Remove custom metadata tool (#50813)

Adds a command-line tool to remove broken custom metadata from the cluster state.

Relates to #48701

docs/reference/commands/node-tool.asciidoc

@@ -20,16 +20,20 @@ bin/elasticsearch-node repurpose|unsafe-bootstrap|detach-cluster|override-versio
 [float]
 === Description
 
-This tool has five modes:
+This tool has a number of modes:
 
 * `elasticsearch-node repurpose` can be used to delete unwanted data from a
   node if it used to be a <<data-node,data node>> or a
   <<master-node,master-eligible node>> but has been repurposed not to have one
   or other of these roles.
 
 * `elasticsearch-node remove-settings` can be used to remove persistent settings
-   from the cluster state in case where it contains incompatible settings that
-   prevent the cluster from forming.
+  from the cluster state in case where it contains incompatible settings that
+  prevent the cluster from forming.
+
+* `elasticsearch-node remove-customs` can be used to remove custom metadata
+  from the cluster state in case where it contains broken metadata that
+  prevents the cluster state from being loaded.
 
 * `elasticsearch-node unsafe-bootstrap` can be used to perform _unsafe cluster
   bootstrapping_.  It forces one of the nodes to form a brand-new cluster on
@@ -100,6 +104,24 @@ The intended use is:
 * Repeat for all other master-eligible nodes
 * Start the nodes
 
+[float]
+==== Removing custom metadata from the cluster state
+
+There may be situations where a node contains custom metadata, typically
+provided by plugins, that prevent the node from starting up and loading
+the cluster from disk.
+
+The `elasticsearch-node remove-customs` tool allows you to forcefully remove
+the problematic custom metadata. The tool takes a list of custom metadata names
+as parameters that should be removed, and also supports wildcard patterns.
+
+The intended use is:
+
+* Stop the node
+* Run `elasticsearch-node remove-customs name-of-custom-to-remove` on the node
+* Repeat for all other master-eligible nodes
+* Start the nodes
+
 [float]
 ==== Recovering data after a disaster
 
@@ -407,6 +429,33 @@ You can also use wildcards to remove multiple settings, for example using
 node$ ./bin/elasticsearch-node remove-settings xpack.monitoring.*
 ----
 
+[float]
+==== Removing custom metadata from the cluster state
+
+If the on-disk cluster state contains custom metadata that prevents the node
+from starting up and loading the cluster state, you can run the following
+commands to remove this custom metadata.
+
+[source,txt]
+----
+node$ ./bin/elasticsearch-node remove-customs snapshot_lifecycle
+
+    WARNING: Elasticsearch MUST be stopped before running this tool.
+
+The following customs will be removed:
+snapshot_lifecycle
+
+You should only run this tool if you have broken custom metadata in the
+cluster state that prevents the cluster state from being loaded.
+This tool can cause data loss and its use should be your last resort.
+
+Do you want to proceed?
+
+Confirm [y/N] y
+
+Customs were successfully removed from the cluster state
+----
+
 [float]
 ==== Unsafe cluster bootstrapping
 

server/src/main/java/org/elasticsearch/cluster/coordination/NodeToolCli.java

@@ -42,6 +42,7 @@ public NodeToolCli() {
         subcommands.put("detach-cluster", new DetachClusterCommand());
         subcommands.put("override-version", new OverrideNodeVersionCommand());
         subcommands.put("remove-settings", new RemoveSettingsCommand());
+        subcommands.put("remove-customs", new RemoveCustomsCommand());
     }
 
     public static void main(String[] args) throws Exception {

server/src/main/java/org/elasticsearch/cluster/coordination/RemoveCustomsCommand.java

