使用parallel-ssh批量执行远程shell命令

pssh使用场景

假设现在需要对数百台服务器节点进行配置更新或者执行一些简短command，而目前并没有完备的部署工具软件，那可以选择向pssh这样的并行登录远程终端并执行指定命令的shell工具。
以前机器节点少的时候，直接用shell写个for循环来执行命令，也没什么问题。当节点数量多了之后，一个shell命令可能要消耗几秒，这时才能感受到pssh这种并行方式的好处，省时省力。

pssh可选配置参数列表

除了pssh，当需要传递登录密码时，可以用到sshpass命令：

pintai@MG:~/bak$ pssh --help
Usage: pssh [OPTIONS] command [...]

Options:
  --version show program's version number and exit
  --help show this help message and exit
  -h HOST_FILE,--hosts=HOST_FILE
                        hosts file (each line "[user@]host[:port]")
  -H HOST_STRING,--host=HOST_STRING
                        additional host entries ("[user@]host[:port]")
  -l USER,--user=USER username (OPTIONAL)
  -p PAR,--par=PAR max number of parallel threads (OPTIONAL)
  -o OUTDIR,--outdir=OUTDIR
                        output directory for stdout files (OPTIONAL)
  -e ERRDIR,--errdir=ERRDIR
                        output directory for stderr files (OPTIONAL)
  -t TIMEOUT,--timeout=TIMEOUT
                        timeout (secs) (0 = no timeout) per host (OPTIONAL)
  -O OPTION,--option=OPTION
                        SSH option (OPTIONAL)
  -v,--verbose turn on warning and diagnostic messages (OPTIONAL)
  -A,--askpass Ask for a password (OPTIONAL)
  -x ARGS,--extra-args=ARGS
                        Extra command-line arguments,with processing for
                        spaces,quotes,and backslashes
  -X ARG,--extra-arg=ARG
                        Extra command-line argument
  -i,--inline inline aggregated output and error for each server
  --inline-stdout inline standard output for each server
  -I,--send-input read from standard input and send as input to ssh
  -P,--print print output as we get it

Example: pssh -h hosts.txt -l irb2 -o /tmp/foo uptime

pintai@MG:~/bak$ sshpass --help
sshpass: invalid option -- '-'
Usage: sshpass [-f|-d|-p|-e] [-hV] command parameters
   -f filename   Take password to use from file
   -d number     Use number as file descriptor for getting password
   -p password   Provide password as argument (security unwise)
   -e            Password is passed as env-var "SSHPASS"
   With no parameters - password will be taken from stdin

   -h            Show help (this screen)
   -V            Print version information
At most one of -f,-d,-p or -e should be used

1.使用sshpass传递登录密码

先把需要远程登录的host集中写到一个文件，比如叫hostlist，写入host列表:

192.168.1.11:22
192.168.1.12:22
192.168.1.13:22

然后将ssh登录密码写到另一个文件，比如叫remotepass，写入密码:

yourpassword

最后执行相关命令，直接打印每个节点的输出内容：

sshpass -f remotepass pssh -h hostlist -l yourloginname -A -i "hostname"

输出结果如下

Warning: do not enter your password if anyone else has superuser
privileges or access to your account.
[1] 11:23:21 [SUCCESS] 192.168.1.11:22
test1.hostname
[2] 11:23:21 [SUCCESS] 192.168.1.12:22
test2.hostname
[3] 11:23:21 [SUCCESS] 192.168.1.13:22
test3.hostname

2.将结果输出到指定文件

如果需要将输出结果收集起来，那么可以通过-o选项来指定结果输出目录，比如：

sshpass -f remotepass pssh -h hostlist -l yourloginname -o outputdir -A "hostname"

执行时终端输出:

Warning: do not enter your password if anyone else has superuser
privileges or access to your account.
[1] 11:23:21 [SUCCESS] 192.168.1.11:22
[2] 11:23:21 [SUCCESS] 192.168.1.12:22
[3] 11:23:21 [SUCCESS] 192.168.1.13:22

而当前目录会生成outputdir目录，目录中每个host占一个文件，如：

pintai@MG:~/bak$ ls output/
192.168.1.11:22 192.168.1.12:22 192.168.1.13:22
pintai@MG:~/bak$ cat output/*
test1.hostname
test2.hostname
test3.hostname

3. 执行sudo命令

有些shell命令可能需要通过sudo权限来执行，一般来说本地可以这么执行

echo your_sudo_pass | sudo -S your_command

而在pssh中可以这么做：

sshpass -f remotepass pssh -h hostlist -l yourloginname -o outputdir -A "echo your_sudo_pass | sudo -S netstat -antup | grep xxx"

执行完毕后，具体输出结果可以在outputdir目录下查找。