KodeKloud Notes

Consul’s key/value (KV) store lets you centrally manage configuration data, feature flags, and more. You can interact with the KV store in three ways:

Interface	Description	Ideal For
HTTP API	Perform CRUD operations over HTTP	Applications, automation, SDKs
Command-Line	`consul kv` subcommands for KV management	Administrators, scripts
Web UI	Browser-based view and edit	Exploratory or ad hoc changes

Below, we’ll explore each interface in detail.

1. Consul KV HTTP API

The HTTP API exposes a /v1/kv endpoint. Use standard HTTP verbs (PUT, GET, DELETE) to manage keys.

1.1 Writing a Key (`PUT`)

curl --request PUT \
     --data 'enabled' \
     https://consul.example.com:8500/v1/kv/data/app4
# => true

A response of true means the write succeeded. If the path (data/app4) doesn’t exist, Consul creates it automatically.

1.2 Reading a Key (`GET`)

curl https://consul.example.com:8500/v1/kv/data/app4 | jq

[
  {
    "LockIndex": 0,
    "Key": "data/app4",
    "Flags": 0,
    "Value": "J2VuYWJsZWQn",
    "CreateIndex": 69,
    "ModifyIndex": 87
  }
]

The Value field is Base64-encoded. Decode it:

echo "J2VuYWJsZWQn" | base64 --decode
# => 'enabled'

Note

Base64 encoding is not encryption. Data at rest in Consul is unencrypted by default; the API simply returns values encoded in Base64.

For full API reference, see the Consul KV HTTP API documentation.

2. Consul Command-Line Interface

The consul kv set of commands provides a quick way to interact with the KV store from your terminal.

# Write or update a key
consul kv put app1/config/apikey 4fe20s12a02$23
# Read back the value
consul kv get app1/config/apikey
# Delete the key
consul kv delete app1/config/apikey
# Output: Success! Data deleted at key: app1/config/apikey

Subcommand	Action
`put`	Create or update a key
`get`	Retrieve the plaintext value
`delete`	Remove a key and its data

Consult the Consul CLI documentation for additional flags and examples.

3. Consul Web UI

The Consul UI provides a visual way to browse and modify KV entries.

Log in to your Consul cluster.
Click on the Key/Value tab in the top navigation.
Drill down through key prefixes to locate your entry.
Click on a key to view or edit its value in JSON, YAML, or HCL format.

The image is a screenshot of a user interface for accessing a key/value store, highlighting the key name, key value, and options to view data in different formats. It includes labeled annotations and a cartoon character in the bottom right corner.

4. Limiting Access with ACLs

By default, Consul’s KV store is open to all clients. To enforce security:

Enable ACLs in your Consul configuration.
Bootstrap an ACL management token.
Create policies that grant read/write permissions on specific key prefixes.
Distribute tokens to users or applications.

Warning

Once ACLs are enabled, all API, CLI, and UI requests require a valid token. Plan your migration and token distribution carefully.

For a deep dive, see the Consul ACL guide.

Links and References

Watch Video

Watch video content