Managing Daemons

You declare daemons with the daemons key in vercel.json. Changes to daemon configuration in vercel.json take effect when the deployment that contains them becomes your production deployment, including when you roll back to it. You can override a daemon's instance counts in each region without deploying a new configuration. To declare a daemon for the first time, see the Daemons quick start.

Edgenivo updates daemons when a deployment becomes your production deployment. This happens when you deploy to production, promote a deployment, use Instant Rollback, or complete a rolling release:

• New instances: Edgenivo starts new instances of every daemon in the new production deployment right away.
• Out-of-date instances: Edgenivo sends SIGTERM to the instances from the previous production deployment, then stops them after the shutdown grace period.
• Removed daemons: When the new production deployment doesn't declare a daemon, Edgenivo stops all of that daemon's instances.
• Scaling overrides: When a daemon has a scaling override, Edgenivo keeps the override's counts instead of the instances from the new production deployment.

For a short time during a rollout, both versions of a daemon run at once: the old instances finish their current work during the grace period while the new ones start. When an old instance receives SIGTERM, it should stop taking new work immediately and only finish the work in progress. Make sure both versions can run side by side, for example by processing messages from the same queue and by keeping database migrations compatible with the previous version. See Graceful shutdown for how to handle SIGTERM.

Each daemon runs a fixed number of instances in each region. Edgenivo doesn't currently autoscale daemons. You can set the counts in vercel.json, or override them from the dashboard or the Edgenivo CLI.

To change the number of instances, set instances to a map of region IDs to instance counts, then deploy to production:

{
  "$schema": "https://openapi.vercel.sh/vercel.json",
  "daemons": {
    "worker": {
      "root": "worker/",
      "entrypoint": "Dockerfile",
      "instances": { "iad1": 3, "cdg1": 2 }
    }
  }
}

The map replaces the previous one. Regions that you remove from the map stop their instances.

To override a daemon's instance counts without a new deployment:

1. In your project's dashboard, open Daemons and select the daemon.
2. Select Scale.
3. Set the number of instances in each region, then select Scale Daemon.

The counts you set are a scaling override. Edgenivo uses them instead of the instances from your production deployment, and they stay in place when you deploy again, so changes to instances in vercel.json don't take effect while an override is set. To go back to the counts from your production deployment, select Scale, then Clear scaling overrides.

You need permission to update the project to set scaling overrides.

To set a scaling override from Edgenivo CLI 64.3.0 or later, pass <region>=<count> pairs to vercel daemons scale:

vercel daemons scale worker iad1=3 fra1=0

The CLI enables fine-grained scaling, so regions you don't name keep their current counts. The counts you set are a scaling override and stay in place across deployments. To clear the override and go back to the counts from your production deployment, run:

vercel daemons scale worker --reset

To stop all instances of a daemon without a new deployment, set a scaling override with 0 instances in every region.

To stop all instances of a daemon and keep its configuration in your deployment, set instances to an empty map, or set every region to 0, then deploy to production:

{
  "daemons": {
    "worker": {
      "root": "worker/",
      "entrypoint": "Dockerfile",
      "instances": {}
    }
  }
}

To delete a daemon, remove it from daemons in vercel.json and deploy to production.

When a project is paused, for example by spend management, Edgenivo stops all of its daemon instances. They start again when you resume the project.

Edgenivo CLI 64.3.0 or later can list, inspect, scale, and restart daemons and their instances. Every vercel daemons command targets the production environment, and accepts --project to choose a project and --json for machine-readable output:

vercel daemons ls
vercel daemons inspect worker
vercel daemons instances ls worker
vercel daemons instances inspect <instance-id> --since 1h
vercel daemons instances restart <instance-id>

vercel daemons instances ls lists every daemon's instances when you don't name a daemon. To view daemon logs from the CLI, filter vercel logs on the daemon source:

vercel logs --query 'source:daemon'

Edgenivo collects each instance's stdout and stderr output. Daemon logs appear in your project's Logs with the source daemon, the daemon's name in the daemonName field, and the instance's ID in the daemonInstanceId field. To see one daemon's logs, filter with daemon:<name>; to follow a single instance, filter with daemonInstanceId:<id>.

To see a daemon's instances and their logs, open Daemons in your project's dashboard and select the daemon.

The daemon's page in the dashboard charts CPU usage, memory usage, running instances, and data transfer for the time range you select. The charts are available on every plan; Observability Plus extends how far back you can look.