---
layout: docs
page_title: 'Commands: Config Write'
sidebar_title: write
---

# Consul Config Write

Command: `consul config write`

The `config write` command creates or updates a centralized config entry.
See the [configuration entries docs](/docs/agent/config_entries) for more
details about configuration entries.

## Usage

Usage: `consul config write [options] FILE`

#### API Options

@include 'http_api_options_client.mdx'

#### Enterprise Options

@include 'http_api_namespace_options.mdx'

#### Config Write Options

- `-cas` - Specifies to use a Check-And-Set operation. If the index is
  0, Consul will only store the entry if it does not already exist. If the index is
  non-zero, the entry is only set if the current index matches the `ModifyIndex`
  of that entry.

## Examples

From file:

    $ consul config write web-defaults.json

From stdin:

    $ consul config write -

### Config Entry examples

All config entries must have a `Kind` when registered. Currently, the only
supported types are `service-defaults` and `proxy-defaults`.

#### Service defaults

Service defaults control default global values for a service, such as the
protocol and Connect fields.

```json
{
  "Kind": "service-defaults",
  "Name": "web",
  "Protocol": "http"
}
```

- `Name` - Sets the name of the config entry. For service defaults, this must be
  the name of the service being configured.

- `Protocol` - Sets the protocol of the service. This is used by Connect proxies
  for things like observability features.

- `Connect` - This block contains Connect-related fields for the service.

  - `SidecarProxy` - Sets whether or not instances of this service should get a
    sidecar proxy by default.

#### Proxy defaults

Proxy defaults allow for configuring global config defaults across all services
for Connect proxy config. Currently, only one global entry is supported.

```json
{
  "Kind": "proxy-defaults",
  "Name": "global",
  "Config": {
    "foo": 1
  }
}
```

- `Name` - Sets the name of the config entry. Currently, only a single `proxy-defaults`
  entry with the name `global` is supported.

* `Config` - An arbitrary map of configuration values used by Connect proxies.