[Question] SSH agent forwarding on one-off containers?

[David-Guillot]

Hi there,

In the context of a one-off container, after installing the Scalingo CLI (following this example from the docs), in order to get something done with it, I need to perform

scalingo login

In order to achieve that easily, I'd like to be able to reuse my SSH agent. But for now I haven't been able to, and I'm not sure if it's because I missed something or because it's currently not supported.

What I did on my system:

1. In ~/.ssh/config:

   Host *.scalingo.io
     ForwardAgent yes
   
   Host *.scalingo.com
     ForwardAgent yes
   

2. Before launching scalingo run:

   ssh-add ~/.ssh/my_ssh_private_key
   

Yet when I get logged in my Scalingo one-off container (launched with scalingo run --app=myapp bash), after installing the Scalingo CLI, scalingo login refuses to log me in using SSH credentials.

Am I doing something wrong?

Thanks

[EtienneM]

Hi @David-Guillot,

The ideal way for you to get a quick answer on your question would be to contact our support team via the chat available in the Scalingo dashboard.

I'll try to give you some leads:

1. Assuming you use Linux, can you try ssh -T git@ssh.osc-fr1.scalingo.com? This command checks your SSH setup is working. The output should be "You've successfully authenticated on Scalingo, but there is no shell access" (https://doc.scalingo.com/platform/getting-started/setup-ssh-linux#check-everything-is-working)
2. You shouldn't need anything specific in ~/.ssh/config, even though it looks good (you can remove the scalingo.io entry).
3. ssh-add ~/.ssh/my_ssh_private_key may be needed, but only once. If you need to execute it every time there is something strange with your SSH agent.

Yet when I get logged in my Scalingo one-off container (launched with scalingo run --app=myapp bash), after installing the Scalingo CLI, scalingo login refuses to log me in using SSH credentials.

I'm not sure I understand this last part of your message. Could you try to rephrase to describe differently the steps you took, and copy-paste the exact output you have?

[David-Guillot]

Hi @EtienneM , thanks for your quick response. I'll get in touch with the support team.

For the sake of documenting this thing here:

can you try ssh -T git@ssh.osc-fr1.scalingo.com?

It's working successfully ✔️

And yeah sorry the last part of my message wasn't clear ; what I want to achieve is creating a one-off container from within another one-off container (the idea is to transfer files from an application to another one, without having to setup an external storage), without having to enter my login/password.

So here is what I do:

1. On my local:

   scalingo run --app {my-app-name} bash

2. In the one-off container:

   install-scalingo-cli
   scalingo run --app {my-other-app-name} bash

And here is the output I get:

Trying login with SSH…
! SSH connection failed.
Trying login with user/password:

Username or email:

This is why I thought I should do something to explicitly setup SSH agent forwarding. But nothing I tried did the trick.