Rocky Linux 9.8 on Azure User Guide

Overview

This guide covers the deployment and configuration of Rocky Linux 9.8 on Microsoft Azure using cloudimg's pre configured virtual machine image from the Azure Marketplace.

Rocky Linux is a community driven enterprise Linux distribution, built by the Rocky Enterprise Software Foundation to be binary compatible with Red Hat Enterprise Linux 9. Version 9.8 is a point release in the RHEL 9 family, and this image is pinned to it: the machine reports release 9.8 and carries every update available for that stream at build time.

What's included:

• Rocky Linux 9.8, binary compatible with RHEL 9
• Every available update applied at build time, verified with a zero pending check
• Unattended updates already armed, so the machine keeps patching itself
• Azure Linux Agent (waagent) and cloud-init for Azure integration
• Chronyd for NTP time synchronisation
• SELinux in enforcing mode, both at runtime and persisted for the next boot
• BaseOS, AppStream and Extras repositories enabled, with signature checking on
• Exactly one externally reachable port: SSH on 22
• Gen2 Hyper V virtual machine support
• 24/7 cloudimg support

Platform: Microsoft Azure (Gen2 Hyper V) Default user: azureuser

Security posture

This image ships with no known credential. There is no default password and no baked in SSH key:

• The root account password is locked, so no one can log in as root with a password.
• PasswordAuthentication is disabled in the SSH daemon, so every login is by key.
• KbdInteractiveAuthentication is also disabled, closing the other password path.
• PermitRootLogin is set to prohibit-password, so root cannot be reached with a password even if one were later set.
• The only key that works is the public key you supply when you create the virtual machine. Azure injects it into azureuser at first boot, so no two machines you launch ever share a secret.
• No SSH host keys are baked into the image. Each machine generates its own at first boot, so two machines built from this image never share a host identity.
• /etc/machine-id ships empty and is regenerated per machine.
• SELinux is left in enforcing mode, the Rocky Linux default.

Prerequisites

Before deploying this image, ensure you have:

1. An active Microsoft Azure subscription
2. Access to the Azure Portal or Azure CLI
3. An SSH key pair for Linux VM access
4. Familiarity with Azure VM management

Recommended VM Size: Standard_B2s (2 vCPU, 4 GB RAM) or larger.

Step 1: Deploy the Virtual Machine

Option A: Azure Portal

1. Navigate to the Azure Marketplace and search for "Rocky Linux 9.8 cloudimg"
2. Select the image and click Create
3. Configure the basics:
4. Subscription: Select your Azure subscription
5. Resource Group: Create new or select existing
6. Virtual Machine Name: Enter a name for your VM
7. Region: Select your preferred Azure region
8. Size: Standard_B2s recommended
9. Under Administrator Account, select SSH public key and enter your key
10. Under Inbound Port Rules, allow SSH (port 22)
11. Click Review + Create, then Create

Option B: Azure CLI

az vm create \
  --resource-group myResourceGroup \
  --name my-rocky-9-8-vm \
  --image cloudimg:rocky-9-8:default:latest \
  --size Standard_B2s \
  --admin-username azureuser \
  --generate-ssh-keys \
  --public-ip-sku Standard

Step 2: Connect via SSH

Run these on your own workstation, not on the VM. Find the public IP, then connect:

az vm show --resource-group myResourceGroup --name my-rocky-9-8-vm --show-details --query publicIps -o tsv
ssh azureuser@<vm-ip>

There is no password to enter. If SSH asks you for one, the key you supplied at create time is not the key your client is offering.

Step 3: Confirm the release

Check that the machine is the Rocky Linux 9.8 release you expect:

cat /etc/rocky-release
grep -E '^(NAME|VERSION|ID|PLATFORM_ID)=' /etc/os-release
uname -rm

Expected output:

Rocky Linux release 9.8 (Blue Onyx)
NAME="Rocky Linux"
VERSION="9.8 (Blue Onyx)"
ID="rocky"
PLATFORM_ID="platform:el9"
5.14.0-687.29.1.el9_8.x86_64 x86_64

The kernel version carries an el9_8 tag. That is the marker that the machine is on the 9.8 stream rather than an older 9 series minor.

