centos init

centos init

#调整分区大小
$ sudo resize2fs /dev/xvda1

service sshd start
yum -y install setuptool
yum -y install  ntsysv system-config-firewall-tui system-config-network-tui
yum -y install openssh-clients
yum -y install telnet  vim ntpdate wget
yum install ntp ntpdate ntp-doc
yum install mkfontscale  （字体工具）

chkconfig ntpd on
service ntpd start



#编译开发环境的简易安装
sudo yum groupinstall -y  "Development tools"

#couchbase要安装openssl098e
yum install openssl098e

Please note that you have to update your firewall configuration to
allow connections to the following ports: 11211, 11210, 11209, 4369,
8091, 8092 and from 21100 to 21299.
#安装scp服务端，不然会显示bash: scp: command not found lost connection

change 

#添加google DNS 8.8.8.8

setenforce 0
/etc/sysconfig/selinux
SELINUX=disabled
#SELINUX=enforcing
#close selinux
setenforce 0
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/sysconfig/selinux
echo "selinux off"


service iptables stop

service ip6tables stop

#chkconfig
chkconfig --level 35 ip6tables off
chkconfig --level 35 iptables off
chkconfig --level 35 bluetooth off
echo "chkconfig iptables off"
 


Selection Command
-----------------------------------------------
*+ 1 /usr/java/jdk1.6.0_17/bin/java

Enter to keep the current selection[+], or type selection number:

http://gigabud01.oss-cn-hangzhou.aliyuncs.com/software/jdk-8u161-linux-x64.tar.gz
#jdk8 installing
JAVA_HOME=/usr/java/jdk1.8.0_161
PATH=$JAVA_HOME/bin:$PATH
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME
export PATH
export CLASSPATH
update-alternatives --install /usr/bin/java java /usr/java/jdk1.8.0_131/bin/java 100
update-alternatives --config java
update-alternatives --install /usr/bin/javac java /usr/java/jdk1.8.0_131/bin/javac 100
update-alternatives --config javac

禁用GSSAPI和 DNS反向解析来提高ssh连接速度
 同时关闭空密码用户登陆，允许root login
vi /etc/ssh/sshd_config
设置以下几项为
GSSAPIAuthentication no
UseDNS no
PermitEmptyPasswords no
PermitRootLogin ye
 

tcp 性能优化

vi  /etc/sysctl.conf
加入
net.ipv4.tcp_fin_timeout = 1 
net.ipv4.tcp_keepalive_time = 1200 
net.ipv4.tcp_mem = 94500000 915000000 927000000 
net.ipv4.tcp_tw_reuse = 1 
net.ipv4.tcp_timestamps = 0 
net.ipv4.tcp_synack_retries = 1 
net.ipv4.tcp_syn_retries = 1 
net.ipv4.tcp_tw_recycle = 1 
net.core.rmem_max = 16777216 
net.core.wmem_max = 16777216 
net.core.netdev_max_backlog = 262144 
net.core.somaxconn = 262144 
net.ipv4.tcp_max_orphans = 3276800 
net.ipv4.tcp_max_syn_backlog = 262144 
net.core.wmem_default = 8388608 
net.core.rmem_default = 8388608 
 

调整最大打开文件数调整为65535

vi /etc/security/limits.conf
加入
*           soft   nofile       65535 
*           hard   nofile       65535 

#临时调整 ulimit -n 65535
#显示状态ulimit -a
调整为美东时区


cp /usr/share/zoneinfo/America/New_York /etc/localtime

cp -f /usr/share/zoneinfo/Asia/Shanghai     /etc/localtime


ln -sf /usr/share/zoneinfo/Asia/Hong_Kong /etc/localtime
/usr/share/zoneinfo/Asia/Hong_Kong
# date -R
Mon, 25 Nov 2013 05:32:08 -0500
每天四点和国家授时中心进行时间校正

vi /etc/crontab
加入
ntpdate us.pool.ntp.org
* 4 * * * /usr/sbin/ntpdate us.pool.ntp.org
 

禁用ctrl+alt+del自动重启
注释掉
exec /sbin/shutdown -r now "Control-Alt-Delete pressed"