This commit adds the xen_4_8 package to be used instead of
xen (currently at 4.5.5):
* Add packages xen_4_8, xen_4_8-slim and xen_4_8-light
* Add packages qemu_xen_4_8 and qemu_xen_4_8-light to be used
with xen_4_8-slim and xen_4_8-light respectively.
* Add systemd to buildInputs of xen (it is required by oxenstored)
* Adapt xen service to work with the new version of xen
* Use xen-init-dom0 to initlilise dom0 in xen-store
* Currently, the virtualisation.xen.stored option is ignored
if xen 4.8 is used
Provide the option forwardDns in virtualisation.xen.bridge, which
enables forwarding of DNS queries to the default resolver, allowing
outside internet access for the xen guests.
The xen-bridge service accepts the option prefixLength, but does not
use it to set the actual netmask on the bridge. This commit makes
it set the correct netmask.
The dnsmasq instance run by the xen-bridge.service errorenously
hands out 172.16.0.0 as the netmask over DHCP to the VMs. This
commit removes the option responsible for that from dnsmasq.conf,
so that the proper netmask is inferred by dnsmasq instead.
Addresses https://github.com/NixOS/nixpkgs/issues/19883
The calls to iptables in xen-bridge.service were missing the -w switch,
which caused them to fail if another script was calling iptables
at the same time. Fix it by adding the -w switch.
Addresses https://github.com/NixOS/nixpkgs/issues/19849 .
Xen required a few changes in order to be usable:
* Include xenfs module in initrd as loading it in the activation
script was failing.
* Include /etc/default/xendomains, which is needed by
xen-domains service.
* Create /var/log/xen and /var/lib/xen directories in
the xen-store service, which are needed by the xl command.
The directories could be created by any other script as long as
they are guaranteed to exist before xl is called.
* Fix a reference to /bin/ls in the xendomains script.
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
(systemd service descriptions that is, not service descriptions in "man
configuration.nix".)
Capitalizing each word in the description seems to be the accepted
standard.
Also shorten these descriptions:
* "Munin node, the agent process" => "Munin Node"
* "Planet Venus, an awesome ‘river of news’ feed reader" => "Planet Venus Feed Reader"
