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Heads up: Deployment with newly generated SSH key (using ED25519) might fail

Fabian Schwarz
March 09, 2023Software engineer at makandra GmbH

If you use a newer SSH key generated with the ED25519 algorithm instead of RSA (see Create a new SSH key pair), the deployment with Capistrano may fail with the following message:

The deploy has failed with an error: unsupported key type `ssh-ed25519'
net-ssh requires the following gems for ed25519 support:
 * ed25519 (>= 1.2, < 2.0)
 * bcrypt_pbkdf (>= 1.0, < 2.0)
See for more information
Gem::LoadError : "ed25519 is not part of the bundle. Add it to your Gemfile."
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As described in the error message, the ed25519 and bcrypt_pbkdf gems must be added to the Gemfile to solve the problem. Now, the deployment should work faultlessly again.

Posted by Fabian Schwarz to makandra dev (2023-03-09 10:17)