Is the CLI in the web app like it was in flash? Or do I have to use ssh? I gave ssh try using xmsadmin and it kept saying bad password. I confirmed I was using the correct one by logging in to the client.
The "CLI" was actually just an SSH client, with the added advantage that it auto-logged in for you. Doing an SSH client in a HTML5 UI is somewhere between very difficult and impossible, so we had to remove it from the new version.
You can use any SSH client to do the same, but the login is slightly different than in the GUI which is why you're having problems. You need to first login as "xmsadmin" which has the fixed password of "Xtrem10". This will get you to a second-level username/password prompt, which is where you enter your normal XtremIO credentials.
(For what it's worth, we do it that way so that we don't need to create a Linux-level user for every user - it's simpler and more secure that way)