About

A comprehensive guide for collecting, and exporting telemetry data (metrics, logs, and traces) from Docker Swarm environment can be found at swarmlibs/dockerswarm-monitoring-guide.

A Docker Stack deployment for the monitoring suite for Docker Swarm includes (Grafana, Prometheus, cAdvisor, Node exporter and Blackbox prober exporter)

Important

This project is a work in progress and is not yet ready for production use. But feel free to test it and provide feedback.

Table of Contents:

• About
• Concepts
  • Prometheus
  • Configuration providers and config reloader services
• Stacks
• Pre-requisites
• Getting Started
  • Deploy stack
  • Remove stack
  • Verify deployment
• Grafana
  • Injecting Grafana Dashboards
  • Injecting Grafana Provisioning configurations
• Prometheus
  • Register services as Prometheus targets
  • Register a custom scrape config
  • Configure Prometheus
    • Environment variables
• Services and Ports
• Troubleshooting
  • Grafana dashboards are not present
• License

Concepts

This section covers some concepts that are important to understand for day to day Promstack usage and operation.

Prometheus

By design, the Prometheus server is configured to automatically discover and scrape the metrics from the Docker Swarm nodes, services and tasks. You can use Docker object labels in the deploy block to automagically register services as targets for Prometheus. It also configured with config provider and config reloader services.

Prometheus Kubernetes compatible labels

Here is a list of Docker Service/Task labels that are mapped to Kubernetes labels.

Kubernetes	Docker	Scrape config
namespace	__meta_dockerswarm_service_label_com_docker_stack_namespace
deployment	__meta_dockerswarm_service_name
pod	dockerswarm_task_name	dockerswarm/services
service	__meta_dockerswarm_service_name	dockerswarm/services-endpoints

• The dockerswarm_task_name is a combination of the service name, slot and task id.
• The task id is a unique identifier for the task. It depends on the mode of the deployement (replicated or global). If the service is replicated, the task id is the slot number. If the service is global, the task id is the node id.

Configuration providers and config reloader services

The grafana and prometheus service requires extra services to operate, mainly for providing configuration files. There are two type of child services, a config provider and config reloader service.

Here an example visual representation of the services:

We leverage the below services:

• swarmlibs/prometheus-config-provider
• swarmlibs/grafana-provisioning-config-reloader
• prometheus-operator/prometheus-config-reloader

---

Stacks

These are the services that are part of the stack:

• Blackbox exporter: https://github.com/prometheus/blackbox_exporter
• cAdvisor: https://github.com/google/cadvisor
• Grafana: https://github.com/grafana/grafana
• Node exporter: https://github.com/prometheus/node_exporter
• Prometheus: https://github.com/prometheus/prometheus
• Pushgateway: https://github.com/prometheus/pushgateway

Pre-requisites

• Docker running Swarm mode
• A Docker Swarm cluster with at least 3 nodes
• Configure Docker daemon to expose metrics for Prometheus
• The official swarmlibs stack, this provided necessary services for other stacks operate.

Getting Started

To get started, clone this repository to your local machine:

git clone https://github.com/swarmlibs/promstack.git
# or
gh repo clone swarmlibs/promstack

Navigate to the project directory:

cd promstack

Create user-defined networks:

make stack-networks

# or run the following command to create the networks manually

docker network create --scope=swarm --driver=overlay --attachable public
docker network create --scope=swarm --driver=overlay --attachable prometheus
docker network create --scope=swarm --driver=overlay --attachable prometheus_gwnetwork

• This public network is used by Ingress service and Blackbox exporter to perform network probes
• The prometheus network is used to perform service discovery for Prometheus scrape configs.
• The prometheus_gwnetwork network is used for the internal communication between the Prometheus Server, exporters and other agents.

The grafana and prometheus service requires extra services to operate, mainly for providing configuration files. There are two type of child services, a config provider and config reloader service. In order to ensure placement of these services, you need to deploy the swarmlibs stack.

See https://github.com/swarmlibs/swarmlibs for more information.

