thanhtunguet/ssh repository overview

⁠SSH Container for Kubernetes

This repository provides a Docker container configured to run an SSH server. The container is designed to be deployed in a Kubernetes cluster and used for secure access to nodes within the cluster’s network. This approach is particularly useful for scenarios where you need to manage or debug applications and infrastructure inside a Kubernetes environment.

⁠Idea and Workflow

When deploying a server or system for a client using Kubernetes/Rancher, you can leverage Rancher's support for Kubernetes API through its authentication mechanism and token. By doing so, you can download the kubeconfig file of the cluster and use kubectl locally to interact with any cluster connected to Rancher.

⁠How It Works

1. Deploy the SSH Container: Deploy this SSH container to your Kubernetes cluster. The container will run an SSH server that listens on a specific port.

2. Port Forwarding: Use kubectl port-forward to forward the SSH port from the container to your local machine. This allows you to securely access the container’s SSH server from your local machine.

3. SSH Access: Once the port is forwarded, you can SSH into the container using SSH keys. The container's default user is root, and it does not have a password.

⁠Deployment Instructions

⁠Prerequisites

• Kubernetes cluster managed by Rancher.
• Rancher access with the ability to download the kubeconfig file.
• kubectl installed on your local machine.
• SSH public key to be used for authentication.

⁠Building the Docker Image

1. Clone this repository:

   git clone https://github.com/your-repository/ssh-container.git
   cd ssh-container
   

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2. Build the Docker image:

   docker build -t your-dockerhub-username/ssh-container:latest .
   

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⁠Creating a ConfigMap for SSH Keys

1. Create a ConfigMap that contains your SSH public key. Save the following YAML to a file named ssh-keys-configmap.yaml:

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: ssh-keys
   data:
     authorized_keys: |
       ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEArwKz... [email protected]
   

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   Replace ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEArwKz... [email protected] with your actual SSH public key.

2. Apply the ConfigMap to your Kubernetes cluster:

   kubectl apply -f ssh-keys-configmap.yaml
   

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⁠Deploying the Container to Kubernetes

1. Create a Kubernetes deployment file, ssh-deployment.yaml, with the following content:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: ssh-container
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: ssh-container
     template:
       metadata:
         labels:
           app: ssh-container
       spec:
         containers:
           - name: ssh-container
             image: your-dockerhub-username/ssh-container:latest
             ports:
               - containerPort: 22
             volumeMounts:
               - name: ssh-keys
                 mountPath: /root/.ssh/authorized_keys
                 subPath: authorized_keys
         volumes:
           - name: ssh-keys
             configMap:
               name: ssh-keys
   

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2. Apply the deployment to your Kubernetes cluster:

   kubectl apply -f ssh-deployment.yaml
   

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3. Forward the SSH port from the container to your local machine:

   kubectl port-forward deployment/ssh-container 2222:22
   

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⁠Accessing the Container

Once port forwarding is set up, you can SSH into the container using the following command:

ssh root@localhost -p 2222

Make sure that your SSH private key matches the public key stored in the ConfigMap.

⁠Dockerfile

The Dockerfile included in this repository is configured to set up an SSH server in a Debian-based image. Here’s a brief overview of the Dockerfile:

FROM debian:11-slim

RUN apt-get update && apt-get install openssh-server curl wget htop telnet dnsutils net-tools nano vim -y

WORKDIR /usr/local/bin/

COPY docker-entrypoint.sh ./
RUN chmod a+x docker-entrypoint.sh

RUN echo "GatewayPorts yes" >> /etc/ssh/sshd_config

CMD ["/usr/local/bin/docker-entrypoint.sh"]

The Dockerfile installs necessary packages, sets up the SSH server configuration, and specifies the entrypoint script.

⁠License

This project is licensed under the MIT License. See the LICENSE⁠ file for details.

⁠Contributing

Contributions are welcome! Please open an issue or submit a pull request if you have suggestions or improvements.