[SOLVED] Gitlab CI/CD using ssh / knownhosts error

Issue

I'm trying to use gitlab CI/CD to auto deploy my code, after push on an specific branch (in my case 'staging' branch)

after push on 'staging' branch I see following error on jobs section in gitlab UI:

Running with gitlab-runner 15.0.0 (xxxxxx)
  on deploy xxxxxx
Preparing the "ssh" executor
00:36
Using SSH executor...
ERROR: Preparation failed: ssh command Connect() error: ssh Dial() error: ssh: handshake failed: knownhosts: key is unknown

I can see gitlab from my VM and gitlab-runner registered successfully before.

I've also created ssh key and add it to gitlab-runner installation steps.

Solution

You need to check what SSH URL is used in your case.

Something like [email protected]:me/myProject would look for gitlab.com SSH host keys fingerprints in an ~/.ssh/known_hosts file.

Make sure to add first in gitlab-runner server the following to ~/.ssh/known_hosts:

gitlab.com ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAfuCHKVTjquxvt6CM6tdG4SLp1Btn/nOeHHE5UOzRdf
gitlab.com ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCsj2bNKTBSpIYDEGk9KxsGh3mySTRgMtXL583qmBpzeQ+jqCMRgBqB98u3z++J1sKlXHWfM9dyhSevkMwSbhoR8XIq/U0tCNyokEi/ueaBMCvbcTHhO7FcwzY92WK4Yt0aGROY5qX2UKSeOvuP4D6TPqKF1onrSzH9bx9XUf2lEdWT/ia1NEKjunUqu1xOB/StKDHMoX4/OKyIzuS0q/T1zOATthvasJFoPrAjkohTyaDUz2LN5JoH839hViyEG82yB+MjcFV5MU3N1l1QL3cVUCh93xSaua1N85qivl+siMkPGbO5xR/En4iEY6K2XPASUEMaieWVNTRCtJ4S8H+9
gitlab.com ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBFSMqzJeV9rUzU4kWitGjeR4PWSa29SPqJ1fVkhtj3Hw9xjLVXVYrU9QlYWrOLXBpQ6KWjbjTDTdDkoohFzgbEY=

That will skip manual fingerprint confirmation in SSH.
In other words, no more "knownhosts: key is unknown".

Answered By - VonC

Answer Checked By - Mary Flores (WPSolving Volunteer)