Preflight check for usable space and cache size

data-node/src/main/java/org/graylog/datanode/Configuration.java

@@ -254,7 +254,10 @@ public class Configuration {
     @Parameter(value = "metrics_policy")
     private String metricsPolicy = "gl-datanode-metrics-ism";
 
-    @Documentation(value = "Cache size for searchable snaphots")
+    /**
+     * @see <a href="https://opensearch.org/docs/latest/tuning-your-cluster/availability-and-recovery/snapshots/searchable_snapshot/#configuring-a-node-to-use-searchable-snapshots}">Searchable snapshots</a>
+     */
+    @Documentation(value = "Cache size for searchable snaphots. ")
     @Parameter(value = "node_search_cache_size")
     private String searchCacheSize = "10gb";
 

data-node/src/main/java/org/graylog/datanode/bindings/PreflightChecksBindings.java

@@ -25,6 +25,7 @@
 import org.graylog.datanode.bootstrap.preflight.OpensearchBinPreflightCheck;
 import org.graylog.datanode.bootstrap.preflight.OpensearchConfigSync;
 import org.graylog.datanode.bootstrap.preflight.OpensearchDataDirCompatibilityCheck;
+import org.graylog.datanode.bootstrap.preflight.OpensearchCacheSizePreflightCheck;
 import org.graylog.datanode.opensearch.CsrRequester;
 import org.graylog.datanode.opensearch.CsrRequesterImpl;
 import org.graylog2.bindings.providers.MongoConnectionProvider;
@@ -47,6 +48,7 @@ protected void configure() {
         addPreflightCheck(DatanodeDirectoriesLockfileCheck.class);
         addPreflightCheck(OpenSearchPreconditionsCheck.class);
         addPreflightCheck(OpensearchDataDirCompatibilityCheck.class);
+        addPreflightCheck(OpensearchCacheSizePreflightCheck.class);
 
         // Mongodb is needed for legacy datanode storage, where we want to extract the certificate chain from
         // mongodb and store it in local keystore

