pssh HOWTO
Brent Chun

Table of Contents
1. Installation and Setup...............................................................................................................................................2
2. Preliminaries .............................................................................................................................................................2
3. Examples....................................................................................................................................................................2
3.1. pssh.................................................................................................................................................................3
3.2. pscp.................................................................................................................................................................3
3.3. pnuke ..............................................................................................................................................................3
4. Environment Variables .............................................................................................................................................4
5. Feedback ....................................................................................................................................................................5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

2. Preliminaries
All four programs will print their usage and give an example if no arguments are given. For example, with pssh:# psshUsage: pssh [OPTIONS] -h hosts.txt prog [arg0] ..
-h --hosts
hosts file (each line "host[:port] [user]")-l --user
username (OPTIONAL)-p --parmax 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:# pscpUsage: 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 --parmax 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 (substitutezsh with your particular shell).
# ssh-agent zsh# ssh-add
Enter passphrase for /x/bnc/.ssh/identity:2

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3. 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 anode 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 and prsync 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 threemachines from the pssh example). Here you would do the following:# pnuke -h ips.txt -l irb2 java
Success on 128.112.152.122:22

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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 (asreported by ps -ef).

4. 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_USERPSSH_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

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5. Feedback
Send me email if you’re having problems, find bugs, or have any random comments: Brent Chun
(http://www.theether.org) (bnc at theether.org). Thus far, I’ve primarily been testing this software on PlanetLab(http://www.planet-lab.org).

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