Using Jenkins on DC/OS backed by NFS


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In the following blog, I am going to explain about how to use Jenkins on DC/OS and configure NFS for persistence storage. Jenkins on DC/OS works by running the Jenkins master as a one-instance Marathon application. Once the Jenkins master comes online, it registers itself as a Mesos framework (using the jenkins-mesos plugin).

Prerequisites

I assume, you have running cluster of DC/OS on your machine. If not then follow my blog Install DC/OS on Vagrant to install and configure open source DC/OS on vagrant.

About NFS (Network File System) Mounts

NFS, or Network File System, is a distributed filesystem protocol that allows you to mount remote directories on your server. This allows you to leverage storage space in a different location and to write to the same space from multiple servers easily. NFS works well for directories that will have to be accessed regularly.

In my DC/OS cluster, I am running one master and two agent. You can check with vagrant status command:

$ vagrant status


Current machine states:

m1                        running (virtualbox) ===> 192.168.65.90
a1                         running (virtualbox) ===> 192.168.65.111 
a2                         running (virtualbox) ===> 192.168.65.121
p1                         running (virtualbox) ===> 192.168.65.60
boot                      running (virtualbox) ===>

We are going to configure NFS server on p1 VM that will works as NFS server for our a1 and a2 client.

p1 ==> NFS Server ==> 192.168.65.60
a1 ==> Client ==> 192.168.65.111
a2 ==> Client ==> 192.168.65.121

Setup

The system should be set up as root. You can access the root user by typing

$ sudo su

1. Setting Up the NFS Server(192.168.65.60)

a) Download the Required Software

Start off by using yum to install the nfs programs.

$ yum install nfs-utils nfs-utils-lib 

Subsequently, run several startup scripts for the NFS server:

$ chkconfig nfs on 
$ service rpcbind start
$ service nfs start

b)Export the Shared Directory

The next step is to decide which directory we want to share with the
client server. The chosen directory should then be added to the
/etc/exports file, which specifies both the directory to be shared and
the details of how it is shared. We are going to share the directory /jenkins_data.

We need to export the directory:

$ vi /etc/exports 

Add the following lines to the bottom of the file, sharing the directory with the client:


/jenkins_data           192.168.65.111(rw,sync,no_root_squash,no_subtree_check)
/jenkins_data           192.168.65.121(rw,sync,no_root_squash,no_subtree_check)

Once you have entered in the settings for each directory, run the following command to export them:

 $ exportfs -a 

2. Setting Up the NFS Client to Agent a1 (192.168.65.111) and a2 (192.168.65.121)

a) Download the Required Software

Start off by using yum to install the nfs programs.

$ yum install nfs-utils nfs-utils-lib 

b) Mount the Directories
Once the programs have been downloaded to the the client server, create the directory that will contain the NFS shared files

$ mkdir -p /mnt/jenkins 

Then go ahead and mount it

$ mount 192.168.65.60:/jenkins_data /mnt/jenkins 

You can use the df -h command to check that the directory has been mounted. You will see it last on the list.

$ df -h

Filesystem                   Size  Used Avail Use% Mounted on
/dev/mapper/centos-root      8.8G  3.1G  5.7G  35% /
devtmpfs                     739M     0  739M   0% /dev
tmpfs                        749M     0  749M   0% /dev/shm
tmpfs                        749M  8.3M  741M   2% /run
tmpfs                        749M     0  749M   0% /sys/fs/cgroup
/dev/sda1                    497M  164M  334M  33% /boot
none                         455G  164G  292G  36% /vagrant
tmpfs                        150M     0  150M   0% /run/user/501
192.168.65.60:/jenkins_data  8.8G  2.9G  6.0G  33% /mnt/jenkins

Additionally, use the mount command to see the entire list of mounted file systems.

$ mount

systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=28,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
/dev/sda1 on /boot type xfs (rw,relatime,attr2,inode64,noquota)
none on /vagrant type vboxsf (rw,nodev,relatime)
tmpfs on /run/user/501 type tmpfs (rw,nosuid,nodev,relatime,size=153292k,mode=700,uid=501,gid=501)
192.168.65.60:/jenkins_data on /mnt/jenkins type nfs4 (rw,relatime,vers=4.0,rsize=131072,wsize=131072,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=192.168.65.121,local_lock=none,addr=192.168.65.60)

You can ensure that the mount is always active by adding the directory
to the fstab file on the client. This will ensure that the mount starts
up after the server reboots.

$ vi /etc/fstab 

And add blow line:

192.168.65.60:/jenkins_data  /mnt/jenkins   nfs      auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 0 0

3. Testing the NFS Mount
Once you have successfully mounted your NFS directory, you can test that it works by creating a file on the Client and checking its availability on the Server.

Create a file in the directory to try it out:

$ touch /mnt/jenkins/example 

You should then be able to find the files on the Server in the /jenkins_data.

