141 lines
4.3 KiB
Plaintext
141 lines
4.3 KiB
Plaintext
---
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layout: "docs"
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page_title: "Commands: KV Put"
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sidebar_current: "docs-commands-kv-put"
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---
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# Consul KV Put
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Command: `consul kv put`
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The `kv put` command writes the data to the given path in the KV store.
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## Usage
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Usage: `consul kv put [options] KEY [DATA]`
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#### API Options
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<%= partial "docs/commands/http_api_options_client" %>
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<%= partial "docs/commands/http_api_options_server" %>
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#### KV Put Options
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* `-acquire` - Obtain a lock on the key. If the key does not exist, this
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operation will create the key and obtain the lock. The session must already
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exist and be specified via the -session flag. The default value is false.
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* `-base64` - Treat the data as base 64 encoded. The default value is false.
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* `-cas` - Perform a Check-And-Set operation. Specifying this value also
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requires the -modify-index flag to be set. The default value is false.
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* `-flags=<int>` - Unsigned integer value to assign to this KV pair. This
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value is not read by Consul, so clients can use this value however makes sense
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for their use case. The default value is 0 (no flags).
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* `-modify-index=<int>` - Unsigned integer representing the ModifyIndex of the
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key. This is used in combination with the -cas flag.
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* `-release` - Forfeit the lock on the key at the given path. This requires the
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-session flag to be set. The key must be held by the session in order to be
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unlocked. The default value is false.
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* `-session=<string>` - User-defined identifer for this session as a string.
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This is commonly used with the -acquire and -release operations to build
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robust locking, but it can be set on any key. The default value is empty (no
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session).
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## Examples
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To insert a value of "5" for the key named "redis/config/connections" in the
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KV store:
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```
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$ consul kv put redis/config/connections 5
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Success! Data written to: redis/config/connections
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```
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If no data is specified, the key will be created with empty data:
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```
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$ consul kv put redis/config/connections
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Success! Data written to: redis/config/connections
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```
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If the `-base64` flag is set, the data will be decoded before writing:
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```
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$ consul kv put -base64 foo/encoded aGVsbG8gd29ybGQK
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Success! Data written to: foo/encoded
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```
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!> **Be careful when overwriting data!** The above operation would overwrite
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the value at the key to the empty value.
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For longer or sensitive values, it is possible to read from a file by prefixing
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with the `@` symbol:
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```
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$ consul kv put redis/config/password @password.txt
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Success! Data written to: redis/config/connections
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```
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Or read values from stdin by specifying the `-` symbol:
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```
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$ echo "5" | consul kv put redis/config/password -
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Success! Data written to: redis/config/connections
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$ consul kv put redis/config/password -
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5
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<CTRL+D>
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Success! Data written to: redis/config/connections
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```
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~> For secret and sensitive values, you should consider using a secret
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management solution like **[HashiCorp's Vault](https://www.vaultproject.io/)**.
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While it is possible to secure values in Consul's KV store, Vault provides a
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more robust interface for secret management.
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To only update a key if it has not been modified since a given index, specify
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the `-cas` and `-modify-index` flags:
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```
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$ consul kv get -detailed redis/config/connections | grep ModifyIndex
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ModifyIndex 456
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$ consul kv put -cas -modify-index=123 redis/config/connections 10
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Error! Did not write to redis/config/connections: CAS failed
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$ consul kv put -cas -modify-index=456 redis/config/connections 10
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Success! Data written to: redis/config/connections
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```
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To specify flags on the key, use the `-flags` option. These flags are completely
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controlled by the user:
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```
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$ consul kv put -flags=42 redis/config/password s3cr3t
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Success! Data written to: redis/config/password
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```
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To create or tune a lock, use the `-acquire` and `-session` flags. The session must already exist (this command will not create it or manage it):
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```
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$ consul kv put -acquire -session=abc123 redis/lock/update
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Success! Lock acquired on: redis/lock/update
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```
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When you are finished, release the lock:
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```
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$ consul kv put -release -session=acb123 redis/lock/update
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Success! Lock released on: redis/lock/update
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```
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~> **Warning!** If you are trying to build a locking mechanism with these
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low-level primitives, you may want to look at the [<tt>consul
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lock</tt>](/docs/commands/lock.html) command. It provides higher-level
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functionality without exposing the internal APIs of Consul.
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