1、首先，得定位问题，查，到底是哪些进程或线程打开了大量的连接（scoket）没有关闭

lsof -n | awk ‘{print $2}’ | sort | uniq -c | sort -nr | more

3、查看当前进程相关的连接

lsof | grep pid

4、jps查看当前java进程的状态

jps

5、查看当前进程属于哪个应用

ps -ef | grep pid

6、杀掉对应的pid

kill -9 pid

查看版本 lsb_release -a

Distributor ID: Ubuntu
Description:    Ubuntu 22.04.3 LTS
Release:        22.04
Codename:       jammy

备份 sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak

需要修改bionic为codename

deb http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse

更新源 sudo apt-get update

…

行末：$     

行首：^

空格：\s

行末空格：\s+$

行首空格：^\s+

删除行尾多个空格 : %s/\s+$//g

删除行首多个空格 : %s/^ +//g

删除空行：:g/^$/d

set fenc=utf-8

set fencs=utf-8,usc-bom,euc-jp,gb18030,gbk,gb2312,cp936

set nocompatible

set history=50

set tabstop=4

set number

syntax on

set showmatch

set matchtime=5

set expandtab

CentOS7，LVM根分区扩容步骤：

1.查看现有分区大小

df -TH

LVM分区，磁盘总大小为20G,根分区总容量为17G

2.关机增加大小为30G(测试环境使用的Vmware Workstation)

扩展分区到30G

3.查看扩容后磁盘大小

df -TH lsblk

磁盘总大小为30G,根分区为17G

4.创建分区

fdisk /dev/sda

将sda剩余空间全部给sda3

5.刷新分区并创建物理卷

partprobe /dev/sda pvcreate /dev/sda3

6.查看卷组名称，以及卷组使用情况

vgdisplay

VG Name为centos

7.将物理卷扩展到卷组

vgextend centos /dev/sda3

使用sda3扩展VG  centos 

8.查看当前逻辑卷的空间状态

lvdisplay

需要扩展LV  /dev/centos/root

9.将卷组中的空闲空间扩展到根分区逻辑卷

lvextend -l +100%FREE /dev/centos/root

10.刷新根分区

xfs_growfs /dev/centos/root

11.查看磁盘使用情况，扩展之前和之后是不一样的

根分区已经变成27G

CentOS7，非LVM根分区扩容步骤：

1.查看现有的分区大小

非LVM分区，目前磁盘大小为20G，根分区总容量为17G

2.关机增加磁盘大小为30G

3.查看磁盘扩容后状态

lsblk dh -TH

现在磁盘总大小为30G,根分区为17G

4.进行分区扩展磁盘，记住根分区起始位置和结束位置

…

host-only主机可以连接虚拟机，但是虚拟机不能联网 nat虚拟机可以联网，但是不能和主机互通 使用两个网卡实现既能虚拟机联网又能和主机互通