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    Austin Kim

    In the hello_fabric jupyter notebook when I run the “Log into Nodes” code block I get this error.

    “[Errno 2] No such file or directory: ‘/home/fabric/.ssh/id_rsa_fabric'”

    The only thing I’ve added to the code is my bastion username. Is there something else I need to do to make this notebook run?

    Avatar photoPaul Ruth

    You will need to put your private key in the Jupyter container at that path (or some whereelse and change the path in the notebook).

    You can think of the Jupyter container as a personal computer in the “cloud”.  The benefit is that it comes mostly configured for FABRIC.   The only thing you need to do is add your bastion key.

    Another option is to install the FABRIC API on your personal machine (laptop, etc.).  There are some instructions for that here: https://learn.fabric-testbed.net/knowledge-base/install-the-python-api/



    silly question, Paul, but for the noobs here how do you put your private key into the Jupyter container at the path if it’s in the browser?

    Austin Kim

    Just for a quick testing of logins with the keys directly into the servers and through bastion host,
    I created a test server at and inserted UTAH people’s keys into accounts (same usernames for FABRIC) and they can log into this server directly with their ssh-keys.

    ssh -i <SSH_KEY_PRIVATE_PORTION> austinhk_0051496666@

    Once they can login to this server, next step can be to test logins through the bastion host.
    ssh -i <SSH_KEY_PRIVATE_PORTION> -J austinhk_0051496666@bastion-1.fabric-testbed.net austinhk_0051496666@

    If they are able to log in, they can also view the public key we insert to these servers (bastion host and the test server)

    [austinhk_0051496666@Node0 ~]$ cat .ssh/authorized_keys
    < your public key should show here >

    ^ I went through this process and successfully got my public key

    Avatar photoPaul Ruth

    To answer Polina’s question… No, we have not installed you private key in the Jupyter environment (we never had access to your private key).

    More detail can be found in this answer from the other topic: https://learn.fabric-testbed.net/forums/topic/test-server-bastion-host-login/#post-982


    Hi Paul,

    My id_rsa_fabric is called fab_rsa on my local machine and I’ve copied that over to the Jupyter host. I updated the code that you have above to make that one change. And I’m able to build slices, just not able to log in to them. Here’s the stack trace that I’m getting:

    Unknown exception: q must be exactly 160, 224, or 256 bits long
    Traceback (most recent call last):
    File “/opt/conda/lib/python3.9/site-packages/paramiko/transport.py”, line 2109, in run
    handler(self.auth_handler, m)
    File “/opt/conda/lib/python3.9/site-packages/paramiko/auth_handler.py”, line 298, in _parse_service_accept
    sig = self.private_key.sign_ssh_data(blob)
    File “/opt/conda/lib/python3.9/site-packages/paramiko/dsskey.py”, line 108, in sign_ssh_data
    key = dsa.DSAPrivateNumbers(
    File “/opt/conda/lib/python3.9/site-packages/cryptography/hazmat/primitives/asymmetric/dsa.py”, line 244, in private_key
    return backend.load_dsa_private_numbers(self)
    File “/opt/conda/lib/python3.9/site-packages/cryptography/hazmat/backends/openssl/backend.py”, line 826, in load_dsa_private_numbers
    File “/opt/conda/lib/python3.9/site-packages/cryptography/hazmat/primitives/asymmetric/dsa.py”, line 282, in _check_dsa_private_numbers
    File “/opt/conda/lib/python3.9/site-packages/cryptography/hazmat/primitives/asymmetric/dsa.py”, line 274, in _check_dsa_parameters
    raise ValueError(“q must be exactly 160, 224, or 256 bits long”)
    ValueError: q must be exactly 160, 224, or 256 bits long

    Here’s the printed output:
    Node Node1 IP
    q must be exactly 160, 224, or 256 bits long



    Avatar photoPaul Ruth

    Are you able to login from a terminal window?


    In the terminal, I tried

    ssh polinalyub_@ -vvv

    and this is part of the response

    debug1: Offering public key: /home/fabric/.ssh/id_rsa RSA SHA256:j8FrCXHeQrou+3J3NEFD9x+C+6nGiViOl9PKLmZ9cq4
    debug3: send packet: type 50
    debug2: we sent a publickey packet, wait for reply
    debug3: receive packet: type 51


    I worked with Polina today.  She is not able to jump through the bastion and login to the testnode in the process that Mert sent.  She can login to the node with her key without issue.  However, if she tries to use the bastion host, the login fails.  Something seems to be amiss with her username/key pairing on the bastion.  Mert may need to explore and/or do a screen share with her to determine more.





    I worked with Austin today too.  Something is up with his keys as well.  He could no longer pass Mert’s test configuration.  He could not even log in at all to the test host or pass the bastion host.  I had him create new keys and follow up with Mert to request that Mert reset his keys.

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