need to smoothly transition and upgrade clusters. Monitoring API deprecation signals allows you to be proactive rather than reactive.

Deploying kdave only takes a few minutes. I recommend adding it to your Kubernetes clusters to future-proof your stack. The metrics will quickly highlight any deprecated APIs thazlity into API deprecation status, you can have increased confidence when upgrading Kubernetes versions. kdave gives you the data to make deprecation and upgrade decisions systematically.

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