I would like to raise from scratch a build server for .NET applications using Jenkins, please note that i'm new to Jenkins CI.
Several Questions:
1) How should I decide on the build server specs? except for the OS which would be windows server 2012, how should I decide on the RAM and the CPU and HD space?
2) Should the Jenkins sit in the build machine or not, what is the recommended approach? I understood that the build server should be isolated from the Jenkins master
3) How do I decide on the Master/Slave approach, when should I use only Master and when should I use master and slave or slaves?
4) How would you recommend me to run the build and deployment tasks in the Jenkins CI, using NAnt/Python or any other scripting language ?
10x, and sorry for the igonrance :)
Responding to each in turn:
You can run Jenkins as a windows service (instructions here) and the machine can be a VM, so it doesn't have to be huge.
a) RAM and CPU: I'll put these together and will depend on how many jobs you plan to have running at the same time. The default number of build executors is 3 but can be increased as a global config change.
b) HDD: This depends on how many jobs you plan to have. Jenkins will checkout the source code (as well as the compiled output) to its home directory on a per job basis. This can get big. I would also recommend using the ThinBackup plugin to backup the Jenkins configuration.
Jenkins is the build machine. A vanilla installation of Jenkins is the master. In my experience you will not need a separate slave machine unless you're needing to do native builds on other platforms or have LOTS and LOTS of jobs. I've seen single masters running happily with hundreds of jobs.
Further to 2. above, suggest you start with a master and set up a slave later if you really need one.
As you have stated you are building .NET applications, you can simply install the MSBuild plugin which should serve you well. Builds for .NET applications in Jenkins are Freestyle builds so you will be using Windows Batch build steps often as well. This also is a great blog on Jenkins in a .NET environment.
Related
I have a 4-5 java projects build procedure to be configured as CI using Jenkins. Whether it will be time saving to build some/all projects on different machines(connected as Jenkins slaves)?
Are there some any other benefits of Jenkins Master-Slave configuration?
Offloading work to build agents is a very good idea as it keeps load away from the master. This allows you to build more projects in parallel (esp. with dynamic agents launched in some cloud environment).
Further, it makes the systems easier to maintain, as e.g. the Java version/setup of your build agents required to build and test your application does not interfere with the Jenkins master machine.
I'm starting to work with Jenkins , I'm a newbie, and I have a question regarding Master-slave configuration. How's usually used? Is it one slave per application (i.e: 3 applications, 3 slaves)?
PS: If you point me to a good Jenkins tutorial, will be appreciate it
First, my recommendation is to disable all the executors on the master and to build only on slaves.
On our Jenkins platform, we are using 7 CentOS slaves (VM) for the Maven builds (one executor per node).
These slaves have the same Jenkins label ("build linux" for example).
All the Maven projects are restricted to this "build linux" label:
https://serverfault.com/questions/359793/tell-jenkins-to-run-a-specific-project-on-a-particular-slave-node
We also have dedicated slaves per platform (Linux 32bits, Linux 64bits, AIX 6, AIX 7, Windows 2008 R2, Windows 2012).
If you need to deploy your applications on dedicated Application Servers (Tomcat, Weblogic, ...), you can create one slave per platform.
Using Jenkins label is really useful to distribute your builds on the relevant slaves.
First recommendation is to use at least one slave and not use the master for building.
Read https://wiki.jenkins-ci.org/display/JENKINS/Distributed+builds (first answer when googling "jenkins master slave tutorial").
Then, add as much slaves as you want to distribute the load. The load does not directly depends on the number of "applications" but on the number of simultaneous builds and available slaves to perform those builds (you may have multiple jobs for a unique application). Typically, you will add slaves if your builds are "pending" for too much time: see https://wiki.jenkins-ci.org/display/JENKINS/Executor+Starvation
Tie the jobs to labels rather than directly to the slaves.
You will obviously have different slaves per build environment.
If your build is isolated enough and it is not multi-threaded, then it is also recommended to set about as much executors as core CPU. That is to make use of the slave resources; another solution is to use virtualization, containers (VM, docker...) as slaves with one executor per slave.
