[SOLVED] How can I manually restart Jenkins? - jenkins

[SOLVED] How to Manually Restart Jenkins: A Complete Guide

In this guide, we will look at different ways to manually restart Jenkins. Jenkins is a popular tool for automation. It helps with continuous integration and delivery. Knowing how to restart Jenkins is important for keeping it running well. It also makes sure updates happen correctly. Whether we need to fix problems or set up new changes, learning to restart Jenkins can save us time and effort. We will share several ways to do this. Each way will fit different situations.

Solutions We Will Discuss:

Restart Jenkins via Jenkins Web Interface
Restart Jenkins Using the Command Line
Restart Jenkins as a Service
Restarting Jenkins in Docker Containers
Using Jenkins Script Console for Restart
Configuring Automatic Restarts

By the end of this chapter, we will understand how to manually restart Jenkins using these methods. If you want more information, you can check our other articles like how to fix Jenkins pipeline issues and how to schedule jobs in Jenkins. Now, let’s get started!

Part 1 - Restart Jenkins via Jenkins Web Interface

We can manually restart Jenkins using the Jenkins Web Interface. Here are the steps we should follow:

Access Jenkins Dashboard: Open your web browser. Then go to your Jenkins URL like http://your-jenkins-url:8080.
Log In: If it asks, please enter your username and password to log into Jenkins.
Manage Jenkins: Click on “Manage Jenkins” on the left side.
Safe Restart: Scroll down. Choose either “Reload Configuration from Disk” or “Safe Restart”. The “Safe Restart” option lets Jenkins finish any jobs before it restarts. If we want to restart right away, we can choose the “Restart” option.
Confirmation: A message will pop up to ask if we really want to restart. Click “Yes” to continue.

This will start a restart of our Jenkins service without using the command line. For more ways to restart Jenkins, we can check this link for extra methods.

Part 2 - Restart Jenkins Using the Command Line

We can restart Jenkins from the command line in different ways. It depends on how we set up Jenkins. Here are some common methods to do this:

Using systemctl (for systemd-based systems):
```
sudo systemctl restart jenkins
```
Using service command:
```
sudo service jenkins restart
```
Using java -jar: If we run Jenkins as a standalone WAR file, we can use this command:
```
java -jar jenkins.war --httpPort=8080
```
First, we stop the current process. Then, we run the command above to restart Jenkins.
Killing the Jenkins process: First, we need to find the Jenkins process ID (PID) and then kill it:
```
ps aux | grep jenkins
sudo kill <PID>
```
After we kill the process, we start Jenkins again with our chosen method (like java -jar jenkins.war).

We should check the logs for any errors when we restart. We can find Jenkins logs at:

/var/log/jenkins/jenkins.log

If we want to know more about Jenkins settings, we can check how to move Jenkins from one server to another.

Part 3 - Restart Jenkins as a Service

We can manually restart Jenkins when it runs as a service. The commands we use depend on our operating system.

For Linux

If we have Jenkins installed as a service on a Linux system, we can use this command:

sudo systemctl restart jenkins

This command will stop and then start the Jenkins service. To check the status of the Jenkins service after we restart, we can use:

sudo systemctl status jenkins

For Windows

If we run Jenkins as a Windows service, we can restart it using the Command Prompt. First, we need to open the Command Prompt as an administrator. Then we run:

net stop jenkins
net start jenkins

We can also restart Jenkins using PowerShell:

Restart-Service jenkins

Additional Notes

Make sure we have the right permissions to restart services.
For more details about managing Jenkins, we can check the Jenkins documentation.
If we use Jenkins in a Docker container, we should look at the Docker service management commands. For more info, we can see the parts on Docker.

Part 4 - Restarting Jenkins in Docker Containers

We can manually restart Jenkins that runs in Docker containers. We use some simple commands to stop and start the Jenkins container. This way, we can keep our Jenkins instance working without losing any data.

Stop the Jenkins Container:
We use this command to stop the Jenkins container. Just change jenkins_container_name with the name or ID of your Jenkins container.
```
docker stop jenkins_container_name
```
Start the Jenkins Container:
After we stop the container, we can start it again with this command:
```
docker start jenkins_container_name
```

We can also use the restart command. This command stops and starts the container all at once:

docker restart jenkins_container_name

Viewing Logs:
To see the logs for our Jenkins instance after it restarts, we can use:
```
docker logs jenkins_container_name
```
Using Docker Compose:
If we use Docker Compose, we can restart Jenkins with this command:
```
docker-compose restart jenkins
```

This way, Jenkins restarts and all settings and data stay safe. For more steps on how to manage Jenkins in Docker, we can look at this Jenkins Docker setup guide.

