CentOS Stream 9 LVM

Option A: Azure Portal

• Go to the Azure Marketplace and search for "CentOS Stream 9 LVM SecureAnyCloud".
• Select the image and choose Create.
• On the Basics tab, set Subscription to your Azure subscription, Resource Group to a new or existing group, Virtual Machine Name to a name for your VM, Region to your preferred Azure region, and Size to Standard_B2s (recommended).
• Under Administrator Account, select SSH public key and enter your key.
• Under Inbound Port Rules, allow SSH (port 22).
• Choose Review + Create, then Create.

Option B: Azure CLI

az vm image terms accept --urn sac1647283583153:centos-stream-9-lvm:default:latest
az vm create \
  --resource-group myResourceGroup \
  --name my-centos-stream-9-lvm-vm \
  --image sac1647283583153:centos-stream-9-lvm:default:latest \
  --size Standard_B2s \
  --admin-username azureuser \
  --generate-ssh-keys \
  --public-ip-sku Standard

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

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

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

Check that the machine is the CentOS Stream 9 release you expect:

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

Expected output:

CentOS Stream release 9 NAME="CentOS Stream" VERSION="9" ID="centos" PLATFORM_ID="platform:el9" 5.14.0-731.el9.x86_64 x86_64

The kernel version carries an el9 tag. CentOS Stream is a rolling release, so the exact kernel build advances as you apply updates. There is no fixed minor to pin to.

This is the defining feature of this image. The root filesystem is a logical volume, not a plain partition. Confirm the layout:

lsblk -o NAME,TYPE,MOUNTPOINT,SIZE,FSTYPE findmnt /
sudo vgs
sudo lvs

Expected output:

NAME TYPE MOUNTPOINT SIZE FSTYPE sda disk 10G ├─sda1 part /boot/efi 600M vfat ├─sda2 part /boot 1G xfs └─sda3 part 8.4G LVM2_member └─cs-root lvm / 8.4G xfs TARGET SOURCE FSTYPE OPTIONS / /dev/mapper/cs-root xfs rw,relatime,... VG #PV #LV #SN Attr VSize VFree cs 1 1 0 wz--n- 8.41g 0 LV VG Attr LSize root cs -wi-ao---- 8.41g

Root is /dev/mapper/cs-root, a logical volume in the cs volume group. The lvm type against / in lsblk proves that this is the LVM variant.

Growing the root filesystem

Because root is a logical volume, you can grow it online. First resize the OS disk in Azure: stop the VM, set a larger disk size, then start the VM. Then grow the partition, the physical volume, the logical volume and the xfs filesystem in sequence:

# grow partition 3 to fill the enlarged disk
sudo growpart /dev/sda 3
# grow the physical volume into the enlarged partition
sudo pvresize /dev/sda3
# extend the logical volume to use all free space in the volume group sudo lvextend -l +100%FREE /dev/cs/root
# grow the xfs filesystem to fill the enlarged logical volume (xfs grows mounted)
sudo xfs_growfs /

You can also add a second data disk to the volume group and extend root across both. This is the main reason to run an LVM root:

sudo pvcreate /dev/sdc
sudo vgextend cs /dev/sdc
sudo lvextend -l +100%FREE /dev/cs/root
sudo xfs_growfs /

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 "exit code: $?" dnf repolist --enabled

This image also arms dnf-automatic, so security updates are downloaded and applied on a timer without any action from you. You can still run updates on your own schedule:

sudo dnf upgrade -y sudo systemctl reboot
# only if a new kernel was installed

Confirm that SELinux is enforcing, root is locked, and SSH accepts keys only:

getenforce
sudo passwd -S root
sudo sshd -T | grep -E '^(permitrootlogin|passwordauthentication|pubkeyauthentication)'

Expected output:

Enforcing root LK 2009-12-22 -1 -1 -1 -1 (Password locked.) permitrootlogin no pubkeyauthentication yes passwordauthentication no

Confirm that the Azure Linux Agent, cloud-init and time synchronisation are healthy and that unattended security updates are armed. Then check your resources:

systemctl is-active waagent
systemctl is-enabled waagent cloud-init --version
systemctl is-enabled dnf-automatic.timer
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. It should always be active and enabled.

An enabled dnf-automatic.timer is what keeps the machine applying security updates on its own after launch.

