How to use SSH for Linux SysOps management

How to use SSH for Linux SysOps management

Overview:
In Linux system operation and maintenance, SSH (Secure Shell) is a network protocol that can be Remotely log in to the Linux server in an encrypted manner to perform various operations and management tasks. This article will introduce how to use SSH for Linux SysOps management and give specific code examples.

SSH principle:
SSH ensures the security of data transmission through encryption. It uses an asymmetric key encryption algorithm, that is, a public key and a private key, to ensure that the data can only be decrypted on the correct target host.

The SSH connection establishment process is as follows:

1. The client sends an SSH connection request to the server;
2. The server generates a random session key and uses Encrypt it with the client's public key and send it to the client;
3. The client uses its own private key to decrypt the session key, and then uses the session key to symmetrically encrypt the data and sends it to the server;
4. The server side uses the session key to decrypt the data.

SSH usage example:

1. Remote login to the Linux server:

   ssh username@ip_address

   where username is on the server The username, ip_address is the IP address of the server.

2. Execute remote commands:

   ssh username@ip_address 'command'

   Through this command, you can execute specific commands on the remote server, for example:

   ssh username@ip_address 'ls -l'

   This command will Execute the ls -l command on the remote server and return the results to the client.

3. Transfer files to the remote server:

   scp local_file_path username@ip_address:remote_path

   With this command, you can transfer local files to the remote server, for example:

   scp /path/to/local_file.txt username@ip_address:/path/to/remote_file.txt

   This The command will transfer the local /path/to/local_file.txt file to the remote server's /path/to/remote_file.txt location.

4. Download files from the remote server to the local:

   scp username@ip_address:remote_file_path local_path

   With this command, you can download files from the remote server to the local, for example:

   scp username@ip_address:/path/to/remote_file.txt /path/to/local_file.txt

   This The command will download the /path/to/remote_file.txt file on the remote server to the local /path/to/local_file.txt location.

5. Use SSH key:
   a) Generate a key pair on the client:

   ssh-keygen -t rsa

   Enter the key storage location and password as prompted.

b) Copy the public key to the remote server:

ssh-copy-id username@ip_address

This command will copy the client’s public key to ~/.ssh on the remote server /authorized_keys file.

c) Use key to log in:

ssh -i private_key username@ip_address

With this command, you can use the private key to log in to the remote server.

Summary:
Through SSH, you can remotely log in, execute commands, transfer files and other operations in Linux SysOps management. Through the above examples, we can better understand the usage principles and operation methods of SSH. In actual operation and maintenance, SSH is a very common and important tool that helps administrators manage and maintain Linux servers more efficiently.

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