Today we rewrite the operations from the leader with the term of the
following primary because the follower should own its history. The
problem is that a newly promoted primary may re-assign its term to
operations which were replicated to replicas before by the previous
primary. If this happens, some operations with the same seq_no may be
assigned different terms. This is not good for the future optimistic
locking using a combination of seqno and term.
This change ensures that the primary of a follower only processes an
operation if that operation was not processed before. The skipped
operations are guaranteed to be delivered to replicas via either
primary-replica resync or peer-recovery. However, the primary must not
acknowledge until the global checkpoint is at least the highest seqno of
all skipped ops (i.e., they all have been processed on every replica).
Relates #31751
Relates #31113
Also fixed ShardFollowNodeTaskTests to not return ops when responseSize
is empty. Otherwise ops are returned when no ops are expected to be returned.
Co-authored-by: Jason Tedor <jason@tedor.me>
In the CCR docs we want to refer to the endpoint that returns following
stats as the follow stats API. This commit renames the internal
implementation of this endpoint to reflect this usage.
The follower index shard history UUID will be fetched from the indices stats api when the shard follow task starts and will be provided with the bulk shard operation requests. The bulk shard operations api will fail if the provided history uuid is unequal to the actual history uuid.
No longer record the leader history uuid in shard follow task params, but rather use the leader history UUIDs directly from follower index's custom metadata. The resume follow api will remain to fail if leader index shard history UUIDs are missing.
Closes#33956
Since #34099, the FollowingEngine will skip an operation which was
already processed before. With that change, it should be okay to unmute
testFollowIndexAndCloseNode.
This arose when two commits were pushed at roughly the same time, both
of which compiled successfully against master, but not when taken
together. This commit fixes a reference in one of the commits that was
changed in the other commit.
This commit modifies the CCR stats endpoint for indices to be
/{index}/_ccr/stats. This makes this endpoint consistent with other
index-centric endpoints like indices stats.
The unfollow API changes a follower index into a regular index, so that it will accept write requests from clients.
For the unfollow api to work the index follow needs to be stopped and the index needs to be closed.
Closes#33931
This change introduces the indexing optimization using sequence numbers
in the FollowingEngine. This optimization uses the max_seq_no_updates
which is tracked on the primary of the leader and replicated to replicas
and followers.
Relates #33656
Prior to following an index in the follow API, check whether current
user has sufficient privileges in the leader cluster to read and
monitor the leader index.
Also check this in the create and follow API prior to creating the
follow index.
Also introduced READ_CCR cluster privilege that include the minimal
cluster level actions that are required for ccr in the leader cluster.
So a user can follow indices in a cluster, but not use the ccr admin APIs.
Closes#33553
Co-authored-by: Jason Tedor <jason@tedor.me>
The following changes were made:
* Added ElasticsearchSecurityException. For in the case the current user has insufficient privileges while an index is being followed. Prior to following ccr checks whether the current user has sufficient privileges and if not the follow api fails with an error.
* Added Index block exception. If the leader index gets closed, this exception is returned.
* Added ClusterBlockException service unavailable. In case for example the leader cluster is without elected master.
* Removed IndexNotFoundException. If the leader / follower index has been deleted, ccr will need to stop the shard follow tasks with an error.
Closes#33954
* Renamed CCR APIs
Renamed:
* `/{index}/_ccr/create_and_follow` to `/{index}/_ccr/follow`
* `/{index}/_ccr/unfollow` to `/{index}/_ccr/pause_follow`
* `/{index}/_ccr/follow` to `/{index}/_ccr/resume_follow`
Relates to #33931
always use `IndicesOptions.strictExpand()` for indices options.
The follow index may be closed and we still want to get stats from
shard follow task and the whether the provided index name matches with
follow index name is checked when locating the task itself in the ccr
stats transport action.
This commit replicates the max_seq_no_of_updates on the leading index
to the primaries of the following index via ShardFollowNodeTask. The
max_seq_of_updates is then transmitted to the replicas of the follower
via replication requests (that's BulkShardOperationsRequest).
