Jenkins Workflow CD with Kubernetes - jenkins

To clarify, this is not a question about running Jenkins in Kubernetes, this is about deploying to Kubernetess from Jenkins.
I have recently settled on using Jenkins (and the workflow/pipeline plugin) to orchestrate our delivery process. Currently, I'm using the imperative style to deploy as per below:
stage 'Deploy to Integ'
// Clean up old releases
sh "kubectl delete svc,deployment ${serviceName} || true"
def cmd = """kubectl run ${serviceName} --image=${dockerRegistry}/${serviceName}:${env.BUILD_NUMBER} --replicas=2 --port=${containerPort} --expose --service-overrides='{ "spec": { "type": "LoadBalancer" }}' """
// execute shell for the command above
sh cmd
This works well because the ${env.BUILD_NUMBER} persists through the pipeline, making it easy for me to ensure the version I deploy is the same all the way through. The problem I have is that I would like to use the declarative approach as this isn't scalable, and I would like the definition in VCS.
Unfortunately, the declarative approach comes with the adverse effect of needing to explicitly state the version of the image (to be deployed) in the yaml. One way around this might be to use the latest tag, however this comes with its own risks. For example, lets take the scenario where I'm about to deploy latest to production and a new version gets tagged latest. The new latest may not have gone through testing.
I could get into changing the file programmatically, but that feels rather clunky, and doesn't help developers who have the file checked out to understand what is latest.
What have you done to solve this issue? Am I missing something obvious? What workflow are you using?

In my yaml file (server.origin.yml), I set my image as image-name:$BUILD_NUMBER
Then I run: envsubst < ./server.origin.yml > ./server.yml
This command will replace the string $BUILD_NUMBER by the value of the environment variable

Related

Docker Save through Jenkins Pipeline (+ other commands)

I see that there is some documentation on using Docker through Jenkins Pipelines here:
https://www.jenkins.io/doc/book/pipeline/docker/
They have an example for building a Docker image:
node {
checkout scm
def customImage = docker.build("my-image:${env.BUILD_ID}")
customImage.inside {
sh 'make test'
}
}
But I was unable to find the complete list (with examples) of Docker commands supported.
Here's some places I've looked:
https://plugins.jenkins.io/docker-workflow/
https://github.com/jenkinsci/docker-workflow-plugin/
https://docs.cloudbees.com/docs/admin-resources/latest/plugins/docker-workflow
What I was looking to do is docker save. Does anyone know if something like this is supported, or where it might be documented:
// Tar ball or filename+path
def imageTar = docker.save("${ImageFileName}.tar", "${ProjectImage}:${ProjectRelease}")
The commands under the docker keyword are made available by the Docker Pipeline Plugin which is usually installed by default with Jenkins. The full documentation of the plugin is available Here.
In addition because this plugin adds methods as global variables (which are available in Pipeline directly, not as steps) you can see the available options, which are based on the version of the plugin you have installed, in the Global Variable Reference documentation within your Jenkins instance. There are two ways to reach it:
Navigate to: [JENKINS_URL]/pipeline-syntax/globals
Go to one of your pipeline jobs, on the left menu click on the Pipeline Syntax link, then on the left menu select Global Variable Reference
Search for the docker section and you will see all available options.
Back to your original question - it seems that this plugin currently does not support the save command. it only supports tag, push, pull and run (of all kinds).
If you find it useful you can open a feature request in the plugin's Report an issue (Jira) page asking that they add this new capability.

Jenkins - How to access Build number variable and use it as a Prefix/Suffix of a log name during Post build actions

I am trying to use Jenkins' Build Number in the naming of a Log that I would want to be saved as a post build action
Will the below format work
C:\Jenkins\workspace\Jmeter_Jenkins_Test_Job\Jenkins_Results\"${env.BUILD_NUMBER}"results.jtl
As per Building a software project wiki article the environment variable you're looking for is BUILD_NUMBER and in case of Windows operating system you can access it as:
%BUILD_NUMBER%
so if you want to amend JMeter result file name to include build number you can do something like:
jmeter -n -t /path/to/test.jmx -l /path/to/result-%BUILD_NUMBER%-.jtl
and in the runtime the variable will be evaluated to the current Jenkins build number:
More information just in case: Continuous Integration 101: How to Run JMeter With Jenkins
Without having laid my hands on a Jenkins installation for quite some time:
Yes, you can do that and it has been done before!
You could do something like:
pipeline {
agent any
stages {
stage('test') {
sh 'path/to/jmeter.bat -n -t ${env.WORKSPACE}my_test.jmx -l my_test${env.BUILD_ID}_${env.BUILD_NUMBER}.jtl'
}
}
}
I would propose to create the HTML dashboard report first though and then publish that in Jenkins - you could use https://jenkins.io/doc/pipeline/steps/htmlpublisher/ to do that. Further you should avoid absolute paths in favor of using the WORKSPACE environment variable (see https://jenkins.io/doc/book/pipeline/jenkinsfile/#using-environment-variables for reference).
If you need some general idea of how to run the test via Jenkins you could have a look at https://code-maven.com/jenkins-pipeline-running-external-programs and https://jmeter.apache.org/usermanual/get-started.html#non_gui
If you already tried to achieve something and need more specific help, please come forward with some more detail.

