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June 24, 2026

Building SNO — Single Node Openshift Cluster

Last weekend, I was setting up a test cluster and didn’t want to spin up three masters and two workers just to check one thing. that’s when…

By Manohar Shetty

13 min read

Last weekend, I was setting up a test cluster and didn't want to spin up three masters and two workers just to check one thing. that's when i remembered sno, single node openshift, where the whole cluster runs on one machine, master and worker combined. i'd heard about it before but never actually tried it, so this felt like the right time. gave it the minimum cpu and ram it needed, kicked off the install, and went to make coffee. came back and it was just sitting there, running, like it wasn't a big deal at all. took me a minute to actually believe it worked on the first try.

this post is basically me writing down what happened, what i'd double check next time, and why i think more people testing openshift at home should just start here instead of overcomplicating it with a full cluster.

SNO setup configuration:

| Server         | Hostname           | IP Address    | Purpose                                    |
| -------------- | ------------------ | ------------- | ------------------------------------------ |
| DNS Server     | dns.manohar.in     | 192.168.0.200 | DNS resolution for OpenShift               |
| Bastion Server | bastion.manohar.in | 192.168.0.201 | OpenShift installer, oc client, SSH access |
| SNO Cluster    | sno.manohar.in     | 192.168.0.250 | Single Node OpenShift cluster              |

OpenShift DNS Records

| Record                 | IP            |
| ---------------------- | ------------- |
| sno.manohar.in         | 192.168.0.250 |
| api.sno.manohar.in     | 192.168.0.250 |
| api-int.sno.manohar.in | 192.168.0.250 |
| *.apps.sno.manohar.in  | 192.168.0.250 |

Important URLs

| Component         | URL                                                                                                            |
| ----------------- | -------------------------------------------------------------------------------------------------------------- |
| OpenShift Console | [https://console-openshift-console.apps.sno.manohar.in](https://console-openshift-console.apps.sno.manohar.in) |
| OAuth             | [https://oauth-openshift.apps.sno.manohar.in](https://oauth-openshift.apps.sno.manohar.in)                     |
| API Endpoint      | [https://api.sno.manohar.in:6443](https://api.sno.manohar.in:6443)                                             |
| Internal API      | [https://api-int.sno.manohar.in:6443](https://api-int.sno.manohar.in:6443)                                     |

Versions

| Component         | Version |
| ----------------- | ------- |
| OpenShift         | 4.21.19 |
| Kubernetes        | 1.34.8  |
| RHCOS             | 4.21.0  |
| openshift-install | 4.21.19 |
| oc client         | 4.21.19 |
None

Download CoreOS ISO

4.21.0 Edit description

None

Download RHCOS 4.21 Live ISO

curl -O https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.21/4.21.0/rhcos-4.21.0-x86_64-live-iso.x86_64.iso

Verify

ls -lh rhcos-4.21.0-x86_64-live-iso.x86_64.iso

Example output:

-rw-r--r-- 1 root root 1.8G Jun 23 20:00 rhcos-4.21.0-x86_64-live-iso.x86_64.iso

Built DNS Server on Centos 9

Setting up DNS on CentOS Stream 9 — for Openshift Cluster This post walks through everything you pasted and explains it command by command so you know what each step does, why…

Add DNS entries

Assume:

  • Cluster Name: sno
  • Base Domain: manohar.in
  • SNO IP: 192.168.0.250

Forward Zone

api.sno.manohar.in.          IN A    192.168.0.250
api-int.sno.manohar.in.      IN A    192.168.0.250
*.apps.sno.manohar.in.       IN A    192.168.0.250

If your DNS server does not support wildcard entry, add records as applications are created.

Reverse Zone

250.0.168.192.in-addr.arpa.   IN PTR  api.sno.manohar.in.

or

250   IN PTR  sno.manohar.in.

Verify

dig api.sno.manohar.in
dig api-int.sno.manohar.in
dig oauth-openshift.apps.sno.manohar.in
dig -x 192.168.0.250

All should resolve to 192.168.0.50 (and the reverse lookup should return the PTR name you configured).

