Ruby script Net::SSH::HostKeyMismatch but ssh works

Question

I can ssh into a remote host on my aws network but using net/ssh fails in a ruby script. my gem is net-ssh(4.2.0) on Ubuntu 16.04. It doesn't prompt for a passphrase even with non_interactive => false.

error:

Authentication failed for user Net::SSH::AuthenticationFailed

Why does this code fail?

#!/usr/bin/env ruby
require 'rubygems'
require 'net/ssh'

HOST = 'myhost'

Net::SSH.start(HOST,
:auth_methods => ['publickey'],
:passphrase => 'mypassphrase',
:non_interactive => true,
:host_key => "ssh-rsa",
:keys => [ '/home/markhorrocks/.ssh/id_rsa' ]
 ) do |session|
  output = session.exec!('ls')
  puts output
 end

After editing my code to this I get error

(Net::SSH::HostKeyMismatch)

HOST = 'myhost'
USER = 'markhorrocks'

Net::SSH.start(HOST, USER,
:auth_methods => ['publickey'],
:passphrase => 'mypassphrase',
:non_interactive => true,
:host_key => "ssh-rsa",
  :encryption => "blowfish-cbc",
:keys => [ '/home/markhorrocks/.ssh/id_rsa' ],
:port => '1234',
:forward_agent => true,
  :compression => "[email protected]"
 ) do |session|
  output = session.exec!('ls')
  puts output
 end

What is your question?

sawa
– sawa

2018-05-15 05:59:09 +00:00
Commented May 15, 2018 at 5:59 — sawa
– sawa, Commented May 15, 2018 at 5:59
The error shows my question.

markhorrocks
– markhorrocks

2018-05-15 13:10:09 +00:00
Commented May 15, 2018 at 13:10 — markhorrocks
– markhorrocks, Commented May 15, 2018 at 13:10

coderanger · Accepted Answer · 2018-05-15 01:58:07Z

4

The keys array needs to point at your private key(s). authorized_keys is the public fingerprints for keys allowed to log in to the current host. Also you seem to have put a private key type in for host_key.

answered May 15, 2018 at 1:58

coderanger

54.6k4 gold badges60 silver badges85 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

coderanger Over a year ago

ssh-rsa isn't a host key, it's a key type. Remove that.

markhorrocks · Accepted Answer · 2018-05-16 20:55:51Z

1

Here is my solution:

#!/usr/bin/env ruby

require 'net/ssh'

HOST = 'myhost'
USER = 'markhorrocks'

Net::SSH.start(HOST, USER,
:auth_methods => ['publickey'],
:passphrase => 'mypassphrase',
:non_interactive => true,
:host_key => "ssh-rsa",
:encryption => "blowfish-cbc",
:keys => [ '/home/markhorrocks/.ssh/id_rsa' ],
:port => '1234',
:forward_agent => true,
:verify_host_key => false,
:compression => "[email protected]"
 ) do |session|
       begin
          rescue Net::SSH::HostKeyMismatch => e
          puts "remembering new key: #{e.fingerprint}"
          e.remember_host!
          retry
       end

  output = session.exec!('ls')
  puts output
 end

answered May 16, 2018 at 20:55

markhorrocks

1,61021 gold badges95 silver badges175 bronze badges

Collectives™ on Stack Overflow

Ruby script Net::SSH::HostKeyMismatch but ssh works

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related