I have inherited a webserver on AWS running an EC2 instance
which is inherited via CloudFront.
I want to SSH in, but there is no keypair assigned to the EC2 instance.
The previous dev is not very helpful - all he told me was "use cloudfront".
Looking into CloudFront - I saw nothing that indicated I could SSH in that
way. Did I miss something?
Is it possible for me to access the instance via SSH without a private key
via Cloudfront?
I would appreciate any help
You can't ssh into your instance through CloudFront. If you don't have the private key to ssh, there are some options you can use:
Try EC2 Instance Connect which is a web-based ssh client. It will not ask for private key, if it works.
Try AWS Systems Manager Session Manager which is also web client. This will work even if the instance was launched without any ssh client. You will need to read up on how to set it up as it requires special instance role, and the ability of the instance to connect to the SSM service.
Use AWSSupport-ResetAccess SSM Automation to reset the ssh key for the instance.
Use recovery instance as shown in the official AWS video.
The best options would be to try 2 and 1. But depending on how the instance is setup, is it in private or public subnet, does it have internet access, is it Amazon Linux 2 or some non-standard AMI, what kind of roles it has, etc., you may need to perform extra steps to make it work.
Options 3 and 4 will require downtime and making backup before you attempt them would be good choice. Options 1 and 2 may work without any downtime, depending on the instance current setup.
Related
When I go through the documents, using session manager we can connect instance in private subnet without having bastion host itself [direct port forwarding from local to private ec2].
But in RDS case, even though we are making connection using session manager we need a EC2 instance in between local and private RDS.
Could you anyone explain me why it is like that? please share some document that explains that as well.
AWS Systems Manager Session Manager allows you to connect to an instance in a Private Subnet because the instance is actually running an 'SSM Agent'. This piece of code creates an outbound connection to the AWS Systems Manager service.
Then, when you request a connection to the instance, your computer connects to the AWS Systems Manager service, which forwards the request to the agent on the instance. The AWS Systems Manager service is effectively acting as a Bastion for your connection.
AWS Systems Manager Session Manager cannot provide a connection to an Amazon RDS server because there is no ability to 'login' to an Amazon RDS server. Given that your RDS server is running in a Private Subnet, it is therefore necessary to port-forward via an EC2 instance in the same VPC as the RDS server. This can be done via a traditional Bastion EC2 instance in a Public Subnet, or via an EC2 instance in a Private Subnet by taking advantage of the Port Forwarding capabilities of AWS Systems Manager Session Manager.
I have got answered the same question in the AWS repost by #Uwe K. Please refer below.
SSM allows many more functions - and changes! - to an instance then just connecting to it. Having full SSM functionality on an RDS instance thus would undermine the Shared Responsibility Model we use for RDS (you could also say: it would violate the "Black Box" principle of RDS). Therefore, you need an intermediary instance that forwards the TCP Port exposed by RDS to your local machine.
Further reading:
The RDS-specific Shared Responsibility Model is explained here https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/UsingWithRDS.html
a general overview of the Shared responsibility model https://aws.amazon.com/compliance/shared-responsibility-model/
In order to connect to any EC2 instance with AWS systems manager, the SSM agent must be installed on that machine and the appropriate permissions need to be set up for the instance.
At the moment, AWS does not support this to RDS directly. In order for them to support such a setup, they'd probably need to install the agent on all RDS instances which generates quite some overhead and who knows what else the complexities of such a setup would have.
So at the present moment the most effective way to connect is setting up a tunnel via an EC2 instance.
I need that all instances that I launch in a public subnet of a VPC can access via SSH without providing a .pem, just with its private IP. Additionally, I need to create an OpenVPN server in one of them so anyone that can access to the subnet via VPN can access to any instance via SSH without providing a .pem using its private IP too.
I do not know if this is possible, but if there is another way to do that I would appreciate it if you could tell me.
Yes, it's possible, you can access your instances without .pem file by using AWS System Manager.
Use Session Manager service of AWS System manager through the AWS console page.
Session Manager: Users who want to connect to an instance with just one click from the browser or AWS CLI without having to provide SSH keys.
A user who wants to monitor and track instance access and activity, close down inbound ports on instances or enable connections to instances that do not have a public IP address.
I am setting up a new EC2 Amazon Linux 2 AMI and am having a try at setting up EC2 Instance Connect as it's preinstalled on my new instance.
From what I've understood the docs to mean, I should be able to create an IAM user, add a public key to that user and then SSH into the box using the IAM user's (public) key without having to create the .ssh folder on the EC2 instance.
