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Description

This error indicates an issue with the ACL (Access Control List) command in Redis. It occurs when the provided subcommand is unrecognized or when required arguments are missing during ACL command execution.

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Error Message

ERR Unknown ACL subcommand

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Known Causes

4 known causes

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Typographical Error

The ACL subcommand was misspelled, leading to Redis not recognizing the intended operation.

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Missing Arguments

The ACL subcommand requires specific arguments that were not provided, resulting in an incomplete command.

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Incorrect Version

The specific ACL subcommand used is not supported in the version of Redis being used.

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ACL Disabled

ACL functionality might be disabled in the Redis configuration, rendering ACL commands invalid.

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Solutions

4 solutions available

1. Verify ACL Subcommand Syntax and Existence easy

This solution involves checking the Redis documentation to ensure the correct subcommand is being used and that it's supported by the Redis version. It also addresses potential typos.

1

Consult the official Redis ACL documentation for your specific Redis version. Common ACL subcommands include `SETUSER`, `GETUSER`, `DELUSER`, `LIST`, `SAVE`, `LOAD`, `GENPASS`, `HELP`.

https://redis.io/commands/acl/

2

Carefully review the command you are trying to execute. Ensure there are no typos in the subcommand. For example, `ACL SETUSER` is correct, while `ACL SETUSR` would be incorrect.

redis-cli> ACL SETUSER myuser on >mypass ~* +@all

3

If you are using a custom script or application, double-check how the ACL command is constructed to avoid any programmatic errors.

Example Python snippet:

```python
r = redis.Redis(decode_responses=True)
r.execute_command('ACL', 'SETUSER', 'myuser', 'on', '>mypass', '~*', '+@all')
```

2. Ensure Required Arguments are Provided easy

The 'Unknown ACL subcommand' error can also occur if the subcommand is valid but is missing essential arguments. This solution focuses on verifying that all necessary parameters are supplied.

1

Refer back to the Redis ACL documentation for the specific subcommand you are using. Each subcommand has a defined set of required arguments.

For example, `ACL SETUSER` requires at least a username and potentially authentication information and permissions.

2

Check the command execution to confirm all required arguments are present. For instance, if you tried `ACL SETUSER myuser`, it might fail because it's missing authentication or permission details.

redis-cli> ACL SETUSER myuser on

3

Correct the command by adding the missing arguments. For `ACL SETUSER`, a minimal correct command might look like this:

redis-cli> ACL SETUSER myuser on >mypass

4

If you're using `ACL GENPASS`, ensure you specify the desired length. For example, `ACL GENPASS 64`.

redis-cli> ACL GENPASS 64

3. Check Redis Version Compatibility medium

ACLs were introduced in Redis 6.0. If you are using an older version of Redis, ACL commands will not be recognized. This solution involves checking your Redis version and upgrading if necessary.

1

Determine your current Redis server version. You can do this by connecting to your Redis instance using `redis-cli` and executing the `INFO` command, then looking for the `redis_version` field.

redis-cli> INFO server
# Server
redis_version:5.0.9

2

Compare your Redis version with the version where ACLs were introduced. ACLs are available from Redis 6.0 onwards.

If `redis_version` is less than 6.0, ACL commands will not work.

3

If your Redis version is older than 6.0, plan and execute an upgrade to Redis 6.0 or a later version. Consult the official Redis documentation for upgrade procedures specific to your operating system and deployment method.

Refer to the Redis upgrade guide: https://redis.io/topics/admin#upgrading-redis

4

After upgrading, reconnect to your Redis instance and try the ACL command again.

redis-cli> ACL SETUSER default on

4. Troubleshoot Redis Configuration for ACLs advanced

While less common for 'Unknown ACL subcommand', certain Redis configuration settings or issues with the ACL configuration file itself could potentially lead to unexpected behavior. This solution involves checking the Redis configuration and ensuring ACLs are properly enabled and accessible.

1

Locate your Redis configuration file (e.g., `redis.conf`). Ensure that `aclfile` is commented out or points to a valid file if you are using a separate ACL file. If `aclfile` is not set, Redis uses its default internal ACL management.

In `redis.conf`:
# aclfile /etc/redis/acl.conf
# Or if not present, it uses internal ACLs.

2

If you are using a separate `aclfile`, verify that the file exists, is readable by the Redis user, and contains valid ACL syntax. An invalid entry or permission issue in the `aclfile` could cause problems, though typically it would result in different errors than 'Unknown ACL subcommand'.

Check file permissions:
ls -l /etc/redis/acl.conf

3

Restart Redis after making any changes to the configuration file to ensure the new settings are loaded.

sudo systemctl restart redis

4

If you suspect issues with the Redis server process itself, review Redis server logs for any related errors or warnings that might provide more context.

Check Redis logs, often located at `/var/log/redis/redis-server.log` or accessible via `journalctl -u redis`.

Fix Redis Error ACL: Unknown Subcommand