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Default Username for Ubuntu Server AMI Images on Amazon EC2

Ubuntu 12

In this article, we will delve into the topic of default usernames for Ubuntu Server AMI (Amazon Machine Images) on Amazon EC2 (Elastic Compute Cloud). This is a crucial piece of information that is required to connect to your instance after it has been launched.

Quick Answer

The default username for Ubuntu Server AMI images on Amazon EC2 is "ubuntu".

What is an AMI?

An Amazon Machine Image (AMI) is a template that contains a software configuration (for example, an operating system, an application server, and applications). From an AMI, you launch an instance, which is a copy of the AMI running as a virtual server in the cloud.

Default Username for Ubuntu Server AMI

The default username for Amazon AMI images of Ubuntu Server is ubuntu. This means that when you are connecting to your instance using SSH (Secure Shell), you should use the following command:

$ ssh -i your-ssh-key.pem ubuntu@external.dns.name

In the above command, -i specifies the path to your SSH key file, your-ssh-key.pem is the name of your SSH key file, ubuntu is the default username, and external.dns.name is the public DNS of your instance.

Authenticating with SSH Key

It’s important to note that you need to authenticate using the SSH key you injected into the instance at launch, rather than a password. This provides a secure way of logging into your instance without the need for a password. Once authenticated, you can issue password-less root commands with sudo.

Connecting with PuTTY

If you are using PuTTY to connect, the username is still ubuntu and there is no password. You will need to convert the .pem file you received from Amazon into a format that PuTTY can use. More details on this can be found in the AWS documentation.

Simplifying the SSH Command

You can simplify the SSH command by adding your key to ~/.ssh/ and modifying the ~/.ssh/config file. This allows you to use ssh ubuntu@host instead of specifying the key file.

Making ‘ubuntu’ the Default User

If you frequently log in to EC2 hosts using the “ubuntu” user, you can make it the default by adding a section to the ~/.ssh/config file. This allows you to simply type ssh hostname without specifying the user.

Community AMIs

For community AMIs created by Bitnami, the default username is “bitnami”. This information is specific to Bitnami AMIs and may not apply to all Amazon AMIs.

Conclusion

In summary, the default username for Amazon AMI images of Ubuntu Server is “ubuntu”. However, it’s important to check the specific documentation or resources provided by the AMI creator for any variations or specific instructions. By understanding the default username and how to use it, you can effectively manage your EC2 instances and ensure a secure and efficient workflow.

How do I find the public DNS of my instance?

You can find the public DNS of your instance by going to the EC2 Dashboard on the AWS Management Console, selecting your instance, and looking for the "Public DNS (IPv4)" value under the "Description" tab.

Can I change the default username for an Ubuntu Server AMI?

Yes, you can change the default username for an Ubuntu Server AMI. However, it requires modifying the AMI itself before launching an instance. This process is more advanced and may not be recommended for beginners.

Can I log in to my instance using a password instead of an SSH key?

By default, Ubuntu Server AMIs on Amazon EC2 do not allow password authentication. You must use an SSH key for authentication. This is considered a more secure method of logging in.

Can I use a different SSH key for authentication?

Yes, you can use a different SSH key for authentication. When launching an instance, you can specify the SSH key to be used. Make sure you have the private key corresponding to the public key you specified.

How can I convert the .pem file to a format that PuTTY can use?

To convert the .pem file to a format that PuTTY can use, you can use the PuTTYgen tool. Open PuTTYgen, go to "Conversions" in the menu, and select "Import Key". Choose the .pem file and click "Save private key" to convert it to a .ppk file.

Can I use a different username when connecting with PuTTY?

No, when connecting with PuTTY to an Ubuntu Server AMI, you still need to use the default username "ubuntu". The username cannot be changed when using PuTTY.

Are there any other default usernames for Ubuntu Server AMIs?

The default username for Ubuntu Server AMIs on Amazon EC2 is "ubuntu". However, it’s important to note that for community AMIs created by Bitnami, the default username is "bitnami". This may not apply to all Amazon AMIs, so it’s always recommended to check the specific documentation or resources provided by the AMI creator.

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