---
title: Turn down OpenTelemetry noise without a redeploy
description: >-
  Connect a Python service and a host to Fleet Management in Pydantic Logfire,
  then change the service's log level, redaction and sampling, and the host's
  Collector, while both keep running.
date: '2026-11-10'
authors:
  - Bill Easton
categories:
  - Pydantic Logfire
  - OpenTelemetry
  - New Features
canonical: 'https://pydantic.dev/articles/fleet-hands-on'
---
> ## Documentation Index
> Fetch the complete documentation index at: https://pydantic.dev/llms.txt
> Use this file to discover all available pages before exploring further.

## Querying This Documentation

**warning**: agent query parameters (`goal` and `organization`) not included.

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---


> Markdown version of [Turn down OpenTelemetry noise without a redeploy](https://pydantic.dev/articles/fleet-hands-on) — the canonical HTML page.
>
> By [Bill Easton](https://pydantic.dev/authors/bill-easton.md) · 2026-11-10 · Pydantic Logfire, OpenTelemetry, New Features
>
> Related: [Manage your telemetry in Logfire, send it anywhere](https://pydantic.dev/articles/fleet-management-launch.md) · [I received the AAIF Outstanding Technical Contribution Award](https://pydantic.dev/articles/aaif-outstanding-technical-contribution-award.md)
>
> All articles: [/articles.md](https://pydantic.dev/articles.md) · Site index: [/llms.txt](https://pydantic.dev/llms.txt)

---

# Turn down OpenTelemetry noise without a redeploy

> **Note: Fleet launch week**
>
> This is the second of three posts. The first, [Manage your telemetry in Logfire, send it anywhere](https://pydantic.dev/articles/fleet-management-launch), explains what Fleet Management is.

This post connects a service and the host it runs on to [Fleet Management](https://pydantic.dev/logfire/fleet-management) in Pydantic Logfire, then changes the service's log level, redaction and sampling and the host's Collector while both keep running.

You need a Logfire project (Fleet is on for every plan), a [write token](https://pydantic.dev/docs/logfire/manage/create-write-tokens/), Python 3.11 or later, and [uv](https://docs.astral.sh/uv/getting-started/installation/). Every step below also works for Node.js, Java, .NET and Go; the differences are in one table.

## Why change it live?

`checkout-api` logs at debug, puts a card token on one of its spans, and traffic just tripled, taking the ingest bill with it. You want less of all three, and you want it now, not after a deploy.

## The service: a FastAPI app with `fleet=True`

Here's `checkout-api`, a FastAPI app on the Logfire SDK. The only Fleet-specific part is `fleet=True`:

```python
import logfire
from fastapi import FastAPI

logfire.configure(service_name='checkout-api', fleet=True)

app = FastAPI()
logfire.instrument_fastapi(app)


@app.post('/checkout/{order_id}')
async def checkout(order_id: str, card_token: str) -> dict[str, str]:
    logfire.debug('cart loaded for {order_id}', order_id=order_id)
    with logfire.span('charge card', order_id=order_id, card_token=card_token):
        logfire.info('charged {order_id}', order_id=order_id)
    return {'status': 'ok'}
```

`fleet=True` needs Logfire 5.5.0 or later with the `fleet` extra. Setting `LOGFIRE_FLEET=true` does the same without a code change. Without a Fleet endpoint, `configure()` warns and the app runs unmanaged, so you can deploy the code before the Fleet settings.

```bash
uv venv
source .venv/bin/activate
uv pip install --upgrade 'logfire[fleet,fastapi]' fastapi uvicorn
```

## Connect the app to Fleet

In **Fleet management**, open **SDKs** and select **Add application**. Name it `checkout-api`, choose **Python with Logfire**, and select **Get setup instructions**.

Logfire shows a **Fleet connection key** once. Put it in your secret manager. Then set the variables the setup shows and start the app:

```bash
export OTEL_SERVICE_NAME=checkout-api
export OTEL_OPAMP_ENDPOINT=...   # from the setup
export OTEL_OPAMP_HEADERS=...    # Authorization with your connection key
uvicorn app:app
```

The app logs `OpAMP: connected to ...; this SDK is managed as checkout-api` when it reaches Fleet. Select **Check connection** in the setup, and the service shows as connected with its policy applied.

