Currently, the rsync module where the replicators send data is static. It
forbids administrators to set rsync configuration based on their current
deployment or needs.
As an example, the rsyncd configuration example encourages to set a connections
limit for the modules account, container and object. It permits to protect
devices from excessives parallels connections, because it would impact
performances.
On a server with many devices, it is tempting to increase this number
proportionally, but nothing guarantees that the distribution of the connections
will be balanced. In the worst scenario, a single device can receive all the
connections, which is a severe impact on performances.
This commit adds a new option named 'rsync_module' to the *-replicator sections
of the *-server configuration file. This configuration variable can be
extrapolated with device attributes like ip, port, device, zone, ... by using
the format {NAME}. eg:
rsync_module = {replication_ip}::object_{device}
With this configuration, an administrators can solve the problem of connections
distribution by creating one module per device in rsyncd configuration.
The default values are backward compatible:
{replication_ip}::account
{replication_ip}::container
{replication_ip}::object
Option vm_test_mode is deprecated by this commit, but backward compatibility is
maintained. The option is only effective when rsync_module is not set. In that
case, {replication_port} is appended to the default value of rsync_module.
Change-Id: Iad91df50dadbe96c921181797799b4444323ce2e
71f6fd025e