> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Prometheus Configuration > How to configure Prometheus scrape jobs and global settings, examples, authentication, reloading, and verifying targets in the UI Once Prometheus is installed and one or more hosts are exposing metrics, you must configure Prometheus so it knows which targets to scrape. Prometheus uses a pull model: the server is explicitly configured to retrieve metrics from targets. These settings live in the Prometheus YAML configuration file (commonly `/etc/prometheus/prometheus.yml`). Example minimal Prometheus config: ```yaml theme={null} # my global config global: scrape_interval: 1m scrape_timeout: 10s scrape_configs: - job_name: "prometheus" static_configs: - targets: ["localhost:9090"] ``` Overview of important sections * `global`: Default parameters that apply to all scrape jobs. Individual `scrape_configs` can override these defaults. * `scrape_configs`: Defines jobs (logical groups of targets) and how Prometheus should scrape them. Each job may define its own `scrape_interval`, `scrape_timeout`, `metrics_path`, `scheme`, authentication, discovery mechanism, and static targets. A more detailed example showing per-job overrides and a node metrics job: > Note: the example below demonstrates overriding defaults for a job; `scheme` and `metrics_path` are illustrative. Most exporters use `http` and the default `metrics_path` (`/metrics`). ```yaml theme={null} global: scrape_interval: 1m # default scrape interval for jobs that don't override it scrape_timeout: 10s # default scrape timeout scrape_configs: - job_name: "prometheus" static_configs: - targets: ["localhost:9090"] - job_name: "nodes" scrape_interval: 15s # overrides global scrape_interval for this job scrape_timeout: 5s # per-job scrape timeout scheme: https # defaults to http if not set metrics_path: /stats/metrics static_configs: - targets: ["192.168.1.168:9100"] ``` Common fields and what they do * `job_name`: Logical name for the job — added as a `job` label to all scraped metrics. * `scrape_interval`: How often Prometheus pulls metrics from targets in this job. * `scrape_timeout`: How long Prometheus will wait for a scrape before it times out. * `metrics_path`: HTTP path where metrics are exposed (defaults to `/metrics`). * `scheme`: `http` or `https` (defaults to `http`). * `static_configs.targets`: List of `host:port` targets to scrape (Node Exporter commonly uses port `9100`). * `basic_auth`: If targets require basic auth, set `username` and either `password` or `password_file` (mutually exclusive). Table: Common scrape config fields | Field | Purpose | Example | | ------------------------ | -------------------------------------------------------- | ---------------------------------------------------------------------- | | `job_name` | Logical name added to scraped metrics as the `job` label | `job_name: "node"` | | `scrape_interval` | How frequently to scrape targets | `scrape_interval: 15s` | | `scrape_timeout` | Per-scrape timeout | `scrape_timeout: 5s` | | `metrics_path` | Path where metrics are exposed | `metrics_path: /metrics` | | `scheme` | Protocol used for scrapes | `scheme: https` | | `static_configs.targets` | Explicit list of `host:port` targets | `- targets: ["192.168.1.168:9100"]` | | `basic_auth` | Basic authentication for scrapes | `basic_auth: { username: "user", password_file: "/etc/secrets/pass" }` | Reference-style documented options: ```yaml theme={null} scrape_configs: # How frequently to scrape targets from this job. # [ scrape_interval: | default = ] # Per-scrape timeout when scraping this job. # [ scrape_timeout: | default = ] # The HTTP resource path on which to fetch metrics from targets. # [ metrics_path: | default = /metrics ] # Configures the protocol scheme used for requests. # [ scheme: | default = http ] # Sets the ‘Authorization’ header on every scrape request with the configured username and password. # password and password_file are mutually exclusive. basic_auth: # [ username: ] # [ password: ] # [ password_file: ] ``` Editing the configuration and reloading Prometheus 1. Edit the config file (example path): ```bash theme={null} sudo vi /etc/prometheus/prometheus.yml ``` 2. After saving changes, Prometheus does not automatically pick them up. You have several options to apply the new config: * If you started Prometheus manually (for example with `./prometheus --config.file=/etc/prometheus/prometheus.yml`), stop it with Ctrl+C and start it again the same way. * Send a SIGHUP to the Prometheus process to request a config reload: ```bash theme={null} # find the pid (example) pidof prometheus # then: kill -HUP ``` * If Prometheus is managed via systemd, restart it: ```bash theme={null} sudo systemctl restart prometheus ``` After updating `prometheus.yml`, restart Prometheus, send a SIGHUP, or use the `/-/reload` HTTP endpoint (if available) so new scrape jobs take effect. Verifying targets in the Prometheus UI * Open the Prometheus UI at `http://:9090/`. * Navigate to Status -> Targets to view all configured targets and their scrape status. A green "UP" indicates a successful scrape. Example output showing two targets appears in the Prometheus Targets view: The image shows a Prometheus monitoring dashboard with two targets labeled "node" and "prometheus." Both targets are in an "UP" state, indicating successful data scraping. You can also confirm target status by querying the `up` metric in the Prometheus expression browser: ```text theme={null} up{instance="192.168.1.168:9100",job="node"} up{instance="localhost:9090",job="prometheus"} ``` Putting it together — a common `/etc/prometheus/prometheus.yml` example ```yaml theme={null} # my global config global: scrape_interval: 15s # scrape targets every 15s evaluation_interval: 15s # evaluate rules every 15s alerting: alertmanagers: - static_configs: - targets: ["alertmanager:9093"] rule_files: # - "first_rules.yml" # - "second_rules.yml" scrape_configs: - job_name: "prometheus" static_configs: - targets: ["localhost:9090"] - job_name: "node" scrape_interval: 15s static_configs: - targets: ["192.168.1.168:9100"] ``` This minimal configuration allows Prometheus to scrape itself and a Node Exporter instance. From here you can extend jobs with service discovery, relabeling, authentication, TLS settings, alerting, and rule files as required. Links and references * Prometheus official docs: [https://prometheus.io/docs/](https://prometheus.io/docs/) * Prometheus configuration reference: [https://prometheus.io/docs/prometheus/latest/configuration/configuration/](https://prometheus.io/docs/prometheus/latest/configuration/configuration/) * Node Exporter: [https://github.com/prometheus/node\_exporter](https://github.com/prometheus/node_exporter)