使用cloud-init新建虚拟机后重启系统网络IP地址丢失

cloud-init 是 Linux 平台的⼀个开源⼯具，可以为云平台的 Linux 虚拟机完成⼀系列系统初始化配置。作为⼀个⾮常驻服务，开机启动时执⾏后⽴即退出，不会监听任何端⼝。

环境

• Red Hat OpenStack
• cloud-init
• SmartX

问题

• cloud-init在新建虚拟机时修改网络配置后引发异常
• SmartX在使用cloud-init模板部署虚拟机时新增网卡后，创建的虚拟机在配置Ip地址后，重启虚拟机IP地址会被重置为dhcp。
• RedHat OpenStack相关报错如下：

util.py[DEBUG]: Reading from /sys/class/net/ens3/type (quiet=False)
util.py[DEBUG]: Read 2 bytes from /sys/class/net/ens3/type
util.py[WARNING]: failed stage init
util.py[DEBUG]: failed stage init
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/cloudinit/cmd/main.py", line 653, in status_wrapper
ret = functor(name, args)
File "/usr/lib/python3.6/site-packages/cloudinit/cmd/main.py", line 362, in main_init
init.apply_network_config(bring_up=bool(mode != sources.DSMODE_LOCAL))
File "/usr/lib/python3.6/site-packages/cloudinit/stages.py", line 681, in apply_network_config
netcfg, src = self._find_networking_config()
File "/usr/lib/python3.6/site-packages/cloudinit/stages.py", line 646, in _find_networking_config
if self.datasource and hasattr(self.datasource, 'network_config'):
File "/usr/lib/python3.6/site-packages/cloudinit/sources/DataSourceConfigDrive.py", line 152, in network_config
self.network_json, known_macs=self.known_macs)
File "/usr/lib/python3.6/site-packages/cloudinit/sources/helpers/openstack.py", line 683, in convert_net_json
raise ValueError("Unable to find a system nic for %s" % d)
ValueError: Unable to find a system nic for {'type': 'physical', 'mtu': 1500, 'subnets': [{'type': 'dhcp4'}], 'mac_address': ''}
atomic_helper.py[DEBUG]: Atomically writing to file /var/lib/cloud/data/status.json (via temporary file /var/lib/cloud/data/tmpm9hc8a2w) - w: [644] 790 bytes/chars
util.py[DEBUG]: Reading from /proc/uptime (quiet=False)
util.py[DEBUG]: Read 13 bytes from /proc/uptime
util.py[DEBUG]: cloud-init mode 'init' took 0.124 seconds

解决方案

如果在firstboot部分之后不使用cloud init服务，解决此问题的方法是禁用并停止cloud init服务。在第一个引导步骤之后，禁用cloud init服务。

# systemctl stop cloud-init
# systemctl disable cloud-init
#systemctl mask cloud-init

原因

Cloudinit通过UserData获得了网络配置，并在firstboot时配置网络以进行设置。虽然第一次引导后不需要服务，但该服务在firstboot之后启用并运行。当Cloudinit检测到新接口时，它会在现有配置中搜索定义的NIC。然后当CloudInit找不到NIC时，它抛出异常。