This changes the ip allocation logic to round robin. Before this, host-local IPAM searched for available IPs from start of subnet. Hence it tends to allocate IPs that had been used recently. This is not ideal since it may cause collisions.
Add a namespace object interface for somewhat cleaner code when
creating and switching between network namespaces. All created
namespaces are now mounted in /var/run/netns to ensure they
have persistent inodes and paths that can be passed around
between plugin components without relying on the current namespace
being correct.
Also remove the thread-locking arguments from the ns package
per https://github.com/appc/cni/issues/183 by doing all the namespace
changes in a separate goroutine that locks/unlocks itself, instead of
the caller having to track OS thread locking.
This is an attempt to testing the PluginMain() function of the skel pkg.
We should be able to do better by using a mockable interface for the
plugins, but this is a start.
Allow users to tune net network parameters such as somaxconn.
With this patch, users can add a new network configuration:
> {
> "name": "mytuning",
> "type": "tuning",
> "sysctl": {
> "net.core.somaxconn": "500"
> }
> }
The value /proc/sys/net/core/somaxconn will be set to 500 in the network
namespace but will remain unchanged on the host.
Only sysctl parameters that belong to the network subsystem can be
modified.
Related to: https://github.com/coreos/rkt/pull/2140
This takes some of the machinery from CNI and from the rkt networking
code, and turns it into a library that can be linked into go apps.
Included is an example command-line application that uses the library,
called `cnitool`.
Other headline changes:
* Plugin exec'ing is factored out
The motivation here is to factor out the protocol for invoking
plugins. To that end, a generalisation of the code from api.go and
pkg/plugin/ipam.go goes into pkg/invoke/exec.go.
* Move argument-handling and conf-loading into public API
The fact that the arguments get turned into an environment for the
plugin is incidental to the API; so, provide a way of supplying them
as a struct or saying "just use the same arguments as I got" (the
latter is for IPAM plugins).
