The rsync command stopped working on a shared hosting – is the suspicion correct?

rsync

I'm using a "rocket-science" bash script to quickly deploy a WordPress code to a shared hosting from my local machine. Everything was working till yesterday. Now I'm just involved in a discussion with the hosting administrators trying to suggest that everything is OK on my end.

Here's the script:

#!/bin/bash
printf "Running gulp\n"
gulp --production

printf "Running rsync\n"
rsync -vzrP --update ~/Code/Project/wp-content/themes/foo-theme mylogin@shared-hosting-server.com:/home/mylogin/domains/example.com/public_html/wp-content/themes/ --delete

To not be prompted about password all the time, I added my key to known_hosts on server's .ssh directory. And for months it was working with absolutely no issues. Yesterday I got message that "identification has changed…"

Running rsync
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SHA256:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.
Please contact your system administrator.
Add correct host key in /Users/slick/.ssh/known_hosts to get rid of this message.
Offending RSA key in /Users/slick/.ssh/known_hosts:7
RSA host key for shared-hosting-server.com has changed and you have requested strict checking.
Host key verification failed.
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(226) [sender=3.1.2]

I solved this by removing suggested line no. 7 from /Users/slick/.ssh/known_hosts and accepting new key.

but that didn't solve the rsync problem.

I always get:

bash: rsync: command not found
rsync: connection unexpectedly closed (0 bytes received so far) [Receiver]
rsync error: remote command not found (code 127) at io.c(226) [Receiver=3.1.2]

Please answer my questions or confirm that my way of understanding is correct.

1) Am I right that the issue is caused by the hosting side and on my end everything is OK?

2) Am I right that rsync has to exist on both ends (my local Mac) and shared hosting as well? According to this post – rsync needs to be on both ends.

3) I can log into the server on remote with no issues ssh -l mylogin shared-hosting-server.com – it doesn't ask for password so my known_hosts stuff is setup correctly. On the remote server I typed:

rsync

got

-bash: rsync: command not found

and

which rsync

got

/usr/bin/which: no rsync in
(/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/mylogin/bin)

It means that rsync does not exist anymore on the hosting or stopped being available to me. Is that the source of the issue?

Thanks for any explanations.

Best Answer

The rsync command needs to be installed on both sides of the transfer.

You need to make sure it is installed on your hosted server. That is all.

Related Solutions

Ssh – Crontab + Rsync – nothing happens :(

Put full path to rsync even to your /usr/bin/backup, so the line in that file would start

/usr/bin/rsync <your other options>

And try to put a line like

logger -t my_backup Hello from /usr/bin/backup

to your /usr/bin/backup script and see if anything gets logged to /var/log/messages (or other log file, depending on your syslog setup). Alternatively you might replace the logger with

echo "Hello from /usr/bin/backup" >/tmp/backuptest

Oh, sometimes SELinux might cause problems like you have encountered. Is it in use?

Hope this helps.

EDIT: Make your /usr/bin/backup rsync line be like

/usr/bin/rsync <your options> || echo "rsync died with error code $?" >> your_log

Perhaps we'll catch why rsync is so upset.

YET ANOTHER EDIT: OK, rsync error code 5. That means

rsync error: error starting client-server protocol

Most of the time that happens due the wrong password, even though the message looks more cryptic.

If you manually run your rsync script as niklas, that works, right?

EDIT 3: Spotted your mention about keyring. I think cron doesn't use the same keyring than the user niklas during your login. That's why the login goes p00f when trying to run it from cron. Could you use a passwordless RSA key for this instead and just restrict it to run rsync?

EDIT 4: Use RSYNC_PASSWORD environment variable. That can be done by putting this to top of your backup script:

export RSYNC_PASSWORD="myprecioussssssss"

or if you would like to store the password in a textfile, create a file and provide a --password-file option to rsync.

If that doesn't work, you may provide -e 'ssh -o IdentityFile=/path/to/your_file option to rsync.

Sshd_config ForceCommand /usr/bin/rsync error “connection unexpectedly closed”

The why is easy... ForceCommand does exactly what it says: You connect, it forces you to run that command no matter what you actually wanted to do. In this case, that command is /usr/bin/rsync with no flags.

rsync works by running another copy of rsync on the other side of the connection and talking to it over ssh. In this case though, it's unable to start the other side with the flags it needs because the command is replaced by /usr/bin/rsync

Your rsync-validate script is probably the best way to go about this. It checks the request to make sure it is a valid rsync server command, and only then does it run it. rsync probably could be modified to check the $SSH_ORIGINAL_COMMAND directly when its run without arguments, but there's probably a good security reason not to do so.

Best Answer

Related Solutions

Ssh – Crontab + Rsync – nothing happens :(

Sshd_config ForceCommand /usr/bin/rsync error “connection unexpectedly closed”

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