SSH¶

SSH (Secure Shell) is a network protocol that enables secure remote login and command execution over insecure networks.
Using SSH, users can securely access container instances on the platform from their local machines.

Log in to a Container Instance Using SSH Username/Password¶

In the container instance's terminal, check whether the SSH server is installed.

command -v sshd

If this returns the path to sshd, skip the installation. Otherwise, run cat /etc/os-release to identify the container image's Linux distribution, then run the matching installation command as root.

Linux distribution	Installation command
Debian / Ubuntu	`apt-get update && apt-get install -y openssh-server`
Fedora / Rocky Linux / AlmaLinux	`dnf install -y openssh-server`
CentOS / RHEL images using yum	`yum install -y openssh-server`
Alpine Linux	`apk add --no-cache openssh-server`

After installation, run command -v sshd again to confirm that the server executable is available. Installing only openssh-client or finding ssh in a package list does not confirm that the SSH server is installed.

Before logging in, also ensure that the SSH server is running, using the image's startup mechanism. Installing the package does not mean the service has started, and container images do not necessarily use systemd. See Service Auto-start to configure services in a container instance.

After the container starts, click the SSH Login button in the container instance list to open a dialog with login information.
Use the provided username and password in your local terminal to log in. If successful, you'll see a confirmation message:

After importing your SSH public key in User Center → SSH Keys, newly created or restarted instances will support passwordless login.

Step 1: Check for Existing SSH Public Key¶

Before generating a new SSH key, check if you already have one. SSH key pairs are usually stored in the local user’s home directory.

For Linux/macOS, use the commands below.
Windows users can use WSL (Windows 10+) or Git Bash.

ED25519 key:
```
cat ~/.ssh/id_ed25519.pub
```
RSA key:
```
cat ~/.ssh/id_rsa.pub
```

If a long string starting with ssh-ed25519 or ssh-rsa is returned, a key already exists.
You may skip Step 2 and proceed to Step 3.

Step 2: Generate SSH Key¶

If Step 1 returns nothing, generate a new SSH key:

Open your terminal (on Windows, use WSL or Git Bash) and run ssh-keygen.

Choose the algorithm and optional comment (usually your email address):

For ED25519:

ssh-keygen -t ed25519 -C "<your-comment>"

For RSA:
```
ssh-keygen -t rsa -C "<your-comment>"
```

Press Enter to accept the default save path:

Example (ED25519):
```
Enter file in which to save the key (/home/user/.ssh/id_ed25519):
```
- Private key: /home/user/.ssh/id_ed25519
- Public key: /home/user/.ssh/id_ed25519.pub
Optionally set a passphrase:
```
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
```
You can leave it empty to avoid entering a password every time.
Press Enter to complete the key pair generation.

Step 3: Copy Public Key¶

You can either copy the key manually from the terminal or use one of the following commands depending on your OS:

Windows (in WSL or Git Bash):
```
cat ~/.ssh/id_ed25519.pub | clip
```

macOS:

tr -d '\n' < ~/.ssh/id_ed25519.pub | pbcopy

GNU/Linux (requires xclip):

xclip -sel clip < ~/.ssh/id_ed25519.pub

Step 4: Add SSH Key on the Platform¶

Log in to the d.run UI, and go to User Center → SSH Keys.
Paste your SSH public key into the input field.

<!--

→
- Key Title: A name to help you identify the key.
- Expiration Time: Set a key expiration date. The key becomes invalid after that time. Leave blank for permanent validity.