jenkins pipeline DOCKER_HOST

I need to run a docker-container inside my pipeline.
My problem is, there is no docker.sock available inside the Jenkins-container. And actual no chance to get it.
But I found some jobs using docker with this Option:
"Inject environment variables to the build process" -> "Properties
Content"
And following configured:
DOCKER_HOST=tcp://<ip>:<port>
DOCKER_CERT_PATH=/var/jenkins_home/certs
In my understanding, this is equivalent to the docker.sock and useable as plugin, isnt it?
But how can i use it inside a (multi-)pipeline project?
I've tried using this Block inside my Note:
environment {
DOCKER_HOST = 'tcp://<ip>:<port>'
DOCKER_CERT_PATH = '/var/jenkins_home/certs'
}
But got same issue: "docker: not found"
I might have a logical fallacy. Hope someone could help.
Otherwise is it possible to create a jenkins-slave including a docker.sock?
But got same issue: "docker: not found"
This indicates that your Jenkins slave, the one running the pipeline script, does not have the docker command line tools. This depends on your distribution, but in my case I fixed it by changing my build-slave/pipeline-runner creation steps to include:
yum install -y docker-client
Note that you'll still need that for the Cloudbees docker plugin (the thing which provides stuff like docker.build() and docker.image()) because it translates those nice pipeline directives down into shell commands.

How can I test a change made to Jenkinsfile locally?

