open-consul/website/source/api/kv.html.md

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---
layout: api
page_title: KV Store - HTTP API
sidebar_current: api-kv-store
description: |-
The /kv endpoints access Consul's simple key/value store, useful for storing
service configuration or other metadata.
---
# KV Store Endpoints
The `/kv` endpoints access Consul's simple key/value store, useful for storing
service configuration or other metadata.
It is important to note that each datacenter has its own KV store, and there is
no built-in replication between datacenters. If you are interested in
replication between datacenters, please view the
[Consul Replicate](https://github.com/hashicorp/consul-replicate) project.
~> Values in the KV store cannot be larger than 512kb.
For multi-key updates, please consider using [transaction](/api/txn.html).
## Read Key
This endpoint returns the specified key. If no key exists at the given path, a
404 is returned instead of a 200 response.
For multi-key reads, please consider using [transaction](/api/txn.html).
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| Method | Path | Produces |
| ------ | ---------------------------- | -------------------------- |
| `GET` | `/kv/:key` | `application/json` |
The table below shows this endpoint's support for
[blocking queries](/api/features/blocking.html),
[consistency modes](/api/features/consistency.html),
[agent caching](/api/features/caching.html), and
[required ACLs](/api/index.html#authentication).
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| Blocking Queries | Consistency Modes | Agent Caching | ACL Required |
| ---------------- | ----------------- | ------------- | ------------ |
| `YES` | `all` | `none` | `key:read` |
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### Parameters
- `key` `(string: "")` - Specifies the path of the key to read.
- `dc` `(string: "")` - Specifies the datacenter to query. This will default to
the datacenter of the agent being queried. This is specified as part of the
URL as a query parameter.
- `recurse` `(bool: false)` - Specifies if the lookup should be recursive and
`key` treated as a prefix instead of a literal match. This is specified as
part of the URL as a query parameter.
- `raw` `(bool: false)` - Specifies the response is just the raw value of the
key, without any encoding or metadata. This is specified as part of the URL as
a query parameter.
- `keys` `(bool: false)` - Specifies to return only keys (no values or
metadata). Specifying this implies `recurse`. This is specified as part of the
URL as a query parameter.
- `separator` `(string: "")` - Specifies the string to use as a separator
for recursive key lookups. This option is only used when paired with the `keys`
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parameter to limit the prefix of keys returned, only up to the given separator.
This is specified as part of the URL as a query parameter.
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- `ns` `(string: "")` - **(Enterprise Only)** Specifies the namespace to query.
If not provided, the namespace will be inferred from the request's ACL token,
or will default to the `default` namespace. This is specified as part of the
This is specified as part of the URL as a query parameter.
For recursive lookups, the namespace may be specified as '*' and then results
will be returned for all namespaces. Added in Consul 1.7.0.
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### Sample Request
```text
$ curl \
http://127.0.0.1:8500/v1/kv/my-key
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```
### Sample Response
#### Metadata Response
```json
[
{
"CreateIndex": 100,
"ModifyIndex": 200,
"LockIndex": 200,
"Key": "zip",
"Flags": 0,
"Value": "dGVzdA==",
"Session": "adf4238a-882b-9ddc-4a9d-5b6758e4159e"
}
]
```
- `CreateIndex` is the internal index value that represents when the entry was
created.
- `ModifyIndex` is the last index that modified this key. This index corresponds
to the `X-Consul-Index` header value that is returned in responses, and it can
be used to establish blocking queries by setting the `?index` query parameter.
You can even perform blocking queries against entire subtrees of the KV store:
if `?recurse` is provided, the returned `X-Consul-Index` corresponds to the
latest `ModifyIndex` within the prefix, and a blocking query using that
`?index` will wait until any key within that prefix is updated.
- `LockIndex` is the number of times this key has successfully been acquired in
a lock. If the lock is held, the `Session` key provides the session that owns
the lock.
- `Key` is simply the full path of the entry.
- `Flags` is an opaque unsigned integer that can be attached to each entry.
Clients can choose to use this however makes sense for their application.
- `Value` is a base64-encoded blob of data.
#### Keys Response
When using the `?keys` query parameter, the response structure changes to an
array of strings instead of an array of JSON objects. Listing `/web/` with a `/`
separator may return:
```json
[
"/web/bar",
"/web/foo",
"/web/subdir/"
]
```
Using the key listing method may be suitable when you do not need the values or
flags or want to implement a key-space explorer.
#### Raw Response
When using the `?raw` endpoint, the response is not `application/json`, but
rather the content type of the uploaded content.
```
)k<><6B><EFBFBD><EFBFBD><EFBFBD><EFBFBD>z^<5E>-<2D>ɑj<C991>q<EFBFBD><71><EFBFBD><EFBFBD>#u<>-R<>r<EFBFBD><72>T<EFBFBD>D<EFBFBD><44>٬<EFBFBD>Y<EFBFBD><59>l,<2C>ιK<CEB9><4B>Fm<46><6D>}<7D>#e<><65>
```
(Yes, that is intentionally a bunch of gibberish characters to showcase the
response)
## Create/Update Key
This endpoint updates the value of the specified key. If no key exists at the given
path, the key will be created.
