Amazon EC2 Permission denied (publickey)

Question

This seems to be a common problem but my specific case seems a little different.

I set up a new Amazon EC2 instance using the command line tools and connected via SSH and did some configuration work.

Initially, though, I couldn't ssh on to the instance, I had to stop and restart the instance, then i could connect. Before restarting I just got the response.

Permission denied (publickey). 

That was last night, this morning I go back to the same instance and now all I get is

Permission denied (publickey). 

I've tried rebooting the instance with no joy.

Can anyone point me in the right direction here? The same command that worked last night no longer works, I'm connecting from my Macbook Pro.

Answer 1

I'm going to answer my own question in case anyone else sees the same thing... Last night i had done:

ssh-add ~/.ssh/[keypair name] 

then been connecting with:

ssh ec2-user@[ec2 instance ip] 

This morning I tried the same and couldn't connect. But doing

ssh -i ~/.ssh/[keypair name] ec2-user@[ec2 instance ip] 

gets me in.

Using ssh-add on the key pair again gets me in. I'm guessing ssh-add only works within the shell I'd issued it in. When I closed the terminal window and opened another I no longer had that keypair available without being explicit.

Answer 2

This was happening for me because I wasn't using the right username. I was able to log in when using an AMI used in a tutorial I was following, but when I tried to use a different AMI (ubuntu + LAMP from Bitnami) I would get the Permission denied (public key). error. I finally realized that if I changed the username for the tutorial ami from ubuntu to ec2-user I would get the same error.

So a quick google tells that the username for Bitnami AMIs is bitnami. Problem solved.