[ovs-dev] [PATCH v6] ovn: Allow for automatic dynamic updates of IPAM

[Jakub Sitnicki]

Hi Mark,

On Thu,  2 Aug 2018 08:18:12 -0400
Mark Michelson <mmichels at redhat.com> wrote:

> OVN offers a method of IP address management that allows for an IPv4
> subnet or IPv6 prefix to be specified on a logical switch. Then by
> specifying a switch port's address as "dynamic" or "<mac address>
> dynamic", OVN will automatically assign addresses to the switch port.
> 
> While this works great for initial assignment of addresses, addresses
> do not automatically adjust when changes are made to the switch's
> configuration. For instance:
> * If the subnet, ipv6_prefix, or exclude_ips for a logical switch
> changes, the affected switch ports are not updated.
> * If a switch port with a static IP address is added to the switch,
> and that address conflicts with a dynamically assigned IP address, the
> dynamic address is not updated.
> * If a MAC address switched from being statically assigned to
> dynamically assigned, the MAC address would not be updated.
> * If a statically assigned MAC address changed, then the IPv6 address
> would not be updated.
> 
> This patch solves all of the above issues by changing the algorithm
> for IPAM assignment. There are essentially three steps.
> 1) While joining logical ports, all statically-assigned addresses
> (i.e. any ports without "dynamic" addresses) have their addresses
> registered to IPAM. This gives them top priority.
> 2) All logical ports with dynamic addresses are inspected. Any changes
> that must be made to the addresses are collected to be made later. Any
> addresses that do not require change are registered to IPAM. This
> allows for previously assigned dynamic addresses to be kept.
> 3) All gathered changes are enacted.
> 
> The change contains new tests that ensure that dynamic addresses are
> updated when appropriate.
> 
> This patch also alters some existing IPAM tests. Those tests assumed
> that dynamic addresses would not be updated automatically, so those
> tests either had to be altered or removed.
> 
> Signed-off-by: Mark Michelson <mmichels at redhat.com>
> Acked-by: Jakub Sitnicki <jkbs at redhat.com>
> ---
> v5->v6:
>  * Rebased
> 
> v4->v5:
>  Cleanups suggested by Jakub Sitnicki + rebase
>  * Add some convenience pointers for shortened code.
>  * Separate checking of updates of dynamic addresses and registration
>    of unchanged addresses.
>  * Use OVS_NOT_REACHED() instead of ovs_assert(0)
> 
> v3->v4:
>  Print warning when multiple dynamic addresses are configured on a
>  switch port. Ensure that dynamic addresses beyond the first on a
> switch port are ignored. Found by Ben Pfaff.
> 
> v2->v3:
>  Fixed a checkpatch problem (line too long)
> 
> v1->v2:
>  Rebased
> ---

Recent fix pushed to master, 4d0214a365ae ("ovn: Fix typos in "ovn --
Address Set generation... test."), will cause the following test to
fail with this patch applied:

2578: ovn -- Address Set generation from Port Groups (dynamic addressing)

To fix the test you need to revert the mentioned commit and squash the
diff with your changes.

Thanks,
Jakub