fixing-vagrant-ssh-issues.md

If you've had to re-associate your virtual machine with vagrant, but vagrant ssh now requires a password to connect, this is because the ssh key associated with the box disappeared. You can still get in with the password vagrant (usually), but many workflows will need the automatic connection.

Here's how to regain public/private key authentication to ssh into your vagrant virtual machine:

Run vagrant up, then vagrant ssh-config to find the IdentityFile:

$ vagrant ssh-config
Host default
  HostName 127.0.0.1
  User vagrant
  Port 2222
  UserKnownHostsFile /dev/null
  StrictHostKeyChecking no
  PasswordAuthentication no
  IdentityFile "/Users/blk/.vagrant.d/insecure_private_key"
  IdentitiesOnly yes
  LogLevel FATAL

cd to the directory of that identity file, and look for a .pub or public file. If it doesn't exist, create one:

$ cd /Users/blk/.vagrant.d/
$ ls -l
drwxr-xr-x  4 blk  staff   136B Apr  5 11:26 boxes/
drwxr-xr-x  8 blk  staff   272B Apr 26 19:10 data/
drwxr-xr-x  9 blk  staff   306B May 26  2015 gems/
-rw-------  1 blk  staff   1.6K May 14  2015 insecure_private_key
-rw-r--r--  1 blk  staff   147B Nov 16 12:13 plugins.json
drwxr-xr-x  3 blk  staff   102B May 14  2015 rgloader/
-rw-r--r--  1 blk  staff     3B May 14  2015 setup_version
drwxr-xr-x  2 blk  staff    68B Apr  5 11:26 tmp/

Note the lack of a public key or a .pub file.

$ file insecure_private_key
insecure_private_key: ASCII text
$ ssh-keygen -y -f insecure_private_key > ./insecure_public_key.pub
$ cat insecure_public_key.pub

And that will output the content of the public key. Copy that with your mouse.

$ vagrant ssh
Enter password:
vagrant@vagrant $ cd ~/.ssh/
vagrant@vagrant $ ls
authorized_keys
vagrant@vagrant $ vim authorized_keys

Then press the [escape] key, type :set paste, press [enter], [g] [g] [O], paste the line you copied, [escape] [:] [w] [q]

Those are the vim instructions; you can do it with nano or pico or emacs or ed or cat if you want; just make sure that the copied text ends up on its own line at the end of the file.

Then exit the vagrant machine and reconnect to test.

vagrant@vagrant $ exit
$ vagrant ssh
vagrant@vagrant $ 

Hey, it works!

---

If this does not work, cd to the folder containing the VM's Vagrantfile while the machine is running. Run ls -al and look for an entry named .vagrant.

If the .vagrant directory exists, cd .vagrant. Then:

/.vagrant$ tree .
.
└── machines
    └── default
        └── virtualbox
            ├── action_provision
            ├── action_set_name
            ├── id
            ├── private_key
            └── synced_folders

3 directories, 5 files

See private_key there? That's going to be useful.

cd machines/default/virtualbox/, then follow the steps listed above, begining with ssh-keygen.

how to config ssh in win10? I can not find authorized_keys

Thank you! Your guide helped me to deal with that!

Please note that this gist was last revised in 2016, and may not be up-to-date with current versions of Vagrant. It assumes a *nix-like box (Linux, OSX) as a host.