[root@bastion ~]# dig api.sno.manohar.in
dig api-int.sno.manohar.in
dig oauth-openshift.apps.sno.manohar.in
dig -x 192.168.0.250

; <<>> DiG 9.16.23-RH <<>> api.sno.manohar.in
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61114
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: db8a032202debd94010000006a3ac677bf04da5869c991fd (good)
;; QUESTION SECTION:
;api.sno.manohar.in.            IN      A

;; ANSWER SECTION:
api.sno.manohar.in.     86400   IN      A       192.168.0.250

;; Query time: 1 msec
;; SERVER: 192.168.0.200#53(192.168.0.200)
;; WHEN: Tue Jun 23 23:16:31 IST 2026
;; MSG SIZE  rcvd: 91

; <<>> DiG 9.16.23-RH <<>> api-int.sno.manohar.in
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9346
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: 52f8187aaad82e7a010000006a3ac67785d3235629c9f50b (good)
;; QUESTION SECTION:
;api-int.sno.manohar.in.                IN      A

;; ANSWER SECTION:
api-int.sno.manohar.in. 86400   IN      A       192.168.0.250

;; Query time: 2 msec
;; SERVER: 192.168.0.200#53(192.168.0.200)
;; WHEN: Tue Jun 23 23:16:31 IST 2026
;; MSG SIZE  rcvd: 95

; <<>> DiG 9.16.23-RH <<>> oauth-openshift.apps.sno.manohar.in
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12267
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: 55fe711f3cade39d010000006a3ac6776ee39cd5683838b6 (good)
;; QUESTION SECTION:
;oauth-openshift.apps.sno.manohar.in. IN        A

;; ANSWER SECTION:
oauth-openshift.apps.sno.manohar.in. 86400 IN A 192.168.0.250

;; Query time: 1 msec
;; SERVER: 192.168.0.200#53(192.168.0.200)
;; WHEN: Tue Jun 23 23:16:31 IST 2026
;; MSG SIZE  rcvd: 108

; <<>> DiG 9.16.23-RH <<>> -x 192.168.0.250
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39823
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: 452e33bd5176746a010000006a3ac677a21fec1d44b0ca7c (good)
;; QUESTION SECTION:
;250.0.168.192.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
250.0.168.192.in-addr.arpa. 86400 IN    PTR     sno.manohar.in.

;; Query time: 1 msec
;; SERVER: 192.168.0.200#53(192.168.0.200)
;; WHEN: Tue Jun 23 23:16:31 IST 2026
;; MSG SIZE  rcvd: 111

Prepare the OpenShift Installation Workspace

Create a dedicated working directory to store all OpenShift installation files, ignition files, pull secrets, and configuration artifacts.

mkdir sno
cd ~/sno

Download OpenShift Installation Utilities

Download the OpenShift Installer and OpenShift Client packages that match the target OpenShift version.

# Install Openshift Install
curl -O https://mirror.openshift.com/pub/openshift-v4/x86_64/clients/ocp/stable-4.21/openshift-install-linux.tar.gz

# Install Openshift Client
curl -O https://mirror.openshift.com/pub/openshift-v4/x86_64/clients/ocp/stable-4.21/openshift-client-linux.tar.gz

Extract the Installation Packages

Extract the downloaded archives to obtain the required binaries.

tar -xvf openshift-install-linux.tar.gz
tar -xvf openshift-client-linux.tar.gz

This extracts the following tools:

  • openshift-install – Creates installation assets and ignition files.
  • oc – OpenShift command-line interface.
  • kubectl – Kubernetes command-line utility.

Verify Installed Versions

Confirm that the installer and client versions match the intended OpenShift release.

./openshift-install version
./oc version --client

Expected output:

openshift-install 4.21.x
Client Version: 4.21.x

Install the Binaries System-Wide

Make the binaries executable and place them in a directory available in the system PATH.

chmod +x openshift-install oc kubectl
mv openshift-install oc kubectl /usr/local/bin/

Verify Binary Availability

Confirm that the commands are accessible from anywhere on the system.

openshift-install version
oc version --client
kubectl version --client

At this stage, the bastion host is prepared with all required OpenShift installation utilities and is ready for generating the install-config.yaml file and Single Node OpenShift installation assets.

Generate OpenShift Installation Assets

After creating the install-config.yaml file and placing the pull secret and SSH public key in it, generate the installation assets.

