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Back to basics with RHEL

Hi there AppWorks fans,

Welcome to a new installment of AppWorks tips.

This guide will help you to install a basic and minimal RHEL on the previous new created VM image. We’ll make the installation as clean as possible for a steady image that will keep running till you turn it off. At the end of the post we create an SSH connection, so the image can be left alone for further step in the series for ‘AppWorks installation in 10 great steps’.

This is the list of ingredients we are going to use:

  • The already installed ‘Oracle Virtual Box’ software from the previous post
  • RHEL ISO file that is connected to our VM image from the previous post
  • PuTTY (SSH client). Downloaded from: putty.org
  • WinSCP (SFTP client). Downloaded from: winscp.net
  • MobaXterm (X server and SSH client). Download from: mobatek.net

Let get right into it…

Start the VirtualBox software and select the previous created image. Time to startup our brand-new VM machine. Hit that green ‘Start’ arrow or just double-click on the image to boot it up:

image_installation_001

If you want to exit the image you can hit the right <Ctrl> key on your keyboard (see also on the right-bottom of the running VM)

Make sure you select the option ‘Install RHEL 8.7’ and hit the <Enter> key on your keyboard, so the VM can start doing its magic. The first screen we’ll see is a warm welcome. Select your language setting and hit ‘Continue’

image_installation_002

Now you see the ‘Installation summary’. Browse a bit down to select the ‘Network & Host Name’ settings. It now says: ‘Not connected’!

Set both Ethernet connections ‘ON’ and make sure they get the correct IP addresses from the DHCP server and change the host name to a Fully Qualified Domain Name like: opa.mydomain.com

Notes:

  • Never use localhost or localhost.localdomain in your FQDN; It’s a check on the CARS/OpenLDAP installation!
  • Don’t forget to hit the ‘Apply’ button next to the FQDN field!
  • It is required to have a FQDN is a hostname for the installation of AppWorks!!

Click ‘Done’ to get back to the summary and do the following settings for the other items:

  • Connect to Red Hat from the previous created developer account and make sure to register and subscribe the current system
  • Security Policy: Set to off
  • KDUMP: Disable it by unmarking the related option
  • Installation Destination: Open it once and click ‘Done’, so it gets automatically partitioned
  • Date & Time: Select your region and city
  • Software Selection: Select only Minimal Install from the left panel
  • Set a ‘Root’ password: admin (in my case!)

Because ‘admin’ is a short password, you need to hit twice on the ‘Done’ button to apply

  • Add a new sysadmin user with ‘Administration’ permission and password: admin (in my case!)

I choose that ‘sysadmin’ name wisely! As during the platform installation there is also an account created with that exact same name and that will benefit you in the future…Trust me on that!

Now the summary is fine, and you should be able to hit the nice and shining ‘Begin Installation’

In the meantime…

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if (!installationIsDone()) { 
    log.info("Get a coffee");
} else { 
    log.info("You should see a nice 'Reboot system' button to hit");
}

After rebooting it will startup your brand-new RHEL system:

image_installation_004

On the login prompt:

  • Username: sysadmin
  • Password (if you used the same example): admin

Now the playground is open!

Firstly, we’ll start with some basic stuff:

  • Updating the OS: sudo yum -y update
  • Upgrading the OS: sudo yum -y upgrade
  • Installing ‘net-tools’: sudo yum -y install net-tools
  • Installing ‘xterm’: sudo yum -y install xterm
  • Installing ‘unzip’: sudo yum -y install unzip
  • Installing ‘tar’: sudo yum -y install tar
  • Installing ‘wget’: sudo yum -y install wget

Secondly, we install the Extra Packages for Enterprise Linux repository following this guide:

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subscription-manager repos --enable codeready-builder-for-rhel-8-$(arch)-rpms
sudo dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm

Finally, cleaning up the OS: sudo yum clean all

If you run ifconfig or ip a you’ll see that not all network adapters have on IP address. This is because they are not all active by default on startup. Check with nmcli d. To solve this run the command nmtui. Edit the connection that is not active and make sure to mark the ‘Automatically connect’ option.

image_installation_005

Then restart the network service: systemctl restart NetworkManager

Get the hostname with hostname and set the /etc/hosts file to the correct fqdn with sudo vi /etc/hosts and change like this (for example we forward the hostname to the host-only network adapter):

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192.168.56.107   appworks.mydomain.com appworks
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

Quick vi-reference

  • Hit <Insert> to start making changed
  • Hit <Esc> to stop making changed
  • To save the file (after <Esc>) type: :w
  • To quit the file (after <Esc>) type: :q

We’ll disable IPv6 as it is more inconvenient than it comes in handy.

sudo vi /etc/sysctl.conf…and add these 2 lines:

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net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

Reload with sudo sysctl -p

Let’s also disable the firewall in 3 steps as it’s not required for our VM and will give more pain than pleasure.

  1. systemctl stop firewalld
  2. systemctl disable firewalld
  3. systemctl status firewalld

Check the SSH service status: systemctl status sshd. This is a required service for the next step, so make sure it’s active (running)

Give our image a restart before we continue: sudo reboot

Or if you’re done for now: sudo shutdown -h now

When the image is up and running and shining like a star you can start with SSH…

Startup PuTTY with this information:

  • Host Name (or IP address): The IP address of your VM host-only adapter
    • Run ifconfig on the VM to get the IP result

image_installation_006

You should be able to make a connection now and login with the ‘sysadmin’ user.

Exactly the same can be done with WinSCP:

image_installation_007

And off-course the same for MobaXTerm:

image_installation_008

This images still shows otadmin as account name, but I currently use sysadmin!

Now we’re ready to install all the other requirements, but for this post we give it a nice big ‘DONE’! Next step in the series of ‘AppWorks installation in 10 great steps’ we’ll install Java to support the TomEE application server.

Great work for now and good stuff to learn from…Have a nice day and see you next time on a new installment of AppWorks Tips!