The Azure Network Security Group is the control plane for inbound and outbound traffic. It is the first, and usually the only, place you need to open a port. The image advertises a single inbound port, SSH on 22.

This image binds no unnecessary listeners. rpcbind, the local RPC helper on port 111 that the stock cloud image leaves running, is disabled, because NFSv4, the CentOS Stream 9 default, does not use it. If you need NFSv3, restore it with one command:

sudo systemctl unmask rpcbind.socket
sudo systemctl enable --now rpcbind.socket

Confirm what is listening before you open anything:

ss -tlnp

On a fresh machine, the only listener is sshd on port 22. If your policy also requires a host firewall, firewalld is installed and running with the SSH service already allowed:

sudo firewall-cmd --list-services sudo firewall-cmd --permanent --add-service=https sudo firewall-cmd --reload

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

dnf search nginx
dnf module list nginx
sudo dnf install -y nginx
sudo systemctl enable --now nginx

To add another administrator, create the account with sudo adduser <name> and add it to the wheel group with sudo usermod -aG wheel <name>. Then copy your public key into /home/<name>/.ssh/authorized_keys. Give the file mode 600 and the .ssh directory mode 700, both owned by that user.

Option A: AWS Marketplace console

• Open the SecureAnyCloud CentOS Stream listing on AWS Marketplace. Choose View purchase options, then Subscribe. One subscription covers every version in the listing.
• Once the subscription is active, choose Launch your software.
• Choose One-click launch from AWS Marketplace, or Launch from EC2 Console for full control. In Version, choose CentOS Stream 9 LVM - YYYY-MM-DD, where the date is when the version was added, then choose your Region.
• Choose an instance type. m5.large is recommended, and any current x86_64 type works. The software charge is $0.04 per vCPU per hour.
• Choose your EC2 key pair. It is the only way in. RSA and ED25519 keys both work.
• Set the security group to allow inbound TCP 22 from your own IP address or network only.
• Set the storage. The root volume is 12 GiB gp3 by default. You can choose a larger size. The extra space stays unallocated in the LVM physical volume until you give it to the volumes you choose (Step 12).
• Leave the metadata defaults, because the image already requires IMDSv2. Then choose Launch.

Option B: AWS CLI

Run this on your own workstation. Replace the AMI ID with the one shown for your Region on the Marketplace launch page. Replace the key pair, security group and subnet with your own. The root device of this AMI is /dev/xvda:

aws ec2 run-instances \
  --image-id ami-0123456789abcdef0 \
  --instance-type m5.large \
  --key-name my-key-pair \
  --security-group-ids sg-0123456789abcdef0 \
  --subnet-id subnet-0123456789abcdef0 \
  --block-device-mappings 'DeviceName=/dev/xvda,Ebs={VolumeSize=20,VolumeType=gp3}' \
  --tag-specifications 'ResourceType=instance,Tags=[{Key=Name,Value=centos-stream-9-lvm}]'

You do not need --metadata-options: the AMI already makes IMDSv2 required.

From your workstation, connect as ec2-user with the key pair you chose:

ssh -i ~/.ssh/my-key-pair.pem ec2-user@<public-ip>

There is no password to enter. If SSH asks for one, or says Too many authentication failures, see Troubleshooting below.

You can also connect without opening port 22 at all, through AWS Systems Manager Session Manager, if the instance has an instance profile that allows Systems Manager. The agent is installed and running on this image.

cat /etc/centos-release grep -E '^(NAME|VERSION|ID|VERSION_ID|PLATFORM_ID|PRETTY_NAME)=' /etc/os-release uname -srm

Expected output:

CentOS Stream release 9 NAME="CentOS Stream" VERSION="9" ID="centos" VERSION_ID="9" PLATFORM_ID="platform:el9" PRETTY_NAME="CentOS Stream 9" Linux 5.14.0-758.el9.x86_64 x86_64

CentOS Stream has no point releases. The release is just 9, and the system moves forward through ordinary dnf updates. Your kernel version is newer if updates have installed since this image was built.

