Creating a qcow2 image for RHEL

This section explains the qcow2 image creation for RHEL.

Precondition

Partition with RHEL-7.3 installed and root user access

Update boot loader

1. Go to /etc/zipl.conf and remove all occurrences of rd.zfcp=

2. Add a new rd.zfcp entry

   rd.zfcp=ipldev

3. Empty /etc/zfcp.conf file

   echo “” > /etc/zfcp.conf

4. Create the dasd.conf file # In order to avoid error messages related to dasd configuration

   touch /etc/dasd.conf

5. Go to /usr/lib/dracut/modules.d/95zfcp/parse-zfcp.sh

   Apply the following differences:

   $ diff old_parse-zfcp.sh new_parse-zfcp.sh
   8,9c8,10 < echo $zfcp_arg | grep '0\.[0-9a-fA-F]\.[0-9a-fA-F]\{4\},0x[0-9a-fA-F]\{16\},0x[0-9a-fA-F]\{16\}' >/dev/null
            < test $? -ne 0 && die "For argument 'rd.zfcp=$zfcp_arg'\nSorry, invalid format."
        --- > if [ "$zfcp_arg" == "ipldev" -a "$(cat /sys/firmware/ipl/ipl_type)" == "fcp" ] ; then
            > zfcp_arg="$(cat /sys/firmware/ipl/device),$(cat /sys/firmware/ipl/wwpn),$(cat /sys/firmware/ipl/lun)"
            > fi
   

   The result should look like this:

   #!/bin/sh
   # -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
   # ex: ts=8 sw=4 sts=4 et filetype=sh
   
   getargbool 1 rd.zfcp.conf -d -n rd_NO_ZFCPCONF || rm /etc/zfcp.conf
   
   for zfcp_arg in $(getargs rd.zfcp -d 'rd_ZFCP='); do
       if [ "$zfcp_arg" == "ipldev" -a "$(cat /sys/firmware/ipl/ipl_type)" == "fcp" ] ; then
           zfcp_arg="$(cat /sys/firmware/ipl/device),$(cat /sys/firmware/ipl/wwpn),$(cat /sys/firmware/ipl/lun)"
       fi
       (
          IFS=","
           set $zfcp_arg
           echo "$@" >> /etc/zfcp.conf
       )
   done
   
   zfcp_cio_free
   

6. Rebuild the ramdisk

   dracut -f

7. To apply the above changes to the contents of boot loader script

   zipl -V

Installation of Cloud-init

Install cloud-utils-growpart

This package is required for growing the filesystem.

• Download a version of cloud-utils-growpart < 0.27.13

  Note

  Greater version can not deal with rhel7s old ‘util-linux’ package version

• install it:

  rpm -i cloud-utils-growpart-0.27-9.fc20.noarch.rpm
  

Add the RHEL7.3 yum repository

• Add the yum repository file that points to a network resource

  cat <<EOT > /etc/yum.repos.d/rhel.repo
  [RHEL7.3]
  name=Red Hat Enterprise Linux Repository
  baseurl=https://x.x.x.x
  enabled=1
  gpgcheck=0
  EOT
  

Install cloud-init 0.7.9

Download latest cloud-init from https://launchpad.net/cloud-init/+download

• Install python setuptools

yum install python-setuptools

• Extract it

tar -xf cloud-init-0.7.9.tar.gz

• Enter the extracted directory

cd cloud-init-0.7.9

• Build and install it:

python setup.py build

python setup.py install –init-system systemd

Update cloud-init service files

• Remove Default dependencies

  sed -i '/^\[Unit\]$/,/^\[/ s/^DefaultDependencies=no/#DefaultDependencies=no/' /usr/lib/systemd/system/cloud-init.service
  
  sed -i '/^\[Unit\]$/,/^\[/ s/^DefaultDependencies=no/#DefaultDependencies=no/' /usr/lib/systemd/system/cloud-init-local.service
  

• Remove ordering for sysinit.target

  sed -i '/^\[Unit\]$/,/^\[/ s/^Before=sysinit.target/#Before=sysinit.target/' /usr/lib/systemd/system/cloud-init.service
  
  sed -i '/^\[Unit\]$/,/^\[/ s/^Before=sysinit.target/#Before=sysinit.target/' /usr/lib/systemd/system/cloud-init-local.service
  

• order with systemd-hostnamed.service

  sed -i '/^\[Unit\]$/,/^\[/ s/^After=networking.service/After=networking.service\nAfter=systemd-hostnamed.service/' /usr/lib/systemd/system/cloud-init.service
  

The result should look like this:

cat /usr/lib/systemd/system/cloud-init.service

[Unit]
Description=Initial cloud-init job (metadata service crawler)
#DefaultDependencies=no
Wants=cloud-init-local.service
Wants=sshd-keygen.service
Wants=sshd.service
After=cloud-init-local.service
After=networking.service
After=systemd-hostnamed.service
Before=network-online.target
Before=sshd-keygen.service
Before=sshd.service
#Before=sysinit.target
Before=systemd-user-sessions.service
Conflicts=shutdown.target

[Service]
Type=oneshot
ExecStart=/usr/bin/cloud-init init
RemainAfterExit=yes
TimeoutSec=0

# Output needs to appear in instance console output
StandardOutput=journal+console

[Install]
WantedBy=cloud-init.target

cat /usr/lib/systemd/system/cloud-init-local.service

[Unit]
Description=Initial cloud-init job (pre-networking)
#DefaultDependencies=no
Wants=network-pre.target
After=systemd-remount-fs.service
Before=NetworkManager.service
Before=network-pre.target
Before=shutdown.target
#Before=sysinit.target
Conflicts=shutdown.target
RequiresMountsFor=/var/lib/cloud

