---
layout: "docs"
page_title: "Commands: Config Write"
sidebar_current: "docs-commands-config-write"
---

# Consul Config Write

Command: `consul config write`

The `config write` command creates or updates a centralized config entry.
See the
[agent configuration](/docs/agent/options.html#enable_central_service_config)
for more information on how to enable this functionality for centrally 
configuring services.

## Usage

Usage: `consul config write [options] FILE`

#### API Options

<%= partial "docs/commands/http_api_options_client" %>

#### 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",
    "Connect": {
        "SidecarProxy": false
    }
}
```

* `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.