Recently it was necessary for me to prepare couple of VMs with CentOS Linux 8 to do some labs/practice, and in this blog post I just want to share my notes about the process/steps involved into creating CentOS 8 VM using Virtual Box.
My base OS is Ubuntu 20.04, so I first needed grab DEB package with the latest version of Oracle Virtual Box from official downloads page. I then grabbed full x86-64 ISO file of CentOS Linux 8 (CentOS-Stream-8-x86_64-20210427-dvd1.iso) from CentOS downloads page to avoid any potential need for extra downloads during installation process.
After installing DEB package I quickly created new VM using the following options:
After creating VM I’ve started mounting CentOS iso file and selecting Install CentOS Linux 8
For my purposes it was OK to accept defaults for almost everything. English US for language settings:
I only changed installation type from default Server with GUI to Minimal Install and further assigned Root Password and configured Installation Destination with default options:
Setting up weak root password (which is OK for test box) requires you to click Done twice:
And for disk option it is OK to just accept defaults:
With all settings in place we just hit begin Installation and wait/taking a coffee break 🙂
It is now only a question of observing installation progress for some time and hitting Reboot System bottom at the very end of the process:
Once installation is over and system is rebooted we need to logon and install updates/make sure we have Internet connection, but if we run yum check-update immediately after logon we will see that VM has no internet access:
As you can see from the output we cannot connect/resolve host name to check for updates, so let’s check network status with nmcli general command:
As you can see interfaces are enabled but we have no connectivity, basically it is because VM didn’t receive IP configuration from DHCHP and running dhclient -v command should resolve that (v flag only indicates that we need detailed output from this command):
After that we can re-run nmcli general – state should change to connected and yum check-update or yum update commands should work just fine:
But what I noticed is that after every reboot of VM network connection was again getting back to disconnected state, although yum check-update / yum update commands were not reporting connectivity errors, checking with nmcli general or with curl -I https://mikerodionov.com was showing that I can’t connect and dchclient command was helping only until next reboot. I checked network-scripts folder and interface configuration file did had BOOTPROTO=dhcp option which supposed to be responsible for use of DHCP at boot stage, but ONBOOT setting was set to no – changing it to yes made connectivity available immediately after reboot.
To edit these settings you can use vi as shown below:
After that the only basic thing you may want to do is to adjust/verify hostname of VM which you can do with hostamectl command as shown below:
With that we have CentOS 8 VM with internet connectivity and updates and at it is good idea to create baseline snapshot of VM at this stage. I guess these notes may come in handy to somebody else, especially final part on network configuration.