How to reset a lost Cassandra admin user's password?

Question

I have full access to the Cassandra installation files and a PasswordAuthenticator configured in cassandra.yaml. What do I have to do to reset admin user's password that has been lost, while keeping the existing databases intact?

Answer 1

The hash has changed for Cassandra 2.1:

1. Switch to authenticator: AllowAllAuthenticator
2. Restart cassandra
3. UPDATE system_auth.credentials SET salted_hash = '$2a$10$H46haNkcbxlbamyj0OYZr.v4e5L08WTiQ1scrTs9Q3NYy.6B..x4O' WHERE username='cassandra';
4. Switch back to authenticator: PasswordAuthenticator
5. Restart cassandra
6. Login as cassandra/cassandra
7. CREATE USER and ALTER USER to your heart's content.

Answer 2

Solved with the following steps:

1. Change authenticator in cassandra.yaml to AllowAllAuthenticator and restart Cassandra
2. cqlsh
3. update system_auth.credentials set salted_hash='$2a$10$vbfmLdkQdUz3Rmw.fF7Ygu6GuphqHndpJKTvElqAciUJ4SZ3pwquu' where username='cassandra';
4. Exit cqlsh
5. Change authenticator back to PasswordAuthenticator and restart Cassandra

Now you can log in with

cqlsh -u cassandra -p cassandra

and change the password to something else.