Deploying Magic Castle (virtual slurm cluster)

Magic Castle, developed by the Digital Research Alliance of Canada (formerly Compute Canada), is a terraform template to deploy a virtual slurm cluster. This template has been adapted to launch easily in CACAO.


You will need to setup the following before you deploy any cloud resource using CACAO:

  • Jetstream cloud credentials (aka application credential)
  • your public ssh key

Instructions on installing your first Jetstream cloud credential and adding ssh key in CACAO can be found here.

Magic Castle requires several OpenStack resources, which may impact your quota limits. Here is a summary on minimum resources:

  • 1 floating IP
  • 3 security groups
  • 1 network
  • 1 subnet
  • 1 router
  • 3 volumes
  • 3 instances
  • 8 VCPUs
  • 7 neutron ports
  • 12 GB of RAM
  • 8 security rules
  • 80 GB of volume storage

See this page for more information on these limits. You may need to request a quota increase from Jetstream2 staff if you do not have enough quota.


The steps below will guide you through the process of deploying a Magic Castle (virtual slurm cluster)

  1. Go to Deployments menu in CACAO
  2. If you have more than one ACCESS allocation, you should select the ACCESS project in the left drop down menu.
  3. Select “Add Deployment” from the top right corner.
  4. Click on launch Compute Canada Magic Castle from the list of available templates. You may need to scroll down to find it.

template list

  1. Click the Next button
  2. In the dialog:

    1. Choose your Region
    2. Give a Cluster Name
    3. Select a Boot Image


    You must select either AlmaLinux 8/9 or Rocky 8/9 image

    1. Management Nodes: select the number and size of your management node(s)
    2. Login Nodes: select the number and size of your login node(s)
    3. Worker Nodes: select the number and size of your compute nodes
    4. Size of the NSF Home Volume: enter the size of the home volume in GB
    5. Size of the NSF Project Volume: enter the size of the project volume in GB
    6. Size of the NSF Scratch Volume: enter the size of the scratch volume in GB
    7. Select the number of guest users


    Guest users will be named user1, user2, etc

    1. Enter a guest user shared password or leave blank to generate a random password


    All guest users will use the same password. The usernames and password will be repeated in the accounts.txt file (see below)

magic castle parameters

  1. Click the Next button
  2. After reviewing the parameters, click the “Submit” button
  3. Get a cup of coffee and wait for the deployment to be “Active”. You can monitor the progress of the deployment in the “Deployments” menu.

Accessing your Magic Castle Cluster as the “Sudo” user

When your Magic Castle deployment is “Active”, you have two options to access the cluster as an “sudo” user, the account with elevated privileges.

Option 1: Web Shell

  1. In the Deployments list, click on your deployment
  2. Click on the “Web Shell” button for the login node (see image)

magic castle webshell

Option 2: Using an SSH Client

  1. In the Deployments list, click on your deployment
  2. Copy the public ip address for the login node (see image)
  3. Using an external ssh client with access to your private key that is associated with a public key imported into CACAO, goto: <username>@<public-ip-address>. For example, if your access ci identity (and cacao username) is and the public ip is, then your ssh login to the login node will be wildcat@

magic castle public ip

Verifying that your Magic Castle Cluster is ready to use

  1. When you web shell or ssh into your Magic Castle cluster login node, you should see a message similar to screenshot below.

magic castle terminal

  1. You should see the following information:
    1. The current state of your Magic Castle cluster. The state should be “Ready” when ready, and “Not Ready” when not.
    2. The cli command to re-check the Magic Castle Cluster: mccheck.
    3. The path to the accounts.txt file that contains both the number of guest users and the shared guest user password.

Giving access to your Guest Users

Guest users can access the Magic Castle cluster using an ssh client. The guest user accounts are autogenerated (e.g. user1, user2, etc) and will use the same password. The password is stored in the accounts.txt file in the home directory of the “sudo” user.