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Fix Snapshot Corruption in Edge Case #47552

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merged 1 commit into from
Oct 4, 2019
+56 −43
Merged

Fix Snapshot Corruption in Edge Case #47552

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86 changes: 47 additions & 39 deletions server/src/main/java/org/elasticsearch/cluster/SnapshotsInProgress.java
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
import org.elasticsearch.Version;
import org.elasticsearch.cluster.ClusterState.Custom;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.collect.ImmutableOpenMap;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
Expand Down Expand Up @@ -77,7 +78,7 @@ public String toString() {
return builder.append("]").toString();
}

public static class Entry {
public static class Entry implements ToXContent {
private final State state;
private final Snapshot snapshot;
private final boolean includeGlobalState;
Expand Down Expand Up @@ -211,7 +212,50 @@ public int hashCode() {

@Override
public String toString() {
return snapshot.toString();
return Strings.toString(this);
}

@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject();
builder.field(REPOSITORY, snapshot.getRepository());
builder.field(SNAPSHOT, snapshot.getSnapshotId().getName());
builder.field(UUID, snapshot.getSnapshotId().getUUID());
builder.field(INCLUDE_GLOBAL_STATE, includeGlobalState());
builder.field(PARTIAL, partial);
builder.field(STATE, state);
builder.startArray(INDICES);
{
for (IndexId index : indices) {
index.toXContent(builder, params);
}
}
builder.endArray();
builder.humanReadableField(START_TIME_MILLIS, START_TIME, new TimeValue(startTime));
builder.field(REPOSITORY_STATE_ID, repositoryStateId);
builder.startArray(SHARDS);
{
for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardEntry : shards) {
ShardId shardId = shardEntry.key;
ShardSnapshotStatus status = shardEntry.value;
builder.startObject();
{
builder.field(INDEX, shardId.getIndex());
builder.field(SHARD, shardId.getId());
builder.field(STATE, status.state());
builder.field(NODE, status.nodeId());
}
builder.endObject();
}
}
builder.endArray();
builder.endObject();
return builder;
}

@Override
public boolean isFragment() {
return false;
}

private ImmutableOpenMap<String, List<ShardId>> findWaitingIndices(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards) {
Expand Down Expand Up @@ -506,48 +550,12 @@ public void writeTo(StreamOutput out) throws IOException {
public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
builder.startArray(SNAPSHOTS);
for (Entry entry : entries) {
toXContent(entry, builder, params);
entry.toXContent(builder, params);
}
builder.endArray();
return builder;
}

public void toXContent(Entry entry, XContentBuilder builder, ToXContent.Params params) throws IOException {
builder.startObject();
builder.field(REPOSITORY, entry.snapshot().getRepository());
builder.field(SNAPSHOT, entry.snapshot().getSnapshotId().getName());
builder.field(UUID, entry.snapshot().getSnapshotId().getUUID());
builder.field(INCLUDE_GLOBAL_STATE, entry.includeGlobalState());
builder.field(PARTIAL, entry.partial());
builder.field(STATE, entry.state());
builder.startArray(INDICES);
{
for (IndexId index : entry.indices()) {
index.toXContent(builder, params);
}
}
builder.endArray();
builder.humanReadableField(START_TIME_MILLIS, START_TIME, new TimeValue(entry.startTime()));
builder.field(REPOSITORY_STATE_ID, entry.getRepositoryStateId());
builder.startArray(SHARDS);
{
for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardEntry : entry.shards) {
ShardId shardId = shardEntry.key;
ShardSnapshotStatus status = shardEntry.value;
builder.startObject();
{
builder.field(INDEX, shardId.getIndex());
builder.field(SHARD, shardId.getId());
builder.field(STATE, status.state());
builder.field(NODE, status.nodeId());
}
builder.endObject();
}
}
builder.endArray();
builder.endObject();
}

public enum ShardState {
INIT((byte) 0, false, false),
SUCCESS((byte) 2, true, false),
Expand Down
13 changes: 9 additions & 4 deletions server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -785,19 +785,22 @@ public ClusterState execute(ClusterState currentState) {
ImmutableOpenMap.Builder<ShardId, ShardSnapshotStatus> shards = ImmutableOpenMap.builder();
boolean snapshotChanged = false;
for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardEntry : snapshot.shards()) {
ShardSnapshotStatus shardStatus = shardEntry.value;
final ShardSnapshotStatus shardStatus = shardEntry.value;
final ShardId shardId = shardEntry.key;
if (!shardStatus.state().completed() && shardStatus.nodeId() != null) {
if (nodes.nodeExists(shardStatus.nodeId())) {
shards.put(shardEntry.key, shardEntry.value);
shards.put(shardId, shardStatus);
} else {
// TODO: Restart snapshot on another node?
snapshotChanged = true;
logger.warn("failing snapshot of shard [{}] on closed node [{}]",
shardEntry.key, shardStatus.nodeId());
shards.put(shardEntry.key,
shardId, shardStatus.nodeId());
shards.put(shardId,
new ShardSnapshotStatus(shardStatus.nodeId(), ShardState.FAILED, "node shutdown",
shardStatus.generation()));
}
} else {
shards.put(shardId, shardStatus);
}
}
if (snapshotChanged) {
Expand Down Expand Up @@ -829,6 +832,8 @@ public void onFailure(Exception e) {
}
}, updatedSnapshot.getRepositoryStateId(), false);
}
assert updatedSnapshot.shards().size() == snapshot.shards().size()
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Can we assert in the constructor of SnapshotsInProgress.Entry that for every entry in "indices" there is at least one entry in the shards map and vice versa?

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Yea that sounds good, maybe do it in a follow-up since it requires a bit of a rewrite of org.elasticsearch.snapshots.SnapshotsInProgressSerializationTests#randomSnapshot (it creates all kinds of bogus instances wehre the indices don't match up) and it might be nice to have this change isolated?

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ok

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#47598

: "Shard count changed during snapshot status update from [" + snapshot + "] to [" + updatedSnapshot + "]";
}
if (changed) {
return ClusterState.builder(currentState)
Expand Down