Part 5 - Using Jenkins Script Console for Restart

To restart Jenkins by using the Jenkins Script Console, we can follow these steps:

Go to the Script Console by typing this in the browser:
http://<your-jenkins-url>/script
In the box where we enter the script, we need to type this Groovy code:
```
Jenkins.instance.restart()
```
Then, we click on the Run button to run the script. This will start the restart of our Jenkins instance.

Important Note:

Make sure we have admin rights to use the Script Console.
Restarting Jenkins using the Script Console gives us a clean and quick restart. This is helpful when we make changes to settings or when we have problems.

If we want to learn more about advanced scripting options, we can check out other features in the Jenkins Script Console. If we want to automate this restart even more, we can look into configuring automatic restarts.

Part 6 - Configuring Automatic Restarts

We can configure automatic restarts in Jenkins. We can use built-in options or external tools. Here are some simple ways to set up automatic restarts.

Using Jenkins Configuration:
- Go to Manage Jenkins and then Configure System.
- Scroll down to Jenkins Location. Make sure the Jenkins URL is correct. This is important for webhook callbacks when Jenkins restarts.

Using Systemd (Linux): If our system uses systemd, we can make a service file for Jenkins. This helps to manage automatic restarts. Here is how we can do it:

sudo nano /etc/systemd/system/jenkins.service

We need to add this configuration:

[Unit]
Description=Jenkins Continuous Integration Server
After=network.target

[Service]
User=jenkins
ExecStart=/usr/bin/java -jar /usr/share/jenkins/jenkins.war
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target

After we save the file, we enable and start the service:

sudo systemctl enable jenkins
sudo systemctl start jenkins

Using Cron Jobs: We can also use a cron job to check if Jenkins is healthy. If not, it will restart Jenkins. We edit the crontab like this:
```
crontab -e
```
We add this line to check Jenkins every minute and restart if it is down:
```
* * * * * systemctl is-active --quiet jenkins || systemctl restart jenkins
```
Using Docker Health Checks: If we run Jenkins in a Docker container, we can set a health check in our Dockerfile or docker-compose.yml:
```
healthcheck:
  test: ["CMD", "curl", "-f", "http://localhost:8080/login"]
  interval: 1m30s
  timeout: 10s
  retries: 3
```
This helps if Jenkins stops responding. Docker will try to restart the container automatically.

If we need more details or help with other problems, we can check Jenkins documentation. We can also look at resources like how to fix Jenkins CI pipeline issues and how to move Jenkins from one server to another.

Frequently Asked Questions

1. How can we restart Jenkins if it’s not working?

If Jenkins is not working, we can restart it manually. There are a few ways to do this. The easiest way is to go to the Jenkins web interface. From there, we can restart it from the admin dashboard. We can also use a command in the terminal to restart Jenkins or restart it like a service. For more details, check our guide on how to manually restart Jenkins.

2. What do we do if Jenkins does not restart?

If Jenkins does not restart, we should look at the logs for any error messages. These messages can tell us what went wrong. Common problems are not enough memory or mistakes in the settings. We can try restarting Jenkins again using the command line or as a service. If the issue keeps happening, we can ask the Jenkins community for help.

3. Can we automate Jenkins restarts?

Yes, we can automate Jenkins restarts. This can help keep Jenkins running smoothly. We can set up scheduled jobs or use monitoring tools to restart Jenkins automatically when certain things happen. For more details on how to set this up, see the part about automatic restarts in our guide on how to manually restart Jenkins.

4. Is it safe to restart Jenkins while a build is running?

Restarting Jenkins while a build is running can cause problems. It might lead to incomplete builds or loss of data. It is better to wait until the current build is done before we restart. For tips on how to handle builds and restarts, check our article on how to manually restart Jenkins. We talk about what happens when we restart in different situations.

5. How do we check if Jenkins restarted successfully?

After we restart Jenkins, we can check if it worked by looking at the Jenkins dashboard or the logs. The dashboard should open without issues and the build history should still be there. If we see any problems, we can follow the troubleshooting steps in our guide on restarting Jenkins to fix any issues.

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