Create the installation configuration:

openshift-install create install-config

vi install-config.yaml

apiVersion: v1
baseDomain: manohar.in
metadata:
  name: sno
compute:
  - name: worker
    replicas: 0
controlPlane:
  name: master
  replicas: 1
networking:
  networkType: OVNKubernetes
  clusterNetwork:
    - cidr: 10.128.0.0/14
      hostPrefix: 23
  serviceNetwork:
    - 172.30.0.0/16
platform:
  none: {}
bootstrapInPlace:
  installationDisk: /dev/sda
pullSecret: '{"auths":{"cloud.openshift.com":{"auth":"a3BlbnNoaWZ0LXJlbGVhc2UtZGV2K29jbV9hY2Nlc3NfMzgzNTRmOTBhMGUzNDA4MDg5ODRkOGM0ZDU2YWE4NjA6M1lWSFA5MEs0S0FJRU5WMDBXSUdJRU42TlNPTFhUQVdSV1JTUlVKSEI3RDc3U1UwSkdPWUdWSkdCM1E1NlZCUg==","email":"tradingcontentdrive@gmail.com"},"quay.io":{"auth":"b3BlbnNoaWZ0LXJlbGVhc2UtZGV2K29jbV9hY2Nlc3NfMzgzNTRmOTBhMGUzNDA4MDg5ODRkOGM0ZDU2YWE4NjA6M1lWSFA5MEs0S0FJRU5WMDBXSUdJRU42TlNPTFhUQVdSV1JTUlVKSEI3RDc3U1UwSkdPWUdWSkdCM1E1NlZCUg==","email":"tradingcontentdrive@gmail.com"},"registry.connect.redhat.com":{"auth":"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","email":"tradingcontentdrive@gmail.com"},"registry.redhat.io":{"auth":"fHVoYy1wb29sLTU1MTkyYjE2LWJjNDgtNGQ4OC1hOWI2LWFkNWVkZWVjMTgxYjpleUpoYkdjaU9pSlNVelV4TWlKOS5leUp6ZFdJaU9pSXhNemszTVRNM016bGtNbVEwTVRSbE9EZGpZMlU0TTJSbU4ySTBaVFJoT1NKOS5sOE9XNjhYYTdOYmlWR1pCWlVvcGlkYnh5bU90cmpzUXZacFVYQjg3MTdvLUcwQjdMZy1vRG1sb2ZxLUxwLWtMcHdQdzVsejZydDZjTUlWZ0ZTOXZXeUJ6a0l3bjEzTlo4RlppT0MzaWZOMlZCVW9xVVVORkNlYU0xVVVfWmtrWXVhZ09ET0ZRYUZIUkVyd0x0RGxvMEZ4VW5zc0txQUM3cnpEdHhiR0xacUd6c0RjdDg5bXVIZ1lHZHMzdzd0am0xd3V0VTQxdGZzdWd2RFlUTEdfYTVCUy0waW9WSnlrMm9jbS1OYU53X1ljRGhNWGJnMEJIVHg2YURtM3laYlJETE1qM3ZJNVM3M21BSU5iY3dvbEVTZHU2UEI5bzN3emo2ZFA3WjJjQXNVSTZ6RmxwaFZVa2ZZYU9kNE9KcFJROVlTUl8wR1F0SkNvYzFVRkZOWUQ4eXJaZUNySXZOYllnQmhocnFtSFJ0NFhBRHl5NkM2bVlTNXN3QUJJR0syMWlUY2FjNWJFN3RqNEh5NG1kdHJISTV3clI2dkxWeXN2TzRoMzJjV1JNR0hOLWgzMGkwRVVEQkRGQzNGbjU0TFZIWWpTNGhNQlBsYzNOWUVlNUtINWVLYTUySXlOTUlnSHlvLVhpSEdsZFZBRnhjTmNVV1hQdmMyUGVvd3JTOWpncXJ1ODl5LWJNNnN6cHY2dFpXLWhpYVN1aUFVT3lOU2lKbWVoblZkSkhSeVVIaFgxN2NBVk83YVJMa2N5VU5pWGc4QlJUSi1BQTAyWFEwRWhQcG91LTNhZGdvbkotRXpkNmxncERzS25rbWtsSjhBbWVUbTkxRHBvcWdNdTFMdElQVlZSU3BOLVBKbFR5NzZlM19aSlcxX2hiTTJZOHYtNWkzSU5Qa29BWDR2OA==","email":"tradingcontentdrive@gmail.com"}}}'
sshKey: "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJ6IRCMyxnuc1XXNjcrwmCysbktAH9u7OQZSy+hQOu5y root@bastion"

