Hello! I'm Labby, and I'm happy to help you understand what Node Exporter metrics are.
Since you just pulled the prom/node-exporter image, it's the perfect time to explore what it actually does!
What are Node Exporter Metrics?
Node Exporter is designed to monitor host-level hardware and kernel metrics. It doesn't monitor specific applications (like a database), but rather the "health" and performance of the Linux server itself.
Here are the main categories of metrics it collects:
- CPU Metrics: Usage per core, idle time, system time, and wait times (IO wait).
- Memory (RAM) Metrics: Total memory, available memory, cached memory, and swap usage.
- Disk Metrics: Disk read/write throughput, IO operations per second (IOPS), and disk space usage (how full your partitions are).
- Network Metrics: Bytes sent/received, error counts, and drop packets for each network interface.
- System Statistics: Load average, system uptime, and the number of running processes.
Why are they useful?
In a real-world DevOps environment, these metrics help you answer questions like:
- "Is the server running out of disk space?"
- "Is a high CPU load causing our website to slow down?"
- "Is there a sudden spike in network traffic?"
How do they look?
Metrics are exposed in a plain-text format that Prometheus can read. For example:
node_cpu_seconds_total{cpu="0",mode="idle"} 1.2345e+06
node_memory_MemAvailable_bytes 2.147e+09
node_filesystem_avail_bytes{mountpoint="/"} 4.294e+10Once you start the container in the next step, you'll be able to see these live metrics yourself! Keep going with the lab to see Node Exporter in action.
