pssh是SA的利器，非常好用，适合批量在多台服务器上执行命令及脚本等，以前用过一段时间的tentakel，目前已经不再更新。Linux下一般源码编译即可，MAC下安装软件就靠brew了，下面是具体过程：

brew install pssh
==> Downloading https://parallel-ssh.googlecode.com/files/pssh-2.3.1.tar.gz
==> python setup.py install --prefix=/usr/local/Cellar/pssh/2.3.1 --install-data=/usr/local/Cellar/pssh/2.3.1/share
==> Caveats
If you need Python to find the installed site-packages:
  mkdir -p ~/Library/Python/2.7/lib/python/site-packages
  echo '/usr/local/lib/python2.7/site-packages' > ~/Library/Python/2.7/lib/python/site-packages/homebrew.pth
==> Summary
/usr/local/Cellar/pssh/2.3.1: 40 files, 228K, built in 7 seconds

$ 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

另外pssh安装好后，还有pscp,prsync,pslurp命令可以使用哦，非常方便。