This manual is a fork of the CentOS 5.9 article of the same name , and takes into account the features of the new OS. There is currently no official Centos8 image from centos.org in the AWS Marketplace.

As you know, in the Amazon cloud, virtual instances are launched on the basis of images (the so-called AMI ). Amazon provides a large number of them, you can also use public images prepared by third-party organizations, for which the cloud provider, of course, does not bear any responsibility. But sometimes you need an image of a clean system with the necessary parameters, which is not in the list of images.

Then the only way out is to make your AMI.

The official documentation describes how to create an “instance store-backed AMI."

The disadvantage of this approach is that the finished image will also need to be converted to EBS-backed AMI. Also worth noting is Cockpit Image Builder. It will allow you to create custom images in CLI or WEB GUI mode, but when you already have Centos 8.

How to create your EBS-backed AMI in the Amazon cloud without intermediate steps will be discussed in this article.

Action plan

Prepare the environment
Install a clean system, make the necessary settings
Make a snapshot (snapshot) of the disk
Register AMI

Environment preparation

For our purposes, any official Centos 7 instance of any shape is suitable, at least t2.micro. You can run it through the CLI:

aws ec2 run-instances \
  --image-id ami-4bf3d731 \
  --region us-east-1 \
  --key-name alpha \
  --instance-type t2.micro \
  --subnet-id subnet-240a8618 \
  --associate-public-ip-address \
  --block-device-mappings DeviceName=/dev/sda1,Ebs={VolumeSize=8} \
  --block-device-mappings DeviceName=/dev/sdb,Ebs={VolumeSize=4}

VPC, subnet-id. , , SG 'default' .

ssh, , dnf :

sudo yum update -y && sudo yum install -y dnf && sudo reboot

root.

Centos 8.1

DEVICE=/dev/xvdb
ROOTFS=/rootfs
parted -s ${DEVICE} mktable gpt
parted -s ${DEVICE} mkpart primary ext2 1 2
parted -s ${DEVICE} set 1 bios_grub on
parted -s ${DEVICE} mkpart primary xfs 2 100%

mkfs.xfs -L root ${DEVICE}2
mkdir -p $ROOTFS
mount ${DEVICE}2 $ROOTFS

mkdir $ROOTFS/{proc,sys,dev,run}
mount --bind /proc $ROOTFS/proc
mount --bind /sys $ROOTFS/sys
mount --bind /dev $ROOTFS/dev
mount --bind /run $ROOTFS/run

RPM :

PKGSURL=http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages
rpm --root=$ROOTFS --initdb
rpm --root=$ROOTFS -ivh \
  $PKGSURL/centos-release-8.1-1.1911.0.8.el8.x86_64.rpm \
  $PKGSURL/centos-gpg-keys-8.1-1.1911.0.8.el8.noarch.rpm \
  $PKGSURL/centos-repos-8.1-1.1911.0.8.el8.x86_64.rpm

dnf --installroot=$ROOTFS --nogpgcheck --setopt=install_weak_deps=False \
   -y install audit authselect basesystem bash biosdevname coreutils \
   cronie curl dnf dnf-plugins-core dnf-plugin-spacewalk dracut-config-generic \
   dracut-config-rescue e2fsprogs filesystem firewalld glibc grub2 grubby hostname \
   initscripts iproute iprutils iputils irqbalance kbd kernel kernel-tools \
   kexec-tools less linux-firmware lshw lsscsi ncurses network-scripts \
   openssh-clients openssh-server passwd plymouth policycoreutils prefixdevname \
   procps-ng  rng-tools rootfiles rpm rsyslog selinux-policy-targeted setup \
   shadow-utils sssd-kcm sudo systemd util-linux vim-minimal xfsprogs \
   chrony cloud-init

, , , .

, :

dnf --installroot=$ROOTFS groupinstall base core \
    --excludepkgs "NetworkManager*" \
     -e "i*-firmware"

yum --excludepkgs, , .

dnf group info core core.

