如何用Python对hostname.txt中的多台服务器执行SSH及command.txt内的命令？

Got it, let's tackle this problem step by step. You want to connect to multiple servers listed in hostname.txt and run commands from command.txt via SSH using Python—here's a solid, practical approach using the paramiko library, which is the go-to tool for SSH operations in Python.

Prerequisites #

First, get the necessary tools set up:

• Install the paramiko library:

  pip install paramiko
  

• Format your input files correctly:
  • hostname.txt should have one server hostname/IP per line (no extra spaces or empty lines):

    server1
    server2
    server3
    server4
    server5

  • command.txt should list one Linux command per line:

    service httpd status
    service dhcpd status

Full Implementation Code #

This script handles file reading, SSH connections, command execution, and error handling so you don't have to worry about a single failed server breaking the whole workflow:

import paramiko
from paramiko.ssh_exception import SSHException, NoValidConnectionsError, AuthenticationException

def read_file_lines(file_path):
    """Read non-empty lines from a text file"""
    with open(file_path, 'r') as f:
        return [line.strip() for line in f if line.strip()]

def run_commands_on_server(hostname, username, auth_cred, commands, use_key=False):
    """Connect to a server via SSH and execute a list of commands"""
    ssh_client = None
    try:
        # Initialize SSH client
        ssh_client = paramiko.SSHClient()
        # Auto-add unknown hosts (adjust for production environments!)
        ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        
        # Connect using password or SSH key
        if use_key:
            ssh_client.connect(
                hostname=hostname,
                username=username,
                key_filename=auth_cred,
                timeout=10
            )
        else:
            ssh_client.connect(
                hostname=hostname,
                username=username,
                password=auth_cred,
                timeout=10
            )
        
        print(f"\n=== Connected to {hostname} ===")
        for cmd in commands:
            print(f"\nRunning command: `{cmd}`")
            # Execute the command
            stdin, stdout, stderr = ssh_client.exec_command(cmd)
            # Capture output and errors
            output = stdout.read().decode('utf-8').strip()
            error = stderr.read().decode('utf-8').strip()
            
            if output:
                print("Output:")
                print(output)
            if error:
                print("Error:")
                print(error)
                
    except AuthenticationException:
        print(f"❌ Authentication failed for {hostname} (check credentials/key)")
    except NoValidConnectionsError:
        print(f"❌ Could not connect to {hostname} (verify hostname/network)")
    except SSHException as e:
        print(f"❌ SSH error with {hostname}: {str(e)}")
    except Exception as e:
        print(f"❌ Unexpected error with {hostname}: {str(e)}")
    finally:
        # Clean up the connection
        if ssh_client and ssh_client.get_transport().is_active():
            ssh_client.close()
            print(f"\n=== Disconnected from {hostname} ===")

if __name__ == "__main__":
    # Update these with your actual credentials!
    USERNAME = "your_server_username"
    # Use this for password auth
    PASSWORD = "your_server_password"
    # Use this for SSH key auth (uncomment and set path, then set use_key=True below)
    # PRIVATE_KEY_PATH = "/home/your_user/.ssh/id_rsa"
    
    # Load hosts and commands from files
    hosts = read_file_lines("hostname.txt")
    commands = read_file_lines("command.txt")
    
    # Validate input files
    if not hosts:
        print("⚠️ No servers found in hostname.txt")
    if not commands:
        print("⚠️ No commands found in command.txt")
    
    # Run commands on each server
    for host in hosts:
        # Use password auth by default
        run_commands_on_server(host, USERNAME, PASSWORD, commands)
        # Switch to key auth by uncommenting this line and commenting the one above
        # run_commands_on_server(host, USERNAME, PRIVATE_KEY_PATH, commands, use_key=True)

Key Tips for Production & Improvement #

• Security First: Never hardcode passwords in scripts! Use environment variables or a secure secrets manager instead. SSH key-based auth is always more secure than password auth—switch to that if you can.
• Host Key Safety: The AutoAddPolicy() is convenient for testing, but in production, use RejectPolicy() or load known hosts to avoid man-in-the-middle attacks.
• Timeout Handling: The 10-second timeout prevents the script from hanging on unresponsive servers.
• Logging: For larger workflows, add logging instead of print statements to track activity over time.

Testing the Script #

1. Save the code as ssh_automation.py
2. Update the username and authentication details in the __main__ block
3. Ensure hostname.txt and command.txt are in the same directory as the script
4. Run it with:

   python ssh_automation.py
   

内容的提问来源于stack exchange，提问作者Arv