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Preface

rsync needs to perform user authentication before data synchronization. There are two protocol methods for authentication: SSH protocol and rsync protocol (the default port of rsync protocol is 873)

  • SSH protocol verification login method: use SSH protocol as the basis for user identity authentication (that is, use the system user and password of GNU/Linux itself for verification), and then perform data synchronization.
  • rsync protocol verification login method: use rsync protocol for user identity authentication (non-GNU/Linux system users, similar to vsftpd virtual users), and then perform data synchronization.

Before the specific demonstration of rsync synchronization, you need to use the rsync command. In Rocky Linux 8, the rsync rpm package is installed by default, and the version is 3.1.3-12, as follows:

[root@Rocky ~]# rpm -qa|grep rsync
rsync-3.1.3-12.el8.x86_64

Basic format: rsync [options] original location target location
Commonly used options:
-a: archive mode, recursive and preserves the attributes of the file object, which is equivalent to -rlptgoD (without -H, -A, -X)
-v: Display detailed information about the synchronization process
-z: compress when transferring files
-H: Keep hard link files
-A: retain ACL permissions
-X: retain chattr permissions
-r: Recursive mode, including all files in the directory and subdirectories
-l: still reserved for symbolic link files
-p: Permission to retain file attributes
-t: time to retain file attributes
-g: retain the group belonging to the file attribute (only for super users)
-o: retain the owner of the file attributes (only for super users)
-D: Keep device files and other special files

The author's personal use: rsync -avz original location target location

Environment Description

Item Description
Rocky Linux 8(Server) 192.168.100.4/24
Fedora 34(client) 192.168.100.5/24

You can use Fedora 34 to upload and download

graph LR;
RockyLinux8-->|pull/download|Fedora34;
Fedora34-->|push/upload|RockyLinux8;

You can also use Rocky Linux 8 to upload and download

graph LR;
RockyLinux8-->|push/upload|Fedora34;
Fedora34-->|pull/download|RockyLinux8;

Demonstration based on SSH protocol

Attention!

Here, both Rocky Linux 8 and Fedora 34 use the root user to log in. Fedora 34 is the client and Rocky Linux 8 is the server.

pull/download

Since it is based on the SSH protocol, we first create a user in the server:

[root@Rocky ~]# useradd testrsync
[root@Rocky ~]# passwd testrsync

On the client side, we pull/download it, and the file on the server is /rsync/aabbcc

[root@fedora ~]# rsync -avz testrsync@192.168.100.4:/rsync/aabbcc /root
testrsync@192.168.100.4 ' s password:
receiving incremental file list
aabbcc
sent 43 bytes received 85 bytes 51.20 bytes/sec
total size is 0 speedup is 0.00
[root@fedora ~]# cd
[root@fedora ~]# ls
aabbcc
The transfer was successful.

Attention

If the server's SSH port is not the default 22, you can specify the port in a similar way---rsync -avz -e 'ssh -p [port]'.

push/upload

[root@fedora ~]# touch fedora
[root@fedora ~]# rsync -avz /root/* testrsync@192.168.100.4:/rsync/
testrsync@192.168.100.4 ' s password:
sending incremental file list
anaconda-ks.cfg
fedora
rsync: mkstemp " /rsync/.anaconda-ks.cfg.KWf7JF " failed: Permission denied (13)
rsync: mkstemp " /rsync/.fedora.fL3zPC " failed: Permission denied (13)
sent 760 bytes received 211 bytes 277.43 bytes/sec
total size is 883 speedup is 0.91
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1330) [sender = 3.2.3]

Prompt permission denied, how to deal with it?

First check the permissions of the /rsync/ directory. Obviously, there is no "w" permission. We can use setfacl to give permission:

[root@Rocky ~ ] # ls -ld /rsync/
drwxr-xr-x 2 root root 4096 November 2 15:05 /rsync/

[root@Rocky ~ ] # setfacl -mu:testrsync:rwx /rsync/
[root@Rocky ~ ] # getfacl /rsync/
getfacl: Removing leading ' / ' from absolute path names
# file: rsync/
# owner: root
# group: root
user::rwx
user:testrsync:rwx
group::rx
mask::rwx
other::rx

Try again, success!

[root@fedora ~ ] # rsync -avz /root/* testrsync@192.168.100.4:/rsync/
testrsync@192.168.100.4 ' s password:
sending incremental file list
anaconda-ks.cfg
fedora
sent 760 bytes received 54 bytes 180.89 bytes/sec
total size is 883 speedup is 1.08
Last update: January 4, 2022

Author: tianci li

Contributors: Steven Spencer

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