boundary/website/content/docs/configuration/worker/overview.mdx

---
layout: docs
page_title: Worker - Overview
description: |-
  The worker stanza configures worker-specific parameters.
---

# `worker` Stanza

The `worker` stanza configures Boundary worker-specific parameters. Boundary
supports two different types of workers, differentiated by their means of
authentication to Boundary:
- [KMS Workers][] use a shared KMS to authenticate with controllers
- [PKI Workers][] use certificates issued by Boundary to authenticate with controllers

Different worker types have different configuration requirements, but share the common worker parameters listed below.

## Common Worker Parameters
The following fields are supported for all worker types:

```hcl
worker {
  public_addr = "5.1.23.198"

  initial_upstreams = [
    "10.0.0.1",
    "10.0.0.2",
  ]

  tags {
    type   = ["prod", "webservers"]
    region = ["us-east-1"]
  }
}
```

- `public_addr` - Specifies the public host or IP address (and optionally port)
  at which the worker can be reached _by clients for proxying_. This defaults to
  the address of the listener marked for `proxy` purpose. This is especially
  useful for cloud environments that do not bind a publicly accessible IP to a NIC
  on the host directly, such as an Amazon EIP. 
  
  This value can reference any of the following:
  - a direct address string
  - a file on disk (file://) from which an address will be read
  - an env var (env://) from which the address will be read
  - a [go-sockaddr template](https://godoc.org/github.com/hashicorp/go-sockaddr/template)

- `initial_upstreams` - A list of hosts/IP addresses and optionally ports for
  reaching the boundary cluster. The port will default to `:9201` if not
  specified. This value can be a direct access string array with the addresses,
  or it can refer to a file on disk (`file://`) from which the addresses will be
  read, or an env var (`env://`) from which the addresses will be read. When using
  env or file, their contents must formatted as a JSON array: `["127.0.0.1",
  "192.168.0.1", "10.0.0.1"]`

- `tags` - A map of key-value pairs where values are an array of strings. Most
  commonly used for [filtering](/docs/concepts/filtering) targets a worker can
  proxy via [worker tags](/docs/concepts/filtering/worker-tags). On `SIGHUP`, the
  tags set here will be re-parsed and new values used. It can also be a string
  referring to a file on disk (`file://`) or an env var (`env://`).

[kms workers]: /docs/configuration/worker/kms-worker
[pki workers]: /docs/configuration/worker/pki-worker