Host Metrics
Host Metrics Source
Collect metric data directly from the local system.
The Host Metrics source allows worker to run as a lightweight system agent, periodically collecting resource utilization metrics from the host operating system. It is designed for node-level observability and infrastructure monitoring.
This source is optimized for continuous, low-overhead metric collection on individual hosts.
Collection Model
Worker inspects native operating system interfaces to gather metrics describing system resource usage, including:
- CPU utilization
- Memory consumption
- Disk I/O and usage
- Filesystem capacity
- Network throughput
- Load averages
- Process-level metrics
- cgroups (Linux only)
- TCP connection statistics
Metrics are emitted at a configurable scrape interval and forwarded in batches to downstream sinks.
Operating Environment
Host-Based Execution
- Designed to run directly on virtual machines, bare-metal servers, or nodes
- Commonly deployed as:
- A system service
- A container with host access
- A DaemonSet in Kubernetes environments
Stateless Behavior
- No local state is persisted
- Each scrape cycle is independent
- Suitable for ephemeral and autoscaled environments
Linux cgroups Support
On Linux systems, Host Metrics can collect resource usage from control groups (cgroups):
- Supports cgroups v2 and hybrid configurations
- Enables visibility into:
- Container-level CPU usage
- Memory limits and consumption
- Resource isolation behavior
This is particularly valuable in containerized and multi-tenant environments.
Kubernetes Considerations
When running under Kubernetes, certain virtual filesystems may cause filesystem metric collection errors due to symbolic link recursion.
Typical symptoms include failures when inspecting paths under /proc.
To mitigate this:
- Specific devices, filesystems, or mount points can be excluded from collection
- This exclusion is enabled by default in the official Worker Helm chart
These safeguards prevent unnecessary errors while maintaining accurate host-level metrics.
Metric Namespacing
- All emitted metrics share a configurable namespace
- Defaults to a host prefix
- Helps distinguish host-level metrics from:
- Application metrics
- Container metrics
- Platform-specific telemetry
Collector Architecture
Host Metrics is composed of independent collectors, each responsible for a specific subsystem:
- CPU
- Memory
- Disk
- Filesystem
- Network
- Load
- Processes
- cgroups
- TCP
Collectors can be selectively enabled or disabled to:
- Reduce overhead
- Limit metric cardinality
- Focus on relevant subsystems
Filtering and Scope Control
Fine-grained filtering is supported across multiple dimensions:
- Disk devices
- Network interfaces
- Filesystems
- Mount points
- Process names
- cgroup hierarchies
Pattern-based inclusion and exclusion allow precise control in complex environments with high resource churn.
Reliability Characteristics
- Periodic, interval-based scraping
- Batch-oriented metric delivery
- At-least-once semantics
- No acknowledgement tracking
- Minimal runtime overhead
This design makes Host Metrics suitable for continuous infrastructure monitoring without impacting application performance.
Common Use Cases
- Node-level infrastructure monitoring
- Capacity and utilization tracking
- Kubernetes node observability
- VM and bare-metal monitoring
- Baseline metrics for alerting systems
- Feeding metrics into:
- Prometheus-compatible backends
- Time-series databases
- Centralized observability platforms