When writing jenkins pipelines it seems to be very inconvenient to commit each new change in order to see if it works.
Is there a way to execute these locally without committing the code?
You cannot execute a Pipeline script locally, since its whole purpose is to script Jenkins. (Which is one reason why it is best to keep your Jenkinsfile short and limited to code which actually deals with Jenkins features; your actual build logic should be handled with external processes or build tools which you invoke via a one-line sh or bat step.)
If you want to test a change to Jenkinsfile live but without committing it, use the Replay feature added in 1.14.
JENKINS-33925 tracks the feature request for an automated test framework.
I have a solution that works well for me. It consists of a local jenkins running in docker and a git web hook to trigger the pipeline in the local jenkins on every commit. You no longer need to push to your github or bitbucket repository to test the pipeline.
This has only been tested in a linux environment.
It is fairly simple to make this work although this instruction is a tad long. Most steps are there.
This is what you need
Docker installed and working. This is not part of this instruction.
A Jenkins running in docker locally. Explained how below.
The proper rights (ssh access key) for your local Jenkins docker user to pull from your local git repo. Explained how below.
A Jenkins pipeline project that pulls from your local git repository. Explained below.
A git user in your local Jenkins with minimal rights. Explained below.
A git project with a post-commit web hook that triggers the pipeline project. Explained below.
This is how you do it
Jenkins Docker
Create a file called Dockerfile in place of your choosing. I'm placing it in /opt/docker/jenkins/Dockerfile fill it with this:
FROM jenkins/jenkins:lts
USER root
RUN apt-get -y update && apt-get -y upgrade
# Your needed installations goes here
USER jenkins
Build the local_jenkins image
This you will need to do only once or after you have added something to the Dockerfile.
$ docker build -t local_jenkins /opt/docker/jenkins/
Start and restart local_jenkins
From time to time you want to start and restart jenkins easily. E.g. after a reboot of your machine. For this I made an alias that I put in .bash_aliases in my home folder.
$ echo "alias localjenkinsrestart='docker stop jenkins;docker rm jenkins;docker run --name jenkins -i -d -p 8787:8080 -p 50000:50000 -v /opt/docker/jenkins/jenkins_home:/var/jenkins_home:rw local_jenkins'" >> ~/.bash_aliases
$ source .bash_aliases # To make it work
Make sure the /opt/docker/jenkins/jenkins_home folder exists and that you have user read and write rights to it.
To start or restart your jenkins just type:
$ localjenkinsrestart
Everything you do in your local jenkins will be stored in the folder /opt/docker/jenkins/jenkins_home and preserved between restarts.
Create a ssh access key in your docker jenkins
This is a very important part for this to work. First we start the docker container and create a bash shell to it:
$ localjenkinsrestart
$ docker exec -it jenkins /bin/bash
You have now entered into the docker container, this you can see by something like jenkins#e7b23bad10aa:/$ in your terminal. The hash after the # will for sure differ.
Create the key
jenkins#e7b23bad10aa:/$ ssh-keygen
Press enter on all questions until you get the prompt back
Copy the key to your computer. From within the docker container your computer is 172.17.0.1 should you wonder.
jenkins#e7b23bad10aa:/$ ssh-copy-id user#172.17.0.1
user = your username and 172.17.0.1 is the ip address to your computer from within the docker container.
You will have to type your password at this point.
Now lets try to complete the loop by ssh-ing to your computer from within the docker container.
jenkins#e7b23bad10aa:/$ ssh user#172.17.0.1
This time you should not need to enter you password. If you do, something went wrong and you have to try again.
You will now be in your computers home folder. Try ls and have a look.
Do not stop here since we have a chain of ssh shells that we need to get out of.
$ exit
jenkins#e7b23bad10aa:/$ exit
Right! Now we are back and ready to continue.
Install your Jenkins
You will find your local Jenkins in your browser at http://localhost:8787.
First time you point your browser to your local Jenkins your will be greated with a Installation Wizard.
Defaults are fine, do make sure you install the pipeline plugin during the setup though.
Setup your jenkins
It is very important that you activate matrix based security on http://localhost:8787/configureSecurity and give yourself all rights by adding yourself to the matrix and tick all the boxes. (There is a tick-all-boxes icon on the far right)
Select Jenkins’ own user database as the Security Realm
Select Matrix-based security in the Authorization section
Write your username in the field User/group to add: and click on the [ Add ] button
In the table above your username should pop up with a people icon next to it. If it is crossed over you typed your username incorrectly.
Go to the far right of the table and click on the tick-all-button or manually tick all the boxes in your row.
Please verify that the checkbox Prevent Cross Site Request Forgery exploits is unchecked. (Since this Jenkins is only reachable from your computer this isn't such a big deal)
Click on [ Save ] and log out of Jenkins and in again just to make sure it works.
If it doesn't you have to start over from the beginning and emptying the /opt/docker/jenkins/jenkins_home folder before restarting
Add the git user
