A quick discovery of mine today – a colleague needed to ssh directly onto the overcloud from a system other than the seed vm or undercloud nodes. Those in the know would quickly say “simples” – just copy the private key from the undercloud server /root/.ssh/id_rsa to the ssh client and login using the heat-admin user along with this key.

I tried this quickly on my windows laptop with Putty.exe and got the following error – “Unable to use key file…”

 Switch over to Linux and the problem disappears –

It turns out that Putty requires a proprietary certificate and does not accept a standard OpenSSH key.

The fix is quick and easy though – so long as you trust Puttygen.exe. Run this application and then select “Load an existing private key  file” button and select the id_rsa file downloaded from the undercloud. Once imported save the ‘new’ puttified key.

Use this new key file with Putty.exe on windows and now you should be able to login to the overcloud remotely –