How to achieve cross-server Linux SysOps management via SSH

How to achieve cross-server Linux SysOps management through SSH

Overview:
In Linux system management, it is often necessary to manage multiple remote servers at the same time. Through the SSH (Secure Shell) protocol, we can implement cross-server management operations. This article will introduce how to use SSH to implement cross-server Linux SysOps (system operation and maintenance) management, and provide specific code examples.

1. SSH Introduction:
   SSH is an encrypted remote login protocol that can transmit data between the client and the server through a secure channel. The SSH protocol provides security mechanisms such as identity authentication, data encryption, and data integrity verification to ensure the security of remote login.
2. Generate SSH public and private keys:
   Before using SSH for remote login, you need to generate an SSH public and private key pair. Execute the following command on the client to generate the public and private keys:

ssh-keygen -t rsa

This will generate a pair of public and private key files, which are stored in the user's .ssh directory by default. The public key file name is id_rsa.pub, and the private key file name is id_rsa.

3. Configure password-free login:
   When using SSH for cross-server management, password-free login is usually configured. The specific operations are as follows:

(1) Copy the client’s public key file id_rsa.pub to the remote server that needs to be managed:

ssh-copy-id -i ~/.ssh/id_rsa.pub user@remote_server

Among them, user is the user name on the remote server, remote_server is the IP address or domain name of the remote server.

(2) On the remote server, append the contents of the public key file to the ~/.ssh/authorized_keys file:

cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

(3) Set up the remote server The ~/.ssh directory and the permissions of the ~/.ssh/authorized_keys file:

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

After completing the above configuration, password-free login can be achieved.

4. Use SSH for cross-server management:
   After configuring password-free login, you can use SSH commands to perform cross-server management operations. The following examples are for reference only:

(1) Remote execution command:

ssh user@remote_server 'command'

where, user is the user name on the remote server, remote_server is the IP address or domain name of the remote server, command is the command to be executed on the remote server.

(2) Copy files:

Copy local files to the remote server:

scp local_file user@remote_server:remote_path

Copy files on the remote server to the local:

scp user@remote_server:remote_file local_path

Among them, local_file is the path to the local file, remote_path is the path to the file on the remote server, remote_file is the file path on the remote server, local_path is the path to the local directory.

5. Batch management:
   If you need to manage multiple servers in batches, you can use the loop structure and SSH commands to traverse the server list for operation. The following example is for reference only:

#!/bin/bash

servers=("server1" "server2" "server3")

for server in "${servers[@]}"
do
    ssh user@$server 'command'    
done

where servers is the server list, user is the username on the remote server, command is the command to be executed on the remote server.

Through the above steps, we can use the SSH protocol to achieve cross-server Linux SysOps management. This method can improve management efficiency and reduce the workload of manual operations. At the same time, by studying code examples, we can expand and optimize according to the actual situation, improving the flexibility and reliability of management operations.

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