What else can I try in order to get to my AWS EC2 instance [closed] - linux

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I have an AWS EC2 instance of Ubuntu 14.04. It's been about 6 months since I've logged into it, and now I can't get logged in.
I get Permission denied (Public Key)
The thing is, I backed up my .pem file in 3 places, and none of them work. I'm pretty experienced with AWS, and I've never had this happen before.
The command I'm using is ssh -v -i mykey.pem ubuntu#192.168.0.1
The output I'm getting from the command is this:
OpenSSH_7.1p2, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /usr/local/etc/ssh_config
debug1: Connecting to ec2-192-168-0-1.compute-1.amazonaws.com [192.168.0.1] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: key_load_public: No such file or directory
debug1: identity file mykey.pem type -1
debug1: key_load_public: No such file or directory
debug1: identity file mykey.pem-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.1
debug1: Remote protocol version 2.0, remote software version PaloAltoNetworks_0.2
debug1: no match: PaloAltoNetworks_0.2
debug1: Authenticating to ec2-192-168-0-1.compute-1.amazonaws.com:22 as 'ubuntu'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-sha1 none
debug1: kex: client->server aes128-ctr hmac-sha1 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<7680<8192) sent
debug1: got SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: got SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: ssh-rsa SHA256:Mt8dMlt7QdgQ9kiju3OATK43jnN9oV2pZ4oGZdd46PA
debug1: Host 'ec2-192-168-0-1.compute-1.amazonaws.com' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:34
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: mykey.pem
debug1: Authentications that can continue: publickey
debug1: No more authentication methods to try.
Permission denied (publickey).
I have tried rebooting the machine several times.
I've tried this from 3 different locations, one with no firewall at all, and I get the same thing (except of course the lines about firewalls).
I finally gave up on trying to SSH in, and decided to use the AWS Management Console connect (A Java SSH Client directly from my browser (Java required))
This has failed. It doesn't support Chrome, and when I try from Firefox, it just freezes up, and never does anything...with no error in the browser console (that I can find...I'm kind of noob at browser troubleshooting).
It does the same thing in Edge and IE. I have tried this on all 3 computers, on Ubuntu Desktop, and Windows 10 with no luck.
After that fail, I found somewhere that said I can save it to a snapshot, and start a new instance from that snapshot, and use a different .pem file, just in case all 3 of my copies were somehow magically corrupt. I tried that, and the clone I made wouldn't ever start correctly (1/2 status check).
Is there anything I haven't tried?
EDIT 1
I have also tried changing the permissions of the .pem file to 400 and 600, as well as deleting the known_hosts file. Neither of these proved to be a solution.

Answer 1

Do you have any monitoring on the instance? If the disk filled up, that might explain some of the problems, but Cloudwatch won't be able to tell you how much space is in use. This might explain why an AMI won't boot correctly. You should be able to get to the boot log from the AWS console which might have some information in it. If the problem is disk space, you can launch another instance from your AMI but specify a large disk.
Is it possible that the instance was hacked somehow? If someone took it over, they may have changed/removed the key, or even changed the port sshd is listening to.
If your instance is truly hosed, and you want to get the data off it, you should be able to take a snapshot, create a new volume from that snapshot, and mount the resulting volume on a new instance.

Answer 2

Run
chmod 400 mykey.pem
And then try ssh again. This could be the error for Permission denied (Public Key).
I've had problems when the permissions on my key were to open.