78 lines
3 KiB
Markdown
78 lines
3 KiB
Markdown
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Discover docker containers to scrape based on labels
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====
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This tool aims at discovering containers running
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with `prometheus.io/scrape=true` annotations
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from a given docker engine, and auto-configure prometheus for scraping.
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This tool is standalone and write the discovered containers (services) in a file,
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which is in turn passed to Prometheus file service discovery to start the scraping jobs.
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# Example via a docker-compose
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The following part is giving a complete example of configuring the docker-labels discovery mechanism.
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It is based in three parts, namely:
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- Configure prometheus-docker-labels-discovery
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- Configure Prometheus file_sd_configs
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- Configure your services
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## Configure prometheus-docker-labels-discovery
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```
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prometheus-docker-labels-discovery:
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image: sqooba/prometheus-docker-labels-discovery:v1
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restart: unless-stopped
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networks:
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- monitoring_default # make sure this network exists and is connected to prometheus
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# ports:
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# - "8080"
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security_opt:
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- no-new-privileges:true
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volumes: # Mount the JSON file that will be exchanged with prometheus
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- ./from-docker-labels.json:/tmp/from-docker-labels.json
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environment:
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- PROMETHEUS_CONFIG_FILE_PATH=/tmp/from-docker-labels.json
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- DOCKER_NETWORK_NAME=bridge
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- PROMETHEUS_COMMON_LABELS=commonlabel1=commonvalue1
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```
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## Configure Prometheus
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Prometheus needs to be configured using [file_sd_configs](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#file_sd_config)
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scrape config.
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```
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scrape_configs:
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- job_name: 'docker-labels-sd'
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file_sd_configs:
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- files:
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- 'from_docker_labels.json'
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```
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## Configure your services
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Any service can now be configured using [docker labels](https://docs.docker.com/config/labels-custom-metadata/).
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The following example shows in docker-compose style how this looks like:
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```
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services:
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test-metrics:
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image: dummy-metrics:v1
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labels:
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- "prometheus.io/scrape=true"
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- "prometheus.io/path=/metrics"
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- "prometheus.io/extra-labels=k1:v1,k2:v2"
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```
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The exhaustive list of labels to configure properly your service is provided below:
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| Annotation | Definition | Example |
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| ---------- | ---------- | ------- |
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| `prometheus.io/scrape` | Main label to ensure this container will be scraped by Prometheus. Required value is `true`. Any other value will not be considered. | `prometheus.io/scrape=true`|
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| `prometheus.io/port` | Specify which port to use for the scraping. In case of a single port exposed, this configuration can be omitted. | `prometheus.io/port=8080` |
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| `prometheus.io/path` | Alternative path for scraping the metrics. Default from Prometheus is `/`. | `prometheus.io/path=/metrics` |
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| `prometheus.io/scheme` | Alternative scheme for scraping thee metrics. Default from Prometheus is `http`. | `prometheus.io/scheme=https` |
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| `prometheus.io/extra-labels` | Any extra labels to add to the metrics scraped for this container. Comma separated key:value pairs. | `prometheus.io/extra-labels=label1:value1,label2:value2,...` |
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