:D while your steps were very clear i think i fked up.

cryptsetup luksAddKey /dev/mapper/raid /etc/crypttab.d/keyfile-data.bin --new-key-slot 1 gave: Device /dev/mapper/raid is not a valid LUKS device.. I assume this is a typo from your end since /dev/md0 is my luks volume. But altering this gave me: slot is already in use kind of error.

That can be explained since i tested something simular like you suggested earlier. Afterwhich i removed my key i generated and added to the volume. Then i did cryptsetup luksRemoveKey /dev/md0.

Now when i try to add it i get No key available with this passphrase.

I don't have enough knowledge about cryptsetup to know what excactly i did wrong.

Do you by any change have an explaination?

In case this is usefull:

[root@nfs-rocky-1 ~]# cryptsetup luksDump /dev/md0
LUKS header information
Version:       	2
Epoch:         	6
Metadata area: 	16384 [bytes]
Keyslots area: 	16744448 [bytes]
UUID:          	485df758-6cec-49e3-aceb-438aaaedc833
Label:         	(no label)
Subsystem:     	(no subsystem)
Flags:       	(no flags)

Data segments:
  0: crypt
	offset: 16777216 [bytes]
	length: (whole device)
	cipher: aes-xts-plain64
	sector: 4096 [bytes]

Keyslots:
  1: luks2
	Key:        512 bits
	Priority:   normal
	Cipher:     aes-xts-plain64
	Cipher key: 512 bits
	PBKDF:      argon2id
	Time cost:  4
	Memory:     1048576
	Threads:    4
	Salt:       17 c5 ff 7f b9 10 43 41 16 5a c8 28 44 b9 df 64
	            a8 1d 40 41 9f a1 70 85 34 06 52 8d ba 29 bd ef
	AF stripes: 4000
	AF hash:    sha256
	Area offset:290816 [bytes]
	Area length:258048 [bytes]
	Digest ID:  0
  2: luks2
	Key:        512 bits
	Priority:   normal
	Cipher:     aes-xts-plain64
	Cipher key: 512 bits
	PBKDF:      argon2id
	Time cost:  12
	Memory:     1048576
	Threads:    4
	Salt:       64 97 db 49 f1 18 b9 57 3b 02 53 37 b3 11 8e 44
	            71 d1 70 b2 b9 58 4c db e2 6b 36 95 7c dd d2 be
	AF stripes: 4000
	AF hash:    sha256
	Area offset:548864 [bytes]
	Area length:258048 [bytes]
	Digest ID:  0
Tokens:
Digests:
  0: pbkdf2
	Hash:       sha256
	Iterations: 105703
	Salt:       ae ac f1 9f df 47 27 9e 64 28 52 53 9a 9b cd 77
	            74 15 66 f6 8b 3c bd f4 29 dc f1 b1 c5 15 3b f6
	Digest:     07 5f 2f 6b d3 c5 bf b6 54 58 5e b4 44 df 8c b8
	            2b da fa 5c 40 a5 89 cc 0e 3b 70 69 57 d5 7c f5
[root@nfs-rocky-1 ~]#