How to Run a Single Command at Startup Using Systemd in Ubuntu?

startupsystemd

I’d like to startup an Apache Spark cluster after boot using the following command:

sudo ./path/to/spark/sbin/start-all.sh

Then run this command when the system prepares to reboot/shutdown:

sudo ./path/to/spark/sbin/stop-all.sh

How can I get started? Is there a basic template I can build on?

I’ve tried to use an extremely simple (file: /lib/systemd/system/spark.service):

[Unit]
Description=Spark service

[Service]
ExecStart=sudo ./path/to/spark/sbin/start-all.sh

Which doesn’t work.

Accepted Answer

Your .service file should look like this:

[Unit]
Description=Spark service

[Service]
ExecStart=/path/to/spark/sbin/start-all.sh

[Install]
WantedBy=multi-user.target

Now, take a few more steps to enable and use the .service file:

1. Place it in /etc/systemd/system folder with say a name of myfirst.service
2. Make sure that your script executable with:

chmod u+x /path/to/spark/sbin/start-all.sh

1. Start it:

sudo systemctl start myfirst

1. Enable it to run at boot:

sudo systemctl enable myfirst

1. Stop it:

sudo systemctl stop myfirst

Notes

1. You don’t need to launch Spark with sudo in your service, as the default service user is already root.
2. Look at the links below for more systemd options.

Moreover

Now what we have above is just rudimentary, here is a complete setup for spark:

[Unit]
Description=Apache Spark Master and Slave Servers
After=network.target
After=systemd-user-sessions.service
After=network-online.target

[Service]
User=spark
Type=forking
ExecStart=/opt/spark-1.6.1-bin-hadoop2.6/sbin/start-all.sh
ExecStop=/opt/spark-1.6.1-bin-hadoop2.6/sbin/stop-all.sh
TimeoutSec=30
Restart=on-failure
RestartSec=30
StartLimitInterval=350
StartLimitBurst=10

[Install]
WantedBy=multi-user.target

To setup the service:

sudo systemctl start spark.service
sudo systemctl stop spark.service
sudo systemctl enable spark.service

Further reading

Please read through the following links. Spark is a complex setup, so you should understand how it integrates with Ubuntu’s init service.

• https://datasciencenovice.wordpress.com/2016/11/30/spark-stand-alone-cluster-as-a-systemd-service-ubuntu-16-04centos-7/
• https://www.digitalocean.com/community/tutorials/understanding-systemd-units-and-unit-files
• https://www.freedesktop.org/software/systemd/man/systemd.unit.html

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