diff --git a/xds/src/main/java/io/grpc/xds/RingHashLoadBalancerProvider.java b/xds/src/main/java/io/grpc/xds/RingHashLoadBalancerProvider.java index 84c6dedf631..5bba0dc9b0a 100644 --- a/xds/src/main/java/io/grpc/xds/RingHashLoadBalancerProvider.java +++ b/xds/src/main/java/io/grpc/xds/RingHashLoadBalancerProvider.java @@ -26,6 +26,7 @@ import io.grpc.Status; import io.grpc.internal.JsonUtil; import io.grpc.xds.RingHashLoadBalancer.RingHashConfig; +import io.grpc.xds.RingHashOptions; import java.util.Map; /** @@ -39,11 +40,7 @@ public final class RingHashLoadBalancerProvider extends LoadBalancerProvider { static final long DEFAULT_MIN_RING_SIZE = 1024L; // Same as ClientXdsClient.DEFAULT_RING_HASH_LB_POLICY_MAX_RING_SIZE @VisibleForTesting - static final long DEFAULT_MAX_RING_SIZE = 8 * 1024 * 1024L; - // Maximum number of ring entries allowed. Setting this too large can result in slow - // ring construction and OOM error. - // Same as ClientXdsClient.MAX_RING_HASH_LB_POLICY_RING_SIZE - static final long MAX_RING_SIZE = 8 * 1024 * 1024L; + static final long DEFAULT_MAX_RING_SIZE = 4 * 1024L; private static final boolean enableRingHash = Strings.isNullOrEmpty(System.getenv("GRPC_XDS_EXPERIMENTAL_ENABLE_RING_HASH")) @@ -73,14 +70,20 @@ public String getPolicyName() { public ConfigOrError parseLoadBalancingPolicyConfig(Map rawLoadBalancingPolicyConfig) { Long minRingSize = JsonUtil.getNumberAsLong(rawLoadBalancingPolicyConfig, "minRingSize"); Long maxRingSize = JsonUtil.getNumberAsLong(rawLoadBalancingPolicyConfig, "maxRingSize"); + long maxRingSizeCap = RingHashOptions.getRingSizeCap(); if (minRingSize == null) { minRingSize = DEFAULT_MIN_RING_SIZE; } if (maxRingSize == null) { maxRingSize = DEFAULT_MAX_RING_SIZE; } - if (minRingSize <= 0 || maxRingSize <= 0 || minRingSize > maxRingSize - || maxRingSize > MAX_RING_SIZE) { + if (minRingSize > maxRingSizeCap) { + minRingSize = maxRingSizeCap; + } + if (maxRingSize > maxRingSizeCap) { + maxRingSize = maxRingSizeCap; + } + if (minRingSize <= 0 || maxRingSize <= 0 || minRingSize > maxRingSize) { return ConfigOrError.fromError(Status.UNAVAILABLE.withDescription( "Invalid 'mingRingSize'/'maxRingSize'")); } diff --git a/xds/src/main/java/io/grpc/xds/RingHashOptions.java b/xds/src/main/java/io/grpc/xds/RingHashOptions.java new file mode 100644 index 00000000000..6bb3fc7887e --- /dev/null +++ b/xds/src/main/java/io/grpc/xds/RingHashOptions.java @@ -0,0 +1,62 @@ +/* + * Copyright 2021 The gRPC Authors + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package io.grpc.xds; + +import com.google.common.annotations.VisibleForTesting; +import io.grpc.ExperimentalApi; + +/** + * Utility class that provides a way to configure ring hash size limits. This is applicable + * for clients that use the ring hash load balancing policy. Note that size limits involve + * a tradeoff between client memory consumption and accuracy of load balancing weight + * representations. Also see https://github.com/grpc/proposal/pull/338. + */ +@ExperimentalApi("https://github.com/grpc/grpc-java/issues/9718") +public final class RingHashOptions { + // Same as ClientXdsClient.DEFAULT_RING_HASH_LB_POLICY_MAX_RING_SIZE + @VisibleForTesting + static final long MAX_RING_SIZE_CAP = 8 * 1024 * 1024L; + @VisibleForTesting + // Same as RingHashLoadBalancerProvider.DEFAULT_MAX_RING_SIZE + static final long DEFAULT_RING_SIZE_CAP = 4 * 1024L; + + // Limits ring hash sizes to restrict client memory usage. + private static volatile long ringSizeCap = DEFAULT_RING_SIZE_CAP; + + private RingHashOptions() {} // Prevent instantiation + + /** + * Set the global limit for the min and max number of ring hash entries per ring. + * Note that this limit is clamped between 1 entry and 8,388,608 entries, and new + * limits lying outside that range will be silently moved to the nearest number within + * that range. Defaults initially to 4096 entries. + */ + @ExperimentalApi("https://github.com/grpc/grpc-java/issues/9718") + public static void setRingSizeCap(long ringSizeCap) { + ringSizeCap = Math.max(1, ringSizeCap); + ringSizeCap = Math.min(MAX_RING_SIZE_CAP, ringSizeCap); + RingHashOptions.ringSizeCap = ringSizeCap; + } + + /** + * Get the global limit for min and max ring hash sizes. + */ + @ExperimentalApi("https://github.com/grpc/grpc-java/issues/9718") + public static long getRingSizeCap() { + return RingHashOptions.ringSizeCap; + } +} diff --git a/xds/src/test/java/io/grpc/xds/RingHashLoadBalancerProviderTest.java b/xds/src/test/java/io/grpc/xds/RingHashLoadBalancerProviderTest.java index 9f972eaef92..87615a125c0 100644 --- a/xds/src/test/java/io/grpc/xds/RingHashLoadBalancerProviderTest.java +++ b/xds/src/test/java/io/grpc/xds/RingHashLoadBalancerProviderTest.java @@ -29,6 +29,7 @@ import io.grpc.SynchronizationContext; import io.grpc.internal.JsonParser; import io.grpc.xds.RingHashLoadBalancer.RingHashConfig; +import io.grpc.xds.RingHashOptions; import java.io.IOException; import java.lang.Thread.UncaughtExceptionHandler; import java.util.Locale; @@ -116,16 +117,84 @@ public void parseLoadBalancingConfig_invalid_minGreaterThanMax() throws IOExcept } @Test - public void parseLoadBalancingConfig_invalid_ringTooLarge() throws IOException { - long ringSize = RingHashLoadBalancerProvider.MAX_RING_SIZE + 1; + public void parseLoadBalancingConfig_ringTooLargeUsesCap() throws IOException { + long ringSize = RingHashOptions.MAX_RING_SIZE_CAP + 1; String lbConfig = String.format(Locale.US, "{\"minRingSize\" : 10, \"maxRingSize\" : %d}", ringSize); ConfigOrError configOrError = provider.parseLoadBalancingPolicyConfig(parseJsonObject(lbConfig)); - assertThat(configOrError.getError()).isNotNull(); - assertThat(configOrError.getError().getCode()).isEqualTo(Code.UNAVAILABLE); - assertThat(configOrError.getError().getDescription()) - .isEqualTo("Invalid 'mingRingSize'/'maxRingSize'"); + assertThat(configOrError.getConfig()).isNotNull(); + RingHashConfig config = (RingHashConfig) configOrError.getConfig(); + assertThat(config.minRingSize).isEqualTo(10); + assertThat(config.maxRingSize).isEqualTo(RingHashOptions.DEFAULT_RING_SIZE_CAP); + } + + @Test + public void parseLoadBalancingConfig_ringCapCanBeRaised() throws IOException { + RingHashOptions.setRingSizeCap(RingHashOptions.MAX_RING_SIZE_CAP); + long ringSize = RingHashOptions.MAX_RING_SIZE_CAP; + String lbConfig = + String.format( + Locale.US, "{\"minRingSize\" : %d, \"maxRingSize\" : %d}", ringSize, ringSize); + ConfigOrError configOrError = + provider.parseLoadBalancingPolicyConfig(parseJsonObject(lbConfig)); + assertThat(configOrError.getConfig()).isNotNull(); + RingHashConfig config = (RingHashConfig) configOrError.getConfig(); + assertThat(config.minRingSize).isEqualTo(RingHashOptions.MAX_RING_SIZE_CAP); + assertThat(config.maxRingSize).isEqualTo(RingHashOptions.MAX_RING_SIZE_CAP); + // Reset to avoid affecting subsequent test cases + RingHashOptions.setRingSizeCap(RingHashOptions.DEFAULT_RING_SIZE_CAP); + } + + @Test + public void parseLoadBalancingConfig_ringCapIsClampedTo8M() throws IOException { + RingHashOptions.setRingSizeCap(RingHashOptions.MAX_RING_SIZE_CAP + 1); + long ringSize = RingHashOptions.MAX_RING_SIZE_CAP + 1; + String lbConfig = + String.format( + Locale.US, "{\"minRingSize\" : %d, \"maxRingSize\" : %d}", ringSize, ringSize); + ConfigOrError configOrError = + provider.parseLoadBalancingPolicyConfig(parseJsonObject(lbConfig)); + assertThat(configOrError.getConfig()).isNotNull(); + RingHashConfig config = (RingHashConfig) configOrError.getConfig(); + assertThat(config.minRingSize).isEqualTo(RingHashOptions.MAX_RING_SIZE_CAP); + assertThat(config.maxRingSize).isEqualTo(RingHashOptions.MAX_RING_SIZE_CAP); + // Reset to avoid affecting subsequent test cases + RingHashOptions.setRingSizeCap(RingHashOptions.DEFAULT_RING_SIZE_CAP); + } + + @Test + public void parseLoadBalancingConfig_ringCapCanBeLowered() throws IOException { + RingHashOptions.setRingSizeCap(1); + long ringSize = 2; + String lbConfig = + String.format( + Locale.US, "{\"minRingSize\" : %d, \"maxRingSize\" : %d}", ringSize, ringSize); + ConfigOrError configOrError = + provider.parseLoadBalancingPolicyConfig(parseJsonObject(lbConfig)); + assertThat(configOrError.getConfig()).isNotNull(); + RingHashConfig config = (RingHashConfig) configOrError.getConfig(); + assertThat(config.minRingSize).isEqualTo(1); + assertThat(config.maxRingSize).isEqualTo(1); + // Reset to avoid affecting subsequent test cases + RingHashOptions.setRingSizeCap(RingHashOptions.DEFAULT_RING_SIZE_CAP); + } + + @Test + public void parseLoadBalancingConfig_ringCapLowerLimitIs1() throws IOException { + RingHashOptions.setRingSizeCap(0); + long ringSize = 2; + String lbConfig = + String.format( + Locale.US, "{\"minRingSize\" : %d, \"maxRingSize\" : %d}", ringSize, ringSize); + ConfigOrError configOrError = + provider.parseLoadBalancingPolicyConfig(parseJsonObject(lbConfig)); + assertThat(configOrError.getConfig()).isNotNull(); + RingHashConfig config = (RingHashConfig) configOrError.getConfig(); + assertThat(config.minRingSize).isEqualTo(1); + assertThat(config.maxRingSize).isEqualTo(1); + // Reset to avoid affecting subsequent test cases + RingHashOptions.setRingSizeCap(RingHashOptions.DEFAULT_RING_SIZE_CAP); } @Test