小水实验室 – 海外主机，网站不定时抽风

sample shell : restart golang web program run in background

set -e

exename=golangwebexe
echo "old version sha1: "
sha1sum ./$exename

if [ ! -f "$exename.rc" ]; then
    echo "do not have RC exe file"
    exit
fi

pgrep $exename
pkill -f $exename

rm ./$exename
chmod +x ./$exename.rc
mv ./$exename.rc ./$exename
echo "old version sha1: "
sha1sum ./$exename

nohup ./$exename > run.log 2>&1 & 

sleep 3
pgrep $exename

set -e

exename=golangwebexe

echo "old version sha1: "

sha1sum ./$exename

if [ ! -f "$exename.rc" ]; then

echo "do not have RC exe file"

exit

pgrep $exename

pkill -f $exename

rm ./$exename

chmod +x ./$exename.rc

mv ./$exename.rc ./$exename

echo "old version sha1: "

sha1sum ./$exename

nohup ./$exename > run.log 2>&1 &

sleep 3

pgrep $exename

systemd （systemctl）简单开机自启动任务

编写类似文件 xxxxx.service 放置到/usr/lib/systemd/system 目录下

注意 /root/services/XXXXXX/start.sh 这个文件需要 +x 赋予可执行权限

[Unit]   
Description=judged hz
After=mariadb.service redis.service

[Service]  
Type=forking     
KillMode=control-group   
Restart=no        
ExecStart=/root/services/XXXXXX/start.sh    

[Install]   
WantedBy=multi-user.target

[Unit]

Description=judged hz

After=mariadb.service redis.service

[Service]

Type=forking

KillMode=control-group

Restart=no

ExecStart=/root/services/XXXXXX/start.sh

[Install]

WantedBy=multi-user.target

openwrt pppoe拨号后动作

#!/bin/sh
sleep 5
if [ ${DEVICE} == 'pppoe-wan' && ${ACTION} == 'ifup' ]; then
    wget http://remebermyrequest.ip/index.php?mark=1 -O /dev/null
fi

#!/bin/sh

sleep 5

if [ ${DEVICE} == 'pppoe-wan' && ${ACTION} == 'ifup' ]; then

wget http://remebermyrequest.ip/index.php?mark=1 -O /dev/null

/etc/hotplug.d/iface

cobbler ubuntu 自动应答脚本

网卡自动选择不生效的问题

d-i netcfg/choose_interface select auto 没效果

是个bug ，官方建议如此操作修改ubuntu的发行版的内核引导参数，如下：

cobbler distro edit --name=ubuntu-16.04-x86_64 --kopts="netcfg/choose_interface=auto"

1	cobbler distro edit --name=ubuntu-16.04-x86_64 --kopts="netcfg/choose_interface=auto"

ubuntu 18.04 更新dns设置

先说重点：

* 有多种修改方法
* 直接修改/etc/resolv.conf文件是临时的
* 一般来说 /etc/resolv.conf 是由 resolvconf 命令生成的

修改/run/resolvconf/interface/ethxxx ( 每个网卡一个) 添加最多3个dns 地址
例如：
nameserver 202.106.0.20
nameserver 223.5.5.5

然后 resolveconf -u 更新生效

建议：第一个dns设置服务器所在地的运营商dns ，比如北京联通dns ，第二个dns 设置成公用的dns

远不如 centos 直接从网卡配置文件设置 dns 来的直接

调整linux 系统 tcp 网络参数更好的发送给大量请求

https://stackoverflow.com/questions/410616/increasing-the-maximum-number-of-tcp-ip-connections-in-linux
vim /etc/sysctl.conf

主要是这四个参数
sysctl net.ipv4.tcp_tw_recycle=1
sysctl net.ipv4.tcp_tw_reuse=1
sysctl net.ipv4.ip_local_port_range=”15000 61000″
sysctl net.ipv4.tcp_fin_timeout=30

mysql 提示不能通过root@127.0.0.1连接的问题

在 my.cnf中注释 skip-name-relove
GRANT ALL PRIVILEGES ON *.* TO 'root'@'127.0.0.1' IDENTIFIED BY 'PASSWORD' WITH GRANT OPTION; flush privileges;

tcpdump usage

一、获取适配器列表
$ tcpdump -D

二、监听适配器
使用 -i 或 –interface 参数监听适配器，适配器可以用序号或名字来表示，这些内容可以通过 -D 参数获取。macOS 下监听适配器的话，必须使用 root 权限。
　如果需要详细查看报内容，可以使用 -X 参数。

$ tcpdump -i en0 -X

三、监听适配器过滤
1、过滤主机
抓取所有经过 eth1，目的或源地址是 192.168.1.1 的网络数据
$ tcpdump -i en0 host 192.168.1.1

限定源地址
$ tcpdump -i eth1 src host 192.168.1.1

限定目标地址
$ tcpdump -i eth1 dst host 192.168.1.1

2、过滤端口
抓取所有经过 eth1，目的或源端口是 25 的网络数据
$ tcpdump -i eth1 port 25

限定源端口
$ tcpdump -i eth1 src port 25

限定目标端口
$ tcpdump -i eth1 dst port 25

3、过滤网段
$ tcpdump -i eth1 net 192.168

$ tcpdump -i eth1 src net 192.168

$ tcpdump -i eth1 dst net 192.168

4、协议过滤

$ tcpdump -i eth1 arp
$ tcpdump -i eth1 ip
$ tcpdump -i eth1 tcp
$ tcpdump -i eth1 udp
$ tcpdump -i eth1 icmp

