I am writing a tool (zxcV32/OpenRWC) that fetches wallpapers from Reddit and sets them to the monitor(s) using nitrogen.
To make it easy to install and run automatically, I have created a deb package and a systemd service.
When the service is started using
sudo systemctl start openrwc#$USER.service
nitrogen errors out with exit status 1. (No other error message). And yes, the exec installed by the deb package works fine when manually run from the terminal.
I have compared that the command run by the tool is precisely the same when run through the systemd service or terminal run.
Sample command
nitrogen --set-scaled /home/zxcv32/.config/OpenRWC/fz41kmzk1wj91.jpg --head=0
Service
[Unit]
Description=Reddit Wallpaper Changer for GNU/Linux
Requires=display-manager.service
After=display-manager.service
StartLimitIntervalSec=0
[Service]
Type=simple
ExecStart=/usr/bin/openrwc
Restart=always
RestartSec=5
User=%i
[Install]
WantedBy=graphical.target
What may be wrong with the service? I want the service to be the user's choice, if they want to run it or not.
BTW I found this question that claims that nitrogen works through a service. (maybe there is a difference between running nitrogen directly through system service and through a go funciton)
System: Debian 11 5.10.0-17-amd64
Found the issue.
Systemd does not have access to certain environment variables.
DISPLAY environment variable needs to be set in the openrwc#.service.
[Service]
Environment="DISPLAY=:0"
I would like to start a GUI application when the session starts
It is a CM4 with a 5 inch touch screen, the purpose is to launch an application when Ubuntu starts.
Via a terminal, when I start it (./main) it works without problem
I tried via startup applications but it doesn't work, I don't know why
I tried via systemd but it doesn't seem to work for graphical applications
[Unit]
After=network.service
[Service]
ExecStart=/home/ubuntu/path/main
[Install]
WantedBy=multi-user.target
I tried via /etc/rc5.d but that doesn't work either
What am I doing wrong?
I need running a (bash)Script after each start from my EC2.
The machine stops 90% a day - after wake up - a script should run.
I tried to push it in the USER-DATA - but this only runs on init.
After this I followed up here: https://aws.amazon.com/de/premiumsupport/knowledge-center/execute-user-data-ec2/
but this didn't also work - because to stop a machine and start a machine seems to be no reboot
I also implement a simple output in the rc.local but also: nothing happens.
Is there a way?
So we talk to switch from this Instance-State
to this:
You could use the oneshot feature of systemd
Write scripts for mystart.sh and mystop.sh, chmod/chown them
/etc/systemd/system/mystart.service. Note that we must specify RemainAfterExit=true so that systemd considers the service as active after the setup action is successfully finished.
[Unit]
Description=mystart
After=network.target
[Service]
Type=oneshot
ExecStart=/usr/local/bin/mystart.sh
RemainAfterExit=true
ExecStop=/usr/local/bin/mystop.sh
StandardOutput=journal
[Install]
WantedBy=multi-user.target
Reload the systemd (systemctl reload) and try stopping and starting to test it
Cloud-Init (which runs the User Data script on first boot) can also run scripts:
On every boot
On the next boot only
So, simply install your script in this directory:
/var/lib/cloud/scripts/per-boot/
Each time the instance is booted (started), the script will run. This is a great way to trigger a batch process on the instance.
See also: Auto-Stop EC2 instances when they finish a task - DEV Community
I have a Node.js script that keeps my MongoDB database and the CRM database synced in real-time.
I want to run this script as a background task on my Ubuntu server. I found this solution, but it doesn't work for me. Is there another approach to reach this?
If you just want to start your application, you could use Forever or PM2 for running and auto-restarting on crash. However, this is not a background task.
For a background task that starts on server reboot, the post you linked is the right way to go. If it didn't work, maybe this article will help you. This is from official Express site: Process managers for Express apps
Basically, you create
[Unit]
Description="My Express App"
[Service]
ExecStart=/usr/bin/node server.js
WorkingDirectory=/project/absolute/path
Restart=always
RestartSec=10
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=MyApp
Environment=NODE_ENV=production PORT=8080
[Install]
WantedBy=multi-user.target
Into a /etc/systemd/system/my-app.service file and then use systemctl to start it:
systemctl enable my-app.service
systemctl start my-app.service
Now this assumes your Linux distribution works with systemctl. If your Linux distribution works with upstart or something else, then you need to google up the instruction for that process manager.
