centos7 虚拟机模板

修改网卡名称为 eth0

ifnames=0 biosdevname=0

1. 更新yum源

   curl -q -# https://mirrors.aliyun.com/repo/Centos-7.repo >/etc/yum.repos.d/CentOS-Base.repo 
   yum  clean all && yum makecache

   yum -y install epel-release glibc glibc-devel libstdc++ gcc gcc-c++ autoconf automake make  wget  net-tools lrzsz  tree nmap dos2unix nc \
   lsof tcpdump bridge-utils htop iftop iotop sysstat nethogs vim telnet curl tar \
   gettext iptables zlib zlib-devel openssl openssl-devel libffi-devel \
   openldap-devel git iperf3 jq bind-utils \
   bash-completion bash-completion-extras drbd-bash-completion stress-ng pam-devel

2. 关闭防火墙和 selinux

   setenforce 0
   sed -i  -e s/SELINUX=enforcing/SELINUX=disabled/1 -e s/SELINUX=permissive/SELINUX=disabled/1 /etc/selinux/config
   systemctl stop firewalld.service
   systemctl disable firewalld.service

3. 时间同步

 31  yum install chrony 
 32  vi /etc/chrony.conf   改为ntp.aliyun.com
 33  systemctl start chronyd
 34  chronyc tracking

4. 调整文件描述符

   cat >>/etc/security/limits.conf<<EOF
   # 为所有用户设置软限制，每个进程可以打开的最大文件描述符数量为 65536
   * soft nofile 65536
   # 为所有用户设置硬限制，每个进程可以打开的最大文件描述符数量为 65536。
   * hard nofile 65536
   # 为所有用户设置软限制，每个用户可以拥有的最大进程数为 32000。
   * soft nproc 32000
   # 为所有用户设置硬限制，每个用户可以拥有的最大进程数为 32000。
   * hard nproc 32000
   # 为所有用户设置硬限制，允许锁定的内存量无限制。
   * hard memlock unlimited
   # 为所有用户设置软限制，允许锁定的内存量无限制。
   * soft memlock unlimited
   EOF
    
   cat >> /etc/systemd/system.conf<<EOF
   DefaultLimitNOFILE=65536
   DefaultLimitNPROC=32000
   DefaultLimitMEMLOCK=infinity
   EOF

5. 调整内核参数

   [root@seagullloki01-uat-s2 ~]# cat  /etc/sysctl.conf 
   net.ipv4.ip_forward = 1
   net.bridge.bridge-nf-call-iptables = 1
   net.bridge.bridge-nf-call-ip6tables = 1
   net.bridge.bridge-nf-call-arptables = 1
   net.ipv4.tcp_tw_recycle = 0
   net.ipv4.tcp_tw_reuse = 0
   net.core.somaxconn = 65535
   net.netfilter.nf_conntrack_max=1000000
   vm.swappiness = 0
   vm.max_map_count=655360
   fs.file-max=1000000
   net.ipv4.tcp_keepalive_time = 150
   net.ipv4.tcp_keepalive_intvl = 6
   net.ipv4.tcp_keepalive_probes = 5
   net.ipv4.conf.all.promote_secondaries = 1
   net.ipv4.ip_no_pmtu_disc = 1
   net.ipv4.icmp_echo_ignore_broadcasts = 1
   net.ipv4.conf.all.accept_redirects = 0
   net.ipv4.tcp_timestamps = 1
   net.ipv4.icmp_ignore_bogus_error_responses = 1
   net.ipv4.tcp_max_syn_backlog = 838860
   net.ipv4.tcp_fin_timeout = 60
   net.ipv4.conf.all.send_redirects = 0
   vm.min_free_kbytes = 16384
   vm.vfs_cache_pressure = 100
   vm.dirty_ratio = 40
   vm.page-cluster = 3
   kernel.shmmni = 4096
   kernel.sysrq  = 1
   net.ipv4.tcp_syncookies  = 1
   fs.inotify.max_user_watches = 1048576
   fs.inotify.max_user_instances   = 1024
   net.ipv4.conf.all.rp_filter      = 1
   net.ipv4.neigh.default.gc_thresh1       = 80000
   net.ipv4.neigh.default.gc_thresh2       = 90000
   net.ipv4.neigh.default.gc_thresh3       = 100000
   fs.aio-max-nr   = 50000000

6. 调整ssh客户端超时时长

   ClientAliveInterval，指定了服务器端向客户端请求消息的时间间隔, 默认是0，不发送。
   每一分钟，sshd都和ssh client打个招呼，检测它是否存在，不存时即断开连接。

   ClientAliveCountMax，指如果发现客户端没有响应，则判断一次超时，这个参数设置允许超时的次数，比如10。

   sed -i -e  '/ClientAliveInterval/d' -e '/ClientAliveCountMax/d'  /etc/ssh/sshd_config|grep ClientAliveCountMax
    
   echo -e "ClientAliveInterval 120\nClientAliveCountMax 3" >>/etc/ssh/sshd_config
    
   systemctl restart sshd

   # 永不超时
   export TMOUT=0

7. 设置history 显示格式

   echo 'export HISTTIMEFORMAT="%F-%T `whoami` "' >>/etc/profile