OpenStack Linux 镜像制作-CentOS7.x

1.配置YUM epel源

curl -o /etc/yum.repo.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

2.修改网络信息 /etc/sysconfig/network-scripts/ifcfg-eth0 （删除MAC地址信息），如下：

TYPE=Ethernet
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
NM_CONTROLLED=no

3.删除已生成的网络设备规则,否则制作出来的镜像可能会出现不能上网

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

4.增加一行到/etc/sysconfig/network

NOZEROCONF=yes   #禁用ZEROCONF路由   

5.安装Cloud-init

# yum install -y cloud-utils cloud-init parted

6.修改配置文件 /etc/cloud/cloud.cfg

开头的disable_root和ssh_pwauth 都改成1
users:
 - default
disable_root: 1
ssh_pwauth: 1

在cloud_init_modules下新增：- resolv-conf
cloud_init_modeles:
 - resolv-conf
 - migrator
 - bootcmd
 - write-files
 - growpart

7.设置系统能自动获取openstack指定的hostname和ssh-key

vi /etc/rc.d/rc.local
#!/bin/bash
# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
#
# It is highly advisable to create own systemd services or udev rules
# to run scripts during boot instead of using this file.
#
# In constrast to previous versions due to parallel execution during boot 
# this script will NOT be run after all other services.
#  
# Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure
# that this script will be executed during boot.
if [ ! -d /root/.ssh ]; then
  mkdir -p /root/.ssh
  chmod 700 /root/.ssh
  fi
  # Fetch public key using HTTP
  ATTEMPTS=30
  FAILED=0
  
   
 
 while [ ! -f /root/.ssh/authorized_keys ]; do
 curl -f http://169.254.169.254/latest/meta-data/public-keys/0/openssh-key > /tmp/metadata-key 2>/dev/null
 if [ $? -eq 0 ]; then
 cat /tmp/metadata-key >> /root/.ssh/authorized_keys
 chmod 0600 /root/.ssh/authorized_keys
 restorecon /root/.ssh/authorized_keys
 rm -f /tmp/metadata-key
 echo "Successfully retrieved public key from instance metadata"
 echo "*****************"
 echo "AUTHORIZED KEYS"
 echo "*****************"
 cat /root/.ssh/authorized_keys
 echo "*****************"
 
 curl -f http://169.254.169.254/latest/meta-data/hostname > /tmp/metadata-hostname 2>/dev/null
 if [ $? -eq 0 ]; then
 TEMP_HOST=`cat /tmp/metadata-hostname`
 sed -i "s/^HOSTNAME=.*$/HOSTNAME=$TEMP_HOST/g" /etc/sysconfig/network
 /bin/hostname $TEMP_HOST
 echo "Successfully retrieved hostname from instance metadata"
 echo "*****************"
 echo "HOSTNAME CONFIG"
 echo "*****************"
 cat /etc/sysconfig/network
 echo "*****************"
 
 else
 echo "Failed to retrieve hostname from instance metadata. This is a soft error so we’ll continue"
 fi
 rm -f /tmp/metadata-hostname
 else
 FAILED=$(($FAILED + 1))
 if [ $FAILED -ge $ATTEMPTS ]; then
 echo "Failed to retrieve public key from instance metadata after $FAILED attempts, quitting"
 break
 fi
 echo "Could not retrieve public key from instance metadata (attempt #$FAILED/$ATTEMPTS), retrying in 5 seconds…"
 sleep 5
 fi
 done 
touch /var/lock/subsys/local


给rc.local 读写权限
chmod +x /etc/rc.d/rc.local

8.设置cloud-init相关服务的开机启动

systemctl enable cloud-config.service cloud-final.service cloud-init-local.service cloud-init.service
重启reboot

9.重启后查看cloud-init 相关服务是否启动，如果前面是绿色图标说明正常。

systemctl list-dependencies

10.压缩镜像

压缩镜像是为了让镜像模板小一些，压缩比较大，执行时间耗时很长
执行命令时不要在/var/lib/libvirt/images
# virt-sparsify --compress /var/lib/libvirt/images/CentOS7.5 CentOS7.5.qcow2