Automated Systemd Upload Timer

This repo consists of a simple rsync script and a systemd service and timer component to frequently upload a randomly-sized file to a destination server at a timely interval.

The purpose is to increase the upload stats on a server or a network connection where the ISP or Datacenter requires the uploaded traffic to be much more than the downloaded data. That might sound weird to some people but there are such providers in some "free" countries on this planet who would limit your bandwidth if your download is more than your upload because they wouldn't want people to run VPN servers on their infrustructure!

I'm gonna write these instructions for the people who might not have much experience with Linux machines, so some parts might sound too obvious to the more advanced users, I ask your majesty's forgiveness beforehand!

The terms that are probably gonna be used a lot in the following instructions are these:

• Main Server: This is the server that's on the sh**ty network that limits people's bandwidth!
• Destination Server: This would be the server that you're connecting and uploading to.

Instructions

First of all I suggest for the ease of your job, add the IP address of the destination server to your /etc/hosts file.

#IP         friendlyname
1.2.3.4     myserver

Second thing that should be done is to authorize the Main Server to SSH into the Destination Server using an SSH Public Key.

On the Main Server run:

ssh-keygen

Press Enter until the process ends.

Then copy the contents of the file id_rsa.pub

cat ~/.ssh/id_rsa.pub

SSH into the Destination Server, open the authorized_keys file for the user that you're gonna SSH into with a text editor.

vim ~/.ssh/authorized_keys

Paste the contents that you copied in the previous step into a new line.

Script Setup

Then go back to the main server, create a directory somewhere for the script file and the logs. I use the following paths for the examples:

#Script Directory
/opt/upscript/
#Logs Directory
/opt/upscript/logs/

This script automatically creates a file of random size between 500MB and 1500MB defined as UpFileSize, or you could set a specific size or download a relatively large file yourself, like Ubuntu's ISO image!

Copy the file script.sh to the script directory and replace the following variables with correct information about your server and paths:

ScriptDir=/opt/upscript
LogDir=$ScriptDir/logs
LogFile=upscript-$(date +%s).log

SshPort=2222
SshUser=username
ServerAddr=myserver

SenderName=$(hostname)
UpDir=/opt/upscript/$SenderName

BwLimit=$(( ( RANDOM % 2000 ) +700 ))

Notice that the values starting with Ssh should be filled with the connection information for the Destination Server.

BwLimit is the upload rate in Kilo Bytes Per Second. It will limit the upload rate so that rsync wouldn't employ the whole upload bandwidth of the server which might cause other issues such as network inaccessibilty during the upload or cause your service to get suspended due to using too much resources at a time! I also made it a randomized number like the uploded file's size. In the above example it chooses a random number between 700 and 2700 and applies it as the amount of bandwidth (in KBps) that would be employed during the upload of the file.

Service and Timer Setup

Okay, now we're setting up the systemd Service and Timer to run the script with a time interval in between, here 26 minutes after the previous run was finished.

First create 2 file called upscript.service and upscript.time in the systemd directory:

sudo touch /etc/systemd/system/upscript.service
sudo touch /etc/systemd/system/upscript.timer

Then edit the Service file and paste the contents of the upscript.service file into it:

sudo vim /etc/systemd/system/upscript.service

Note that you should set the following variables in that file to fit your directories, paths, and username. The value of TimeoutStartSec stops the script if the upload speed is too slow and it's defined in seconds.

User=username
Group=usergroup
ExecStart=bash /opt/upscript/script.sh
TimeoutStartSec=3600
StandardOutput=file:/opt/upscript/logs/upscript.log
StandardError=file:/opt/upscript/logs/upscript-error.log

Then edit the Timer file and paste the contents of the upstript.timer file into it:

sudo vim /etc/systemd/system/upscript.timer

Note that you can change these variable as you desire:

OnUnitInactiveSec=26m
OnBootSec=33m

OnUnitInactiveSec here means that 26 minutes after the past upload was finished, a new one would be started. This prevents overlaps (compared to OnUnitActive).

At the end, run the following commands:

sudo systemctl daemon-reload
sudo systemctl enable upscript
sudo systemctl start upscript

Final Tests and Notes

You should test the SSH connection to your destination server and accept the SSH key on your main server at least once manually.

ssh -p port username@myserver

You could trigger the run manually via running either of these:

sudo systemctl start upscript.service
bash /opt/upscript/script.sh
# And Tail the logfile to see the progress:
# tail -f /opt/upscript/logs/upscript-newesttime.log

Every run of the script leaves a log file inside the LogDir named using the Unix timestamp of the time of run. This is for the sake of debugging and log checks; you could run a logrotate service or manually delete them as they'd increase in number over time! Or you could disable it by commenting out this part inside script.sh:

# >> $LogDir/$LogFile

Bonus: I myself have a cronjob that deletes the log files older than 7 days. You could set it up using crontab -e like this:

0 0 * * * /usr/bin/find /opt/upscript/logs/ -name "script-1*.log" -type f -mtime +7 -delete

Stuff To Do On The Destination Server

Something else that you obviously should do on the destination server is to create the UpDir on it and give write permission to the user that SSHes into that server!

Also if your destination server is low on storage, you could easily add a Cronjob to look for the uploaded file every few minutes and if it exists, delete it:

*/10 * * * * rm -f /opt/upscript/*/upfile.iso

This will delete any file called upfile.iso inside any folder under the directory /opt/upscript/ every 10 minutes!

Okay, that's it! Good Luck with your endevours! :))