We need to allow our git hook to login to our local Jenkins with minimal rights. Just to see and build jobs is sufficient. Therefore we create a user called git with password login.
Direct your browser to http://localhost:8787/securityRealm/addUser and add git as username and login as password.
Click on [ Create User ].
Add the rights to the git user
Go to the http://localhost:8787/configureSecurity page in your browser. Add the git user to the matrix:
Write git in the field User/group to add: and click on [ Add ]
Now it is time to check the boxes for minimal rights to the git user. Only these are needed:
overall:read
job:build
job:discover
job:read
Make sure that the Prevent Cross Site Request Forgery exploits checkbox is unchecked and click on [ Save ]
Create the pipeline project
We assume we have the username user and our git enabled project with the Jenkinsfile in it is called project and is located at /home/user/projects/project
In your http://localhost:8787 Jenkins add a new pipeline project. I named it hookpipeline for reference.
Click on New Item in the Jenkins menu
Name the project hookpipeline
Click on Pipeline
Click [ OK ]
Tick the checkbox Poll SCM in the Build Triggers section. Leave the Schedule empty.
In the Pipeline section:
select Pipeline script from SCM
in the Repository URL field enter user#172.17.0.1:projects/project/.git
in the Script Path field enter Jenkinsfile
Save the hookpipeline project
Build the hookpipeline manually once, this is needed for the Poll SCM to start working.
Create the git hook
Go to the /home/user/projects/project/.git/hooks folder and create a file called post-commit that contains this:
#!/bin/sh
BRANCHNAME=$(git rev-parse --abbrev-ref HEAD)
MASTERBRANCH='master'
curl -XPOST -u git:login http://localhost:8787/job/hookpipeline/build
echo "Build triggered successfully on branch: $BRANCHNAME"
Make this file executable:
$ chmod +x /home/user/projects/project/.git/hooks/post-commit
Test the post-commit hook:
$ /home/user/projects/project/.git/hooks/post-commit
Check in Jenkins if your hookpipeline project was triggered.
Finally make some arbitrary change to your project, add the changes and do a commit. This will now trigger the pipeline in your local Jenkins.
Happy Days!
TL;DR
Jenkins Pipeline Unit testing framework
Jenkinsfile Runner
Long Version
Jenkins Pipeline testing becomes more and more of a pain. Unlike the classic declarative job configuration approach where the user was limited to what the UI exposed the new Jenkins Pipeline is a full fledged programming language for the build process where you mix the declarative part with your own code. As good developers we want to have some unit tests for this kind of code as well.
There are three steps you should follow when developing Jenkins Pipelines. The step 1. should cover 80% of the uses cases.
Do as much as possible in build scripts (eg. Maven, Gradle, Gulp etc.). Then in your pipeline scripts just calls the build tasks in the right order. The build pipeline just orchestrates and executes the build tasks but does not have any major logic that needs a special testing.
If the previous rule can't be fully applied then move over to Pipeline Shared libraries where you can develop and test custom logic on its own and integrate them into the pipeline.
If all of the above fails you, you can try one of those libraries that came up recently (March-2017). Jenkins Pipeline Unit testing framework or pipelineUnit (examples). Since 2018 there is also Jenkinsfile Runner, a package to execution Jenkins pipelines from a command line tool.
Examples
The pipelineUnit GitHub repo contains some Spock examples on how to use Jenkins Pipeline Unit testing framework
Jenkins has a 'Replay' feature, which enables you to quickly replay a job without updating sources:
At the moment of writing (end of July 2017) with the Blue Ocean plugin you can check the syntax of a declarative pipeline directly in the visual pipeline editor. The editor, works from the Blue Ocean UI when you click "configure" only for github projects (this is a known issue and they are working to make it work also on git etc).
But, as explained in this question you can open the editor browsing to:
[Jenkins URL]/blue/organizations/jenkins/pipeline-editor/
Then click in the middle of the page, and press Ctrl+S, this will open a textarea where you can paste a pipeline declarative script. When you click on Update, if there is a syntax error, the editor will let you know where the syntax error is. Like in this screenshot:
If there is no syntax error, the textarea will close and the page will visualize your pipeline. Don't worry it won't save anything (if it's a github project it would commit the Jenkinsfile change).
I'm new to Jenkins and this is quite helpful, without this I had to commit a Jenkinsfile many times, till it works (very annoying!). Hope this helps. Cheers.
A bit late to the party, but that's why I wrote jenny, a small reimplementation of some core Jenkinsfile steps. (https://github.com/bmustiata/jenny)
In my development setup – missing a proper Groovy editor – a great deal of Jenkinsfile issues originates from simple syntax errors. To tackle this issue, you can validate the Jenkinsfile against your Jenkins instance (running at $JENKINS_HTTP_URL):
curl -X POST -H $(curl '$JENKINS_HTTP_URL/crumbIssuer/api/xml?xpath=concat(//crumbRequestField,":",//crumb)') -F "jenkinsfile=<Jenkinsfile" $JENKINS_HTTP_URL/pipeline-model-converter/validate
The above command is a slightly modified version from
https://github.com/jenkinsci/pipeline-model-definition-plugin/wiki/Validating-(or-linting)-a-Declarative-Jenkinsfile-from-the-command-line
