A Technical I.T./DevOps Blog
Question
You have noticed that Docker and Jenkins are regularly used together. Why is this?
Answer
1. The docker build command produces one artifact. Jenkins lends itself to well-defined tasks.
2. The logic and dependencies of the build can usually be completely contained in the Dockerfile (page 20 of Docker Up and Running). Simple lines of text can standardize many aspects of a given build (e.g.,
…
Problem scenario
You want to create a Jenksinfile for a pipeline. Where can you find a complete list of the reserved words for Declarative pipeline syntax?
Answer
This external page has something close. It does not go into into how “sh” works. Using “sh” you can run Linux commands. There are “bat” and “powershell” options too. Here is an example (taken from Jenkins’ website) :
pipeline {
agent any
stages {
stage(‘Build’) {
steps {
sh ‘echo “Hello World”‘
sh ”’
echo “Multiline shell steps works too”
ls -lah
”’
}
}
}
} …
Problem scenario
You want to use the Docker Pipline (with the Jenkins ID of “docker-workflow”). What do you do?
Solution
Prerequisites
Jenkins needs to be installed. If you need assistance, see this posting if you are using a CentOS/RHEL/Fedora server; if you want to install Jenkins on a Debian/Ubuntu server, see this posting.
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Continue reading “How Do You Use the Docker Pipeline Plugin with Jenkins?”
Problem scenario
You have an existing GitLab set up on a Linux server. You have access to the back-end. You want to find the port number to connect to. How do you do this?
Solution
First find the external IP address (e.g., curl icanhazip)
Second, install nmap (e.g., sudo yum -y install nmap or sudo apt-get -y install nmap).
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Problem scenario
You are using Bitbucket and Jenkins. You have configured triggers to happen on certain events. The events have happened, but you see no corresponding action, no alerts or error messages and nothing in any relevant log. What should you do?
Possible solution #1
In Bitbucket, log in. Go to the relevant repository. Then go to Settings -Workflow -Hooks.
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Continue reading “How Do You Troubleshoot Triggers in a CI/CD Pipeline That Are Not Functioning?”
Problem scenario
You inherited a Jenkins server running on Debian or Ubuntu Linux. You want to know what version of Jenkins you have. What do you do?
Solution
Run this command: dpkg -l | grep -i jenkins | awk ‘{print $3}’
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Continue reading “How Do You Find the Version of Jenkins That is Installed on Debian/Ubuntu Linux?”
Problem Scenario
You want to use the credentials from the Jenkins credentials plugin in a Jenkins pipeline. When you assign the credentials to a variable in a pipeline, is it the username, the password, both or something else?
Solution
It is the username and password, but the two are separated by a colon. You will only see “****” in the console output (for security reasons).
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Question
What is a Jenkins executor?
Answer
It is a designation in the Jenkins master server’s settings that governs resource allocation (e.g., CPU and RAM) on any Jenkins nodes and the master server itself. When a server (either the master or a node) is designated as having two or more executors, the server can process as many jobs simultaneously as the number of executors for which it has been designated.
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Problem scenario
To trigger a Jenkins build after code is inserted into a Bitbucket repository, I have two options. I can use a Bitbucket plugin in Jenkins and do the configuration there. Or I can create a webhook in Bitbucket.
I tried both with a great deal of troubleshooting. But neither worked, and there was no error message. I found nothing in the logs. The triggering event clearly happened.
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Problem scenario
Your Jenkins pipeline jobs will not run. You see “Build Scheduled” when you click on the “Build now” link. But nothing happens. You see an error that your /var/lib/jenkins/ is running low on disk space. You have no access to the back-end of the server that runs Jenkins. What should you do?
Solution
Look at the dashboard view. Next to the date and time of the most recent success of the job (build,
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