![The last step of the application setup: Application connected, policy applied on 1 instance](https://pydantic.dev/assets/blog/fleet-hands-on/connected.webp)

The connection key only manages settings. Your app keeps sending telemetry with its existing write token.

Other languages connect the same way, with one change at start:

- **Python, plain OpenTelemetry:** `uv pip install logfire-fleet-otel`, then run under `opentelemetry-instrument`.
- **Node.js 22+, Logfire SDK:** `npm install @pydantic/logfire-node @pydantic/logfire-fleet-otel`, then pass `fleet: true` to `logfire.configure()` (0.22.0 or later).
- **Node.js 22+, plain OpenTelemetry:** `npm install @pydantic/logfire-fleet-otel`, then start with `node --import @pydantic/logfire-fleet-otel/register app.js`.
- **Java 17+:** add the Fleet extension to the OpenTelemetry Java agent with `-Dotel.javaagent.extensions=logfire-fleet-javaagent-extension.jar`.
- **.NET 8+:** add the `Logfire.Fleet.AutoInstrumentation` plugin to OpenTelemetry automatic instrumentation.
- **Go 1.25+:** call `opampotel.Setup(ctx)` in `main`, in place of your SDK setup.

The [applications guide](https://pydantic.dev/docs/logfire/observe/fleet/applications/) has the full commands for each.

## Change 1: stop the debug flood

Open `checkout-api`'s SDK policy from the **SDKs** tab. Each section says **Set by policy** or **Application controlled**. Everything starts as Application controlled: a policy only changes what you tell it to.

Under **Volume controls**, set **Minimum log level** to **Warn**. Select **Review policy**, check the change, and publish.

![The Volume controls section of the SDK policy, set by policy, with Minimum log level set to Warn](https://pydantic.dev/assets/blog/fleet-hands-on/warn-level.webp)

Within seconds the debug and info logs stop arriving in the [Live view](https://pydantic.dev/docs/logfire/observe/live/). The process didn't restart. Its own log level didn't change either: Fleet drops the records at export, so a later policy can bring them back.

The application's page in Fleet lists each setting with what the policy asks for and what the instances are running.

![checkout-api in Fleet: three instances connected, the SDK policy applied on all three, and Log levels set to Warn and above by the policy and running](https://pydantic.dev/assets/blog/fleet-hands-on/log-level-applied.webp)

## Change 2: redact the token

Under **Attribute redaction**, add `*token*` to the attributes to mask, and publish. The SDK replaces each matching attribute's value with `[REDACTED]` before the span is exported, so it never reaches Logfire or any other backend the SDK sends to. **Scrubbing** goes further and matches values as well as keys, using the same patterns the Logfire SDK scrubs by default.

![The Attribute redaction section of the SDK policy, set by policy, masking attributes that match *token*](https://pydantic.dev/assets/blog/fleet-hands-on/redaction.webp)

## Change 3: sample a tenth of the traffic

Under **Trace sampling**, set the rate to 10%. Under **Sampling rules**, add a rule that drops `/health*` entirely; the first rule a new trace's root span matches decides its rate, before the overall rate applies. A span whose parent was sampled is still sampled, so traces stay whole.

Publish. Traces you don't sample never reach Logfire, so the review step is worth reading.

## Try it on two instances first

That last change is the kind you'd rather try small. Rollouts are in early access now. Where you have them, select **Settings** in Fleet management and turn on **Use rollouts**. Now publishing a version sends it to nobody until you start a rollout:

1. Publish the policy, then select **Roll out policy**.
2. Choose how many instances join the pilot, say two, and start it.
3. Watch **Policies › Rollouts**: it counts the instances that applied the version and any that failed.

A pilot doesn't grow on its own. When the two instances look right, start another rollout with more. If they don't, open the previous version from the policy's history, select **Restore into editor**, and publish it.