Relates #33656
We start tracking max seq_no_of_updates on the primary in #33842. This
commit replicates that value from a primary to its replicas in replication
requests or the translog phase of peer-recovery.
With this change, we guarantee that the value of max seq_no_of_updates
on a replica when any index/delete operation is performed at least the
max_seq_no_of_updates on the primary when that operation was executed.
Relates #33656
If numWrites is between 2 and 9, we will issue an invalid range because
the from_seq_no is negative. This commit makes sure that numWrites is at
least 10, and adds an explicit test to verify invalid request ranges.
This PR is the first step to use seq_no to optimize indexing operations.
The idea is to track the max seq_no of either update or delete ops on a
primary, and transfer this information to replicas, and replicas use it
to optimize indexing plan for index operations (with assigned seq_no).
The max_seq_no_of_updates on primary is initialized once when a primary
finishes its local recovery or peer recovery in relocation or being
promoted. After that, the max_seq_no_of_updates is only advanced internally
inside an engine when processing update or delete operations.
Relates #33656
Instead of having one constructor that accepts all arguments, all parameters
should be provided via setters. Only leader and follower index are required
arguments. This makes using this class in tests and transport client easier.
The following stats are being kept track of:
1) The total number of times that auto following a leader index succeed.
2) The total number of times that auto following a leader index failed.
3) The total number of times that fetching a remote cluster state failed.
4) The most recent 256 auto follow failures per auto leader index
(e.g. create_and_follow api call fails) or cluster alias
(e.g. fetching remote cluster state fails).
Each auto follow run now produces a result that is being used to update
the stats being kept track of in AutoFollowCoordinator.
Relates to #33007
* [CCR] Do not unnecessarily wrap fetch exception in a ElasticSearch exception and
properly map fetch_exception.exception field as object.
The extra caused by level is not necessary here:
```
"fetch_exceptions": [
{
"from_seq_no": 1,
"retries": 106,
"exception": {
"type": "exception",
"reason": "[index1] IndexNotFoundException[no such index]",
"caused_by": {
"type": "index_not_found_exception",
"reason": "no such index",
"index_uuid": "_na_",
"index": "index1"
}
}
}
],
```
When a leader index is created, it may not have a mapping yet.
Currently if you follow such an index the shard follow tasks fail with
NoSuchElementException, because they expect a single mapping.
This commit fixes that, by allowing that a leader index does not yet have
a mapping.
Rather than scheduling pings to the leader index when we are caught up
to the leader, this commit introduces long polling for changes. We will
fire off a request to the leader which if we are already caught up will
enter a poll on the leader side to listen for global checkpoint
changes. These polls will timeout after a default of one minute, but can
also be specified when creating the following task. We use these time
outs as a way to keep statistics up to date, to not exaggerate time
since last fetches, and to avoid pipes being broken.
This commit moves these REST tests (possibly temporarily) to a
sub-project of ccr. We do this (again, possibly temporarily) to keep
them within the ccr sub-project yet there are changes within 6.x that
prevent these from being in the top-level project (the cluster formation
tasks are trying to install x-pack-ccr into the
integ-test-zip). Therefore, we isolate these for now until we can
understand why there are differences between 6.x and master.
When developing ccr it is not ideal if tests are in multiple modules.
Even the classes these tests test are in the core module, it is easier
if these tests are in ccr module in order to avoid running the test task
in core module. This results in running many non ccr tests.
This way when developing ccr we can run locally:
./gradlew x-pack:plugin:core:precommit x-pack:plugin:ccr:check
before pushing to PR branches and be confident that the PR build passes,
without running x-pack:plugin:core:check task.
and if so debug log it and otherwise rethrow.
This should fix a couple of test failures where during test teardown tests
failed due to uncaught exceptions being detected.
The follow index api checks if the recorded uuid in the follow index matches
with uuid of the leader index and fails otherwise. This validation will
prevent a follow index from following an incompatible leader index.
