Exploring Agent Client Collector for Kubernetes – Visibility
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Summary of Exploring Agent Client Collector for Kubernetes – Visibility
Agent Client Collector for Kubernetes – Visibility enables ServiceNow customers to gain comprehensive visibility into both on-premises Kubernetes clusters and various cloud deployments. It continuously discovers Kubernetes resources, detects changes, and updates the ServiceNow Configuration Management Database (CMDB) with accurate, up-to-date information. This ensures your CMDB reflects the current state of your Kubernetes environment, supporting effective configuration and asset management.
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How It Works
- Upon deployment, a Kubernetes Deployment resource is created, containing a pod called the Informer.
- The Informer connects to the Kubernetes API server to receive real-time events about resource changes within the cluster.
- It communicates with your ServiceNow instance via a secured secret and sends data through the External Communication Channel (ECC) Queue using the ServiceNow Table API.
- The Informer updates the CMDB tables with new, modified, or deleted Kubernetes resources accordingly.
- If the Informer cannot report changes (e.g., due to network issues), additions are captured during the next full discovery, while deletions are marked as Absent and removed after two full discovery cycles.
Initial and Periodic Discovery
- The initial discovery identifies all Kubernetes resources and reports them to the ServiceNow instance.
- Data is sent every 30 seconds, up to 1 MB at a time, allowing timely updates even for large clusters.
- A single Informer pod can efficiently handle clusters with tens of thousands of pods.
- If the Informer pod stops, Kubernetes automatically restarts it to maintain continuous monitoring.
- Deleted resources are marked with installstatus=Absent and cleaned from the CMDB within hours.
Performance and Impact
- The Informer minimizes load on the Kubernetes API server by fetching the full resource list only once and then synchronizing incrementally.
- Periodic and on-demand full discovery cycles resend cached resource lists to ensure CMDB accuracy.
- For detailed performance and scalability benchmarks, customers can refer to the relevant ServiceNow Knowledge Base articles.
Practical Benefits for ServiceNow Customers
- Maintains an accurate, up-to-date CMDB reflecting your Kubernetes environment across on-premises and cloud deployments.
- Enables proactive visibility into resource changes, supporting better configuration management and troubleshooting.
- Scales efficiently to support large Kubernetes clusters with minimal impact on cluster performance.
- Automatic recovery and robust handling of network interruptions ensure continuous data integrity.
Agent Client Collector for Kubernetes – Visibility enables you to gain visibility into on-premises Kubernetes clusters as well as the various Cloud deployments.
Agent Client Collector for Kubernetes – Visibility detects changes on resources in a Kubernetes cluster. It performs continuous discovery, reports any changes back to your instance, and updates the Configuration Management Database (CMDB) with the latest data. For the latest information on supported cloud deployments, see the Agent Client Collector for Kubernetes – Visibility support matrix article in the Now Support Knowledge Base.
How it works
When you deploy Agent Client Collector for Kubernetes – Visibility, Kubernetes creates a Deployment resource in the cluster with the latest data. For the latest information on supported cloud deployments, see the Agent Client Collector for Kubernetes – Visibility support matrix article in the Now Support Knowledge Base. This resource uses a secret stored in Kubernetes to connect to your ServiceNow instance.
The Agent Client Collector for Kubernetes – Visibility Deployment resource contains a pod called Informer, which connects to the Kubernetes API server and receives events on the resources in the cluster from it. The Informer sends the collected data to the instance through the External Communication Channel (ECC) Queue table, using the ServiceNow Table API to read from and write to the queue. The Informer then updates the appropriate tables in the CMDB.
For more information about the Kubernetes resources on which the Informer collects data and the CMDB tables it populates, see Data collected by Agent Client Collector for Kubernetes – Visibility.
Initial and periodic discovery
In its initial discovery, the Informer finds all the resources in the Kubernetes cluster and reports them to your instance. Every 30 seconds, the Informer sends up to 1 MB of data to the instance. It typically takes up to two minutes to report data on a cluster containing 1,000 pods and another minute for every additional 1,000 pods. A single Informer pod can handle a cluster with tens of thousands of pods. If the Informer exits for any reason, Kubernetes restarts it automatically.
After the initial discovery, the Informer continuously monitors the addition, updating, and deletion of resources in the cluster. Resources that were deleted from the cluster are marked with install_status=Absent and deleted from the CMDB within hours in a regular cleanup.
Impact of the Informer on the Kubernetes API server
The Informer has minimal impact on the Kubernetes API server. It fetches the complete list of relevant resources only once and saves it to memory. From then on, it synchronizes with the Kubernetes API server and never pulls the complete list again. During the periodic and on-demand full discovery cycles, the Informer resends the saved list of resources to the instance.
Agent Client Collector for Kubernetes – Visibility performance and scalability benchmark
For Agent Client Collector for Kubernetes – Visibility benchmarks, see the Performance results for Kubernetes Visibility Agent [KB1555851] article in the Now Support Knowledge Base.