@@ -0,0 +1,102 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.cluster.coordination;
+
+import com.carrotsearch.hppc.cursors.ObjectCursor;
+import joptsimple.OptionSet;
+import joptsimple.OptionSpec;
+import org.elasticsearch.cli.ExitCodes;
+import org.elasticsearch.cli.Terminal;
+import org.elasticsearch.cli.UserException;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.metadata.MetaData;
+import org.elasticsearch.common.collect.Tuple;
+import org.elasticsearch.common.regex.Regex;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.gateway.PersistedClusterStateService;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.List;
+
+public class RemoveCustomsCommand extends ElasticsearchNodeCommand {
+
+    static final String CUSTOMS_REMOVED_MSG = "Customs were successfully removed from the cluster state";
+    static final String CONFIRMATION_MSG =
+        DELIMITER +
+            "\n" +
+            "You should only run this tool if you have broken custom metadata in the\n" +
+            "cluster state that prevents the cluster state from being loaded.\n" +
+            "This tool can cause data loss and its use should be your last resort.\n" +
+            "\n" +
+            "Do you want to proceed?\n";
+
+    private final OptionSpec<String> arguments;
+
+    public RemoveCustomsCommand() {
+        super("Removes custom metadata from the cluster state");
+        arguments = parser.nonOptions("custom metadata names");
+    }
+
+    @Override
+    protected void processNodePaths(Terminal terminal, Path[] dataPaths, OptionSet options, Environment env)
+        throws IOException, UserException {
+        final List<String> customsToRemove = arguments.values(options);
+        if (customsToRemove.isEmpty()) {
+            throw new UserException(ExitCodes.USAGE, "Must supply at least one custom metadata name to remove");
+        }
+
+        final PersistedClusterStateService persistedClusterStateService = createPersistedClusterStateService(dataPaths);
+
+        terminal.println(Terminal.Verbosity.VERBOSE, "Loading cluster state");
+        final Tuple<Long, ClusterState> termAndClusterState = loadTermAndClusterState(persistedClusterStateService, env);
+        final ClusterState oldClusterState = termAndClusterState.v2();
+        terminal.println(Terminal.Verbosity.VERBOSE, "custom metadata names: " + oldClusterState.metaData().customs().keys());
+        final MetaData.Builder metaDataBuilder = MetaData.builder(oldClusterState.metaData());
+        for (String customToRemove : customsToRemove) {
+            boolean matched = false;
+            for (ObjectCursor<String> customKeyCur : oldClusterState.metaData().customs().keys()) {
+                final String customKey = customKeyCur.value;
+                if (Regex.simpleMatch(customToRemove, customKey)) {
+                    metaDataBuilder.removeCustom(customKey);
+                    if (matched == false) {
+                        terminal.println("The following customs will be removed:");
+                    }
+                    matched = true;
+                    terminal.println(customKey);
+                }
+            }
+            if (matched == false) {
+                throw new UserException(ExitCodes.USAGE,
+                    "No custom metadata matching [" + customToRemove + "] were found on this node");
+            }
+        }
+        final ClusterState newClusterState = ClusterState.builder(oldClusterState).metaData(metaDataBuilder.build()).build();
+        terminal.println(Terminal.Verbosity.VERBOSE,
+            "[old cluster state = " + oldClusterState + ", new cluster state = " + newClusterState + "]");
+
+        confirm(terminal, CONFIRMATION_MSG);
+
+        try (PersistedClusterStateService.Writer writer = persistedClusterStateService.createWriter()) {
+            writer.writeFullStateAndCommit(termAndClusterState.v1(), newClusterState);
+        }
+
+        terminal.println(CUSTOMS_REMOVED_MSG);
+    }
+}

server/src/test/java/org/elasticsearch/cluster/coordination/RemoveCustomsCommandIT.java