The create_and_follow api will automatically add this custom index metadata
when it creates the follow index.
Closes#31505
For correctness we need to verify whether the history uuid of the leader
index shards never changes while that index is being followed.
* The history UUIDs are recorded as custom index metadata in the follow index.
* The follow api validates whether the current history UUIDs of the leader
index shards are the same as the recorded history UUIDs.
If not the follow api fails.
* While a follow index is following a leader index; shard follow tasks
on each shard changes api call verify whether their current history uuid
is the same as the recorded history uuid.
Relates to #30086
Co-authored-by: Nhat Nguyen <nhat.nguyen@elastic.co>
Improve failure handling of retryable errors by retrying remote calls in
a exponential backoff like manner. The delay between a retry would not be
longer than the configured max retry delay. Also retryable errors will be
retried indefinitely.
Relates to #30086
* [CCR] Delay auto follow license check
so that we're sure that there are auto follow patterns configured
Otherwise we log a warning in case someone is running with basic or gold
license and has not used the ccr feature.
This is a new index privilege that the user needs to have in the follow cluster.
This privilege is required in addition to the `manage_ccr` cluster privilege in
order to execute the create and follow api.
Closes#33555
We may use different global checkpoints to validate/normalize the range
of a change request if the global checkpoint is advanced between these
calls. If this is the case, then we generate an invalid request range.
This commit reverses the logic for CCR license checks in a few
actions. This is done so that the successful case, which tends to be a
larger block of code, does not require indentation.
We have some listeners in the CCR license tests that invoke Assert#fail
if the onSuccess method for the listener is unexpectedly invoked. This
can leave the main test thread hanging until the test suite times out
rather than failing quickly. This commit adds some latch countdowns so
that we fail quickly if these cases are hit.
This commit adds license checks for the auto-follow implementation. We
check the license on put auto-follow patterns, and then for every
coordination round we check that the local and remote clusters are
licensed for CCR. In the case of non-compliance, we skip coordination
yet continue to schedule follow-ups.
Instead of passing DirectoryService which causes yet another dependency
on Store we can just pass in a Directory since we will just call
`DirectoryService#newDirectory()` on it anyway.
This commit allows us to use different TranslogRecoveryRunner when
recovering an engine from its local translog. This change is a
prerequisite for the commit-based rollback PR.
Relates #32867
Auto Following Patterns is a cross cluster replication feature that
keeps track whether in the leader cluster indices are being created with
names that match with a specific pattern and if so automatically let
the follower cluster follow these newly created indices.
This change adds an `AutoFollowCoordinator` component that is only active
on the elected master node. Periodically this component checks the
the cluster state of remote clusters if there new leader indices that
match with configured auto follow patterns that have been defined in
`AutoFollowMetadata` custom metadata.
This change also adds two new APIs to manage auto follow patterns. A put
auto follow pattern api:
```
PUT /_ccr/_autofollow/{{remote_cluster}}
{
"leader_index_pattern": ["logs-*", ...],
"follow_index_pattern": "{{leader_index}}-copy",
"max_concurrent_read_batches": 2
... // other optional parameters
}
```
and delete auto follow pattern api:
```
DELETE /_ccr/_autofollow/{{remote_cluster_alias}}
```
The auto follow patterns are directly tied to the remote cluster aliases
configured in the follow cluster.
Relates to #33007
Co-authored-by: Jason Tedor jason@tedor.me
This test fails several times due to timeout when asserting the number
of docs on the following and leading indices. This change reduces
the number of docs to index and increases the timeout.
These response classes did not add any value and in that case just AcknowledgedResponse should be used.
I also changed the formatting of methods to take one line per parameter in
FollowIndexAction.java and UnfollowIndexAction.java files to make
reviewing diffs in the future easier.
This commit makes primary-replica resyncer use Lucene as the source of
history operation instead of translog if soft-deletes is enabled. With
this change, we no longer expose translog snapshot directly in IndexShard.
