[ovs-dev] [PATCH] ovs-ctl: Don't overwrite external-id hostname

[Ilya Maximets]

On 5/26/20 8:30 AM, Han Zhou wrote:
> On Mon, May 25, 2020 at 8:28 AM Daniel Alvarez <dalvarez at redhat.com> wrote:
>>
>> ovs-ctl started to add the hostname as external-id [0] at some point.
>>
>> However, this can be problematic as if it's already set by an external
>> entity it will get overwritten. In RHEL systems, systemd will invoke
>> ovs-ctl to start OVS and that will overwrite it to the hostname of the
>> machine.
>>
>> For OVN this can have a big impact because if, for whatever reason the
>> hostname changes and the host gets restarted, ovn-controller won't
>> claim the ports back leaving the workloads unaccessible.
>>
>> Also, it makes sense to not overwrite it as 1) it's an external_id,
>> so it will actually let external entities to configure it (unlike now),
>> and 2) it's optional. In the case that some systems were relying on
>> ovs-ctl to set the external-id for the first time (e.g onboarding
>> of a new hypervisor), this patch is not changing such behavior.
>>
>> For more details, see discussion at [1].
>>
>> [0] https://mail.openvswitch.org/pipermail/ovs-dev/2016-March/312054.html
>> [1] https://mail.openvswitch.org/pipermail/ovs-dev/2020-May/370813.html
>>
>> Signed-off-by: Daniel Alvarez <dalvarez at redhat.com>
>> ---
>>  utilities/ovs-ctl.in | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/utilities/ovs-ctl.in b/utilities/ovs-ctl.in
>> index 8c5cd7032..9be9c9871 100644
>> --- a/utilities/ovs-ctl.in
>> +++ b/utilities/ovs-ctl.in
>> @@ -43,7 +43,8 @@ set_hostname () {
>>      else
>>          hn="$(uname -n)"
>>      fi
>> -    ovs_vsctl set Open_vSwitch . external-ids:hostname="$hn"
>> +    # Set the hostname if it wasn't set before
>> +    ovs_vsctl add Open_vSwitch . external-ids hostname="$hn"
>>  }
>>
>>  set_system_ids () {
>> --
>>
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> 
> Acked-by: Han Zhou <hzhou at ovn.org>

Thanks, Daniel and Han!
Sorry for so long delay.

Applied to master and down to 2.13.

Best regards, Ilya Maximets.