Step 4: Check the patch level

The image is fully updated at build time. dnf check-update returns exit code 100 when updates are pending and 0 when none are:

sudo dnf check-update
echo "check-update exit code: $?"

Confirm no reboot is outstanding. needs-restarting -r returns 0 when nothing requires a restart:

sudo dnf needs-restarting -r
echo "needs-restarting exit code: $?"

List the enabled repositories to confirm your update path is intact:

dnf repolist --enabled

Expected output:

repo id                         repo name
appstream                       Rocky Linux 9 - AppStream
baseos                          Rocky Linux 9 - BaseOS
extras                          Rocky Linux 9 - Extras

CodeReady Builder (crb) is not enabled on this image. It carries developer and build time packages that most server workloads do not need. Enable it yourself if you need it:

echo "crb state: $(dnf repolist --all 2>/dev/null | grep -c '^crb ')"

To turn it on, run sudo dnf config-manager --set-enabled crb.

Package signatures are verified on every install: no repository on this image sets gpgcheck=0.

Step 5: Unattended updates are already armed

This image does not just ship patched, it keeps patching itself. dnf-automatic is installed, configured to apply updates, and its timer is enabled so it starts on every boot:

systemctl is-enabled dnf-automatic.timer
systemctl is-active dnf-automatic.timer
grep -E '^(upgrade_type|download_updates|apply_updates)' /etc/dnf/automatic.conf

Expected output:

enabled
active
upgrade_type = default
download_updates = yes
apply_updates = yes

upgrade_type is deliberately set to default rather than security. The security only mode resolves against errata metadata, and where that metadata is not published a security only policy silently resolves to nothing and applies no updates at all. Setting default means every available update is applied, which cannot quietly do nothing.

If you would rather control the schedule yourself, disable the timer and patch on your own cadence:

echo "to take manual control: sudo systemctl disable --now dnf-automatic.timer"

To patch by hand at any time, run sudo dnf upgrade -y, then reboot with sudo systemctl reboot if a new kernel was installed.

Step 6: Verify the security posture

Confirm SELinux is enforcing, root is locked, and SSH is key only:

getenforce
grep -E '^[[:space:]]*SELINUX=' /etc/selinux/config
sudo passwd -S root
sudo sshd -T | grep -E '^(permitrootlogin|passwordauthentication|pubkeyauthentication|kbdinteractiveauthentication)'

Expected output:

Enforcing
SELINUX=enforcing
root LK 2009-12-22 -1 -1 -1 -1 (Alternate authentication scheme in use.)
permitrootlogin without-password
pubkeyauthentication yes
passwordauthentication no
kbdinteractiveauthentication no

without-password is how OpenSSH reports the prohibit-password setting. Both names mean the same thing: root may not authenticate with a password.

Both the runtime mode and the persisted /etc/selinux/config value are checked, because a runtime setting that is not persisted would silently revert on your next reboot.

Step 7: Verify Azure integration

Confirm the Azure Linux Agent, cloud-init and time synchronisation are healthy, and check your resources:

systemctl is-active waagent
systemctl is-enabled waagent
cloud-init --version
systemctl is-active chronyd
df -h /
free -h

waagent is what lets Azure provision your SSH key, resize the OS disk, run extensions and report VM health, so it should always be active and enabled.

Note that free -h reports 0B of swap. That is deliberate. Azure manages swap on the ephemeral resource disk through waagent rather than on the OS disk, and a swap file baked into a Marketplace image fails certification. Configure swap yourself through waagent if your workload needs it.

Step 8: Networking and open ports

The Azure Network Security Group is the control plane for inbound and outbound traffic, and it is the first and usually the only place you need to open a port.

This image is a minimal build, so firewalld is not installed. That is deliberate: with no host firewall in the way, your NSG rules take effect exactly as written, with no second layer to keep in sync. Confirm what is listening before you open anything:

ss -tlnu

On a fresh machine SSH on port 22 is the only externally bound listener. Chrony appears on 127.0.0.1:323, which is loopback only and not reachable from the network.

rpcbind is disabled on this image. The stock Rocky cloud image enables it because nfs-utils depends on it, which leaves TCP and UDP port 111 open on every interface. NFSv4, the default in Rocky Linux 9, does not use rpcbind at all, so this image disables it and closes the port while keeping nfs-utils installed and fully working for NFSv4 mounts:

echo "rpcbind.socket: $(systemctl is-enabled rpcbind.socket 2>/dev/null || echo disabled)"
rpm -q nfs-utils

If you specifically need NFSv3, which does require the portmapper, turn it back on with one command:

echo "to re-enable NFSv3 support: sudo systemctl enable --now rpcbind.socket"

It is disabled rather than masked precisely so that command works without further steps.