The disk and its volumes:

lsblk -o NAME,SIZE,TYPE,FSTYPE,MOUNTPOINTS /dev/nvme0n1

Expected output with the default 12 GiB root volume:

NAME SIZE TYPE FSTYPE MOUNTPOINTS nvme0n1 12G disk ├─nvme0n1p1 1M part ├─nvme0n1p2 200M part vfat /boot/efi ├─nvme0n1p3 1G part xfs /boot └─nvme0n1p4 10.8G part LVM2_member ├─cs-root 4G lvm xfs / ├─cs-home 1G lvm xfs /home ├─cs-tmp 1G lvm xfs /tmp ├─cs-var 1.5G lvm xfs /var ├─cs-var_tmp 512M lvm xfs /var/tmp ├─cs-var_log 1G lvm xfs /var/log └─cs-var_log_audit 1G lvm xfs /var/log/audit

The volume group, its logical volumes and the mount options each volume carries:

sudo vgs
sudo lvs -o lv_name,lv_size,lv_path cs for m in / /home /tmp /var /var/tmp /var/log /var/log/audit /boot /dev/shm; do printf '%-15s %-36s %s\n' "$m" "$(findmnt -no SOURCE "$m")" "$(findmnt -no OPTIONS "$m" | tr , '\n' | grep -xE 'rw|ro|nodev|nosuid|noexec' | paste -sd, -)"; done

Expected output:

VG #PV #LV #SN Attr VSize VFree cs 1 7 0 wz--n- 10.80g 820.00m LV LSize Path home 1.00g /dev/cs/home root 4.00g /dev/cs/root tmp 1.00g /dev/cs/tmp var 1.50g /dev/cs/var var_log 1.00g /dev/cs/var_log var_log_audit 1.00g /dev/cs/var_log_audit var_tmp 512.00m /dev/cs/var_tmp / /dev/mapper/cs-root rw /home /dev/mapper/cs-home rw,nosuid,nodev /tmp /dev/mapper/cs-tmp rw,nosuid,nodev,noexec /var /dev/mapper/cs-var rw,nosuid,nodev /var/tmp /dev/mapper/cs-var_tmp rw,nosuid,nodev,noexec /var/log /dev/mapper/cs-var_log rw,nosuid,nodev,noexec /var/log/audit /dev/mapper/cs-var_log_audit rw,nosuid,nodev,noexec /boot /dev/nvme0n1p3 rw,nosuid,nodev /dev/shm tmpfs rw,nosuid,nodev,noexec

• The disk has a 1 MiB BIOS boot partition, a 200 MiB EFI system partition, a 1 GiB /boot (XFS) and one LVM physical volume. The AMI boots in legacy BIOS mode. The EFI partition is carried but not used to boot. It is mounted at /boot/efi from /etc/fstab.
• systemd also offers the same partition at /efi on demand, through an automount created by systemd-gpt-auto-generator, as on every CentOS Stream 9 image. While that automount is active, for example in the first minutes after boot, lsblk lists /efi as a second mount point.
• The mount options are set in /etc/fstab by filesystem UUID, so they survive reboots and apply on every instance launched from the image. The last column shows the options that matter for the benchmark. findmnt lists the rest.
• The volume group keeps 820 MiB free at the default size, so you can grow the volume that fills first without touching EBS (Step 12).

The kernel finds its root filesystem on the logical volume. The same arguments are recorded in /etc/kernel/cmdline, so every kernel that a future update installs boots from the logical volume too:

grep -o 'root=[^ ]*\|rd.lvm[^ ]*' /proc/cmdline
grep -o 'root=[^ ]*\|rd.lvm[^ ]*' /etc/kernel/cmdline rpm -q lvm2 cloud-utils-growpart xfsprogs

Expected output:

root=/dev/mapper/cs-root rd.lvm.lv=cs/root root=/dev/mapper/cs-root rd.lvm.lv=cs/root lvm2-2.03.33-6.el9.x86_64 cloud-utils-growpart-0.33-1.el9.x86_64 xfsprogs-6.4.0-9.el9.x86_64

The evaluation the build ran after its reboot ships on the image:

ls -lh /usr/share/doc/sac/ python3 -c "import json; s=json.load(open('/usr/share/doc/sac/cis-l1-summary.json')); print('profile: ', s['profileLabel'], '(SCAP Security Guide', s['ssgVersion'] + ')'); print('scored rules: ', s['scored'], ' pass:', s['pass'], ' fail:', s['fail'], ' rate:', str(s['ratePct']) + '%'); print('waived: ', s['waived'], ' not applicable:', s['notapplicable']); print('evaluated at: ', s['evaluatedAt'])"