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| Method | Path | Produces |
| ------ | ---------------------------- | -------------------------- |
| `PUT` | `/kv/:key` | `application/json` |
Even though the return type is `application/json`, the value is either `true` or
`false`, indicating whether the create/update succeeded.
The table below shows this endpoint's support for
[blocking queries](/api/features/blocking.html),
[consistency modes](/api/features/consistency.html),
[agent caching](/api/features/caching.html), and
[required ACLs](/api/index.html#authentication).
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| Blocking Queries | Consistency Modes | Agent Caching | ACL Required |
| ---------------- | ----------------- | ------------- | ------------ |
| `NO` | `none` | `none` | `key:write` |
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### Parameters
- `key` `(string: "")` - Specifies the path of the key.
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- `dc` `(string: "")` - Specifies the datacenter to query. This will default to
the datacenter of the agent being queried. This is specified as part of the
URL as a query parameter.
- `flags` `(int: 0)` - Specifies an unsigned value between `0` and `(2^64)-1`.
Clients can choose to use this however makes sense for their application. This
is specified as part of the URL as a query parameter.
- `cas` `(int: 0)` - Specifies to use a Check-And-Set operation. This is very
useful as a building block for more complex synchronization primitives. If the
index is 0, Consul will only put the key if it does not already exist. If the
index is non-zero, the key is only set if the index matches the `ModifyIndex`
of that key.
- `acquire` `(string: "")` - Supply a session ID to use in a lock acquisition operation.
This is useful as it allows leader election to be built on top of Consul. If the
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lock is not held and the session is valid, this increments the `LockIndex` and
sets the `Session` value of the key in addition to updating the key contents.
A key does not need to exist to be acquired. If the lock is already held by
the given session, then the `LockIndex` is not incremented but the key
contents are updated. This lets the current lock holder update the key
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contents without having to give up the lock and reacquire it. **Note that an update
that does not include the acquire parameter will proceed normally even if another
session has locked the key.**
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For an example of how to use the lock feature, see the [Leader Election Guide]
(https://learn.hashicorp.com/consul/developer-configuration/elections).
- `release` `(string: "")` - Supply a session ID to use in a release operation. This is
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useful when paired with `?acquire=` as it allows clients to yield a lock. This
will leave the `LockIndex` unmodified but will clear the associated `Session`
of the key. The key must be held by this session to be unlocked.
- `ns` `(string: "")` - **(Enterprise Only)** Specifies the namespace to query.
If not provided, the namespace will be inferred from the request's ACL token,
or will default to the `default` namespace. This is specified as part of the
URL as a query parameter. Added in Consul 1.7.0.
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### Sample Payload
The payload is arbitrary, and is loaded directly into Consul as supplied.
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### Sample Requests
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```bash
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$ curl \
--request PUT \
--data @contents \
http://127.0.0.1:8500/v1/kv/my-key
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# or
$ curl \
--request PUT \
--data-binary @contents \
http://127.0.0.1:8500/v1/kv/my-key
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```
### Sample Response
```json
true
```
## Delete Key
This endpoint deletes a single key or all keys sharing a prefix.
| Method | Path | Produces |
| -------- | ---------------------------- | -------------------------- |
| `DELETE` | `/kv/:key` | `application/json` |
The table below shows this endpoint's support for
[blocking queries](/api/features/blocking.html),
[consistency modes](/api/features/consistency.html),
[agent caching](/api/features/caching.html), and
[required ACLs](/api/index.html#authentication).
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| Blocking Queries | Consistency Modes | Agent Caching | ACL Required |
| ---------------- | ----------------- | ------------- | ------------ |
| `NO` | `none` | `none` | `key:write` |
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### Parameters
- `recurse` `(bool: false)` - Specifies to delete all keys which have the
specified prefix. Without this, only a key with an exact match will be
deleted.
- `cas` `(int: 0)` - Specifies to use a Check-And-Set operation. This is very
useful as a building block for more complex synchronization primitives. Unlike
`PUT`, the index must be greater than 0 for Consul to take any action: a 0
index will not delete the key. If the index is non-zero, the key is only
deleted if the index matches the `ModifyIndex` of that key.
- `ns` `(string: "")` - **(Enterprise Only)** Specifies the namespace to query.
If not provided, the namespace will be inferred from the request's ACL token,
or will default to the `default` namespace. This is specified as part of the
URL as a query parameter. Added in Consul 1.7.0.
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### Sample Request
```text
$ curl \
--request DELETE \
http://127.0.0.1:8500/v1/kv/my-key
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```
### Sample Response
```json
true
```