UPDATE: This is likely because cloud-init is failing to get information from the various sources it can get information from.
For the people of the future, the ones who get an error message about connections being reset by peer when trying to ssh into a server, check to see if the server does indeed have server keys in /etc/ssh.
I spent like an hour or more looking into this. I’m not sure why, but an Ubuntu image I was using wouldn’t create the servers ssh keys, though the files were there…they were of zero size.
Below is an example of an attempted connection.
root@client# ssh -vvvv ubuntu@192.168.122.217
OpenSSH_5.9p1 Debian-5ubuntu1.1, OpenSSL 1.0.1 14 Mar 2012
debug1: Reading configuration data /root/.ssh/config
debug1: /root/.ssh/config line 1: Applying options for 192.168.122.*
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.122.217 [192.168.122.217] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.5p1 Ubuntu-4
debug1: match: OpenSSH_6.5p1 Ubuntu-4 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9p1 Debian-5ubuntu1.1
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "192.168.122.217" from file "/dev/null"
debug3: load_hostkeys: loaded 0 keys
debug1: SSH2_MSG_KEXINIT sent
Read from socket failed: Connection reset by peer
To fix this I regenerated the keys on the server (by logging into the console) and restarted. Then I was able to ssh into the server.
root@server# ssh-keygen -q -f /etc/ssh/ssh_host_key -N '' -t rsa1
root@server# ssh-keygen -f /etc/ssh/ssh_host_rsa_key -N '' -t rsa
root@server# ssh-keygen -f /etc/ssh/ssh_host_dsa_key -N '' -t dsa
root@server# service ssh restart
I have no idea why this is happening in this image. Obviously something is broken.