Deploy stack

This will deploy the stack to the Docker Swarm cluster. Please ensure you have the necessary permissions to deploy the stack and the swarmlibs stack is deployed. See Pre-requisites for more information.

Important

It is important to note that the promstack is the default stack namespace for this deployment.
It is NOT RECOMMENDED to change the stack namespace as it may cause issues with the deployment.

make deploy

Remove stack

Warning

This will remove the stack and all the services associated with it. Use with caution.

make remove

Verify deployment

To verify the deployment, you can use the following commands:

docker service ls --filter label=com.docker.stack.namespace=promstack

# ID  NAME                                                 MODE         REPLICAS               IMAGE
# **  promstack_blackbox-exporter                          replicated   1/1 (max 1 per node)   prom/blackbox-exporter:v0.25.0
# **  promstack_cadvisor                                   global       1/1                    gcr.io/cadvisor/cadvisor:v0.47.0
# **  promstack_grafana                                    replicated   1/1 (max 1 per node)   swarmlibs/grafana:main
# **  promstack_grafana-dashboard-provider                 replicated   1/1 (max 1 per node)   swarmlibs/prometheus-config-provider:0.1.0-rc.1
# **  promstack_grafana-provisioning-config-reloader       replicated   1/1 (max 1 per node)   swarmlibs/grafana-provisioning-config-reloader:0.1.0-rc.1
# **  promstack_grafana-provisioning-dashboard-provider    replicated   1/1 (max 1 per node)   swarmlibs/prometheus-config-provider:0.1.0-rc.1
# **  promstack_grafana-provisioning-datasource-provider   replicated   1/1 (max 1 per node)   swarmlibs/prometheus-config-provider:0.1.0-rc.1
# **  promstack_node-exporter                              global       1/1                    prom/node-exporter:v1.8.1
# **  promstack_prometheus                                 global       1/1                    swarmlibs/genconfig:0.1.0-rc.1
# **  promstack_prometheus-config-provider                 global       1/1                    swarmlibs/prometheus-config-provider:0.1.0-rc.1
# **  promstack_prometheus-config-reloader                 global       1/1                    quay.io/prometheus-operator/prometheus-config-reloader:v0.74.0
# **  promstack_prometheus-server                          replicated   1/1 (max 1 per node)   prom/prometheus:v2.45.6
# **  promstack_pushgateway                                replicated   1/1 (max 1 per node)   prom/pushgateway:v1.9.0

You can continously monitor the deployment by running the following command:

# The `watch` command will continously monitor the services in the stack and update the output every 2 seconds.
watch docker service ls --filter label=com.docker.stack.namespace=promstack

---

Grafana

The Grafana service is configured with config provider and config reload services. The config provider service is responsible for providing the configuration files for the Grafana service. The config reloader service is responsible for reloading the Grafana service configuration when the config provider service updates the configuration files.

The following configuration are supported:

• Grafana Dashboards
• Provisioning (Datasources, Dashboards)

Injecting Grafana Dashboards

To inject a Grafana Provisioning configurations, you need to specify config object in your docker-compose.yml or docker-stack.yml file as shown below. The label io.grafana.dashboard=true is used by the config provider service to inject the dashboards into Grafana.

# See grafana/docker-stack.yml
configs:
  # Grafana & Prometheus dashboards
  gf-dashboard-grafana-metrics:
    name: gf-dashboard-grafana-metrics-v1
    file: ./dashboards/grafana-metrics.json
    labels:
      - "io.grafana.dashboard=true"

Injecting Grafana Provisioning configurations

To inject a Grafana Provisioning configurations, you need to specify config object in your docker-compose.yml or docker-stack.yml file as shown below.

There are two types of provisioning configurations:

• Dashboards: Use io.grafana.provisioning.dashboard=true label to inject the provisioning configuration for dashboards.
• Datasources: Use io.grafana.provisioning.datasource=true label to inject the provisioning configuration for data sources.