Relates #29530
These were broken when fetch exceptions were introduced to the status
object but equals and hash code were not updated then. This commit
addresses that.
Today we fetch the mapping from the leader and apply it as a mapping
update whenever the index metadata version on the leader changes. Yet,
the index metadata can change for many reasons other than a mapping
update (e.g., settings updates, adding an alias, or a replica being
promoted to a primary among many other reasons). This commit builds on
the addition of a mapping version to the index metadata to only fetch
mapping updates when the mapping version increases. This reduces the
number of these fetches and application of mappings on the follower to
the bare minimum.
* master:
Adjust BWC version on mapping version
Token API supports the client_credentials grant (#33106)
Build: forked compiler max memory matches jvmArgs (#33138)
Introduce mapping version to index metadata (#33147)
SQL: Enable aggregations to create a separate bucket for missing values (#32832)
Fix grammar in contributing docs
SECURITY: Fix Compile Error in ReservedRealmTests (#33166)
APM server monitoring (#32515)
Support only string `format` in date, root object & date range (#28117)
[Rollup] Move toBuilders() methods out of rollup config objects (#32585)
Fix forbiddenapis on java 11 (#33116)
Apply publishing to genreate pom (#33094)
Have circuit breaker succeed on unknown mem usage
Do not lose default mapper on metadata updates (#33153)
Fix a mappings update test (#33146)
Reload Secure Settings REST specs & docs (#32990)
Refactor CachingUsernamePassword realm (#32646)
This commit adds tracking and reporting for fetch exceptions. We track
fetch exceptions per fetch, keeping track of up to the maximum number of
concurrent fetches. With each failing fetch, we associate the from
sequence number with the exception that caused the fetch. We report
these in the CCR stats endpoint, and add some testing for this tracking.
This commit implements licensing for CCR. CCR will require a platinum
license, and administrative endpoints will be disabled when a license is
non-compliant.
If a leader index is deleted while there is an active follower, the
follower will send shard changes requests bound for the leader
index. Today this will result in a null pointer exception because there
will not be an index routing table for the index. A null pointer
exception looks like a bug to a user so this commit addresses this by
throwing an index not found exception instead.
For a new feature like CCR we will go without this extra layer of
indirection. This commit replaces all /_xpack/ccr/_(\S+) endpoints by
/_ccr/$1 endpoints.
Today ShardFollowNodeTask might fetch some operations more than once.
This happens because we ask the leading for up to max_batch_count
operations (instead of the left-over size) for the left-over request.
The leading then can freely respond up to the max_batch_count, and at
the same time, if one of the previous requests completed, we might issue
another read request whose range overlaps with the response of the
left-over request.
Closes#32453
Today we do not check if the `following_index` setting of the follower
is enabled or not when processing a follow-request. If that setting is
disabled, the follower will use the default engine, not the following
engine. This change checks and rejects such invalid follow requests.
Relates #30086
Today it's possible to encounter an Index operation in Lucene whose
_source is disabled, and _recovery_source was pruned by the MergePolicy.
If it's the case, we create a Translog#Index without source and let the
caller validate it later. However, this approach is challenging for the
caller.
Deletes and No-Ops don't allow invoking "source()" method. The caller
has to make sure to call "source()" only on index operations. The
current implementation in CCR does not follow this and fail to replica
deletes or no-ops. Moreover, it's easier to reason if a Translog#Index
always has the source.
Today we consider a read request is exhausted if from_seqno is equal to
or greater than the max_required_seqno. However, if we stop when
from_seqno equals to the max_required_seqno, we will miss an operation
whose seqno is max_required_seqno because we have not seen that
operation yet.
We modified the way we calculate to_seqno in #32121 but did not adjust
this test accordingly. If min_seqno equals to max_seqno, the size should be
one instead of zero.
Relates #32121
Martijn van Groningen
Nhat Nguyen
Jason Tedor
Tanguy Leroux
Simon Willnauer