I have recently completed the Wiki web development tutorial (http://golang.org/doc/articles/wiki/). I had tons of fun and I would like to experiment more with the net/http package.
However, I noticed that when I run the wiki from a console, the wiki takes over the console. If I close the console terminal or stop the process with CTRL+Z then the server stops.
How can I get the server to run in the background? I think the term for that is running in a daemon.
I'm running this on Ubuntu 12.04. Thanks for any help.
Simple / Usable things first
If you want a start script without much effort (i.e. dealing with the process, just having it managed by the system), you could create a systemd service. See Greg's answer for a detailled description on how to do that.
Afterwards you can start the service with
systemctl start myserver
Previously I would have recommended trying xinetd or something similar for finer granuarlity regarding resource and permission management but systemd already covers that.
Using the shell
You could start your process like this:
nohup ./myexecutable &
The & tells the shell to start the command in the background, keeping it in the job list.
On some shells, the job is killed if the parent shell exits using the HANGUP signal.
To prevent this, you can launch your command using the nohup command, which discards the HANGUP signal.
However, this does not work, if the called process reconnects the HANGUP signal.
To be really sure, you need to remove the process from the shell's joblist.
For two well known shells this can be achieved as follows:
bash:
./myexecutable &
disown <pid>
zsh:
./myexecutable &!
Killing your background job
Normally, the shell prints the PID of the process, which then can be killed using the kill command, to stop the server. If your shell does not print the PID, you can get it using
echo $!
directly after execution. This prints the PID of the forked process.
You could use Supervisord to manage your process.
Ubuntu? Use upstart.
Create a file in /etc/init for your job, named your-service-name.conf
start on net-device-up
exec /path/to/file --option
You can use start your-service-name, as well as: stop, restart, status
This will configure your service using systemd, not a comprehensive tutorial but rather a quick jump-start of how this can be set up.
Content of your app.service file
[Unit]
Description=deploy-webhook service
After=network.target
[Service]
ExecStart=/usr/bin/go webhook.go
WorkingDirectory=/etc/deploy-webhook
User=app-svc
Group=app-svc
Restart=always
RestartSec=10
KillSignal=SIGINT
SyslogIdentifier=deploy-webhook-service
PrivateTmp=true
Environment=APP_PARAM_1=ParamA
Environment=APP_PARAM_2=ParamB
[Install]
WantedBy=multi-user.target
Starting the Service
sudo systemctl start deploy-webhook.service
Service Status
sudo systemctl status deploy-webhook.service
Logs
journalctl -u deploy-webhook -e
After you press ctrl+z (putting the current task to sleep) you can run the command bg in the terminal (stands for background) to let the latest task continue running in the background.
When you need to, run fg to get back to the task.
To get the same result, you can add to your command & at the end to start it in the background.
To add to Greg's answer:
To run the Go App as a service you need to create a new service unit file.
However, the App needs to know where Go is installed. The easiest way to lookup that location is by running this command:
which go
which gives you an output like this:
/usr/local/go/bin/go
With this piece of information, you can create the systemd service file. Create a file named providus-app.service in the /etc/systemd/system/ using the command below:
sudo touch /etc/systemd/system/providus-app.service
Next open the newly created file:
sudo nano /etc/systemd/system/providus-app.service
Paste the following configuration into your service file:
[Unit]
Description=Providus App Service
After=network.target
[Service]
Type=forking
User=deploy
Group=deploy
ExecStart=/usr/local/go/bin/go run main.go
WorkingDirectory=/home/deploy/providus-app
Restart=always
RestartSec=10
KillSignal=SIGINT
SyslogIdentifier=providus-app-service
PrivateTmp=true
[Install]
WantedBy=multi-user.target
When you are finished, save and close the file.
Next, reload the systemd daemon so that it knows about our service file:
sudo systemctl daemon-reload
Start the Providus App service by typing:
sudo systemctl restart providus-app
Double-check that it started without errors by typing:
sudo systemctl status providus-app
And then enable the Providus App service file so that Providus App automatically starts at boot, that is, it can start on its own whenever the server restarts:
sudo systemctl enable providus-app
This creates a multi-user.target symlink in /etc/systemd/system/multi-user.target.wants/providus-app.service for the /etc/systemd/system/providus-app.service file that you created.
To check logs:
sudo journalctl -u providus-app