Exploring Variants of Linux

Rackspace Cloud Linux One of the very cool aspects of the Rackspace Cloud is the number of Linux/GNU variants.  As I'm already very intimately familiar with Red Hat / CentOS, I decided to take a look at the other seven. Dealing with an array of cloud servers can be a little tedious, so I wrote a little program to run commands on all of them for me:  github_gist:/PaulReiber/run This article documents my exploration of Ubuntu, Arch, FreeBSD, Debian, Gentoo, Fedora, and openSUSE.

Ubuntu CentOS Red Hat

Arch Debian Fedora

FreeBSD Gentoo openSUSE

$ run 'hostname'|egrep ^pbr\|stdout
pbr_ubuntu12.10_512
  @stdout="pbr-ubuntu12.10-512\r\n">]
pbr_freebsd9_512
  @stdout="pbr-freebsd9-512\r\n">]
pbr_opensuse12.1_512
  @stdout="pbr-opensuse12.1-512\r\n">]
pbr_fedora17_512
  @stdout="pbr-fedora17-512\r\n">]
pbr_gentoo12.3_512
  @stdout="pbr-gentoo12.3-512\r\n">]
pbr_debian6_512
  @stdout="pbr-debian6-512\r\n">]
pbr_arch2012.08_512
  @stdout="bash: hostname: command not found\r\n">]

Grepping JSON output isn't pretty, but you can see from the above how my program "run" works - it prints out the name of each cloud server then the JSON output of running a command via the ruby fog "ssh" API.

The output above also highlights something I ran into a LOT - various "standard" commands are simply not present on some distros!  Let's take a look - is "vim" available on all of the distros?

$ run 'which vim'|egrep ^pbr\|stdout
pbr_ubuntu12.10_512
  @stdout="/usr/bin/vim\r\n">]
pbr_freebsd9_512
  @stdout="vim: Command not found.\r\n">]
pbr_opensuse12.1_512
  @stdout="/usr/bin/vim\r\n">]
pbr_fedora17_512
  @stdout="/bin/vim\r\n">]
pbr_gentoo12.3_512
  @stdout="which: no vim in (/usr/bin:/bin:/usr/sbin:/sbin)\r\n">]
pbr_debian6_512
  @stdout="">]
pbr_arch2012.08_512
  @stdout="/usr/bin/vim\r\n">]

From this it seems that FreeBSD, Gentoo, and Debian don't come with vim pre-installed.   How about 'make'?

$ run 'which make'|egrep ^pbr\|stdout
pbr_ubuntu12.10_512
  @stdout="/usr/bin/make\r\n">]
pbr_freebsd9_512
  @stdout="/usr/bin/make\r\n">]
pbr_opensuse12.1_512
  @stdout="/usr/bin/make\r\n">]
pbr_fedora17_512
  @stdout="/bin/make\r\n">]
pbr_gentoo12.3_512
  @stdout="/usr/bin/make\r\n">]
pbr_debian6_512
  @stdout="/usr/bin/make\r\n">]
pbr_arch2012.08_512
  @stdout="which: no make in (/usr/bin:/bin:/usr/sbin:/sbin)\r\n">]

No make command is available on arch.  Arch is not for the faint of heart, I guess.

I'll be updating this blog post, and adding additional posts as I continue exploration of these various Linux distros.

Running commands on all of your cloud servers

I consider my cloud servers to be one big array of servers.

I decided to use "fog" - the Ruby API for the Rackspace Cloud - to build something to let me, in one step, run commands on all of the servers.  It turned out to be pretty straightforward.


You might have a different model - an array of web servers, another array of db servers, and another array of compute servers, for example.  If so, you can easily extend the code to work with your different groups of servers by querying for whatever differentiates them.