ssh 脚本返回 255 错误

Question

在我的代码中，我有以下内容来运行远程脚本。

 ssh [e-mail] "sh /home/user/backup_mysql.sh"

出于某种原因，我一直在 255’ing。有任何想法吗？

我可以 SSH 进入盒子就好了（无密码设置）

远程脚本：

 MUSER='root'
MPASS='123123'
MHOST="127.0.0.1"
VERBOSE=0

### Set bins path ###
GZIP=/bin/gzip
MYSQL=/usr/bin/mysql
MYSQLDUMP=/usr/bin/mysqldump
RM=/bin/rm
MKDIR=/bin/mkdir
MYSQLADMIN=/usr/bin/mysqladmin
GREP=/bin/grep

### Setup dump directory ###
BAKRSNROOT=/.snapshots/tmp

#####################################
### ----[ No Editing below ]------###
#####################################
### Default time format ###
TIME_FORMAT='%H_%M_%S%P'

### Make a backup ###
backup_mysql_rsnapshot(){
        local DBS="$($MYSQL -u $MUSER -h $MHOST -p$MPASS -Bse 'show databases')"
        local db="";
        [ ! -d $BAKRSNROOT ] && ${MKDIR} -p $BAKRSNROOT
        ${RM} -f $BAKRSNROOT/* >/dev/null 2>&1
#       [ $VERBOSE -eq 1 ] && echo "*** Dumping MySQL Database ***"
#       [ $VERBOSE -eq 1 ] && echo -n "Database> "
        for db in $DBS
        do
                local tTime=$(date +"${TIME_FORMAT}")
                local FILE="${BAKRSNROOT}/${db}.${tTime}.gz"
#               [ $VERBOSE -eq 1 ] && echo -n "$db.."
                ${MYSQLDUMP} --single-transaction -u ${MUSER} -h ${MHOST} -p${MPASS} $db | ${GZIP} -9 > $FILE
        done
#               [ $VERBOSE -eq 1 ] && echo ""
#               [ $VERBOSE -eq 1 ] && echo "*** Backup done [ files wrote to $BAKRSNROOT] ***"
}

### Die on demand with message ###
die(){
        echo "$@"
        exit 999
}

### Make sure bins exists.. else die
verify_bins(){
        [ ! -x $GZIP ] && die "File $GZIP does not exists. Make sure correct path is set in $0."
        [ ! -x $MYSQL ] && die "File $MYSQL does not exists. Make sure correct path is set in $0."
        [ ! -x $MYSQLDUMP ] && die "File $MYSQLDUMP does not exists. Make sure correct path is set in $0."
        [ ! -x $RM ] && die "File $RM does not exists. Make sure correct path is set in $0."
        [ ! -x $MKDIR ] && die "File $MKDIR does not exists. Make sure correct path is set in $0."
        [ ! -x $MYSQLADMIN ] && die "File $MYSQLADMIN does not exists. Make sure correct path is set in $0."
        [ ! -x $GREP ] && die "File $GREP does not exists. Make sure correct path is set in $0."
}

### Make sure we can connect to server ... else die
verify_mysql_connection(){
        $MYSQLADMIN  -u $MUSER -h $MHOST -p$MPASS ping | $GREP 'alive'>/dev/null
        [ $? -eq 0 ] || die "Error: Cannot connect to MySQL Server. Make sure username and password are set correctly in $0"
}

### main ####
verify_bins
verify_mysql_connection
backup_mysql_rsnapshot

原文由 Amanada Smith 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

这通常发生在遥控器关闭/不可用时；或者远程机器没有安装 ssh；或者防火墙不允许与远程主机建立连接。

ssh 发生错误时返回 255 或远程脚本返回 255：

  EXIT STATUS

     ssh exits with the exit status of the remote command or
     with 255 if an error occurred.

通常您会收到类似于以下内容的错误消息：

 ssh: connect to host host.domain.com port 22: No route to host

或者

ssh: connect to host HOSTNAME port 22: Connection refused

清单：

• 如果直接从命令行运行 ssh 命令会发生什么？

• 你能 ping 那台机器吗？

• 遥控器是否安装了 ssh？

• 如果已安装，那么 ssh 服务是否正在运行？

原文由 P.P 发布，翻译遵循 CC BY-SA 3.0 许可协议