.作者：邓聪聪
一.SSH 连接速度慢优化
同步时间：timedatectl list-timezones
1>.关闭DNS PTR反向查询
UseDNS 选项打开状态下，当客户端试图登录SSH服务器时，服务器端先根据客户端的IP地址进行DNS PTR反向查询出客户端的主机名，然后根据查询出的客户端主机名进行DNS正向A记录查询，验证与其原始IP地址是否一致，这是防止客户端欺骗的一种措施，但一般我们的是动态IP不会有PTR记录，打开这个选项不过是在白白浪费时间而已，不如将其关闭。
[root@node101 ~]# [root@node101 ~]# grep UseDNS /etc/ssh/sshd_config #UseDNS yes [root@node101 ~]# [root@node101 ~]# sed -i 's@#UseDNS yes@UseDNS no@g' /etc/ssh/sshd_config [root@node101 ~]# [root@node101 ~]# grep UseDNS /etc/ssh/sshd_config UseDNS no [root@node101 ~]#
2>.关闭GSSAPI身份验证
GSSAPIAuthentication 当这个参数开启（ GSSAPIAuthentication yes ）的时候，通过SSH登陆服务器时候会有些会很慢！这是由于服务器端启用了GSSAPI。登陆的时候客户端需要对服务器端的IP地址进行反解析，如果服务器的IP地址没有配置PTR记录，那么就容易在这里卡住了。
[root@node101 ~]# grep GSSAPIAuthentication /etc/ssh/sshd_config GSSAPIAuthentication yes [root@node101 ~]# [root@node101 ~]# sed -i 's@^GSSAPIAuthentication yes@GSSAPIAuthentication no@g' /etc/ssh/sshd_config [root@node101 ~]# [root@node101 ~]# grep GSSAPIAuthentication /etc/ssh/sshd_config GSSAPIAuthentication no [root@node101 ~]# [root@node101 ~]# systemctl restart sshd [root@node101 ~]#
二.更换yum源
1>.创建备份目录
[root@node101 ~]# ll /etc/yum.repos.d/ total 28 -rw-r--r--. 1 root root 1664 Dec 9 2015 CentOS-Base.repo -rw-r--r--. 1 root root 1309 Dec 9 2015 CentOS-CR.repo -rw-r--r--. 1 root root 649 Dec 9 2015 CentOS-Debuginfo.repo -rw-r--r--. 1 root root 290 Dec 9 2015 CentOS-fasttrack.repo -rw-r--r--. 1 root root 630 Dec 9 2015 CentOS-Media.repo -rw-r--r--. 1 root root 1331 Dec 9 2015 CentOS-Sources.repo [root@node101 ~]# mkdir -p /etc/yum.repos.d/{default,back} [root@node101 ~]# ll /etc/yum.repos.d/ total 28 drwxr-xr-x. 2 root root 6 Mar 3 05:34 back -rw-r--r--. 1 root root 1664 Dec 9 2015 CentOS-Base.repo -rw-r--r--. 1 root root 1309 Dec 9 2015 CentOS-CR.repo -rw-r--r--. 1 root root 649 Dec 9 2015 CentOS-Debuginfo.repo -rw-r--r--. 1 root root 290 Dec 9 2015 CentOS-fasttrack.repo -rw-r--r--. 1 root root 630 Dec 9 2015 CentOS-Media.repo -rw-r--r--. 1 root root 1331 Dec 9 2015 CentOS-Sources.repo -rw-r--r--. 1 root root 1952 Dec 9 2015 CentOS-Vault.repo drwxr-xr-x. 2 root root 6 Mar 3 05:34 default [root@node101 ~]# mkdir -p /etc/yum.repos.d/{default,back}
2>.备份所有默认的配置文件
[root@node101 ~]# ll /etc/yum.repos.d/ total 28 drwxr-xr-x. 2 root root 6 Mar 3 05:34 back -rw-r--r--. 1 root root 1664 Dec 9 2015 CentOS-Base.repo -rw-r--r--. 1 root root 1309 Dec 9 2015 CentOS-CR.repo -rw-r--r--. 1 root root 649 Dec 9 2015 CentOS-Debuginfo.repo -rw-r--r--. 1 root root 290 Dec 9 2015 CentOS-fasttrack.repo -rw-r--r--. 1 root root 630 Dec 9 2015 CentOS-Media.repo -rw-r--r--. 1 root root 1331 Dec 9 2015 CentOS-Sources.repo -rw-r--r--. 1 root root 1952 Dec 9 2015 CentOS-Vault.repo drwxr-xr-x. 2 root root 6 Mar 3 05:34 default [root@node101 ~]# mv /etc/yum.repos.d/*repo /etc/yum.repos.d/default/ [root@node101 ~]# [root@node102 ~]# ll /etc/yum.repos.d/ total 4 drwxr-xr-x. 2 root root 6 Mar 3 05:34 back drwxr-xr-x. 2 root root 4096 Mar 3 05:34 default [root@node101 ~]# mv /etc/yum.repos.d/*repo /etc/yum.repos.d/default/
3>.获取yum 源
[root@node101 ~]# ll /etc/yum.repos.d/ total 4 drwxr-xr-x. 2 root root 6 Mar 3 05:34 back drwxr-xr-x. 2 root root 4096 Mar 3 05:34 default [root@node101 ~]# [root@node101 ~]# [root@node101 ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 2523 100 2523 0 0 15349 0 --:--:-- --:--:-- --:--:-- 15478 [root@node101 ~]# ll /etc/yum.repos.d/ total 8 drwxr-xr-x. 2 root root 6 Mar 3 05:34 back -rw-r--r--. 1 root root 2523 Mar 3 05:35 CentOS-Base.repo drwxr-xr-x. 2 root root 4096 Mar 3 05:34 default [root@node101 ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
4>.生成缓存