I'm new to Jenkins and Continous Integration, and I noticed that it supports master / slave nodes. I really don't know what that means.
Can someone please tell in what scenario do I need slave agent?
Here is a scenario:
Our main Jenkins master is running on Windows machine (yes I know... I know...). We are doing iOS mobile development. There are some things that can only be done using Xcode (which only runs on Mac OS). I have a Jenkins Slave running on that Mac, that takes care of executing those tasks that can only run on a Mac.
Why not just setup a new instance on that Mac? Cause that job is tied together with other jobs (on Master) in dependencies and the flow. Even promotions on those Xcode tasks are run on Master.
Jenkins' Master / Slave architecture is used to manage distributed builds.
There are many different scenarios you might want to use a distributed build system. It is all based on your projects load and dependencies.
Pretty much, the Master is what you're probably currently using, and is responsible for scheduling builds, dispatching jobs to slaves, and monitoring the results, but can also execute jobs itself. A slave is a java executable that sits on a remote server waiting for instructions from the master (to execute build).
To use this functionality in Jenkins, go to "Manage Jenkins" screen, and click on "Manage Nodes"
https://wiki.jenkins-ci.org/display/JENKINS/Distributed+builds
For a more in depth summary of distributed builds with Jenkins, as well as some scenarios where this system would be useful, and how to implement it, please read chapter 11: Distributed Builds of Jenkins: The Definitive Guide by John Ferguson Smart
http://wakaleo.com/books/jenkins-the-definitive-guide/download-jtdg-pdf
Travis CI has a really nice feature, builds are run within VirtualBox VMs. Each time a build is started, the box is refreshed from a snapshot and the code copied on to it. Any problems with the build cannot affect the host, and you can use any OS to run your builds on.
This would be really good, for example, compiling and testing code on a guest OS that matches your production env. Also, you can keep your host free of any installation dependencies you might need (e.g. a database server) and run ITs without worrying about things like port conflicts.
Does such a thing exist for Jenkins?
Check out the Vagrant Plugin https://wiki.jenkins-ci.org/display/JENKINS/Vagrant-plugin
This plugin allows booting of Vagrant virtual machines, provisioning them and also executing scripts inside of them
You can run Jenkins in a Master Slave Setup. Your Master instance manages all the jobs but lets all the slaves do the actual work. These Slaves can be VMs or physical machines. Go To Manage Jenkins -> Manage Nodes -> New Node to add Nodes to your Jenkins Setup.
There is the vSphere Cloud Plugin and the Scripted Cloud Plugin that can be used for this purpose.
I am using Jenkins for CI,
I've heard that I should have a dedicated server and slave for running Jenkins and building tasks, respectively -
is this true?
I can understand this as the server may not be powerful enough to handle the server itself and running build tasks,
but is there any defined technical reason for this?
Best practice is to have a separate machine for Jenkins-Server,
and not to use it for builds at all.
This has nothing to do with CPU-power or memory-resources -
A build-machine should have a predefined configuration,
and Jenkins should not be part of it.
(Jenkins requirements may even conflict with those of the build-machine)
You should be able to boot / clone / upgrade / restore / trash the build-machine
without any impact on Jenkins.
Of course you can settle for a single machine, if your resources are limited,
but if you are serious about build-automation - Jenkins should have its own server.
You probably don't need dedicated hardware/VM to run a Jenkins server because the actual Jenkins process (no builds running) uses very little resources. But it all depends on what you want to accomplish with your Jenkins setup.
Do you want to run continuous builds across multiple platforms for multiple projects? Then using a master with slaves is the only way to go. If, on the other hand, you're running fairly simple builds for just a few projects, then you only need one machine to run the builds and the Jenkins process.
You can configure Jenkins to have multiple builds running concurrently so if you have a quad-core machine, you can safely run 2 builds and possibly a third once you analyze resource usage.
At my last gig, I used a quad-core machine with 8GB RAM to run:
Jenkins running Selenium builds
VirtualBox VM with Windows XP
Two instances of Tomcat each with two applications deployed.
And the machine still had more to spare.