Generate the Single Node OpenShift ignition files:

openshift-install create single-node-ignition-config

Verify that the required installation artifacts are created:

ls

Expected output:

auth/
bootstrap-in-place-for-live-iso.ign
metadata.json
worker.ign

The most important file is:

bootstrap-in-place-for-live-iso.ign

This ignition file contains all configuration required to bootstrap the Single Node OpenShift cluster.

Install CoreOS Installer

Install the CoreOS installer utility that is used to embed ignition and network configuration into the RHCOS ISO.

dnf install -y coreos-installer

Verify installation:

coreos-installer --version

Embed Ignition Into the RHCOS ISO

Embed the generated ignition file into the RHCOS live ISO.

coreos-installer iso ignition embed \
-fi bootstrap-in-place-for-live-iso.ign \
rhcos-4.21.0-x86_64-live-iso.x86_64.iso

To assign the static IP 192.168.0.250 to the SNO VM, create a NetworkManager connection file before embedding it into the ISO:

cat > static.nmconnection <<EOF
[connection]
id=ens18
type=ethernet
interface-name=ens18
[ipv4]
address1=192.168.0.250/24,192.168.0.1
dns=192.168.0.200;
method=manual
[ipv6]
method=disabled

Then embed it into the RHCOS ISO:

Embed Static Network Configuration (Optional)

If static networking is required, create a NetworkManager keyfile and embed it into the ISO.

coreos-installer iso network embed \
-n static.nmconnection \
/root/rhcos-4.21.0-x86_64-live-iso.x86_64.iso

The resulting ISO is now a bootable Single Node OpenShift installation ISO that can be attached to the target VM or physical server for deployment.

Verify:

[root@bastion ~]# coreos-installer iso network extract \
/root/rhcos-4.21.0-x86_64-live-iso.x86_64.iso
########## static.nmconnection ##########
[connection]
id=ens18
type=ethernet
interface-name=ens18

[ipv4]
address1=192.168.0.250/24,192.168.0.1
dns=192.168.0.200;
method=manual

[ipv6]
method=disabled

This configures:

| Parameter  | Value               |
| ---------- | ------------------- |
| IP Address | 192.168.0.250       |
| Netmask    | /24 (255.255.255.0) |
| Gateway    | 192.168.0.1         |
| DNS Server | 192.168.0.200       |
| Interface  | ens18               |

After booting the VM from the modified ISO, verify:

ip a

Expected:

ens18
inet 192.168.0.250/24

And verify DNS:

dig api.sno.manohar.in

Copy Modified RHCOS ISO Back to Proxmox

After embedding the ignition file and static network configuration into the RHCOS ISO, copy the modified ISO back to the Proxmox server so it can be attached to the SNO VM. This ISO will be used to create the Single Node OpenShift virtual machine.

# Copy the ISO from Bastion to Proxmox
scp root@192.168.0.201:/root/rhcos-4.21.0-x86_64-live-iso.x86_64.iso \
/var/lib/vz/template/iso/sno-4.21.iso

Verify the ISO is available on the Proxmox server:

ls -lh /var/lib/vz/template/iso/sno-4.21.iso

Expected output:

-rw-r--r-- 1 root root 1.8G sno-4.21.iso

Use sno-4.21.iso as the boot media when creating the Single Node OpenShift virtual machine in Proxmox. The ISO already contains:

  • OpenShift Bootstrap Ignition
  • Static Network Configuration
  • SSH Key Configuration
  • Single Node OpenShift Bootstrap-in-Place Configuration

No additional ignition server or bootstrap node is required.

The VM can now be created and booted directly using sno-4.21.iso.

Create the Single Node OpenShift VM in Proxmox

Once the customized sno-4.21.iso is available on the Proxmox server, create a virtual machine that will host the Single Node OpenShift cluster.