[root@node101 ~]# yum makecache Loaded plugins: fastestmirror base | 3.6 kB 00:00:00 extras | 3.4 kB 00:00:00 updates | 3.4 kB 00:00:00 (1/8): extras/7/x86_64/filelists_db | 231 kB 00:00:00 extras/7/x86_64/other_db FAILED http://mirrors.cloud.aliyuncs.com/centos/7/extras/x86_64/repodata/d072100fade170a6b781b00657e1a6c116f84b59b35c21b98a280e598512508c-other.sqlite.bz2: [Errno 14] curl#6 - "Could not resolve host: mirrors.cloud.aliyuncs.com; Name or service not known" Trying other mirror. (2/8): updates/7/x86_64/filelists_db | 1.9 MB 00:00:00 (3/8): updates/7/x86_64/other_db | 344 kB 00:00:00 (4/8): extras/7/x86_64/other_db | 118 kB 00:00:00 (5/8): base/7/x86_64/filelists_db | 7.1 MB 00:00:01 base/7/x86_64/other_db FAILED http://mirrors.aliyuncs.com/centos/7/os/x86_64/repodata/fbebcd3de05e22bd1cd526e594f235968401471d4a9aef3c1ad356b6d1965365-other.sqlite.bz2: [Errno 14] curl#7 - "Failed connect to mirrors.aliyuncs.com:80; Connection refused" Trying other mirror. extras/7/x86_64/prestodelta FAILED http://mirrors.aliyuncs.com/centos/7/extras/x86_64/repodata/ea35765e72afae3e1539686da06393ce09fe26a04dbf576e218f994e4b7a706a-prestodelta.xml.gz: [Errno 14] curl#7 - "Failed connect to mirrors.aliyuncs.com:80; Connection refused" Trying other mirror. (6/8): extras/7/x86_64/prestodelta | 47 kB 00:00:00 (7/8): base/7/x86_64/other_db | 2.6 MB 00:00:00 updates/7/x86_64/prestodelta FAILED http://mirrors.aliyuncs.com/centos/7/updates/x86_64/repodata/fd2186bbf3d231d441dc73bc0d0a3f2b79d5c212d14ceadf9a878fb2a5808de3-prestodelta.xml.gz: [Errno 14] curl#7 - "Failed connect to mirrors.aliyuncs.com:80; Connection refused" Trying other mirror. (8/8): updates/7/x86_64/prestodelta | 343 kB 00:00:00 Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Metadata Cache Created [root@node101 ~]# yum makecache
5>.备份yum 源
[root@node101 ~]# cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/back/ [root@node101 ~]# [root@node101 ~]# ll /etc/yum.repos.d/back/ total 4 -rw-r--r--. 1 root root 2523 Mar 3 05:37 CentOS-Base.repo [root@node101 ~]# [root@node101 ~]# ll /etc/yum.repos.d/default/ total 28 -rw-r--r--. 1 root root 1664 Dec 9 2015 CentOS-Base.repo -rw-r--r--. 1 root root 1309 Dec 9 2015 CentOS-CR.repo -rw-r--r--. 1 root root 649 Dec 9 2015 CentOS-Debuginfo.repo -rw-r--r--. 1 root root 290 Dec 9 2015 CentOS-fasttrack.repo -rw-r--r--. 1 root root 630 Dec 9 2015 CentOS-Media.repo -rw-r--r--. 1 root root 1331 Dec 9 2015 CentOS-Sources.repo -rw-r--r--. 1 root root 1952 Dec 9 2015 CentOS-Vault.repo [root@node101 ~]# [root@node101 ~]# ll /etc/yum.repos.d/ total 8 drwxr-xr-x. 2 root root 29 Mar 3 05:37 back -rw-r--r--. 1 root root 2523 Mar 3 05:35 CentOS-Base.repo drwxr-xr-x. 2 root root 4096 Mar 3 05:34 default [root@node101 ~]# cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/back/
三、修改网卡名称
1.修改网卡配置文件的名字
[root@node101 ~]# cd /etc/sysconfig/network-scripts/ [root@node101 network-scripts]# [root@node101 network-scripts]# mv ifcfg-eno16777736 ifcfg-eth0 [root@node101 network-scripts]#
2.修改网卡配置文件里面的内容
[root@node101 network-scripts]# pwd /etc/sysconfig/network-scripts [root@node101 network-scripts]# [root@node101 network-scripts]# cat ifcfg-eth0 TYPE=Ethernet DEVICE=eth0 ONBOOT=yes BOOTPROTO=static IPADDR=172.30.1.102 NETMASK=255.255.255.0 GATEWAY=172.30.1.254 DNS1=172.30.1.254 [root@node101 network-scripts]#
3.GRUB 添加kernel 参数
[root@node101 ~]# cat /etc/sysconfig/grub GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="crashkernel=auto rhgb net.ifnames=0 biosdevname=0 quiet" GRUB_DISABLE_RECOVERY="true" [root@node101 ~]#
4.使配置生效
[root@node101 ~]# grub2-mkconfig -o /boot/grub2/grub.cfg Generating grub configuration file ... Found linux image: /boot/vmlinuz-3.10.0-327.el7.x86_64 Found initrd image: /boot/initramfs-3.10.0-327.el7.x86_64.img Found linux image: /boot/vmlinuz-0-rescue-d1667a8e7e71407d8b380ec3588d6c19 Found initrd image: /boot/initramfs-0-rescue-d1667a8e7e71407d8b380ec3588d6c19.img done [root@node101 ~]#
5.系统重启