Expected output:

total 39M -rw-r--r--. 1 root root 37M Oct 21 13:08 cis-l1-arf.xml -rw-r--r--. 1 root root 2.3M Oct 21 13:08 cis-l1-report.html -rw-r--r--. 1 root root 1.2K Oct 21 13:08 cis-l1-summary.json -rw-r--r--. 1 root root 1.5K Oct 21 13:08 cis-l1-tailoring.xml -rw-r--r--. 1 root root 2.0K Oct 21 13:08 cis-l1-waivers.txt -rw-r--r--. 1 root root 1.6K Oct 21 13:04 scap-security-guide-LICENSE.txt profile: CIS Level 1 Server (SCAP Security Guide 0.1.82) scored rules: 273 pass: 272 fail: 1 rate: 99.6% waived: 5 not applicable: 17 evaluated at: 2026-10-21T13:08:17Z

• cis-l1-report.html is the full OpenSCAP report, rule by rule. Copy it to your workstation and open it in a browser.
• cis-l1-arf.xml is the same evaluation in the machine-readable ARF format, for compliance tooling.
• cis-l1-tailoring.xml is the exact tailoring used, so you can re-run the same evaluation (Step 6).
• The pass rate is pass / (pass + fail + error + unknown). Rules that are not applicable to this machine, not selected, or waived are not counted.
• Compared with the single-volume versions of this listing, the partition rules (/tmp, /var, /var/tmp, /var/log, /var/log/audit and /home on their own partitions, and their mount options) are scored here and pass.

To copy the report to your workstation, run this command on the workstation:

scp -i ~/.ssh/my-key-pair.pem ec2-user@<public-ip>:/usr/share/doc/sac/cis-l1-report.html .

The five waived rules

grep -v '^#' /usr/share/doc/sac/cis-l1-waivers.txt | cut -f1,2

Expected output:

grub2_password [serial-console-and-boot] ensure_root_password_configured [serial-console-and-boot] accounts_maximum_age_login_defs [key-only-account-aging] account_disable_post_pw_expiration [key-only-account-aging] sshd_limit_user_access [ssh-access-list]

The full reason for each is the third column of the same file. In short:

• Boot loader and root passwords: a GRUB or root password would have to be baked into the image, giving every instance the same secret. Root stays locked with no password. Set your own if you need serial console access (see Step 11).
• Password ageing defaults: the accounts cloud-init creates are key-only. An ageing limit would expire them and lock the SSH key out. Accounts that do have a password are still aged.
• SSH AllowUsers/AllowGroups: a list fixed at build time would refuse accounts you create later. Your security group restricts who can reach port 22.

The one rule that does not pass

python3 -c "import json; [print(r) for r in json.load(open('/usr/share/doc/sac/cis-l1-summary.json'))['failingRules']]"

Expected output:

ensure_journald_and_rsyslog_not_active_together

journald and rsyslog together. The benchmark wants one logging system, not both. CentOS Stream runs journald and rsyslog together by default. journald keeps the structured system journal (persistent, in /var/log/journal). rsyslog writes the traditional text logs (/var/log/messages, /var/log/secure, /var/log/cron) that many log shippers and audit procedures read.

The image keeps both, so neither kind of tooling loses its logs. If you standardise on one, for example the journal only, run sudo systemctl disable --now rsyslog on your instance and re-run Step 6.

You can repeat the evaluation at any time with the same content and tailoring. It takes about a minute:

sudo oscap xccdf eval \
  --tailoring-file /usr/share/doc/sac/cis-l1-tailoring.xml \
  --profile xccdf_co.sac_profile_cis-l1_ec2_lvm \
  --results /tmp/cis-check-results.xml --report /tmp/cis-check-report.html \
  /usr/share/xml/scap/ssg/content/ssg-cs9-ds.xml > /tmp/cis-check.log 2>&1 echo "oscap exit code: $? (2 = at least one rule did not pass)"
sudo python3 -c "import re,collections; c=collections.Counter(re.findall(r'<result>(\w+)</result>', open('/tmp/cis-check-results.xml').read())); s=sum(c[k] for k in ('pass','fail','error','unknown')); print(dict(sorted(c.items()))); print('pass rate: %.1f%%' % (100.0*c['pass']/s))"

Expected output:

oscap exit code: 2 (2 = at least one rule did not pass) {'fail': 1, 'notapplicable': 17, 'notselected': 1250, 'pass': 272} pass rate: 99.6%

Your own report is at /tmp/cis-check-report.html.

