2017年1月4日星期三

pssh HOWTO Parallel SSHpssh HOWTO Parallel SSH

pssh HOWTO Parallel SSHpssh HOWTO Parallel SSH

Table of Contents 1. Installation and Setup 2. Preliminaries 3. Examples 3.1. pssh 3.2. pscp 3.3. pnuke4. Environment Variables 5. Feedback

  1. Installation and Setup

To install the software, become root on your machine and do the following (on RedHat systems):

rpm -ivh pssh-0.2.3-1.i386.rpm

Preparing... ########################################### [100%] 1:pssh ########################################### [100%]

By default, the software installs itself in /usr/localbin and /usr/local/lib. Thus, you'll next want to modify your PATH if needed:

export PATH=$PATH:/usr/local/bin

  1. Preliminaries

All four programs will print their usage and give an example if no arguments are given. For example, with pssh:

pssh

Usage: pssh [OPTIONS] -h hosts.txt prog [arg0] ..

 -h --hosts   hosts file (each line "host[:port] [user]")
 -l --user    username (OPTIONAL)
 -p --par     max number of parallel threads (OPTIONAL)
 -o --outdir  output directory for stdout files (OPTIONAL)
 -t --timeout timeout in seconds to do ssh to a host (OPTIONAL)
 -v --verbose turn on warning and diagnostic messages (OPTIONAL)
 -O --options SSH options (OPTIONAL)

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

And for pscp:

pscp

Usage: pscp [OPTIONS] -h hosts.txt local remote

 -h --hosts     hosts file (each line "host[:port] [login]")
 -r --recursive recusively copy directories (OPTIONAL)
 -l --user      username (OPTIONAL)
 -p --par       max number of parallel threads (OPTIONAL)
 -t --timeout   timeout in seconds to do scp to a host (OPTIONAL)
 -O --options   SSH options (OPTIONAL)

Example: pscp -h hosts.txt -l irb2 foo.txt /home/irb2/foo.txt

Note that before using any of these tools, you will need to start ssh-agent! This can be done as follows (substitute zsh with your particular shell).

ssh-agent zsh

ssh-add

Enter passphrase for /x/bnc/.ssh/identity:

  1. Examples

3.1. pssh

The following example runs hostname on three machines (IPs or hostnames) specified in the file ips.txt using login irb2 and saves the output in /tmp/foo.

cat ips.txt

128.112.152.122 18.31.0.190 128.232.103.201

pssh -h ips.txt -l irb2 -o /tmp/foo hostname

Success on 128.112.152.122:22 Success on 18.31.0.190:22 Success on 128.232.103.201:22

ls /tmp/foo

128.112.152.122 128.232.103.201 18.31.0.190

cat /tmp/foo/*

planetlab-1.cs.princeton.edu planetlab1.xeno.cl.cam.ac.uk planetlab1.lcs.mit.edu

By default, pssh uses at most 32 ssh processes in parallel to ssh to the various nodes. (This is somewhat important if you're controlling hundreds or thousands of machines.) By default, it also uses a timeout of one minute to ssh to a node and obtain a result. For ssh commands that take longer than this (e.g., sleep 61), the -t option can be used. Note that pssh and pnuke have a default timeout of one minute. pscp andprsync have no default timeout, but one can be specified using the -t option.

3.2. pscp

Here's an example of using pscp to copy files in parallel to a set of machines.

pscp -h ips.txt -l irb2 /etc/hosts /tmp/hosts

Success on 128.112.152.122:22 Success on 18.31.0.190:22 Success on 128.232.103.201:22

Using the -r option will perform a recursive copy for copying entire directories.

3.3. pnuke

The pnuke command is useful when you want to kill a bunch of processes on a set of machines. For example, suppose you've got a bunch of java processes running on three nodes that you'd like to nuke (let's use the three machines from the pssh example). Here you would do the following:

pnuke -h ips.txt -l irb2 java

Success on 128.112.152.122:22 Success on 18.31.0.190:22 Success on 128.232.103.201:22

The result of the above is to send kill -9 to all processes owned by irb2 with the string java in their name (as reported by ps -ef).

  1. Environment Variables

All four programs take similar sets of options. All of these options can be set using the following environment variables: PSSH_HOSTS PSSH_USER PSSH_PAR PSSH_OUTDIR PSSH_VERBOSE PSSH_OPTIONS

Here are some example settings:

export PSSH_HOSTS="/x/bnc/ips.txt"

export PSSH_USER="irb2"

export PSSH_PAR="32"

export PSSH_OUTDIR="/tmp/bar"

export PSSH_VERBOSE="0"

export PSSH_OPTIONS="UserKnownHostsFile /tmp/known_hosts"

Using the above settings, the examples can be executed succinctly as:

pssh hostname

Success on 128.112.152.122:22 Success on 18.31.0.190:22 Success on 128.232.103.201:22

ls /tmp/bar

128.112.152.122 128.232.103.201 18.31.0.190

cat /tmp/bar/*

planetlab-1.cs.princeton.edu planetlab1.xeno.cl.cam.ac.uk planetlab1.lcs.mit.edu

pscp /etc/hosts /tmp/hosts

Success on 128.112.152.122:22 Success on 18.31.0.190:22 Success on 128.232.103.201:22

pnuke java

Success on 128.112.152.122:22 Success on 18.31.0.190:22 Success on 128.232.103.201:22

  1. Feedback

Send me email if you're having problems, find bugs, or have any random comments: Brent Chun (bnc at theether.org). Thus far, I've primarily been testing this software on PlanetLab.