From 4a8171cda56fa8419e4b2898712feaf40dee7bfb Mon Sep 17 00:00:00 2001 From: srini100 Date: Sun, 14 Jun 2020 20:02:36 -0700 Subject: [PATCH] xds features per release --- doc/grpc_xds_features.md | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 doc/grpc_xds_features.md diff --git a/doc/grpc_xds_features.md b/doc/grpc_xds_features.md new file mode 100644 index 00000000000..7e0921c88c4 --- /dev/null +++ b/doc/grpc_xds_features.md @@ -0,0 +1,40 @@ +# xDS Features in gRPC + +This document lists the [xDS](https://github.com/envoyproxy/data-plane-api/tree/master/envoy/api/v2) +features supported in various gRPC language implementations and versions. + +Note that a gRPC client will simply ignore the configuration of a feature it +does not support. The gRPC client does not generate a log +to indicate that some configuration was ignored. It is impractical to generate +a log and keep it up-to-date because xDS has a large number of APIs that gRPC +does not support and the APIs keep evolving too. We recommend reading the +[first gRFC](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md) +on xDS support in gRPC to understand the design philosophy. + +The EDS policy will *not* support +[overprovisioning](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/load_balancing/overprovisioning), +which is different from Envoy. Envoy takes the overprovisioning into +account in both [locality-weighted load balancing](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/load_balancing/locality_weight) +and [priority failover](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/load_balancing/priority), +but gRPC assumes that the xDS server will update it to redirect traffic +when this kind of graceful failover is needed. gRPC will send the +[`envoy.lb.does_not_support_overprovisioning` client +feature](https://github.com/envoyproxy/envoy/pull/10136) to the xDS +server to tell the xDS server that it will not perform graceful failover; +xDS server implementations may use this to decide whether to perform +graceful failover themselves. + +The EDS policy will not support per-endpoint stats; it will report only +per-locality stats. + +An [`lb_endpoint`](https://github.com/envoyproxy/envoy/blob/master/api/envoy/api/v2/endpoint/endpoint_components.proto) +is ignored if the `health_status` is not HEALTHY or UNKNOWN. +The optional `load_balancing_weight` is always ignored. + +Initially, only `google_default` channel creds will be supported +to authenticate with the xDS server. + +Features | gRFCs | [C++, Python,
Ruby, PHP, C#](https://github.com/grpc/grpc/releases) | [Java](https://github.com/grpc/grpc-java/releases) | [Go](https://github.com/grpc/grpc-go/releases) +---------|--------|--------------|------|------ +**xDS Infrastructure:**
LDS->RDS->CDS->EDS flow,
ADS stream,
Client-side Load reporting via [LRS](https://github.com/envoyproxy/data-plane-api/blob/master/envoy/service/load_stats/v2/lrs.proto), | [A27](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md) | v1.30.0 | v1.30.0 | v1.30.0 | +**Load Balancing:**
Virtual host matching,
Only default path ("" or "/") matching,
Priority-based weighted round-robin locality picking,
Round-robin endpoint picking within locality,
Cluster route action| [A27](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md) | v1.30.0 | v1.30.0 | v1.30.0 |