autossh不生效_autossh 让你的 ssh 不掉线

[摘要] ssh是OPS及DEV同学登录服务器进行维护，部署等的必备工具。我们总会遇到长时间连接ssh后会自动断开需要重连的情况，之前我们都是使用screen来保证ssh不断线，现在有了一个更加给力的工具－－autossh，autossh 是在ssh的基础之上，增加了一个监控端口，防止ssh session 过期，并可以重新连接保证不掉线，这保证我们在ssh执行远程服务器上的运行时间长的脚本时不会出现意外失联的情况。

下载地址：

download autossh-1.4c.tgz

源码安装，一次编译，到处执行：

gunzip -c autossh-1.4c.tgz | tar xvf -

cd autossh-1.4c

./configure

make

copy binary to where you wish it, or "make install" will install it under /usr/local by default.

examine autossh.host for example wrapper script and options

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gunzip-cautossh-1.4c.tgz|tarxvf-

cdautossh-1.4c

./configure

make

copybinarytowhereyouwishit,or"make install"willinstallitunder/usr/localbydefault.

examineautossh.hostforexamplewrapperscriptandoptions

脚本用法

# ./autossh

usage: autossh [-V] [-M monitor_port[:echo_port]] [-f] [SSH_OPTIONS]

-M specifies monitor port. May be overridden by environment

variable AUTOSSH_PORT. 0 turns monitoring loop off.

Alternatively, a port for an echo service on the remote

machine may be specified. (Normally port 7.)

-f run in background (autossh handles this, and does not

pass it to ssh.)

-V print autossh version and exit.

Environment variables are:

AUTOSSH_GATETIME - how long must an ssh session be established

before we decide it really was established

(in seconds). Default is 30 seconds; use of -f

flag sets this to 0.

AUTOSSH_LOGFILE - file to log to (default is to use the syslog

facility)

AUTOSSH_LOGLEVEL - level of log verbosity

AUTOSSH_MAXLIFETIME - set the maximum time to live (seconds)

AUTOSSH_MAXSTART - max times to restart (default is no limit)

AUTOSSH_MESSAGE - message to append to echo string (max 64 bytes)

AUTOSSH_PATH - path to ssh if not default

AUTOSSH_PIDFILE - write pid to this file

AUTOSSH_POLL - how often to check the connection (seconds)

AUTOSSH_FIRST_POLL - time before first connection check (seconds)

AUTOSSH_PORT - port to use for monitor connection

AUTOSSH_DEBUG - turn logging to maximum verbosity and log to

stderr

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# ./autossh

usage:autossh[-V][-Mmonitor_port[:echo_port]][-f][SSH_OPTIONS]

-Mspecifiesmonitorport.Maybeoverriddenbyenvironment

variableAUTOSSH_PORT.0turnsmonitoringloopoff.

Alternatively,aportforanechoserviceontheremote

machinemaybespecified.(Normallyport7.)

-fruninbackground(autosshhandlesthis,anddoesnot

passittossh.)

-Vprintautosshversionandexit.

Environmentvariablesare:

AUTOSSH_GATETIME-howlongmustansshsessionbeestablished

beforewedecideitreallywasestablished

(inseconds).Defaultis30seconds;useof-f

flagsetsthisto0.

AUTOSSH_LOGFILE-filetologto(defaultistousethesyslog

facility)

AUTOSSH_LOGLEVEL-leveloflogverbosity

AUTOSSH_MAXLIFETIME-setthemaximumtimetolive(seconds)

AUTOSSH_MAXSTART-maxtimestorestart(defaultisnolimit)

AUTOSSH_MESSAGE-messagetoappendtoechostring(max64bytes)

AUTOSSH_PATH-pathtosshifnotdefault

AUTOSSH_PIDFILE-writepidtothisfile

AUTOSSH_POLL-howoftentochecktheconnection(seconds)

AUTOSSH_FIRST_POLL-timebeforefirstconnectioncheck(seconds)

AUTOSSH_PORT-porttouseformonitorconnection

AUTOSSH_DEBUG-turnloggingtomaximumverbosityandlogto

stderr

下面是使用autossh登录服务器的列子：

./autossh -M port remote-ssh-server-IP

如：

./autossh -M 12345 sudops@172.32.5.239

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./autossh-Mportremote-ssh-server-IP

如：

./autossh-M12345sudops@172.32.5.239

创建ssh隧道的例子：

autossh -M 12345 -N -D -v localhost:7070 sudops@172.32.5.239 -p 22

会看到如下监听端口：其中7070为本地

tcp 0 0 127.0.0.1:7070 0.0.0.0:* LISTEN 7466/ssh

tcp 0 0 127.0.0.1:12345 0.0.0.0:* LISTEN 7466/ssh

tcp 0 0 127.0.0.1:12346 0.0.0.0:* LISTEN 7465/autossh

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autossh-M12345-N-D-vlocalhost:7070sudops@172.32.5.239-p22

会看到如下监听端口：其中7070为本地

tcp00127.0.0.1:70700.0.0.0:*LISTEN7466/ssh

tcp00127.0.0.1:123450.0.0.0:*LISTEN7466/ssh

tcp00127.0.0.1:123460.0.0.0:*LISTEN7465/autossh

能够看到autossh启动了一个echo service port 12345作为监控，另外还启动了一个port＋1的端口12346作为接收端口，文档描述如下：

When no echo service port is specified, this port and the port

immediately above it (port# + 1) should be something nothing

else is using. autossh will send test data on the base monitoring

port, and receive it back on the port above.

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Whennoechoserviceportisspecified,thisportandtheport

immediatelyaboveit(port# + 1) should be something nothing

elseisusing.autosshwillsendtestdataonthebasemonitoring

port,andreceiveitbackontheportabove.

怎么样，有意思不，赶快体验下传说中的“高大上” autossh 吧。