How many packages have been installed for kernel. Loading the nbd module prompts me that I can't find this module?

problems encountered when using KVM on CentOS 7.5 when partitioning after creating an image.

Command: modprobe nbd
error: modprobe: FATAL: Module nbd not found.

the solution on the Internet is to install several packages related to kernel, but I already have these packages on my CentOS7. What"s going on?

how to solve this problem?

Kvm
Jun.23,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1be83c3-318d6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1be83c3-318d6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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