Tag: openshift k8s kubernetes

We started a CP4D installation on AWS, but without using AWS ROSA. We create a new cluster from scratch.
In our lab everything worked perfectly but when the client went to do its installation the Openshift CLI displayed the following error message:

assertion failed [inst.has.value()]: failed to decode instruction: 0x0

After much analysis, we discovered that the client’s Administrator was using a MacBook Pro M1 laptop.

We found the solution at this link https://veducate.co.uk/



Openshift comes with a set of default templates, you can use oc get templates -n openshift to show them
Each template contains specifc sections
  • The objects section: defines a list of resources that will be created
  • The parameters section: defines parameters that are used in the template objects
1 – Inspect the template file for the parameters
I export the postgresql-ephemeral to a yaml file using :  oc get template postgresql-ephemeral -o yaml -n openshift > postgresql.yaml 
Then inspect the yaml file  oc process --parameters -f <filename.yaml>
2 – Create the application using oc process
oc process -f postgresql.yaml -l app=mydb -p DATABASE_SERVICE_NAME=dbservice -p POSTGRESQL_USER=dbuser \
-p POSTGRESQL_PASSWORD=password -p POSTGRESQL_DATABASE=books | oc create -f -


I am studying to take some RedHat certification exams including the OpenShift Enterprise Administration (DO280) exam.  I could set up Linux cloud servers such as IBM Cloud or even on AWS but I have an old laptop and decided to setup

a cluster with 3 Linux machines on it. I will start building a small k8s cluster. The first step was to install Ubuntu 20.04 as host.

My old laptop is a Toshiba Satellite P875 – S3210 32GB RAM 512GB SSD 750 GB HD SATA

Install and Enable SSH server on Ubuntu 20.04

  1. Update ubuntu : sudo apt-get update
  2. Install OpenSSH: sudo apt-get install openssh-server
  3. Verify the status: sudo systemctl status sshd
  4. Enable ssh connections on the host: sudo ufw allow ssh
  5.  Check if openssh is enabled:  sudo systemctl list-unit-files | grep enabled | grep ssh6
  6. If you have no results on step 5: sudo systemctl enable ssh

Now I can connect to my ubuntu laptop using ssh.

The second step was to install Timeshift and perform a backup of the system.

  1. Add the repository: add-apt-repository -y ppa:teejee2008/ppa2
  2. Install TimeShift: apt install timeshift

Then I made the first backup and started the KVM installation

Install KVM on Ubuntu 20.04

Install KVM:

  1. sudo apt install qemu qemu-kvm libvirt-clients libvirt-daemon-system virtinst bridge-utilsb
  2. sudo systemctl enable libvirtd
  3. sudo systemctl start libvirtd

Configure VNC:  VNC support should be available by default, and I do this configuration:

Edit /etc/libvirt/qemu.conf and add: vnc_listen = “”
This will enable VNC on all networks. This is not a problem for me because it’s a local machine. Don’t do this if you are using a machine exposed to internet.b.

Edit /etc/libvirt/libvirtd.conf and add: listen_tcp = 1

Reboot the machine.

Enable VNC connections: sudo ufw allow 5900:5903 (VNC uses TCP port 5900+n and I will setup 3 machines)

Setup a bridge network

 The default network virbr0, created by KVM does not allow virtual machines to communicate with external hosts (inbound and outbound).

Using the nmcli tool I setup a bridge network. I try to use my wireless connection but it’s not work, some documents show that this only work with ethernet interfaces. My host ethernet connection is enp1s0

nmcli con add ifname br0 type bridge con-name br0

nmcli con add type bridge-slave ifname enp1s0 master br0

nmcli con down “Wired connection 1”

nmcli con up br0

Declaring KVM Bridged Network Create a xml file anmed bridge.xml with the lines:

<network>  <name>br0</name>  <forward mode="bridge"/>  <bridge name="br0" /></network>

Use the file to define the new network:

virsh net-define ./bridge.xml 

Start the network and configure it for auto-start

 virsh net-start br0virsh net-autostart br0   

Now I can use this network on the Virtual Machines 

For example using virt-install –network option

  Next step is to setup 3 machines and K8s