1. Create a New Virtual Machine

  1. Login to the Proxmox Web Console.
  2. Click Create VM.
  3. Configure the following:
| Category | Setting    | Value                     |
| -------- | ---------- | ------------------------- |
| General  | VM ID      | 100 (or any available ID) |
| General  | Name       | sno                       |
| General  | OS Type    | Linux                     |
| General  | ISO Image  | sno-4.21.iso              |
| System   | BIOS       | OVMF (UEFI)               |
| System   | Machine    | q35                       |
| System   | EFI Disk   | Enabled                   |
| System   | TPM        | Optional                  |
| Disk     | Bus/Device | VirtIO SCSI               |
| Disk     | Disk Size  | 150 GB or larger          |
| Disk     | Cache      | Default                   |
| CPU      | Sockets    | 1                         |
| CPU      | Cores      | 8                       |
| CPU      | Type       | Host                      |
| Memory   | RAM        | 16384 MB (16 GB) minimum  |
| Network  | Bridge     | vmbr0                     |
| Network  | Model      | VirtIO                    |
| Network  | VLAN       | Optional                  |
None

2. Select the Uploaded ISO

None

3. Configure Disk

None

4. Configure CPU

None

5. Configure Memory

None

7. Select Default Network

None

8. Start the VM

After reviewing the configuration:

None

9. Check Console

None

The RHCOS live ISO boots automatically and starts the Bootstrap-in-Place installation process using the embedded ignition configuration.

Access the OpenShift Cluster

After the installation is complete, configure the OpenShift CLI to communicate with the cluster.

Set the kubeconfig file:

export KUBECONFIG=auth/kubeconfig

Verify cluster access:

oc get nodes

SSH into the node

ssh-keygen -f "/root/.ssh/known_hosts" -R "192.168.0.250" && ssh -i /root/ocp-key core@192.168.0.250
ssh core@192.168.0.250
sudo journalctl -b -f -u release-image.service -u bootkube.service -u node-image-pull.service

The installation is complete when all Cluster Operators report Available=True and the node reaches the Ready state.

If cluster is not Ready yet. Then do below steps

Check the running container inside the node

CONTAINER           IMAGE
    CREATED              STATE               NAME                             ATTEMPT             POD ID              POD
                                NAMESPACE
fb316e59c23a8       1f346ead4c33d3b45fe35dbaf31aa28841ec9d90159984526028aa8c9f124ff5
    About a minute ago   Running             kube-controller-manager          1                   5d0c9993fcce4       bootstrap-kube-cont
roller-manager-sno.manohar.in   kube-system
ad4f9137f8429       quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:c1adea1a9bbe0bb607b36fd996edeeeb33d04badb9c6204ba63bf45a744ea36
0   About a minute ago   Running             cluster-policy-controller        0                   5d0c9993fcce4       bootstrap-kube-cont
roller-manager-sno.manohar.in   kube-system
4fe626a1849b0       quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:95ecc9b2e6efbdea01353946364ad49d20a23959893c3756e4c55ec2766bb52
c   About a minute ago   Running             kube-scheduler                   0                   a0985d6a0f495       bootstrap-kube-sche
duler-sno.manohar.in            kube-system
2b492ca0de78b       d22d74de8c5947d04984b5d45391b6307701760bb22a305c8014934e661c7588
    About a minute ago   Running             kube-apiserver-insecure-readyz   0                   727177d806df4       bootstrap-kube-apis
erver-sno.manohar.in            openshift-kube-apiserver
5cb8b288e5832       1f346ead4c33d3b45fe35dbaf31aa28841ec9d90159984526028aa8c9f124ff5
    About a minute ago   Running             kube-apiserver                   0                   727177d806df4       bootstrap-kube-apis
erver-sno.manohar.in            openshift-kube-apiserver
bb9e6f79e4f66       e2fd08a37a54f9d55e141a0f360a4339f65f955e64007b5daee1b244efa28801
    2 minutes ago        Running             cloud-credential-operator        0                   ed6efc6e6bbe5       cloud-credential-op
erator-sno.manohar.in           openshift-cloud-credential-operator
1fabfe863b412       fa11a41e639118d81aaa136c911c5103d73a52a439a518d23bb7b8c76baa4dad
    3 minutes ago        Running             machine-config-server            0                   2245159eba6e4       bootstrap-machine-c
onfig-operator-sno.manohar.in   default
218d1e6b018ea       d6609fce858c16b9182e2f19478d11693e00ee3f030637885d13715feda9ccfe
    7 minutes ago        Running             etcd                             0                   4abee1608273b       etcd-sno.manohar.in
-sno.manohar.in                 openshift-etcd
007b8067d4e89       quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:fc4787f69db199e7642c5cf5188cffac3762a479b65a2e234ae07db89a295b9
8   7 minutes ago        Running             etcdctl                          0                   4abee1608273b       etcd-sno.manohar.in
-sno.manohar.in                 openshift-etcd