[Service]
Type=oneshot
ExecStart=/usr/bin/cloud-init init --local
ExecStart=/bin/touch /run/cloud-init/network-config-ready
RemainAfterExit=yes
TimeoutSec=0

# Output needs to appear in instance console output
StandardOutput=journal+console

[Install]
WantedBy=cloud-init.target

Configure cloud-init for autostart

systemctl daemon-reload

systemctl enable cloud-init.service

systemctl enable cloud-init-local.service

systemctl enable cloud-final.service

systemctl enable cloud-config.service

Use the following cloud.cfg file

• Keep this cloud.cfg file in /etc/cloud/

  # The top level settings are used as module
  # and system configuration.
  
  # A set of users which may be applied and/or used by various modules
  # when a 'default' entry is found it will reference the 'default_user'
  # from the distro configuration specified below
  users:
     - default
  
  # If this is set, 'root' will not be able to ssh in and they
  # will get a message to login instead as the above $user (ubuntu)
  disable_root: false
  
  # This will cause the set+update hostname module to not operate (if true)
  preserve_hostname: false
  
  #datasource_list: [ ConfigDrive, None ]
  
  # Example datasource config
  # datasource:
  #    Ec2:
  #      metadata_urls: [ 'blah.com' ]
  #      timeout: 5 # (defaults to 50 seconds)
  #      max_wait: 10 # (defaults to 120 seconds)
  
  # The modules that run in the 'init' stage
  cloud_init_modules:
   - migrator
  # - ubuntu-init-switch
   - seed_random
   - bootcmd
   - write-files
   - growpart
   - resizefs
   - disk_setup
   - mounts
   - set_hostname
   - update_hostname
   - update_etc_hosts
   - ca-certs
   - rsyslog
   - users-groups
   - ssh
  
  # The modules that run in the 'config' stage
  cloud_config_modules:
  # Emit the cloud config ready event
  # this can be used by upstart jobs for 'start on cloud-config'.
   - emit_upstart
   - snap_config
   - ssh-import-id
   - locale
   - set-passwords
  # - grub-dpkg
  # - apt-pipelining
  # - apt-configure
   - ntp
   - timezone
   - disable-ec2-metadata
   - runcmd
   - byobu
  
  # The modules that run in the 'final' stage
  cloud_final_modules:
   - snappy
   - package-update-upgrade-install
   - fan
   - landscape
   - lxd
   - puppet
   - chef
   - salt-minion
   - mcollective
   - rightscale_userdata
   - scripts-vendor
   - scripts-per-once
   - scripts-per-boot
   - scripts-per-instance
   - scripts-user
   - ssh-authkey-fingerprints
   - keys-to-console
   - phone-home
   - final-message
   - power-state-change
  
  # System and/or distro specific settings
  # (not accessible to handlers/transforms)
  system_info:
     # This will affect which distro class gets used
     distro: rhel
  
  

Test-It

Run it once to see if things are working

cloud-init –init

Note

This might take a few minutes, as cloud-init tries to access various network datasources, which probably are not available in your image build environment.But they should be available in your OpenStack cloud. For debugging you might need to set “datasource_list: [ ConfigDrive, None ]” in cloud.cfg. This excludes those network data sources and boot is pretty fast.

Add DPM-Guest Tools

• Install git and clone nova-dpm repository into the guest image.

  git clone https://github.com/openstack/nova-dpm.git

• Copy the following files from nova-dpm directory into the guest image

  cp nova-dpm/guest_image_tools/usr/bin/autoconfigure_networking.sh  /usr/bin/autoconfigure_networking.sh
  
  cp nova-dpm/guest_image_tools/usr/lib/systemd/system/autoconfigure_networking.service  /usr/lib/systemd/system/autoconfigure_networking.service
  
  cp nova-dpm/guest_image_tools/usr/bin/setmac.sh  /usr/bin/setmac.sh
  
  cp nova-dpm/guest_image_tools/usr/bin/dpm_guest_image_tools_common  /usr/bin/
  
  cp nova-dpm/guest_image_tools/etc/udev/rules.d/80-setmac.rules /etc/udev/rules.d/80-setmac.rules
  

• Ensure permissions

  chmod 644 /usr/lib/systemd/system/autoconfigure_networking.service

• Enable the service for autostart

  systemctl enable autoconfigure_networking.service

Cleanup

• Cleanup logs and journalctl

rm -rf /var/log/*

• Remove repo file and update repo

rm -f /etc/yum.repos.d/rhel.repo

yum clean all

yum update

yum repolist

• Remove data from last cloud-init run

rm -rf /var/lib/cloud/*

• Remove persistent mac address interface mappings

rm -f /etc/udev/rules.d/70-persistent-net.rules

• Remove persistent network configs

rm -f /etc/sysconfig/network-scripts/ifcfg-enc*

• Clear /etc/hostname

  echo “” > /etc/hostname

• Cleanup home directory

  rm -rf ~/*

Create qcow2 image

• In order to nullify space

  dd if=/dev/zero of=~/tmpfile

  rm -rf ~/tmpfile

• Now stop the partition and access the LUN used for image creation from other machine

• copy disk content byte-by-byte into a raw image

  dd status=progress if=/path/to/installed/lun of=RHEL.img

• Convert this raw image to qcow

  qemu-img convert -f raw -O qcow2 RHEL.img RHEL.qcow

Test qcow2 image

• Deploy this image on another LUN

  qemu-img convert RHEL.qcow /path/to/new/lun

• Use this new LUN to boot the machine