虚拟化服务libvirtd无法正常启动，报错：error : virModuleLoadFile:53 : internal error: Failed to load module ‘/usr/lib64/libvirt/storag e-backend/libvirt_storage_backend_rbd.so’: /usr/lib64/libvirt/storage-backend/libvirt_storage_backend_rbd.so: undefined symbol: rbd_diff_iterate2 。
问题原因：older version of libvirt-daemon-driver-storage-rbd usually used in older RHEL 7.x version which is missing the librbd1 dependency。（动态链接库缺失）
具体可以通过如下方法查看：
[root@rhvh42 storage-backend]# file libvirt_storage_backend_rbd.solibvirt_storage_backend_rbd.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=f0289019f4ff9a0c87c47c928457be3672448e47, stripped
缺失的链接库文件在librbd1包里，解决方法如下：
yum update librbd1systemctl restart libvirtd