, fstab, grub2 169.254 AWS DNS NTP.

cat > $ROOTFS/etc/resolv.conf << HABR
nameserver 169.254.169.253
HABR

cat > $ROOTFS/etc/sysconfig/network << HABR
NETWORKING=yes
NOZEROCONF=yes
HABR

cat > $ROOTFS/etc/sysconfig/network-scripts/ifcfg-eth0  << HABR
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
HABR

cat > $ROOTFS/etc/fstab << HABR
LABEL=root / xfs defaults,relatime 1 1
HABR

sed -i  "s/cloud-user/centos/" $ROOTFS/etc/cloud/cloud.cfg
echo "server 169.254.169.123 prefer iburst minpoll 4 maxpoll 4" >> $ROOTFS/etc/chrony.conf
sed -i "/^pool /d" $ROOTFS/etc/chrony.conf
sed -i "s/^AcceptEnv/# \0/" $ROOTFS/etc/ssh/sshd_config

cat > $ROOTFS/etc/default/grub << HABR
GRUB_TIMEOUT=1
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=auto console=ttyS0,115200n8 console=tty0 net.ifnames=0 biosdevname=0"
GRUB_DISABLE_RECOVERY="true"
GRUB_ENABLE_BLSCFG=true
HABR

, GRUB_CMDLINE_LINUX selinux=0, SELinux.

initramfs chroot

grub fstab .
:

KERNEL=$(ls $ROOTFS/lib/modules/) 
chroot $ROOTFS dracut -f -v /boot/initramfs-$KERNEL.img $KERNEL
chroot $ROOTFS grub2-mkconfig -o /boot/grub2/grub.cfg
chroot $ROOTFS grub2-install $DEVICE
chroot $ROOTFS update-crypto-policies --set FUTURE

update-crypto-policies — , :)

"", :

chroot $ROOTFS fips-mode-setup --enable
chroot $ROOTFS grub2-mkconfig -o /boot/grub2/grub.cfg
chroot $ROOTFS grub2-install $DEVICE

, update-crypto-policies --show FIPS.

chroot $ROOTFS systemctl enable network.service
chroot $ROOTFS systemctl enable sshd.service
chroot $ROOTFS systemctl enable cloud-init.service
chroot $ROOTFS systemctl mask tmp.mount

dnf --installroot=$ROOTFS clean all
truncate -c -s 0 $ROOTFS/var/log/*.log
rm -rf var/lib/dnf/*
touch $ROOTFS/.autorelabel

autorelabel — SELinux .

sync
umount $ROOTFS/{proc,sys,dev,run}
umount $ROOTFS

AMI

ebs- ami, :

aws ec2 create-snapshot \
    --volume-id vol-09f26eba4c50da110  --region us-east-1 \
    --description 'centos-release-8.1-1.1911.0.8 4.18.0-147.5.1 01'

- . SnapshotId:

aws ec2   describe-snapshots  --region us-east-1 --snapshot-ids snap-0b665542fc59e58ed

"State": "completed", AMI :

aws ec2 register-image \
    --region us-east-1 \
    --name 'CentOS-8.1-1.1911.0.8-minimal' \
    --description 'centos-release-8.1-1.1911.0.8 4.18.0-147.5.1 01' \
    --virtualization-type hvm --root-device-name /dev/sda1 \
    --block-device-mappings '[{"DeviceName":"/dev/sda1","Ebs": { "SnapshotId": "snap-0b665542fc59e58ed", "VolumeSize":4,  "DeleteOnTermination": true, "VolumeType": "gp2"}}]' \
    --architecture x86_64 --sriov-net-support simple --ena-support

aws ec2 modify-image-attribute \
    --region us-east-1 \
    --image-id ami-011ed2a37dc89e206 \
    --launch-permission 'Add=[{Group=all}]'

. .

, , Linux-. , Debian ( debootstrap ) RHEL-.

UPDATE . Packer, . .

Create your image with pure CentOS 8.1 in the Amazon cloud

Action plan

Environment preparation

Centos 8.1

initramfs chroot

AMI

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