Similar question there: Problem configuring Gitlab CI -> ssh: handshake failed - #3 by cClaude
Here is debug process for this situation.
Verify you can logging to remote ssh server manually using same local user and same key file than gitlab-runner
sudo su - USER
eval `ssh-agent -s`
ssh-add YOUR_SSH_KEY_FILE
ssh REMOTEU_SER@REMOTE_SERVER
You should solve any issue here before continue.
Run gitlab-runner with log in debug mode
sudo vi /etc/gitlab-runner/config.toml
Add log_level = "debug"
# Sample
concurrent = 1
check_interval = 0
log_level = "debug"
...
Then restart gitlab-runner
sudo gitlab-runner restart
Retry to run buggy job.
If it does not help go to next step.
Launch remote sshd in debug mode
Run SSH daemon on another port as a part of the command (then you don’t need to lost your existing session, if already connect thought ssh)
sudo /usr/sbin/sshd -d -p 2200
# sudo /usr/sbin/sshd -dd -p 2200 - if you need more logs
# sudo /usr/sbin/sshd -ddd -p 2200 - if you need all logs
Warn: You should run this for each ssh connection.
Then modify gitlab-runner configuration (on gitlab runner host)
sudo vi /etc/gitlab-runner/config.toml
Add port = "2200"
...
[[runners]]
name = "XXXXX"
url = "https://XXXXX/"
token = "XXXXX"
executor = "ssh"
[runners.ssh]
user = "XXXXX"
host = "XXXXX"
port = "2200"
identity_file = "XXXXX"
...
Retry to run buggy job.
On console sshd console you are able to see all gitlab-runner actions and you should be able to understand what is the issue.
