Pdsh(Parallel Distributed Shell)

Pdsh is a high-performance, parallel remote shell utility. It uses a sliding window of threads to execute remote commands, conserving socket resources while allowing some connections to timeout if needed. It was originally written as a replacement for IBM's DSH on clusters at LLNL.

The core functionality of pdsh is supplemented by many available dynamically loadable modules. The modules may implement a new connection protocol, target host filtering (e.g. removing hosts that are "down" from the target host list) and/or other host selection options (e.g. -a selects all hosts from a config file).

The pdsh distribution also contains a parallel remote copy utility (pdcp - copy from local host to a group of remote hosts in parallel), reverse parallel remote copy (rpdcp, copy from a group of hosts to localhost in parallel), and a script dshbak for formatting and demultiplexing pdsh output.

常用参数:

-w TARGETS,... : 指定主机列表, 以逗号分隔(中间不能有空格).

-x host,host,... : 排除指定主机

-l user : 指定登录用户

配置主机组:

dshgroup module options
The dshgroup module allows pdsh to use dsh (or Dancer's shell) style group files from /etc/dsh/group/ or ~/.dsh/group/.

-g groupname,...
Target nodes in dsh group file "groupname" found in either ~/.dsh/group/groupname or /etc/dsh/group/groupname.

-X groupname,...
Exclude nodes in dsh group file "groupname."

将主机组列表文件放在 /etc/dsh/group/ 或 ~/.dsh/group/ 下, 主机组名就是文件名, 主机一行一个.

$ more ~/.dsh/group/myhosts
192.168.1.12
192.168.1.13
$ pdsh -g myhosts -l root uptime
192.168.1.13:  10:47:12 up 38 days, 14:37,  0 users,  load average: 0.04, 0.06, 0.05
192.168.1.12:  10:47:12 up 10 days, 23:53,  5 users,  load average: 0.22, 0.26, 0.28

因为pdsh需要配置好公私钥后才可以使用，而配置了公私钥后，如果从未登录过某台机器，第一次登录时默认交互式的确认Yes或No来将ECDSA签名写入~/.ssh/known_hosts文件. 这是如果用pdsh执行命令会失败. 可以通过批量执行ssh -o StrictHostKeyChecking=no来将这个签名写入文件, 并执行命令.

$ pdsh -R exec -g myhosts ssh -o StrictHostKeyChecking=no -l root %h uptime
host1: Warning: Permanently added 'host1,192.168.1.12' (ECDSA) to the list of known hosts.
host2: Warning: Permanently added 'host2,192.168.1.13' (ECDSA) to the list of known hosts.
host1:  10:34:01 up 38 days, 14:24,  0 users,  load average: 0.02, 0.06, 0.05
host2:  10:34:02 up 10 days, 23:40,  5 users,  load average: 0.12, 0.22, 0.25

注意这里的 -l root 是 ssh 的参数选项, 不是 pdsh 的.

dshbak

dshbak 是 pdsh 的一个配套工具, 用于格式化输出结果.

一般使用 dshbak -c 将输出结果归类, 相同结果不会重复输出, 方便查看差异结果:

$ pdsh -g myhosts -l root whoami | dshbak -c
----------------
192.168.1.[12-13]
----------------
root

pdcp

pdcp 是一个批量传输的工具，也是pdsh工具集中的一个，还有一个反向的rpdcp

比如要传一个目录到/home目录下:

pdcp -r -l root -g myhosts /dir /home/