What I've done is:
Create a user on the EC2 instance which my IAM user should map to (let's call him bob)
Uploaded my public OpenSSH key to the IAM user
Created a permission policy which allows the action ec2-instance-connect:SendSSHPublicKey (as per the docs)
Once these are all done, if I try to SSH into the box, it doesn't work and in my /var/log/secure I see a preauth failure.
If I create the .ssh/authorized_keys file and set the permissions correctly, everything works fine.
However, my understanding of the EC2 Instance Connect approach is that it gives me a central way to manage public-key based access to my instances.
Am I correct?
Am I missing something in how I'm setting this up?
I'm finding the documentation a little unclear, so some insight would be helpful.
Thank!
EC2 Instance Connect works as follows:
You issue a command that pushes a temporary public key to the instance, such as:
$ aws ec2-instance-connect send-ssh-public-key --instance-id i-001234a4bf70dec41EXAMPLE --availability-zone us-west-2b --instance-os-user ec2-user --ssh-public-key file://my_rsa_key.pub
You then establish an SSH connection to the instance using the private half of the keypair
Within the instance, the EC2 Instance Connect software interfaces with the ssh process and checks whether the SSH key provided matches the public key that was pushed with send-ssh-public-key (and it is within 60 seconds of receiving that key)
If they match, the SSH session is permitted
See: Connect Using EC2 Instance Connect - Amazon Elastic Compute Cloud
EC2 Instance Connect also provides a web-based interface that can both initiate the above process (using a temporary random keypair) and provide an SSH interface. When doing so, the SSH connection appears to come from within AWS, not your own IP address. This is because the web interface uses HTTPS to AWS, then AWS establishes the SSH connection to the instance. This has an impact on security group configuration.
I have an instance and s3 bucket in AWS (which I'm limiting to a range of IPs). I'm wanting to create a VPN and be able to authenticate myself while trying to log into that VPN to get to that instance.
To simplify, I'm trying to set up a dev environment for my site. I'm wanting to make sure I can limit access to that instance. I'm wanting to use a service to authenticate anybody wanting to get to that instance. Is there a way to do all of this in AWS?
Have you looked at AWS Client VPN:
https://docs.aws.amazon.com/vpn/latest/clientvpn-admin/what-is.html
This allows you to create a managed VPN server in your VPC which you can connect to using any OpenVPN client. You could then allow traffic from this vpn to your instance using security group rules.
Alternatively you can achieve the same effect using OpenVPN on an EC2 server, available from the marketplace:
https://aws.amazon.com/marketplace/pp/B00MI40CAE/ref=mkt_wir_openvpn_byol
Requires a bit more set up but works just fine, perfect if AWS Client VPN isn't available in your region yet.
Both these approaches ensure that your EC2 instance remains in a private subnet and is not accessible directly from the internet. Also, the OpenVPN client for mac works just fine.
I've installed SSM Agent (2.2.607.0) on Windows Server 2012 R2 Standard instance with the EC2 Config (4.9.2688.0). After installing it, i cannot see the server on the Managed Instances screen. I did the same steps on other servers (Windows and Linux) and it worked.
Tried to uninstall the EC2 Config, reinstalled it again with no luck. Tried to install a different SSM Agent version (2.2.546.0) with no luck also.
Any thoughts?
The agent is installed, but the instance still needs the proper role to communicate with the systems manager. Particularly this step of Configuring Access to Systems Manager.
By default, Systems Manager doesn't have permission to perform actions
on your instances. You must grant access by using an IAM instance
profile. An instance profile is a container that passes IAM role
information to an Amazon EC2 instance at launch.
You should review the whole configuration guide and make sure you have configured all required roles appropriately.
I had this problem, and of the four troubleshooting steps - SSM Agent, IAM instance role, Service Endpoint connectivity, Target operating system type, it turned out that the problem was endpoint connectivity.
My VPC, Subnet, route table, and internet gateway all looked correct (and were identical to another instance which was being managed by SSM). But the instance didn't have a public IP, and without that you can't use the IGW. You can't use a VPC endpoint and an Internet Gateway. So adding a public IP allowed the instance to connect to SSM and become managed.
Extra complication : I was trying to use EC2 Image Builder, which creates an instance without a public IP. So there is no way to use Image Builder in a VPC which has an Internet Gateway.
New SSM agent version comes with a diagnostic package.. You can run that to see which prerequisites is missing.
https://docs.aws.amazon.com/systems-manager/latest/userguide/ssm-cli.html