how to login to ec2 machine? - ssh

Question

I was given some login information for an EC2 machine, basically an ec2-X-X-X.compute-X.amazonaws.com plus a username and password.
How do I access the machine? I tried sshing:
ssh username#ec2-X-X-X.compute-X.amazonaws.com
but I get a Permission denied, please try again. when I enter the password. Is sshing the right way to access the EC2 machine? (Google hits I found suggested that you could ssh into the machine, but they also used keypairs.) Or is it more likely that the problem is that I was given invalid login credentials?

Answer 1

If you are new to AWS and need to access a brand new EC2 instance via ssh, keep in mind that you also need to allow incoming traffic on port 22.
Assuming that the EC2 instance was created accepting all the default wizard suggestions, access to the machine will be guarded by the default security group, which basically prohibits all inbound traffic. Thus:
Go to the AWS console
Choose Security Groups on the left navigation pane
Choose default from the main pane (it may be the only item in the list)
In the bottom pane, choose Inbound, then Create a new rule: SSH
Click Add rule and then Apply Rule Changes
Next, assuming that you are in possession of the private key, do the following:
$ chmod 600 path/to/mykey.pem
$ ssh -i path/to/mykey.pem root#ec2-X-X-X.compute-X.amazonaws.com
My EC2 instance was created from a Ubuntu 32-bit 12.04 image, whose configuration does not allow ssh access to root, and asks you to log in as ubuntu instead:
$ ssh -i path/to/mykey.pem ubuntu#ec2-X-X-X.compute-X.amazonaws.com
Cheers,
Giuseppe

Answer 2

Our Amazon AMI says to "Please login as the ec2-user user rather than root user.", so it looks like each image may have a different login user, e.g.
ssh -i ~/.ssh/mykey.pem ec2-user#ec2-NN-NNN-NN-NN.us-foo-N.compute.amazonaws.com
In short, try root and it will tell you what user you should login as.
[Edit] I'm supposing that you don't have AWS management console credentials for the account, but if you do, then you can navigate to the EC2->Instances panel of AWS Management Console, right click on the machine name and select "Connect..." A list of the available options for logging in will be displayed. You will (or should) need a key to access an instance via ssh. You should have been given this or else it may need to be generated.
If it's a Windows instance, you may need to use Remote Desktop Connection to connect using the IP or host name, and then you'll also need a Windows account login and password.

Answer 3

The process of connecting to an AWS EC2 Linux instance via SSH is covered step-by-step (including the points mentioned below) in this video.
To correct this particular issue with SSH-ing to your EC2 instance:
The ssh command you ran is not in the correct format. It should be:
ssh -i /path/my-key-pair.pem ec2-user#ec2-198-51-100-1.compute-1.amazonaws.com
Note, you need access to the private key (.pem) file to use in the command above. AWS prompts you to download this file when you first launch your instance. You will need to run the following command to ensure that only your root user has read-access to it:
chmod 400 /path/to/yourKeyFile.pem
Depending on your Linux distribution, the user you need to specify when you run ssh may be one of the following:
For Amazon Linux, the user name is ec2-user.
For RHEL, the user name is ec2-user or root.
For Ubuntu, the user name is ubuntu or root.
For Centos, the user name is centos.
For Fedora, the user name is ec2-user.
For SUSE, the user name is ec2-user or root.
Otherwise, if ec2-user and root don't work, check with your AMI provider.
You need to enable an inbound SSH firewall. This can be done under the Security Groups section of AWS. Full details for this piece can be found here.

Answer 4

For this you need to be have a private key it's like keyname.pem.
Open the terminal using ctrl+alt+t.
change the file permission as a 400 or 600 using command chmod 400 keyname.pem or chmod 600 keyname.pem
Open the port 22 in security group.
fire the command on terminal ssh -i keyname.pem username#ec2-X-X-X.compute-X.amazonaws.com

Answer 5

Indeed EC2 (Amazon Elastic Compute Cloud) does not allow password authentication to their instances (linux machines) by default.
The only allowed authentication method is with an SSH key that is created when you create the instance. During creation they allow you to download the SSH key just once, so if you loose it, then you have to regenerate it.
This SSH key is only for the primary user - usually named
"ec2-user" (Amazon Linux, Red Hat Linux, SUSE Linux)
"root" (Red Hat Linux, SUSE Linux)
"ubuntu" (Ubuntu Linux distribution)
"fedora" (Fedora Linux distribution)
or similar (depending on distribution)
See connection instructions: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AccessingInstances.html
If you want to add a new user the recommended way is to generate and add a new SSH key for the new user, but not specify a password (which would be useless anyway since password authentication is not enabled by default).
Managing additional users: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/managing-users.html
After all if you want to enable password authentication, which lowers down the security and is not recommended, but still you might need to do that for your own specific reasons, then just edit
/etc/ssh/sshd_config
For example:
sudo vim /etc/ssh/sshd_config
find the line that says:
PasswordAuthentication no
and change it to
PasswordAuthentication yes
Then restart the instance
sudo reboot
After restarting, you are free to create additional users with password authentication.
sudo useradd newuser
sudo passwd newuser
Add the new user to the sudoers list:
sudo usermod -a -G sudo newuser
Make sure user home folder exists and is owned by the user
sudo mkdir /home/newuser
sudo chown newuser:newuser /home/newuser
New you are ready to try and login with newuser via ssh.
Authentication with ssh keys will continue to work in parallel with password authentication.