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The C based gRPC (C++, Python, Ruby, Objective-C, PHP, C#)
https://grpc.io/
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41 lines
3.9 KiB
41 lines
3.9 KiB
# xDS Features in gRPC |
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This document lists the [xDS](https://github.com/envoyproxy/data-plane-api/tree/master/envoy/api/v2) |
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features supported in various gRPC language implementations and versions. |
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Note that a gRPC client will simply ignore the configuration of a feature it |
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does not support. The gRPC client does not generate a log |
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to indicate that some configuration was ignored. It is impractical to generate |
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a log and keep it up-to-date because xDS has a large number of APIs that gRPC |
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does not support and the APIs keep evolving too. We recommend reading the |
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[first gRFC](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md) |
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on xDS support in gRPC to understand the design philosophy. |
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The EDS policy will *not* support |
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[overprovisioning](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/load_balancing/overprovisioning), |
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which is different from Envoy. Envoy takes the overprovisioning into |
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account in both [locality-weighted load balancing](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/load_balancing/locality_weight) |
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and [priority failover](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/load_balancing/priority), |
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but gRPC assumes that the xDS server will update it to redirect traffic |
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when this kind of graceful failover is needed. gRPC will send the |
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[`envoy.lb.does_not_support_overprovisioning` client |
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feature](https://github.com/envoyproxy/envoy/pull/10136) to the xDS |
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server to tell the xDS server that it will not perform graceful failover; |
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xDS server implementations may use this to decide whether to perform |
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graceful failover themselves. |
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The EDS policy will not support per-endpoint stats; it will report only |
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per-locality stats. |
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An [`lb_endpoint`](https://github.com/envoyproxy/envoy/blob/12a4bc430eaf440ceb0d11286cfbd4c16b79cdd1/api/envoy/api/v2/endpoint/endpoint_components.proto#L72) |
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is ignored if the `health_status` is not HEALTHY or UNKNOWN. |
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The optional `load_balancing_weight` is always ignored. |
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Initially, only `google_default` channel creds will be supported |
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to authenticate with the xDS server. |
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Features | gRFCs | [C++, Python,<br> 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) |
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---------|--------|--------------|------|------ |
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**xDS Infrastructure in gRPC client channel:**<ul><li>LDS->RDS->CDS->EDS flow</li><li>ADS stream</li></ul> | [A27](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md) | v1.30.0 | v1.30.0 | v1.30.0 | |
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**Load Balancing:**<ul><li>[Virtual host](https://www.envoyproxy.io/docs/envoy/latest/api-v2/api/v2/route/route_components.proto#route-virtualhost) domains matching</li><li>Only default path ("" or "/") matching</li><li>Priority-based weighted round-robin locality picking</li><li>Round-robin endpoint picking within locality</li><li>[Cluster](https://www.envoyproxy.io/docs/envoy/latest/api-v2/api/v2/route/route_components.proto#envoy-api-msg-route-routeaction) route action</li><li>Client-side Load reporting via [LRS](https://github.com/envoyproxy/data-plane-api/blob/master/envoy/service/load_stats/v2/lrs.proto)</li></ul> | [A27](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md) | v1.30.0 | v1.30.0 | v1.30.0 | |
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Request matching based on:<ul><li>[Path](https://www.envoyproxy.io/docs/envoy/latest/api-v2/api/v2/route/route_components.proto#route-routematch) (prefix, full path and safe regex)</li><li>[Headers](https://www.envoyproxy.io/docs/envoy/latest/api-v2/api/v2/route/route_components.proto#route-headermatcher)</li></ul>Request routing to multiple clusters based on [weights](https://www.envoyproxy.io/docs/envoy/latest/api-v2/api/v2/route/route_components.proto#route-weightedcluster) | [A28](https://github.com/grpc/proposal/blob/master/A28-xds-traffic-splitting-and-routing.md) | v1.31.0 | v1.31.0 | v1.31.0 |
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