Use the ssg-cs9-ds.xml content shown above. The scap-security-guide package also ships ssg-rhel9-ds.xml, but that content applies only to Red Hat Enterprise Linux. On CentOS Stream it reports almost every rule as not applicable.

/tmp is noexec, which does not affect oscap, because it runs its check scripts through their interpreter. As you install software and change settings, re-run the evaluation to see how your changes affect the result.

curl -s -o /dev/null -w 'IMDSv1 request without a token: HTTP %{http_code}\n' http://169.254.169.254/latest/meta-data/instance-id
TOKEN=$(curl -s -X PUT -H 'X-aws-ec2-metadata-token-ttl-seconds: 60' http://169.254.169.254/latest/api/token)
curl -s -H "X-aws-ec2-metadata-token: $TOKEN" -w '\n' http://169.254.169.254/latest/meta-data/placement/region

Expected output (your Region may differ):

IMDSv1 request without a token: HTTP 401 us-east-1

A request without a session token is refused with HTTP 401, and the same request with a token works. Scripts and SDKs on the instance must use IMDSv2. Every current AWS SDK and the AWS CLI do this automatically.

sudo firewall-cmd --state sudo firewall-cmd --list-all sudo ss -tlnp

Expected output (the process IDs may differ):

running public (active) target: default icmp-block-inversion: no interfaces: eth0 sources: services: dhcpv6-client ssh ports: protocols: forward: yes masquerade: no forward-ports: source-ports: icmp-blocks: rich rules: State Recv-Q Send-Q Local Address:Port Peer Address:PortProcess LISTEN 0 128 0.0.0.0:22 0.0.0.0:* users:(("sshd",pid=1277,fd=7)) LISTEN 0 128 [::]:22 [::]:* users:(("sshd",pid=1277,fd=8))

• Only sshd listens, on port 22. Nothing else on the image opens a TCP port.
• The network interface is eth0. The official CentOS Stream 9 image for EC2 boots with net.ifnames=0, so the first interface keeps the traditional name.
• The public zone allows ssh and dhcpv6-client. The latter carries replies to the instance's IPv6 DHCP client, which is how an instance in an IPv6-enabled subnet gets its address. The CentOS default cockpit service is removed from the zone, and Cockpit is not installed.
• The loopback interface sits in firewalld's trusted zone, with rules that drop traffic claiming a loopback source from anywhere else. This is a CIS requirement.

Opening a port for your own service takes two steps. Allow it in the instance's security group, and allow it in firewalld. For example, for a web server on 443, run this on the instance:

sudo firewall-cmd --permanent --add-service=https sudo firewall-cmd --reload

If a port is open in the security group but not in firewalld, or the other way round, the traffic does not arrive.

systemctl is-active chronyd amazon-ssm-agent chronyc -n sources

Expected output (the timings vary):

active active MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^* 169.254.169.123 3 4 37 5 -3572ns[ -128us] +/- 461us

The ^* marks the source chrony is using: 169.254.169.123, the Amazon Time Sync Service. It is reachable from every instance without internet access, so time stays correct in a private subnet too.

The AWS Systems Manager agent is installed from Amazon's own package at its current release (3.3.5390.0 on this build). It is not in the CentOS Stream repositories, so dnf does not update it. Systems Manager can keep it current for you, through the AWS-UpdateSSMAgent document or the Auto update SSM Agent setting in Fleet Manager.

The image is fully patched at build time. Check what is pending now and how automatic updates are set up:

sudo dnf -q check-update --refresh echo "dnf check-update exit code: $? (0 = nothing to update, 100 = updates available)" grep -E '^(upgrade_type|apply_updates|reboot) =' /etc/dnf/automatic.conf systemctl is-enabled dnf-automatic.timer systemctl cat dnf-automatic.timer | grep -E '^(OnCalendar|RandomizedDelaySec)' uname -r

Expected output on an instance launched soon after the image was built. Later launches list the updates released since, with exit code 100:

dnf check-update exit code: 0 (0 = nothing to update, 100 = updates available) upgrade_type = default apply_updates = yes reboot = never enabled OnCalendar=*-*-* 6:00 RandomizedDelaySec=60m 5.14.0-758.el9.x86_64

dnf-automatic is configured on this image as follows:

• upgrade_type = default installs every available update, not only security fixes. CentOS Stream's repositories carry no security advisory data, so a security-only setting would install nothing at all.
• apply_updates = yes installs the updates instead of only downloading them.
• The timer runs daily at 06:00 (instance time, UTC by default) with a random delay of up to an hour.
• reboot = never means that a new kernel or core library is installed but takes effect only after you reboot, at a time you choose.

