Run vs code on a private AWS ec2 instance without ssh (with AWS CDK examples)

December 7, 2024•3 min read

Use the browser based vs code for file handling on a private ec2 instance without ssh

Use case

You have a private EC2 instance in your AWS account and you want to edit files outside of the terminal or just with the help of vs code and vs code extensions on this instance without using SSH. CDK is already in place and can be used to provision the necessary resources.

Setup

The following steps are necessary to set up the environment.

Configure SSM Session Manager for the private instance
Installation of the SSM plugin for the AWS CLI
Installation of vs code with the code code-server

Prerequisites

The VPC network setting already exists.
The private subnet has access to the internet

Configure SSM Session Manager for the private instance

The configuration is described here.

The needed VPC endpoints can be created like this:

const subnetsPrivateIsolated = props.vpc.selectSubnets({
  subnetType: SubnetType.PRIVATE_ISOLATED,
});
props.vpc.addInterfaceEndpoint("VpcEndpointSsm", {
  service: InterfaceVpcEndpointAwsService.SSM,
  privateDnsEnabled: true,
  subnets: subnetsPrivateIsolated,
});
props.vpc.addInterfaceEndpoint("VpcEndpointSsmMessages", {
  service: InterfaceVpcEndpointAwsService.SSM_MESSAGES,
  privateDnsEnabled: true,
  subnets: subnetsPrivateIsolated,
});
props.vpc.addInterfaceEndpoint("VpcEndpointEc2Message", {
  service: InterfaceVpcEndpointAwsService.EC2_MESSAGES,
  privateDnsEnabled: true,
  subnets: subnetsPrivateIsolated,
});

Here is a list of AMIs, which has the SSM agent preinstalled: https://docs.aws.amazon.com/systems-manager/latest/userguide/ami-preinstalled-agent.html

The creation of the instance can than look like this:

const roleSsm2Ec2 = new Role(this, "RoleSsm2Ec2", {
  assumedBy: new ServicePrincipal("ec2.amazonaws.com"),
});
this.roleSsm2Ec2.addManagedPolicy(
  ManagedPolicy.fromAwsManagedPolicyName("AmazonSSMManagedInstanceCore"),
);

new Instance(this, "Instance", {
  vpc: props.vpc,
  instanceType: InstanceType.of(InstanceClass.T2, InstanceSize.MICRO),
  machineImage: MachineImage.latestAmazonLinux2023(),
  role: roleSsm2Ec2,
});

The attached role is importent for the SSM Session Manager to work.

Installation of the SSM plugin for the AWS CLI

Before the instance can be accessed via the AWS Systems Manager Session Manager, the AWS CLI needs the SSM plugin. The installation is described here.

Installation of vs code via AWS Systems Manager Session Manager

Now the instance can be accessed via the AWS Systems Manager Session Manager.

aws ssm start-session --target <<instance-id>> --region <<region>>

With the following commands vs code can than be installed.

curl -fsSL https://code-server.dev/install.sh | sh

install code-server

More details here: https://github.com/coder/code-server?tab=readme-ov-file#getting-started

Now run the code-server with the following command:

code-server

run code-server

As you can see, the code-server is running on http://127.0.0.1:8080/ (1.) and the password is in file /home/ssm-user/.config/code-server/config.yaml (2.).

That information are needed to connect to the code-server via the browser.

Connect to vs code via AWS Systems Manager port forwarding

The instance has no public IP and can not be accessed via the browser. But with the help of the AWS Systems Manager port forwarding, the instance can be accessed via the browser.

aws ssm start-session   --region <<region>> \
                        --target <<instance-id>> \
                        --document-name AWS-StartPortForwardingSession \
                        --parameters '{"portNumber":["8080"],"localPortNumber":["9999"]}'

More Details here: https://aws.amazon.com/blogs/aws/new-port-forwarding-using-aws-system-manager-sessions-manager/

Now the code-server can be accessed via the browser with the following URL: http://localhost:9999/

code server login

Now you can handle the files via vs code 🥳

code server file handling