If your policy requires a host firewall as well, install and enable it yourself:

sudo dnf install -y firewalld
sudo systemctl enable --now firewalld
sudo firewall-cmd --permanent --add-port=443/tcp
sudo firewall-cmd --reload

Once firewalld is running, a port must be open in both the Azure NSG and firewalld before traffic reaches your service.

Step 9: Install software

AppStream carries the application packages. Search it, then install what you need:

dnf search nginx

The 9 series still ships modules for some packages: AppStream can carry several versions of the same language or database as separate streams, so you can pick a version rather than take the default.

dnf module list nginx

Expected output:

Rocky Linux 9 - AppStream
Name  Stream Profiles   Summary
nginx 1.22   common [d] nginx webserver
nginx 1.24   common [d] nginx webserver
nginx 1.26   common [d] nginx webserver

Install a package and enable it in the usual way, for example sudo dnf install -y nginx followed by sudo systemctl enable --now nginx.

To add another administrator, create the account with sudo adduser <name>, add it to the wheel group with sudo usermod -aG wheel <name>, then copy your public key into /home/<name>/.ssh/authorized_keys with mode 600 and the .ssh directory mode 700, owned by that user. The image ships with no human accounts at all, so azureuser is the only login until you add one:

getent group wheel

Common Use Cases

• RHEL 9 compatible application hosting
• Enterprise server workloads that need a pinned point release
• A base for software certified on the 9 platform
• Migration target for CentOS 7 and CentOS Stream estates

Troubleshooting

Cannot connect via SSH

1. Verify the VM is in Running state in the Azure Portal
2. Check that port 22 is allowed in the Network Security Group
3. Ensure you are using the correct username: azureuser
4. Verify your SSH key matches the one you supplied at create time. Password login is disabled by design, so a wrong key cannot fall back to a password prompt.

To see which key your client is actually offering, run ssh -v azureuser@<vm-ip> from your workstation and look for the Offering public key lines.

Azure agent not running

systemctl is-active waagent
sudo systemctl enable --now waagent

Package manager issues

Refresh the metadata cache first:

sudo dnf clean all
sudo dnf makecache

If repositories are unreachable, check DNS resolution. This image is minimal, so nslookup and dig are not installed; getent is always present and resolves through the same system resolver:

getent hosts download.rockylinux.org

Install bind-utils if you want dig and nslookup available.

A service is blocked and the logs mention SELinux

SELinux is enforcing on this image. Rather than disabling it, look at what was denied. On a healthy machine there are no recent denials, so the command reports none:

sudo ausearch -m AVC -ts recent 2>/dev/null || echo "no recent AVC denials"

If a denial is genuine, prefer setting the correct file context with semanage fcontext and restorecon, or enabling the relevant boolean with setsebool -P, over turning SELinux off.

Checking for failed services

A healthy machine reports running with nothing failed:

systemctl is-system-running
systemctl list-units --state=failed --no-legend

Important Notes

Rocky Linux is free and open source, and it is a collection of licences rather than a single one. This image carries 463 installed packages between them declaring 103 distinct licence strings, most commonly LGPLv2+, GPLv2+, MIT, GPLv3+, BSD, GPLv2, LGPLv3+ and Public Domain. Each package's own terms are readable on the machine:

rpm -qa --qf '%{LICENSE}\n' | sort | uniq -c | sort -rn | awk 'NR<=8'

No subscription, licence key or support contract is required for any of it.

Rocky Linux 9 is supported until May 2032. This image is pinned to the 9.8 point release; if you would rather track whichever 9 series release is current, use the cloudimg Rocky Linux 9 image instead.

Support

For assistance with this image, contact cloudimg support:

• Website: www.cloudimg.co.uk
• Product Catalogue: www.cloudimg.co.uk/products
• User Guides: www.cloudimg.co.uk/guides
• SLA: 24 hour response guaranteed