Check whether the OpenShift Kubernetes API Server is reachable and running.

[core@sno ~]$ curl -k https://api.sno.manohar.in:6443/version
{
  "major": "1",
  "minor": "34",
  "emulationMajor": "1",
  "emulationMinor": "34",
  "minCompatibilityMajor": "1",
  "minCompatibilityMinor": "33",
  "gitVersion": "v1.34.8",
  "gitCommit": "7838e4cd9555d44f788308bebee8877abd9ba675",
  "gitTreeState": "clean",
  "buildDate": "2026-05-14T17:24:27Z",
  "goVersion": "go1.24.13 (Red Hat 1.24.13-5.el9_6) X:strictfipsruntime",
  "compiler": "gc",
  "platform": "linux/amd64"

If you get:

Could not resolve host

it means DNS is not resolving api.sno.manohar.in.

Many people use this command during SNO installation to quickly verify that the Kubernetes API has started before checking nodes and operators.

Verify OpenShift API Server Availability

During the installation, you can verify whether the Kubernetes API Server is up and responding.

Check API readiness locally on the SNO node:

curl -k https://localhost:6443/readyz

Expected output:

ok

Check API readiness from the Bastion server using the OpenShift CLI:

oc get --raw='/readyz'

Expected output:

ok

An ok response confirms that the OpenShift API Server is healthy and ready to serve requests.

Check Cluster reachability

[root@bastion ~]# oc get nodes
NAME             STATUS   ROLES                         AGE   VERSION
sno.manohar.in   Ready    control-plane,master,worker   78m   v1.34.8

Verify Cluster Installation Progress

During the installation, you can monitor the overall cluster installation status.

oc get clusterversion

Example output during installation:

NAME      VERSION   AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.21.19   False       True          20m     Working towards 4.21.19: 67% complete

This indicates that the cluster installation is still in progress and operators are being deployed and configured.

Once the installation completes successfully, the output changes to:

NAME      VERSION   AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.21.19   True        False         49m     Cluster version is 4.21.19

This confirms that:

  • OpenShift installation is complete
  • Cluster Version Operator is healthy
  • All required operators have successfully reconciled
  • The cluster is ready for use

Verify Machine Config Pool Status

The Machine Config Pool (MCP) status indicates whether the cluster configuration has been successfully applied to all nodes.

oc get mcp

Example output:

NAME     CONFIG                                             UPDATED   UPDATING   DEGRADED   MACHINECOUNT   READYMACHINECOUNT   UPDATEDMACHINECOUNT   DEGRADEDMACHINECOUNT   AGE
master   rendered-master-b893cc5663fc78068b45a51787333961   True      False      False      1              1                   1                     0                      67m
worker   rendered-worker-598e6fd7e73896b6bb01a552da105f1f   True      False      False      0              0                   0                     0                      67m

Important fields:

| Field    | Expected Value |
| -------- | -------------- |
| UPDATED  | True           |
| UPDATING | False          |
| DEGRADED | False          |

This confirms that:

  • Machine configuration has been successfully applied.
  • No configuration updates are currently in progress.
  • No machine configuration errors exist.
  • The Single Node OpenShift control-plane node is fully updated and healthy.

