##1.実行環境
macOS Catalina10.15.6
vagrant 2.2.10
virtualbox 6.0.14
##2.問題

$ vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Clearing any previously set forwarded ports...
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
    default: Adapter 2: hostonly
==> default: Forwarding ports...
    default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: vagrant
    default: SSH auth method: private key
==> default: Machine booted and ready!
[default] No Virtualbox Guest Additions installation found.
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: ftp.tsukuba.wide.ad.jp
 * extras: ftp.tsukuba.wide.ad.jp
 * updates: ftp.tsukuba.wide.ad.jp
Package centos-release-7-8.2003.0.el7.centos.x86_64 already installed and latest version
Nothing to do
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: ftp.tsukuba.wide.ad.jp
 * extras: ftp.tsukuba.wide.ad.jp
 * updates: ftp.tsukuba.wide.ad.jp
No package kernel-devel-3.10.0-957.12.2.el7.x86_64 available.
Error: Nothing to do
==> default: Checking for guest additions in VM...
    default: No guest additions were detected on the base box for this VM! Guest
    default: additions are required for forwarded ports, shared folders, host only
    default: networking, and more. If SSH fails on this machine, please install
    default: the guest additions and repackage the box to continue.
    default: 
    default: This is not an error message; everything may continue to work properly,
    default: in which case you may ignore this message.
The following SSH command responded with a non-zero exit status.
Vagrant assumes that this means the command failed!

yum install -y kernel-devel-`uname -r`

Stdout from the command:

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: ftp.tsukuba.wide.ad.jp
 * extras: ftp.tsukuba.wide.ad.jp
 * updates: ftp.tsukuba.wide.ad.jp
No package kernel-devel-3.10.0-957.12.2.el7.x86_64 available.

Stderr from the command:

Error: Nothing to do

問題はこれ↓

No package kernel-devel-3.10.0-957.12.2.el7.x86_64 available.

kernelの問題なのかな・・
macだから、『yum install -y kernel-devel-uname -r』のコマンド打てないし。。
##3.試したこと
####①vagrantのバージョンを調べてみた！

$ vagrant version
  Installed Version: 2.2.10
  Latest Version: 2.2.10
  // 最新版なので、問題なしと判断！！

####②次にvirtualboxを調べてみた!!
すると古いバージョンであることが判明！古いバージョンだったために発生したエラーでした。
バージョンを

旧：virtualbox 6.0.14
新：virtualbox 6.1.14

に更新したところ解決しました！
以上です！