Hi Envoy community,
Following the release of the v3 major version of the xDS APIs in Envoy 1.13.0 (January 2020), the xDS API lifecycle
implies that we should be removing the deprecated v2 xDS APIs after the Envoy 1.17.0 release (January 2021).
We plan to introduce a runtime flag envoy.reloadable_features.enable_deprecated_v2_api after the Envoy 1.16.0 release (October 2020) that will by default be false and disable support for the v2 xDS APIs. Any attempt to configure the v2 xDS APIs (transport or resource version) or make use of a v2 bootstrap will result in configuration rejection. Any xDS resource message that is delivered with a v2 type URL will be rejected. The runtime flag may be flipped to true for Q4.
We intend to delete support for v2 xDS APIs in Envoy 1.17.0 unless we have an indication that this will impact a significant number of users. We may consider a single quarter grace period in this situation, but for the technical health of Envoy we would like to remove v2 in a bounded period.
We do not plan any new major versions in 2021, so the v3 xDS API will continue to be usable for at least another 2 years. We have incorporated feedback from control plane vendors in the xDS versioning policy
to reduce the rate at which major version transitions occur. We intend to implement a more incremental minor/patch versioning policy
going forward. We also have a ticket tracking a v2 --> v3 postmortem here
, we encourage you to leave any data points that can feed into this and future versioning policies.