Install Java JRE on CentOS7 and set JAVA_HOME

Lets find Java packages for CentOS 7

I am looking for a Java JRE , so I will install it via yum install command:

once its finished installing check the version:

Find if there is any java registered for our $JAVA_HOME:

Find where java is installed, if the above echo command comes back empty:

Now we need to make sure that JAVA_HOME is in the path each time we login or reboot the server, and for that we need to add it to a startup file under profile.d :

The command “echo $JAVA_HOME”  should return the java path now deffinetly:

reboot, and test again to confirm that  “echo $JAVA_HOME” is returning the Java install path.


This should be it, at least for now for the majority of apps we going to use.

Enable networking on CentOS 7 minimal distro

Ifconfig is not included in the minimal install of the CentOS7, and needs to be installed manually. We need to add an IP address to our system via “ip” command, before we can install the net-tools or anything else from repos.

Find network cards attached and their associated names:

Lets add an IP address, network, and name servers:

Now lets add DNS name servers:
edit /etc/resolve.conf and add the DNS servers in the following format

Time to test if IP networking works or not. Lets go with Networking 101:

Lets test the name resolution:

Lets install the ifconfig tool using command “yum install net-tools” it will install couple of packages, and ifconfig works like a charm.


Change the following entry ONBOOT=no to ONBOOT=yes so your networking comes up after each server reboot under  /etc/sysconfig/network-scripts/ifcfg-NICName in my case that  is /etc/sysconfig/network-scripts/ifcfg-eno16777728

The file should look similar to the following:


Now that is up and running we can ssh into it, and make our life a bit easier with managing it remotely.

Great collection of Tips and Tricks for admins on CentoOS’s official website.

Lab1:Server for nested ESXi Host

Currently using a Dell C1100 (cs24-TY) with 2x quad core L5520 CPUs and 72 GB of RAM. Ebay has them plenty for anywhere from $500-$699 with out HDDs, trays included. Unfortunately this server does not come with a RAID controller, and is quite loud when running under a load.
This particular server does not come with hardware RAID, and VMware does not support software RAID. It means you will need/have to use individual drives and wont be able to take advantage of any kind RAID setups for a speed/IOps boost.
I bought it at the moment due to its cost, size (1U), performance/RAM (72GB), and requirements I had in place, originally.

I have populated it with  2 x SAMSUNG 840 240GB and 1 SAMSUNG 850 EVO 250GB SSD drives, and a 2 TB WD 7200 RPM drive, which is used primarily for backups and VMs that require low IOPS.

I am currently running several nested ESXi 5.1, and 5.5 on it, and its handling it all quite well.