# See grafana/docker-stack.yml
configs:
  # Grafana dashboards provisioning config
  gf-provisioning-dashboards:
    name: gf-provisioning-dashboards-v1
    file: ./provisioning/dashboards/grafana-dashboards.yml
    labels:
      - "io.grafana.provisioning.dashboard=true"

  # Grafana datasources provisioning config
  gf-provisioning-datasource-prometheus:
    name: gf-provisioning-datasource-prometheus-v1
    file: ./provisioning/datasources/prometheus.yaml
    labels:
      - "io.grafana.provisioning.datasource=true"

Prometheus

By design, the Prometheus server is configured to automatically discover and scrape the metrics from the Docker Swarm nodes, services and tasks. The default data retention is 182 days or ~6 months.

You can use Docker object labels in the deploy block to automagically register services as targets for Prometheus. It also configured with config provider and config reloader services.

Register services as Prometheus targets

• io.prometheus.enabled: Enable the Prometheus scraping for the service.
• io.prometheus.job_name: The Prometheus job name. Default is <docker_stack_namespace>/<service_name|job_name>.
• io.prometheus.scrape_scheme: The scheme to scrape the metrics. Default is http.
• io.prometheus.scrape_port: The port to scrape the metrics. Default is 80.
• io.prometheus.metrics_path: The path to scrape the metrics. Default is /metrics.
• io.prometheus.param_<name>: The Prometheus scrape parameters.

Example:

# Annotations:
services:
  my-app:
    # ...
    networks:
      prometheus:
    deploy:
      # ...
      labels:
        io.prometheus.enabled: "true"
        io.prometheus.job_name: "my-app"
        io.prometheus.scrape_port: "8080"

# As limitations of the Docker Swarm, you need to attach the service to the prometheus network.
# This is required to allow the Prometheus server to scrape the metrics.
networks:
  prometheus:
    name: prometheus
    external: true

Register a custom scrape config

To register a custom scrape config, you need to specify config object in your docker-compose.yml or docker-stack.yml file as shown below. The label io.prometheus.scrape_config=true is used by the Prometheus config provider service to inject the scrape config into Prometheus.

# See cadvisor/docker-stack.yml
configs:
  prometheus-cadvisor:
    name: prometheus-cadvisor-v1
    file: ./prometheus/cadvisor.yml
    labels:
      - "io.prometheus.scrape_config=true"

Configure Prometheus

You can apply custom configurations to Prometheus via Environment variables by running docker service update command on promstack_prometheus service:

# Register the Alertmanager service address
docker service update --env-add PROMETHEUS_SCRAPE_INTERVAL=15s promstack_prometheus

# Remove the Alertmanager service address
docker service update --env-rm PROMETHEUS_SCRAPE_INTERVAL promstack_prometheus

Environment variables

• PROMETHEUS_SCRAPE_INTERVAL: The scrape interval for Prometheus, default is 10s
• PROMETHEUS_SCRAPE_TIMEOUT: The scrape timeout for Prometheus, default is 5
• PROMETHEUS_EVALUATION_INTERVAL: The evaluation interval for Prometheus, default is 1m
• PROMETHEUS_CLUSTER_NAME: The cluster name for Prometheus, default is promstack
• PROMETHEUS_CLUSTER_REPLICA: The cluster replica for Prometheus, default is 1
• PROMETHEUS_ALERTMANAGER_ADDR: The Alertmanager service address
• PROMETHEUS_ALERTMANAGER_PORT: The Alertmanager service port, default is 9093

Services and Ports

The following services and ports are exposed by the stack:

Service	Port	Mode	Internal DNS
Grafana	3000		grafana.svc.cluster.local
Prometheus	9090		prometheus.svc.cluster.local
Pushgateway			pushgateway.svc.cluster.local
Blackbox exporter			blackbox-exporter.svc.cluster.local
cAdvisor	18080	host
Node exporter	19100	host

Troubleshooting

Grafana dashboards are not present

If the Grafana dashboards are not present, please restart grafana service to reload the dashboards.

docker service update --force promstack_grafana

License

Licensed under the MIT License. See LICENSE for more information.