Monitoring your systems and containers is essential for maintaining a reliable homelab or home server. This guide uses Grafana Alloy’s built-in exporters to collect host and container metrics, with Prometheus for storage and Grafana for visualization — all managed through a single agent instead of separate containers per exporter.
Prerequisites
- Prometheus running and reachable
- Grafana running with Prometheus added as a datasource
- Grafana Alloy installed and running — see Setting Up Your Observability Stack
Host Metrics
Create an Alloy config file for host system metrics:
nano alloy/config/unix.alloy// Host system metrics (CPU, memory, disk, network)
prometheus.exporter.unix "host" {
set_collectors = ["cpu", "diskstats", "filesystem", "loadavg", "meminfo", "netdev", "uname"]
filesystem {
mount_points_exclude = "^/(sys|proc|dev|host|etc)($$|/)"
}
netdev {
device_exclude = "^(veth.*|br.*|docker.*|virbr.*|lo)$$"
}
}
prometheus.scrape "host" {
targets = prometheus.exporter.unix.host.targets
forward_to = [prometheus.remote_write.default.receiver]
job_name = "host"
}The set_collectors list controls which metrics are gathered. The filesystem and netdev excludes prevent virtual mounts and Docker bridge interfaces from cluttering your dashboards.
Container Metrics
Create an Alloy config file for Docker container metrics:
nano alloy/config/docker-metrics.alloy// Docker container metrics (CPU, memory, network per container)
prometheus.exporter.cadvisor "dockermetrics" {
docker_host = "unix:///var/run/docker.sock"
storage_duration = "5m"
}
prometheus.relabel "docker_filter" {
forward_to = [prometheus.remote_write.default.receiver]
rule {
target_label = "job"
replacement = "docker"
}
rule {
target_label = "instance"
replacement = constants.hostname
}
// Drop container_spec metrics that frequently contain NaN values
rule {
source_labels = ["__name__"]
regex = "container_spec_(cpu_period|cpu_quota|cpu_shares|memory_limit_bytes|memory_swap_limit_bytes|memory_reservation_limit_bytes)"
action = "drop"
}
}
prometheus.scrape "dockermetrics" {
targets = prometheus.exporter.cadvisor.dockermetrics.targets
forward_to = [prometheus.relabel.docker_filter.receiver]
scrape_interval = "10s"
}Docker Socket Access
Alloy needs access to the Docker socket to discover containers. Add the following volume mount to your Alloy docker-compose.yml and recreate the container:
volumes:
- /var/run/docker.sock:/var/run/docker.sock:rodocker compose up -d alloyApply Configuration
Restart Alloy to load the new config files:
docker restart alloyVerification
Open the Alloy Web UI and confirm both components are healthy:
prometheus.exporter.unixprometheus.exporter.cadvisor
Then verify data is flowing in Grafana’s Explore view:
node_cpu_seconds_total{job="host"}container_cpu_usage_seconds_total{job="docker"}Grafana Dashboards
You can create your own dashboards or use these as a starting point:
- System Dashboard — host metrics
- Docker Dashboard — container metrics