Ability to select a subset of hosts from hostlist

[dukexar]

Ability to select a subset of hosts from hostlist

[GoogleCodeExporter]

It's an interesting idea.  Could you give a little more detail about why it's 
been cumbersome to maintain separate hostlist files?  It should be possible to 
write a pre-processor that reads a file in the "descriptor" format and outputs 
a set of "classic-style" host files.  Also, what happens when lines in the file 
don't all share the same number of columns?  The "descriptor" format for host 
files seems interesting but a little complicated.

Original comment by [email protected] on 1 Mar 2011 at 2:00

[GoogleCodeExporter]

Cumbersomeness is proportional to the number of host classes one has to deal 
with. Certainly pre-processing is an option, but it adds one extra step. 
Furthermore one has to be careful when cleaning up so as to ensure that a 
command is not run on the wrong host (using a stale, derived hostlist). Albeit 
rather uncommon to run pssh against many different permutations of hostclasses 
it complicates the management overhead even more. Carrying one file around is a 
lot easier than dozens.

With current implementation, the behavior around incorrect number of columns is 
similar to behavior of pssh when it encounters more than 2 fields on a line in 
unpatched version. It prints a message that there was an error parsing a line 
and skips it. It is perhaps wise to adjust this behavior for both the patched 
and the unpatched version.

The feature is difficult to describe in words but it is rather intuitive. 
Perhaps my description is unclear. I would be more than happy to clarify it.

Original comment by [email protected] on 1 Mar 2011 at 2:30

[GoogleCodeExporter]

Original comment by [email protected] on 1 Mar 2011 at 3:48

• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

I think this feature is redundant and is easy to workaround.  All you need is 
grep and process subsitution:

pssh -h <(grep -P ".* veg" hostlist)
pssh -h <(grep -P "red .*" hostlist)

Original comment by [email protected] on 2 Sep 2011 at 11:01

[GoogleCodeExporter]

That's a cool trick. I think we should add something about that to the examples 
section of the man page.

Original comment by [email protected] on 5 Sep 2011 at 2:27

[GoogleCodeExporter]

hi, on Debian i have to use parallel-ssh rather than pssh directly is that 
normal?

Original comment by [email protected] on 9 Feb 2014 at 9:05

[GoogleCodeExporter]

ok got it ... i debian does not use the last version ... i pip install 
--upgrade pssh and now it works as :: pssh -Aih bob sudo apt-get update && sudo 
apt-get upgrade but does not let me select the machine I want.

Original comment by [email protected] on 9 Feb 2014 at 9:19