Openshift running as single node with libvirt kvm

Libvirt configuration — Openshift Single Node SNO

3 min readMar 24, 2023

Just a recipe to create a lab with SNO.

Environment

My environment is below:

Virtualization with libvirt 
libvirt network: default - Range 192.168.130.0/24 
Domain and Single Node IP: *.fajlinux.local 192.168.130.11

This procedure has been tested with RHEL8 and Fedora39 using Openshift 4.10 and 4.14.

Host setup

Libvirt installing

yum groupinstall "Virtualization Host" -y
yum install virt-install libvirt-client -y
systemctl enable --now libvirtd.service

2) Libvirt networking setup

vi net.xml

<network connections='1'>
 <name>sno</name>
 <uuid>49eee855-d342–46c3–9ed3-b8d1758814cd</uuid>
 <forward mode='nat'>
 <nat>
 <port start='1024' end='65535'/>
 </nat>
 </forward>
 <bridge name='sno' stp='on' delay='0'/>
 <ip family='ipv4' address='192.168.130.1' prefix='24'>
 </ip>
</network>

Setting up the network

[root@compute1 ~]# virsh net-define net.xml

[root@compute1 ~]# virsh net-list 
 Name State Autostart Persistent
 - - - - - - - - - - - - - - - - - - - - - - 
 sno active yes yes
 default active yes yes
 labnet1 active yes yes

3) Configuring DNS using dnsmasq and NetworkManager

Domain: fajlinux.local
SNO NODE IP: 192.168.130.11
Name Servers: 192.168.15.1, 8.8.8.8

yum install dnsmasq
echo -e "[main]\ndns=dnsmasq" | sudo tee /etc/NetworkManager/conf.d/openshift.conf
echo listen-address=127.0.0.1 > /etc/NetworkManager/dnsmasq.d/openshift.conf
echo bind-interfaces >> /etc/NetworkManager/dnsmasq.d/openshift.conf
echo server=192.168.15.1 >> /etc/NetworkManager/dnsmasq.d/openshift.conf
echo server=8.8.8.8 >> /etc/NetworkManager/dnsmasq.d/openshift.conf
echo address=/fajlinux.local/192.168.130.11 >> /etc/NetworkManager/dnsmasq.d/openshift.conf

systemctl reload NetworkManager

nslookup master.fajlinux.local

Openshift Setup

1) Extracting openshift-baremetal-install

I’m working in the directory path /opt/openshift

mkdir /opt/openshift
cd /opt/openshift

Download the necessary files and binaries for Openshift 4.10

export VERSION=latest-4.10
export RELEASE_IMAGE=$(curl -s https://mirror.openshift.com/pub/openshift-v4/clients/ocp/$VERSION/release.txt | grep 'Pull From: quay.io' | awk -F ' ' '{print $3}')
wget https://mirror.openshift.com/pub/openshift-v4/clients/ocp/$VERSION/openshift-client-linux.tar.gz
wget https://mirror.openshift.com/pub/openshift-v4/clients/ocp/$VERSION/openshift-install-linux.tar.gz 
tar -xvf openshift-install.tar.gz 
tar -xvf openshift-client-linux.tar.gz

2) Downloading coreos-installer

wget https://mirror.openshift.com/pub/openshift-v4/clients/coreos-installer/v0.8.0-3/coreos-installer
cp ./coreos-installer /usr/local/bin && chmod +x /usr/local/bin/coreos-installer

3) Downloading rhcos live media

wget -v https://rhcos.mirror.openshift.com/art/storage/releases/rhcos-4.10/410.84.202210040010-0/x86_64/rhcos-410.84.202210040010-0-live.x86_64.iso

4) Creating install-config.yaml

Getting the secret at the following link:

https://console.redhat.com/openshift/create/local

click on “Copy pull secret” button in the Pull Secret section.

mkdir /opt/openshift/deploy

Create the install-config.yaml file with the following template:

CLUSTER NAME: fajlinux
BASE DOMAIN: local
MACHINE CIDR: 192.168.130.0/24

vi deploy/install-config.yaml

apiVersion: v1
baseDomain: local
metadata:
 name: fajlinux
networking:
 networkType: OVNKubernetes
 machineCIDR: 192.168.130.0/24
 clusterNetwork:
 - cidr: 10.128.0.0/14
 hostPrefix: 23 
 serviceNetwork:
 - 172.30.0.0/16
compute:
- name: worker
 replicas: 0
controlPlane:
 name: master
 replicas: 1
platform:
 none: {}
BootstrapInPlace:
 InstallationDisk: /dev/sda
pullSecret: "PASTE THE SECRET CONTENT HERE"
sshKey: "PASTE THE SSH PUBLIC KEY HERE"

5) Generating single node media

openshift-install --dir=deploy create single-node-ignition-config

coreos-installer iso ignition embed -fi /opt/openshift/deploy/bootstrap-in-place-for-live-iso.ign /opt/openshift/rhcos-410.84.202210040010-0-live.x86_64.iso
cp -rf rhcos-410.84.202210040010-0-live.x86_64.iso /var/lib/libvirt/images/rhcos-sno-4.10.x86_64-live.x86_64.iso

Installing Single Node Cluster

Based on minimal requirements
https://docs.openshift.com/container-platform/4.10/installing/installing_sno/install-sno-preparing-to-install-sno.html

Static IP configuration

coreos-installer iso kargs modify -a "ip=192.168.130.11::192.168.130.1:255.255.255.0:fajlinux:ens3:off:192.168.130.1:8.8.8.8" /var/lib/libvirt/images/rhcos-sno-4.8.2-x86_64-live.x86_64.iso

Demonstration of the command


coreos-installer iso kargs modify -a “ip=${ip}::${gateway}:${netmask}:${hostname}:${interface}:none:${nameserver1}:${nameserver2}” FILENAME

Create the vm


virt-instal --name=”openshift-sno” \
 --vcpus=4 \
--ram=12288 \
--disk path=/var/lib/libvirt/images/master-snp.qcow2,bus=sata,size=120 \
--network network=sno,model=virtio \
--boot menu=on \
--graphics vnc --console pty,target_type=serial --noautoconsole \
--cpu host-passthrough \
--cdrom /var/lib/libvirt/images/rhcos-sno-4.10.x86_64-live.x86_64.iso

Let’s wait around 40 to 60 minutes.

Troubleshooting commands:

You can check the progress:

openshift-install wait-for install-complete --dir /opt/openshift/deploy 

export KUBECONFIG=/opt/openshift/deploy/auth/kubeconfig
oc get nodes
oc get co 
oc get clusterversion