![Rollouts in Fleet: a Collector pilot with 1 of 2 applied, another with 1 of 4 applied and 1 failed, and a completed SDK rollout with 42 of 42 applied](https://pydantic.dev/assets/blog/fleet-hands-on/rollout.webp)

## Add the host's Collector

`checkout-api` runs on a Linux VM, and you want that VM's metrics and its nginx logs too. In **Collectors**, select **Add Collector**, then **Host**. Under **What to collect**, pick host monitoring, then **Get install command**.

Copy the **enrollment key** (Logfire shows it once) and run the command on the host. For a project in the US region:

```bash
uvx --from 'logfire-cli>=0.1.19' logfire-cli --beta --region us --org <your-org> collector install \
  --project <your-project> --token-stdin --yes
```

`--token-stdin` asks for the key without echoing it, so it stays out of your shell history. The installer asks for administrator access and sets up an OpenTelemetry Collector as a service. The host doesn't sign in to Logfire: the key places it in your project. The setup shows when its first data arrives. The host's metrics then show in the Hosts view, which [The OOM that was not your agent](https://pydantic.dev/articles/logfire-hosts-view) introduces.

To add the nginx logs, open the host's Collector policy, add `/var/log/nginx/*.log` to the file logs, and select **Review version**. If a Collector on the policy lacks a component the new version uses, the review says which. Publish, and the Collector picks it up. A Collector that can't run a version refuses it and keeps its current configuration, and Fleet shows **Failed** with the reason.

## Kubernetes, and the Collectors you already run

For a cluster, **Add Collector › Kubernetes** installs one small bridge that drives the [OpenTelemetry Operator](https://github.com/open-telemetry/opentelemetry-operator). Fleet's policy describes the cluster's Collectors, and the bridge creates, updates and deletes the `OpenTelemetryCollector` resources to match. The setup walks you through four steps, from checking your `kubectl` context to `kubectl apply -f fleet-bridge.yaml`.

If Helm or GitOps already manages your Collectors, or you set one up by hand as in [Observability with Logfire and OpenTelemetry Collector](https://pydantic.dev/articles/logfire-opentelemetry-collector), keep it that way. Select **Add Collector › Existing Collector** to get a connection key and a snippet for the `opamp` extension in Collector Contrib. Each Collector then shows in Fleet with its health, components and the configuration it runs, marked **Report only**. Fleet doesn't change that configuration. See [Connect an existing Collector](https://pydantic.dev/docs/logfire/observe/fleet/existing-collectors/).

## See what a policy changed

**Overview** compares how much your Collectors sent with the period before, by Collector and by policy, so you can see what a Collector policy change did to volume. **Flows** draws where each Collector receives data and where it sends it.

![Fleet Overview: metric data points, log records and spans sent over the last day against the period before, with the top Collectors and policies](https://pydantic.dev/assets/blog/fleet-hands-on/traffic.webp)

## When it doesn't connect

| What you see | What to check |
| --- | --- |
| The app never connects | The Fleet package loads before your app starts, and `OTEL_OPAMP_ENDPOINT` and `OTEL_OPAMP_HEADERS` are set. The app's logs name connection and authentication errors. |
| **Policy status** shows **Failed** | Open the app or Collector in Fleet. It names the setting or component it couldn't apply. |
| No telemetry arrives | Fleet doesn't carry telemetry. Check the write token and region. |

## Getting started

- [Manage applications](https://pydantic.dev/docs/logfire/observe/fleet/applications/), with the commands for every language.
- [Manage Collectors](https://pydantic.dev/docs/logfire/observe/fleet/collectors/), for hosts and Kubernetes.
- [Change policies](https://pydantic.dev/docs/logfire/observe/fleet/policies/), for rollouts and version history.
- The language guides in [pydantic/opamp-clients](https://github.com/pydantic/opamp-clients), with framework and deployment examples.

Tomorrow: how we check the OpAMP clients behind Fleet, ours and upstream.