As far as i know this Pipeline Plugin is the "Engine" of the new Jenkinsfile mechanics, so im quite positive you could use this to locally test your scripts.
Im not sure if there is any additional steps needed when you copy it into a Jenkinsfile, however the syntax etc should be exactly the same.
Edit: Found the reference on the "engine", check this feature description, last paragraph, first entry.
For simplicity, you can create a Jenkinsfile at the root of the git repository, similar to the below example 'Jenkinsfile' based on the groovy syntax of the declarative pipeline.
pipeline {
agent any
stages {
stage('Build the Project') {
steps {
git 'https://github.com/jaikrgupta/CarthageAPI-1.0.git'
echo pwd()
sh 'ls -alrt'
sh 'pip install -r requirements.txt'
sh 'python app.py &'
echo "Build stage gets finished here"
}
}
stage('Test') {
steps {
sh 'chmod 777 ./scripts/test-script.sh'
sh './scripts/test-script.sh'
sh 'cat ./test-reports/test_script.log'
echo "Test stage gets finished here"
}
}
}
https://github.com/jaikrgupta/CarthageAPI-1.0.git
You can now set up a new item in Jenkins as a Pipeline job.
Select the Definition as Pipeline script from SCM and Git for the SCM option.
Paste the project's git repo link in the Repository URL and Jenkinsfile in the script name box.
Then click on the lightweight checkout option and save the project.
So whenever you pushed a commit to the git repo, you can always test the changes running the Build Now every time in Jenkins.
Please follow the instructions in the below visuals for easy setup a Jenkins Pipeline's job.
Aside from the Replay feature that others already mentioned (ditto on its usefulness!), I found the following to be useful as well:
Create a test Pipeline job where you can type in Pipeline code or point to your repo/branch of a Jenkinsfile to quickly test out something. For more accurate testing, use a Multibranch Pipeline that points to your own fork where you can quickly make changes and commit without affecting prod. Stuff like BRANCH_NAME env is only available in Multibranch.
Since Jenkinsfile is Groovy code, simply invoke it with "groovy Jenkinsfile" to validate basic syntax.
Put your SSH key into your Jenkins profile, then use the declarative linter as follows:
ssh jenkins.hostname.here declarative-linter < Jenkinsfile
This will do a static analysis on your Jenkinsfile. In the editor of your choice, define a keyboard shortcut that runs that command automatically. In Visual Studio Code, which is what I use, go to Tasks > Configure Tasks, then use the following JSON to create a Validate Jenkinsfile command:
{
"version": "2.0.0",
"tasks": [
{
"label": "Validate Jenkinsfile",
"type": "shell",
"command": "ssh jenkins.hostname declarative-linter < ${file}"
}
]
}
You can just validate your pipeline to find out syntax issues. Jenkins has nice API for Jenkisfile validation - https://jenkins_url/pipeline-model-converter/validate
Using curl and passing your .Jenkinsfile, you will get syntax check instantly
curl --user username:password -X POST -F "jenkinsfile=<jenkinsfile" https://jenkins_url/pipeline-model-converter/validate
You can add this workflow to editors:
VS Code
Sublime Text
Using the VS Code Jenkins Jack extension, you can have a way to test your Jenkinsfiles without use the git push way, from your local files to a local or remote running Jenkins. And you will have the running log of the job inside VS Code, the ability to create jobs in Jenkins and more staff. I hope this help to more people looking for a way to develop Jenkinsfiles.
i am using replay future , to do some update and run quickly .
With some limitations and for scripted pipelines I use this solution:
Pipeline job with an inlined groovy script:
node('master') {
stage('Run!') {
def script = load('...you job file...')
}
}
Jenkinsfile for testing have same structure as for lesfurets:
def execute() {
... main job code here ...
}
execute()
This is a short solution that lets me test Pipeline code very quickly:
pipeline {
agent any
options {
skipDefaultCheckout true
timestamps()
}
parameters {
text(name: 'SCRIPT', defaultValue: params.SCRIPT,
description: 'Groovy script')
}
stages {
stage("main") {
steps {
script {
writeFile file: 'script.groovy',
text: params.SCRIPT
def groovyScript = load 'script.groovy'
echo "Return value: " + groovyScript
}
} // steps
} // stage
} // stages
} // pipeline
skipDefaultCheckout true because we do not need the files in this tool git repository.
defaultValue: params.SCRIPT sets the default to the latest execution. If used by just one user, it allows for a very quick cycle of short tests.
The given script is written to a file, and loaded and with load.
With this setup I can test everything I can do inside my other Jenkinsfiles, including using shared libraries.

Using Jenkins as graphical frontend - parametrized builds

I have a few build scripts which can be run from the command line. I'd like to have a web UI to run them and I thought about using Jenkins. I see that the Jenkins job supports parameters and then defined parameters are set as environment variables in the build environment. However, I would not like to have to alter my scripts to accept input from environment variables, it would be easier to continue to accept input from command line. I thought about adding the following shell command to the Jenkins job:
eg <build_script> --option1 $JENKINS_PARAM1 --option2 $JENKINS_PARAM2
Then, I would not need to alter my existing build scripts. Is that a common/recommended usage of Jenkins?
Yes, This seems to be perfectly fine for me.

Resources