Verify Cluster Operators

Check the status of all OpenShift Cluster Operators:

[root@bastion ~]# oc get co
NAME                                       VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE   MESSAGE
authentication                             4.21.19   True        False         False      50m
baremetal                                  4.21.19   True        False         False      68m
cloud-controller-manager                   4.21.19   True        False         False      63m
cloud-credential                           4.21.19   True        False         False      95m
cluster-autoscaler                         4.21.19   True        False         False      64m
config-operator                            4.21.19   True        False         False      71m
console                                    4.21.19   True        False         False      50m
control-plane-machine-set                  4.21.19   True        False         False      64m
csi-snapshot-controller                    4.21.19   True        False         False      61m
dns                                        4.21.19   True        False         False      61m
etcd                                       4.21.19   True        False         False      68m
image-registry                             4.21.19   True        False         False      57m
ingress                                    4.21.19   True        False         False      68m
insights                                   4.21.19   True        False         False      57m
kube-apiserver                             4.21.19   True        False         False      61m
kube-controller-manager                    4.21.19   True        False         False      61m
kube-scheduler                             4.21.19   True        False         False      58m
kube-storage-version-migrator              4.21.19   True        False         False      70m
machine-api                                4.21.19   True        False         False      57m
machine-approver                           4.21.19   True        False         False      64m
machine-config                             4.21.19   True        False         False      63m
marketplace                                4.21.19   True        False         False      68m
monitoring                                 4.21.19   True        False         False      51m
network                                    4.21.19   True        False         False      72m
node-tuning                                4.21.19   True        False         False      61m
olm                                        4.21.19   True        False         False      70m
openshift-apiserver                        4.21.19   True        False         False      58m
openshift-controller-manager               4.21.19   True        False         False      62m
openshift-samples                          4.21.19   True        False         False      58m
operator-lifecycle-manager                 4.21.19   True        False         False      62m
operator-lifecycle-manager-catalog         4.21.19   True        False         False      62m
operator-lifecycle-manager-packageserver   4.21.19   True        False         False      61m
service-ca                                 4.21.19   True        False         False      71m
storage                                    4.21.19   True        False         False      62m
| Field       | Expected Value |
| ----------- | -------------- |
| AVAILABLE   | True           |
| PROGRESSING | False          |
| DEGRADED    | False          |

Retrieve the initial kubeadmin password:

cat auth/kubeadmin-password

Use this password to log in to the OpenShift Web Console:

https://console-openshift-console.apps.sno.manohar.in

The kubeadmin user and password are generated automatically during installation and are required for the first login to the cluster.

[root@bastion ~]# oc whoami --show-console
https://console-openshift-console.apps.sno.manohar.in

Add Host Entries on the Windows Client

To access the OpenShift Web Console from a Windows machine without configuring a wildcard DNS entry, add the required host entries to the Windows hosts file.

Open Notepad as Administrator and edit:

C:\Windows\System32\drivers\etc\hosts

Add the following entries:

192.168.0.250 sno.manohar.in
192.168.0.250 api.sno.manohar.in
192.168.0.250 api-int.sno.manohar.in
192.168.0.250 console-openshift-console.apps.sno.manohar.in
192.168.0.250 oauth-openshift.apps.sno.manohar.in

Save the file and flush the DNS cache:

ipconfig /flushdns

Verify name resolution:

ping console-openshift-console.apps.sno.manohar.in
ping oauth-openshift.apps.sno.manohar.in
| Hostname                                      | IP Address    |
| --------------------------------------------- | ------------- |
| sno.manohar.in                                | 192.168.0.250 |
| api.sno.manohar.in                            | 192.168.0.250 |
| api-int.sno.manohar.in                        | 192.168.0.250 |
| console-openshift-console.apps.sno.manohar.in | 192.168.0.250 |
| oauth-openshift.apps.sno.manohar.in           | 192.168.0.250 |

Once the entries are added, access the OpenShift Console:

https://console-openshift-console.apps.sno.manohar.in
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Conclusion:

That's pretty much how sno came together for me. one node doing the job of what usually takes a handful of machines, and honestly it held up better than i expected. if you've been holding off on trying openshift because the hardware ask felt like too much, this is probably the easiest door in. i'm planning to push it further next, maybe see how it handles a real workload instead of just sitting idle, so more on that soon.

if this helped you in any way, hit that clap button, costs nothing and genuinely helps the post reach more people. and if you know someone struggling with the whole "i need three masters just to try openshift" thing, share this with them, might save them a weekend like it saved mine.