CentOS Stream moves ahead of RHEL and updates arrive continuously. If your workload is sensitive to package changes, test updates on a non-production instance first.

To stop automatic updates, run sudo systemctl disable --now dnf-automatic.timer. To update everything now, run:

sudo dnf -y upgrade

Reboot if a new kernel was installed:

sudo systemctl reboot

A new kernel boots from the logical volume like the current one. Its boot entry is written to the /boot partition from /etc/kernel/cmdline (Step 4).

getenforce
sudo passwd -S root
sudo sshd -T | grep -E '^(permitrootlogin|passwordauthentication|pubkeyauthentication|kbdinteractiveauthentication|x11forwarding|maxauthtries|clientaliveinterval|banner) ' cat /etc/issue.net

Expected output:

Enforcing root LK 2024-02-07 0 99999 7 -1 (Alternate authentication scheme in use.) maxauthtries 4 clientaliveinterval 300 permitrootlogin no pubkeyauthentication yes passwordauthentication no kbdinteractiveauthentication no x11forwarding no banner /etc/issue.net Authorized users only. All activity may be monitored and reported.

• Enforcing means SELinux is on and enforcing the targeted policy. Keep it on. If your own software is denied, check sudo ausearch -m avc -ts recent instead of disabling SELinux.
• LK in the second column means the root account is locked.
• sshd -T prints the settings the SSH server actually uses, after every file in /etc/ssh/sshd_config.d/ has been read. maxauthtries 4 and clientaliveinterval 300 come from the CIS profile. SSH allows four authentication attempts per connection and checks idle sessions every five minutes.
• The banner text is shown before login.
• Password quality rules apply to root too (enforce_for_root). A password that fails the quality checks is refused even when root sets it.

EC2 Serial Console and recovery. No account on this image has a password, so the serial console cannot log in until you set one. If you want serial console access, set a password for your own user on your running instance. The password is yours and is not on the image:

sudo passwd ec2-user

sudo vgs cs df -h / /var /var/log
sudo grep -E 'cc_growpart.py.*(SKIPPED|resized|NOCHANGE)' /var/log/cloud-init.log | tail -1 | cut -c1-150 swapon --noheadings --show | wc -l sudo grep -h aide /etc/crontab

Expected output with the default 12 GiB root volume:

VG #PV #LV #SN Attr VSize VFree cs 1 7 0 wz--n- 10.80g 820.00m Filesystem Size Used Avail Use% Mounted on /dev/mapper/cs-root 4.0G 2.1G 2.0G 52% / /dev/mapper/cs-var 1.5G 169M 1.3G 12% /var /dev/mapper/cs-var_log 960M 56M 905M 6% /var/log 2026-10-21 13:31:29,980 - cc_growpart.py[DEBUG]: '/' SKIPPED: Resizing mapped device (/dev/mapper/cs-root) skipped as it is not encrypted. 0 05 4 * * * root /usr/sbin/aide --check

cloud-init does not grow LVM volumes. On a single-volume CentOS Stream image, cloud-init grows the root filesystem to the volume size on first boot. On this image the root filesystem is a logical volume, so cloud-init skips it (the SKIPPED line above). This is deliberate, because you decide which volume gets the space.

When you launch with a bigger root volume, or grow the EBS volume later with aws ec2 modify-volume, add the space in three steps on the instance:

• Grow partition 4 (the LVM physical volume) to the end of the disk, and tell LVM.

sudo growpart /dev/nvme0n1 4
sudo pvresize /dev/nvme0n1p4

• Give space to the volumes that need it. --resizefs grows the XFS filesystem in the same step, online, with no reboot.

sudo lvextend --resizefs -L +4G /dev/cs/root
sudo lvextend --resizefs -L +2G /dev/cs/var

• Check the result.

sudo vgs cs df -h / /var

Example output after growing a 12 GiB volume to 20 GiB and running the commands above. The filesystem geometry that xfs_growfs prints is shortened to ...:

CHANGED: partition=4 start=2510848 old: size=22654943 end=25165790 new: size=39432159 end=41943006 Physical volume "/dev/nvme0n1p4" changed 1 physical volume(s) resized or updated / 0 physical volume(s) not resized File system xfs found on cs/root mounted at /. Size of logical volume cs/root changed from 4.00 GiB (1024 extents) to 8.00 GiB (2048 extents). Extending file system xfs to 8.00 GiB (8589934592 bytes) on cs/root... xfs_growfs /dev/cs/root ... data blocks changed from 1048576 to 2097152 xfs_growfs done Extended file system xfs on cs/root. Logical volume cs/root successfully resized. File system xfs found on cs/var mounted at /var. Size of logical volume cs/var changed from 1.50 GiB (384 extents) to 3.50 GiB (896 extents). Extending file system xfs to 3.50 GiB (3758096384 bytes) on cs/var... xfs_growfs /dev/cs/var ... data blocks changed from 393216 to 917504 xfs_growfs done Extended file system xfs on cs/var. Logical volume cs/var successfully resized. VG #PV #LV #SN Attr VSize VFree cs 1 7 0 wz--n- 18.80g 2.80g Filesystem Size Used Avail Use% Mounted on /dev/mapper/cs-root 8.0G 2.1G 5.9G 26% / /dev/mapper/cs-var 3.5G 130M 3.4G 4% /var

The new sizes persist across reboots. To give a volume all the remaining free space instead, use -l +100%FREE, for example sudo lvextend --resizefs -l +100%FREE /dev/cs/var_log.

Leaving some space unallocated is useful, because you can grow whichever volume fills first without touching EBS. XFS volumes grow online but cannot shrink, so add space in steps.

• Adding a data volume. Attach a new EBS volume, then give it its own volume group (for example sudo pvcreate /dev/nvme1n1, sudo vgcreate datavg /dev/nvme1n1, sudo lvcreate -n data -l 100%FREE datavg, sudo mkfs.xfs /dev/datavg/data). Mount it from /etc/fstab by UUID with the nofail option, so that the instance still boots if the volume is ever detached. Check the device name with lsblk first. On Nitro instances, the second EBS volume is usually /dev/nvme1n1. The image ships no LVM devices file (/etc/lvm/devices/system.devices), so LVM sees every attached disk.
• Swap. The image has no swap. If your workload needs it, create a logical volume for it (for example sudo lvcreate -L 512M -n swap cs, then sudo mkswap /dev/cs/swap and an /etc/fstab entry), or create a swap file on / or /var.
• AIDE. The file integrity database is built from the image's own files. The CIS profile schedules aide --check daily at 04:05 from /etc/crontab.

The instance uses the standard CentOS Stream 9 repositories (BaseOS, AppStream and Extras):

sudo dnf -q list --available nginx

Expected output (the version changes over time):

Available Packages nginx.x86_64 2:1.20.1-32.el9 appstream

Install and start software in the usual way, for example sudo dnf -y install nginx then sudo systemctl enable --now nginx. Open its port in the security group and firewalld (Step 8).

Most software installs under /usr and /etc on the root volume and keeps its data and logs under /var. Watch the / and /var volumes as you add software, and grow them as needed (Step 12).

The CRB repository (build and development dependencies) is installed but disabled. Enable it with sudo dnf config-manager --set-enabled crb if a package needs it. The AWS CLI is not on the image. If you need it, install the current version from AWS (see the AWS CLI install guide).

To add another administrator, create the account, add it to the wheel group and give it an SSH key:

sudo useradd -m -G wheel alice
sudo install -d -m 700 -o alice -g alice /home/alice/.ssh echo "ssh-ed25519 AAAA... alice@laptop" | sudo tee /home/alice/.ssh/authorized_keys
sudo chown alice:alice /home/alice/.ssh/authorized_keys && sudo chmod 600 /home/alice/.ssh/authorized_keys
sudo restorecon -R /home/alice/.ssh

Because SSH is key-only, a new account needs its key in authorized_keys. restorecon gives the file the SELinux label that sshd expects.

The new account has no password, so sudo cannot authenticate it until you give it one with sudo passwd alice. SSH stays key-only, and sudo uses the password. Only ec2-user, created by cloud-init, has password-free sudo.