This changes the implementation of RunCmd from using the popen2 module
to using the (new in 2.4) subprocess module.

This is helpful because the subprocess module has more advanced features
than popen2, the most important ones being the ability to run code in the
child process before the exec and ability to launch with modified
environment.

Reviewed-by: imsnah

Reviewed-by: imsnah

Reviewed-by: iustinp

Debian's default drbd configuration has some enabled directives, which make the
init script throw errors. Document how to disable the defaults and thus get rid
of the errors.

Reviewed-by: imsnah

Reviewed-by: iustinp

Reviewed-by: imsnah

Reviewed-by: iustinp

Reviewed-by: imsnah

Reviewed-By: iustinp

Reviewed-by: imsnah

Also add some debugging output.

- Replace magic values by constants.

Reviewed-by: iustinp

This changes a ';' to '&&' to make sure we run the create script from
the correct directory.

Reviewed-by: imsnah

This adds a check that the initial node's IP name doesn't resolve to a
loopback address (127.x.y.z).

Also remove an unused variable.

Reviewed-by: imsnah

Changes:
  - add note about installing the cron job
  - add an example cron job file and modify top-level Makefile.am to put
    it into the archive
  - modify the tutorial with information about setting a reasonable
    number of minors for DRBD
  - add note about installing on 32-bit the xen libc

Reviewed-by: imsnah

Reviewed-by: roman.marxer

The manpage wrongly states that the default unit for disk sizes is
gibibytes, whereas currently it's mebibytes. Fix that and also update
the '--help' output to display the default unit.

Reviewed-by: roman.marxer

This changelist add:
  - documentation on how to select the kernel and initrd (if needed) for
    instances
  - support in hypervisor.py for the initrd
  - adds note about internet-connectivity and debootstrap requirements
    for the minimal etch os
  - documentation on the miminum xenvg size

Reviewed-by: roman.marxer,ultrotter

This adds more examples and clarifies the existing ones.

Reviewed-by: roman.marxer

This changes the cluster init and node join to refuse a node that has a
different hostname than what the resolver returns.

Reviewed-by: imsnah

This changes a lot of docbook-related stuff and addresses a few consistency
issues.

Reviewed-by: vylavera

This fixes some consistency issues.

Reviewed-by: vylavera

This fixes a compatibility problem with recent mdadm (2.x?) by
reimplementing the zero-ing of the superblocks in ganeti itself.

Reviewed-by: imsnah

Reviewed-by: iustinp

Reviewed-by: iustinp

- Run “gnt-cluster verify” and “gnt-cluster info” after adding all nodes
- Remove unused --cleanup option
- Remove --verbose option and always print executed SSH commands

Reviewed-by: iustinp

This changes:
  - cluster setup, we no longer edit /etc/ssh/ssh_known_hosts but our
    own file
  - node add, we no longer remove root's known_hosts (twice)
  - gnt-instance console, both the LU and the script: since now the ssh
    setup is not standard, we need to build the ssh cmdline in the LU
    (instead of manually building it in the script) with the correct
    parameters and use the command line as returned in the script
  - ssh.py, many changes, split options in module-level constants so
    that building the command line in different places is easier/more
    logical
  - backend.py, we no longer remove root's known_hosts in Add node, and
    we allow our own known_hosts file to be uploaded

Reviewed-by: imsnah

This function used a hand-coded ssh call to remote nodes. Fix it to use the
ssh.SSHCall function, and in the process drop the command field from the
results, as it's too verbose and we can use (in gnt-cluster) what we passed in.

Reviewed-by: schreiberal

_GetWantedNodes is used wrongly by the LUClusterCopyFile. This fixes that.

Reviewed-by: imsnah

Reviewed-by: iustin

This is more in line with the other document names.

Also, change the title to simply "Ganeti installation tutorial".

Reviewed-by: ultrotter

In case one installs from source, make, tar and gzip are also needed. tar and
gzip are almost always installed, but make not, so let's add a note about that.

Also remove a '>' in the apt-get install example so copy-paste works.

Reviewed-by: imsnah

In case we use StrictHostKeyChecking=ask, also add HashKnownHosts=no so that
debugging is easier. The nodes to which we are connecting are anyway visible in
/etc/ssh/ssh_known_hosts.

Reviewed-by: imsnah