@@ -0,0 +1,125 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.cluster.coordination;
+
+import joptsimple.OptionSet;
+import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.cli.MockTerminal;
+import org.elasticsearch.cli.UserException;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.env.TestEnvironment;
+import org.elasticsearch.test.ESIntegTestCase;
+
+import static org.hamcrest.Matchers.containsString;
+
+@ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
+public class RemoveCustomsCommandIT extends ESIntegTestCase {
+
+    public void testRemoveCustomsAbortedByUser() throws Exception {
+        internalCluster().setBootstrapMasterNodeIndex(0);
+        String node = internalCluster().startNode();
+        Settings dataPathSettings = internalCluster().dataPathSettings(node);
+        ensureStableCluster(1);
+        internalCluster().stopRandomDataNode();
+
+        Environment environment = TestEnvironment.newEnvironment(
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build());
+        expectThrows(() -> removeCustoms(environment, true, new String[]{ "index-graveyard" }),
+            ElasticsearchNodeCommand.ABORTED_BY_USER_MSG);
+    }
+
+    public void testRemoveCustomsSuccessful() throws Exception {
+        internalCluster().setBootstrapMasterNodeIndex(0);
+        String node = internalCluster().startNode();
+        createIndex("test");
+        client().admin().indices().prepareDelete("test").get();
+        assertEquals(1, client().admin().cluster().prepareState().get().getState().metaData().indexGraveyard().getTombstones().size());
+        Settings dataPathSettings = internalCluster().dataPathSettings(node);
+        ensureStableCluster(1);
+        internalCluster().stopRandomDataNode();
+
+        Environment environment = TestEnvironment.newEnvironment(
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build());
+        MockTerminal terminal = removeCustoms(environment, false,
+            randomBoolean() ?
+                new String[]{ "index-graveyard" } :
+                new String[]{ "index-*" }
+            );
+        assertThat(terminal.getOutput(), containsString(RemoveCustomsCommand.CUSTOMS_REMOVED_MSG));
+        assertThat(terminal.getOutput(), containsString("The following customs will be removed:"));
+        assertThat(terminal.getOutput(), containsString("index-graveyard"));
+
+        internalCluster().startNode(dataPathSettings);
+        assertEquals(0, client().admin().cluster().prepareState().get().getState().metaData().indexGraveyard().getTombstones().size());
+    }
+
+    public void testCustomDoesNotMatch() throws Exception {
+        internalCluster().setBootstrapMasterNodeIndex(0);
+        String node = internalCluster().startNode();
+        createIndex("test");
+        client().admin().indices().prepareDelete("test").get();
+        assertEquals(1, client().admin().cluster().prepareState().get().getState().metaData().indexGraveyard().getTombstones().size());
+        Settings dataPathSettings = internalCluster().dataPathSettings(node);
+        ensureStableCluster(1);
+        internalCluster().stopRandomDataNode();
+
+        Environment environment = TestEnvironment.newEnvironment(
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build());
+        UserException ex = expectThrows(UserException.class, () -> removeCustoms(environment, false,
+            new String[]{ "index-greveyard-with-typos" }));
+        assertThat(ex.getMessage(), containsString("No custom metadata matching [index-greveyard-with-typos] were " +
+            "found on this node"));
+    }
+
+    private MockTerminal executeCommand(ElasticsearchNodeCommand command, Environment environment, boolean abort, String... args)
+        throws Exception {
+        final MockTerminal terminal = new MockTerminal();
+        final OptionSet options = command.getParser().parse(args);
+        final String input;
+
+        if (abort) {
+            input = randomValueOtherThanMany(c -> c.equalsIgnoreCase("y"), () -> randomAlphaOfLength(1));
+        } else {
+            input = randomBoolean() ? "y" : "Y";
+        }
+
+        terminal.addTextInput(input);
+
+        try {
+            command.execute(terminal, options, environment);
+        } finally {
+            assertThat(terminal.getOutput(), containsString(ElasticsearchNodeCommand.STOP_WARNING_MSG));
+        }
+
+        return terminal;
+    }
+
+    private MockTerminal removeCustoms(Environment environment, boolean abort, String... args) throws Exception {
+        final MockTerminal terminal = executeCommand(new RemoveCustomsCommand(), environment, abort, args);
+        assertThat(terminal.getOutput(), containsString(RemoveCustomsCommand.CONFIRMATION_MSG));
+        assertThat(terminal.getOutput(), containsString(RemoveCustomsCommand.CUSTOMS_REMOVED_MSG));
+        return terminal;
+    }
+
+    private void expectThrows(ThrowingRunnable runnable, String message) {
+        ElasticsearchException ex = expectThrows(ElasticsearchException.class, runnable);
+        assertThat(ex.getMessage(), containsString(message));
+    }
+}