$ ls /jenkins_data 

4. Installing Jenkins backed by NFS
If you already have a mount point, great! Create an options.json file that resembles the following example:

$ cat options.json
{
    "jenkins": {
        "framework-name": "jenkins-prod",
        "host-volume": "/mnt/jenkins",
        "cpus": 2.0,
        "mem": 4096
    }
}

Then, install Jenkins by running the following command:

$ dcos package install jenkins --options=options.json 

Jenkins will now be available with persistence storage.

Install Jenkins on Ubuntu


​Jenkins is a topnotch application.Originally started as Hudson in 2004 but due to a conflict in 2011 they divided and continued under the name, Jenkins. It enables one to build software, deploy software, or websites to various endpoints or to run unit/behaviour-driven software tests. In this blog, I will demonstrate how to install, configure Jenkins, and create your first job.

Step 1. Verify Java Installation

$java –version

If java is installed then, you will see java version like:

​java version "1.8.0_77"
Java(TM) SE Runtime Environment (build 1.8.0_77-b03)
Java HotSpot(TM) 64-Bit Server VM (build 25.77-b03, mixed mode)

If Java is not installed, then follow the step 2 to install and set JAVA_HOME path

Step 2: Install Java and Set JAVA_HOME

$ sudo add-apt-repository ppa:webupd8team/java
$ sudo apt-get update
$ sudo apt-get install oracle-java8-installer
$ sudo apt-get install oracle-java8-set-default

$ cd /usr/lib/jvm/

$ ls -l

​drwxr-xr-x 4 root root 4096 Apr 16 11:07 ./
drwxr-xr-x 163 root root 20480 Apr 11 06:57 ../
lrwxrwxrwx 1 root root 24 Mar 23 2014 default-java -> java-1.7.0-openjdk-amd64/
lrwxrwxrwx 1 root root 20 Mar 24 16:08 java-1.7.0-openjdk-amd64 -> java-7-openjdk-amd64/
-rw-r--r-- 1 root root 2439 Mar 24 16:07 .java-1.7.0-openjdk-amd64.jinfo
drwxr-xr-x 5 root root 4096 Apr 16 11:07 java-7-openjdk-amd64/
drwxr-xr-x 8 root root 4096 Apr 1 08:35 java-8-oracle/
-rw-r--r-- 1 root root 2643 Apr 1 08:35 .java-8-oracle.jinfo

Then change directory to latest java

$ cd java-8-oracle

$ pwd

/usr/lib/jvm/java-8-oracle

$ sudo vi /etc/environment

Add below path as per your java installation at end of file

JAVA_HOME="/usr/lib/jvm/java-8-oracle"

$ source /etc/environment
$ echo $JAVA_HOME

/usr/lib/jvm/java-8-oracle

Step 3. Install jenkins.

Before you can install Jenkins, add the key and source list to apt. First add the key:

$ wget -q -O - http://pkg.jenkins-ci.org/debian/jenkins-ci.org.key | apt-key add -

Then, create a sources list for Jenkins:

echo deb http://pkg.jenkins-ci.org/debian binary/ > /etc/apt/sources.list.d/jenkins.list

Update apt’s cache before installing Jenkins:

$ apt-get update

After the cache has been updated, proceed with installing Jenkins. Please note that it has a large bunch of dependencies, so it might take a few moments to install them all.

$ apt-get install jenkins

Jenkins will be launched as a daemon up on start. Check /etc/init.d/jenkins for more details. To run this service a ‘jenkins’ user is created. The log file will be placed in /var/log/jenkins/jenkins.log . Check this file when in need for troubleshooting.​​

​Step 4. Start Jenkins service.

$ /etc/init.d/jenkins start
$ /etc/init.d/jenkins start

Jenkins will write log files to /var/log/jenkins/jenkins.log. You can also fine-tune the configuration.

Step 5. Access Jenkins.

Finally, after the installation is complete you can visit the following address in your browser http://your-ip-address:8080

Congratulation’s! You have successfully installed jenkins.

Introduction to Jenkins


Jenkins is an adaptable open source software tool built with java language.It helps developers to build and test their software development continuously. Basically CICD is the best practice of running project tests on a non-developer machine automatically everytime when ever they pushed new code into the source repository.

index

With Jenkins, organization can speed up the software development workflow through automation. Jenkins deals and holds development growth processes of all kinds, including building , documenting , testing, packaging, staging, deployment, static analysis and many more……

Jenkins provide itself as a platform where installation, development , deployment and production occurs simultaneously on a large scale machines.

Git_gerrit_jenkins

Jenkins constitute some great features in it like:

  1. Easy installation: Just run java -jar jenkins.war, deploy it in a servlet container. No additional install, no database. Prefer an installer or native package? We have those as well.
  2. Easy configuration: Jenkins can be configured entirely from its friendly web GUI with extensive on-the-fly error checks and inline help.
  3. Rich plugin ecosystem: Jenkins integrates with virtually every SCM or build tool that exists. View plugins.
  4. Extensibility: Most parts of Jenkins can be extended and modified, and it’s easy to create new Jenkins plugins. This allows you to customize Jenkins to your needs.
  5. Distributed builds: Jenkins can distribute build/test loads to multiple computers with different operating systems. Building software for OS X, Linux, and Windows? No problem.