data-node/src/main/java/org/graylog/datanode/bootstrap/preflight/OpensearchCacheSizePreflightCheck.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2020 Graylog, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the Server Side Public License, version 1,
+ * as published by MongoDB, Inc.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * Server Side Public License for more details.
+ *
+ * You should have received a copy of the Server Side Public License
+ * along with this program. If not, see
+ * <http://www.mongodb.com/licensing/server-side-public-license>.
+ */
+package org.graylog.datanode.bootstrap.preflight;
+
+import jakarta.annotation.Nonnull;
+import jakarta.inject.Inject;
+import org.apache.commons.io.FileUtils;
+import org.graylog.datanode.Configuration;
+import org.graylog2.bootstrap.preflight.PreflightCheck;
+import org.graylog2.bootstrap.preflight.PreflightCheckException;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.nio.file.FileStore;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class OpensearchCacheSizePreflightCheck implements PreflightCheck {
+
+    private final String configuredNodeSearchCacheSize;
+    private final Path opensearchDataLocation;
+    private final Function<Path, Long> usableSpaceProvider;
+
+    @Inject
+    public OpensearchCacheSizePreflightCheck(Configuration datanodeConfiguration) {
+        this(datanodeConfiguration.getNodeSearchCacheSize(), datanodeConfiguration.getOpensearchDataLocation(), OpensearchCacheSizePreflightCheck::getUsableSpace);
+    }
+
+    public OpensearchCacheSizePreflightCheck(String cacheSize, Path opensearchDataLocation, Function<Path, Long> usableSpaceProvider) {
+        this.configuredNodeSearchCacheSize = cacheSize;
+        this.opensearchDataLocation = opensearchDataLocation;
+        this.usableSpaceProvider = usableSpaceProvider;
+    }
+
+    @Override
+    public void runCheck() throws PreflightCheckException {
+        final long usableSpace = usableSpaceProvider.apply(opensearchDataLocation);
+        final long cacheSize = toBytes(this.configuredNodeSearchCacheSize);
+        if (cacheSize >= usableSpace) {
+            final String usable = toHumanReadableSize(usableSpace);
+            throw new PreflightCheckException("""
+                    There is not enough usable space for the node search cache. Your system has only %s available.
+                    Either decrease node_search_cache_size configuration or make sure that datanode has enough free disk space.
+                    Current node_search_cache_size=%s"""
+                    .formatted(usable, this.configuredNodeSearchCacheSize));
+
+        }
+    }
+
+    @Nonnull
+    private static String toHumanReadableSize(long usableSpace) {
+        return FileUtils.byteCountToDisplaySize(usableSpace).replaceFirst("\\s", "").toLowerCase(Locale.ROOT);
+    }
+
+    private static long getUsableSpace(Path opensearchDataLocation) {
+        final FileStore fileStore;
+        try {
+            fileStore = Files.getFileStore(opensearchDataLocation);
+            return fileStore.getUsableSpace();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static long toBytes(String cacheSize) {
+        long returnValue = -1;
+        Pattern patt = Pattern.compile("([\\d.]+)([GMK]B)", Pattern.CASE_INSENSITIVE);
+        Matcher matcher = patt.matcher(cacheSize);
+        Map<String, Integer> powerMap = new HashMap<>();
+        powerMap.put("GB", 3);
+        powerMap.put("MB", 2);
+        powerMap.put("KB", 1);
+        if (matcher.find()) {
+            String number = matcher.group(1);
+            int pow = powerMap.get(matcher.group(2).toUpperCase());
+            BigDecimal bytes = new BigDecimal(number);
+            bytes = bytes.multiply(BigDecimal.valueOf(1024).pow(pow));
+            returnValue = bytes.longValue();
+        }
+
+        if (returnValue == -1) {
+            throw new PreflightCheckException(String.format(Locale.ROOT, "Unexpected value %s of node_search_cache_size", cacheSize));
+        }
+
+        return returnValue;
+    }
+
+}

data-node/src/test/java/org/graylog/datanode/bootstrap/preflight/OpensearchCacheSizePreflightCheckTest.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2020 Graylog, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the Server Side Public License, version 1,
+ * as published by MongoDB, Inc.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * Server Side Public License for more details.
+ *
+ * You should have received a copy of the Server Side Public License
+ * along with this program. If not, see
+ * <http://www.mongodb.com/licensing/server-side-public-license>.
+ */
+package org.graylog.datanode.bootstrap.preflight;
+
+import org.assertj.core.api.Assertions;
+import org.graylog2.bootstrap.preflight.PreflightCheckException;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Path;
+
+class OpensearchCacheSizePreflightCheckTest {
+
+    @Test
+    void testIllegalCacheSizeValue(@TempDir Path temp) {
+        final OpensearchCacheSizePreflightCheck check = new OpensearchCacheSizePreflightCheck("10g", temp, path -> gbToBytes(5));
+        Assertions.assertThatThrownBy(check::runCheck)
+                .isInstanceOf(PreflightCheckException.class)
+                .hasMessageContaining("Unexpected value 10g of node_search_cache_size");
+    }
+
+    @Test
+    void testCacheSizeErrors(@TempDir Path temp) {
+        final OpensearchCacheSizePreflightCheck check = new OpensearchCacheSizePreflightCheck("10gb", temp, path -> gbToBytes(5));
+        Assertions.assertThatThrownBy(check::runCheck)
+                .isInstanceOf(PreflightCheckException.class)
+                .hasMessageContaining("There is not enough usable space for the node search cache");
+
+
+        Assertions.assertThatNoException().isThrownBy(() -> new OpensearchCacheSizePreflightCheck("2gb", temp, path -> gbToBytes(15)).runCheck());
+    }
+
+    private static long gbToBytes(long gb) {
+        return gb * 1024 * 1024 * 1024;
+    }
+}