5、使用表达式
与：&& 或 and
或：|| 或 or
非：! 或 not

$ tcpdump -i eth1 ‘((tcp) and (port 80) and ((dst host 192.168.1.254) or (dst host
192.168.1.200)))’

fabric 踩坑记

fabric2是一个使用python 脚本ssh连接服务器执行命令的工具

安装fabric2

坑1 ：由于轻信了一开始搜索到的fabric中文文档网页，该网页已经陈旧，正确安装方式为 fabric2

pip3 install fabric2

#or

pip install fabric2

pip3 install fabric2

#or

pip install fabric2

这里直接上我写好的fabric 脚本

#!/bin/python3
#coding=utf-8
from fabric2 import Connection
from invoke import run as local

def printResult(fabricResult):
    msg = "Ran {0.command!r} on {0.connection.host}, got stdout:\n{0.stdout}----------------------------------------------"
    print(msg.format(fabricResult))

def updateNewVersion(sshConn):
    sshConn.run("sh /root/shells/update_software.sh")
    #printResult(res)


if __name__ == "__main__":
    #compile new version
    local("rm -rf ./bin/shot", pty=True )
    local("CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o ./tar/shot ./src/shot", pty=True )
    local("shasum ./bin/tar",pty=True )
    #push to dev server
    sshConn  = Connection("testserver")
    sshConn.put("./tar/shot", "/root/temp/shot_newversion")
    updateNewVersion(sshConn)

#!/bin/python3

#coding=utf-8

from fabric2 import Connection

from invoke import run as local

def printResult(fabricResult):

msg = "Ran {0.command!r} on {0.connection.host}, got stdout:\n{0.stdout}----------------------------------------------"

print(msg.format(fabricResult))

def updateNewVersion(sshConn):

sshConn.run("sh /root/shells/update_software.sh")

#printResult(res)

if __name__ == "__main__":

#compile new version

local("rm -rf ./bin/shot", pty=True )

local("CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o ./tar/shot ./src/shot", pty=True )

local("shasum ./bin/tar",pty=True )

#push to dev server

sshConn = Connection("testserver")

sshConn.put("./tar/shot", "/root/temp/shot_newversion")

updateNewVersion(sshConn)

配置好本身ssh免密码登录

坑2：macos默认生成的id_rsa密钥格式可能不太正确，需要使用命令转换一下格式

ssh-keygen -p -m PEM -f ~/.ssh/id_rsa_testserver

1	ssh-keygen -p -m PEM -f ~/.ssh/id_rsa_testserver

#这是 ～/.ssh/config 文件中的配置
Host testserver
    HostName 192.168.1.220
    Port 10086
    User root 
    IdentityFile ~/.ssh/id_rsa_testserver

#这是～/.ssh/config 文件中的配置

Host testserver

HostName 192.168.1.220

Port 10086

User root

IdentityFile ~/.ssh/id_rsa_testserver

use jquery ajax load image and put it to image tag src in base64 way

https://stackoverflow.com/questions/19124701/get-image-using-jquery-ajax-and-decode-it-to-base64/25371174

 $.ajax({
            url: "someurltoajpeg",
            type: "GET",
            headers: {
                "Authorization" : "Basic " +  btoa("user:pw")
            },
            xhrFields: {
                withCredentials: true
            },
            mimeType: "text/plain; charset=x-user-defined"
        }).done(function( data, textStatus, jqXHR ) {
            $("#image").attr('src', 'data:image/jpeg;base64,' + base64encode(data));
        }).fail(function( jqXHR, textStatus, errorThrown ) {
            alert("fail: " + errorThrown);
        });

$.ajax({

url: "someurltoajpeg",

type: "GET",

headers: {

"Authorization" : "Basic " + btoa("user:pw")

xhrFields: {

withCredentials: true

mimeType: "text/plain; charset=x-user-defined"

}).done(function( data, textStatus, jqXHR ) {

$("#image").attr('src', 'data:image/jpeg;base64,' + base64encode(data));

}).fail(function( jqXHR, textStatus, errorThrown ) {

alert("fail: " + errorThrown);

});

function base64encode(str) {
        var CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
        var out = "", i = 0, len = str.length, c1, c2, c3;
        while (i < len) {
            c1 = str.charCodeAt(i++) & 0xff;
            if (i == len) {
                out += CHARS.charAt(c1 >> 2);
                out += CHARS.charAt((c1 & 0x3) << 4);
                out += "==";
                break;
            }
            c2 = str.charCodeAt(i++);
            if (i == len) {
                out += CHARS.charAt(c1 >> 2);
                out += CHARS.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
                out += CHARS.charAt((c2 & 0xF) << 2);
                out += "=";
                break;
            }
            c3 = str.charCodeAt(i++);
            out += CHARS.charAt(c1 >> 2);
            out += CHARS.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));
            out += CHARS.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6));
            out += CHARS.charAt(c3 & 0x3F);
        }
        return out;
    }

function base64encode(str) {

var CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

var out = "", i = 0, len = str.length, c1, c2, c3;

while (i < len) {

c1 = str.charCodeAt(i++) & 0xff;

if (i == len) {

out += CHARS.charAt(c1 >> 2);

out += CHARS.charAt((c1 & 0x3) << 4);

out += "==";

break;

}

c2 = str.charCodeAt(i++);

if (i == len) {

out += CHARS.charAt(c1 >> 2);

out += CHARS.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));

out += CHARS.charAt((c2 & 0xF) << 2);

out += "=";

break;

}

c3 = str.charCodeAt(i++);

out += CHARS.charAt(c1 >> 2);

out += CHARS.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));

out += CHARS.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6));

out += CHARS.charAt(c3 & 0x3F);

}

return out;

}