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
With features like CCR building on the CCS infrastructure, the settings
prefix search.remote makes less sense as the namespace for these remote
cluster settings than does a more general namespace like
cluster.remote. This commit replaces these settings with cluster.remote
with a fallback to the deprecated settings search.remote.
Welp, I broke this. I merged a change to auto-discover the CCR QA tests
by making :x-pack:plugin:ccr:check auto-discover the check tasks in the
qa sub-project. Yet, the check tasks for these sub-projects did not
depend on the necessary test tasks (as we were previously doing this
directly from the ccr build file. This commit fixes this!
This commit implements licensing for CCR. CCR will require a platinum
license, and administrative endpoints will be disabled when a license is
non-compliant.
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.
The current shard follow mechanism is complex and does not give us easy ways the have visibility into the system (e.g. why we are falling behind).
The main reason why it is complex is because the current design is highly asynchronous. Also in the current model it is hard to apply backpressure
other than reducing the concurrent reads from the leader shard.
This PR has the following changes:
* Rewrote the shard follow task to coordinate the shard follow mechanism between a leader and follow shard in a single threaded manner.
This allows for better unit testing and makes it easier to add stats.
* All write operations read from the shard changes api should be added to a buffer instead of directly sending it to the bulk shard operations api.
This allows to apply backpressure. In this PR there is a limit that controls how many write ops are allowed in the buffer after which no new reads
will be performed until the number of ops is below that limit.
* The shard changes api includes the current global checkpoint on the leader shard copy. This allows reading to be a more self sufficient process;
instead of relying on a background thread to fetch the leader shard's global checkpoint.
* Reading write operations from the leader shard (via shard changes api) is a separate step then writing the write operations (via bulk shards operations api).
Whereas before a read would immediately result into a write.
* The bulk shard operations api returns the local checkpoint on the follow primary shard, to keep the shard follow task up to date with what has been written.
* Moved the shard follow logic that was previously in ShardFollowTasksExecutor to ShardFollowNodeTask.
* Moved over the changes from #31242 to make shard follow mechanism resilient from node and shard failures.
Relates to #30086
Today if a user omits the `_source` entirely or modifies the source
on indexing we have no chance to re-create the document after it has
been added. This is an issue for CCR and recovery based on soft deletes
which we are going to make the default. This change adds an additional
recovery source if the source is disabled or modified that is only kept
around until the document leaves the retention policy window.
This change adds a merge policy that efficiently removes this extra source
on merge for all document that are live and not in the retention policy window
anymore.
The old perform request methods on the REST client have been deprecated
in favor using request-flavored methods. This commit addresses the use
of these deprecated methods in the CCR test suite.
The TODOs in the rest actions was incorrect. The problem was that
these rest actions used `follow_index` as first named variable in the path
under which the rest actions were registered. Other candidate rest actions that
also have a named variable as first element in the path (but with a different
name) get resolved as rest parameters too and passed down to the rest
action that actually ends up getting executed.
In the case of the follow index api, a `index` parameter got passed down
to `RestFollowExistingAction`, but that param was never used. This caused the
follow index api call to fail, because of unused http parameters.
This change doesn't fixes that problem, but works around it by using
`index` as named variable for the follow index (instead of `follow_index`).
Relates to #30102
This commit adds an API to read translog snapshot from Lucene,
then cut-over from the existing translog to the new API in CCR.
Relates #30086
Relates #29530
The follow index api completely reuses CCS infrastructure that was exposed via:
https://github.com/elastic/elasticsearch/pull/29495
This means that the leader index parameter support the same ccs index
to indicate that an index resides in a different cluster.
I also added a qa module that smoke tests the cross cluster nature of ccr.
The idea is that this test just verifies that ccr can read data from a
remote leader index and that is it, no crazy randomization or indirectly
testing other features.
Jason Tedor
Martijn van Groningen
Nhat Nguyen
Simon Willnauer