The endpoint `_snapshottable_features` is long and implies incorrect
things about this API - it is used not just for snapshots, but also for
the upcoming reset API. Following discussions on the team, this commit
changes the endpoint to `_features` and removes the connection between
this API and snapshots, as snapshots are not the only use for the output
of this API.
Today we rely on blob stores behaving in a certain way so that they can be used
as a snapshot repository. There are an increasing number of third-party blob
stores that claim to be S3-compatible, but which may not offer a suitably
correct or performant implementation of the S3 API. We rely on somesubtle
semantics with concurrent readers and writers, but some blob stores may not
implement it correctly. Hitting a corner case in the implementation may be rare
in normal use, and may be hard to reproduce or to distinguish from an
Elasticsearch bug.
This commit introduces a new `POST /_snapshot/.../_analyse` API which exercises
the more problematic corners of the repository implementation looking for
correctness bugs and measures the details of the performance of the repository
under concurrent load.
This PR expands the meaning of `include_global_state` for snapshots to include system indices. If `include_global_state` is `true` on creation, system indices will be included in the snapshot regardless of the contents of the `indices` field. If `include_global_state` is `true` on restoration, system indices will be restored (if included in the snapshot), regardless of the contents of the `indices` field. Index renaming is not applied to system indices, as system indices rely on their names matching certain patterns. If restored system indices are already present, they are automatically deleted prior to restoration from the snapshot to avoid conflicts.
This behavior can be overridden to an extent by including a new field in the snapshot creation or restoration call, `feature_states`, which contains an array of strings indicating the "feature" for which system indices should be snapshotted or restored. For example, this call will only restore the `watcher` and `security` system indices (in addition to `index_1`):
```
POST /_snapshot/my_repository/snapshot_2/_restore
{
"indices": "index_1",
"include_global_state": true,
"feature_states": ["watcher", "security"]
}
```
If `feature_states` is present, the system indices associated with those features will be snapshotted or restored regardless of the value of `include_global_state`. All system indices can be omitted by providing a special value of `none` (`"feature_states": ["none"]`), or included by omitting the field or explicitly providing an empty array (`"feature_states": []`), similar to the `indices` field.
The list of currently available features can be retrieved via a new "Get Snapshottable Features" API:
```
GET /_snapshottable_features
```
which returns a response of the form:
```
{
"features": [
{
"name": "tasks",
"description": "Manages task results"
},
{
"name": "kibana",
"description": "Manages Kibana configuration and reports"
}
]
}
```
Features currently map one-to-one with `SystemIndexPlugin`s, but this should be considered an implementation detail. The Get Snapshottable Features API and snapshot creation rely upon all relevant plugins being installed on the master node.
Further, the list of feature states included in a given snapshot is exposed by the Get Snapshot API, which now includes a new field, `feature_states`, which contains a list of the feature states and their associated system indices which are included in the snapshot. All system indices in feature states are also included in the `indices` array for backwards compatibility, although explicitly requesting system indices included in a feature state is deprecated. For example, an excerpt from the Get Snapshot API showing `feature_states`:
```
"feature_states": [
{
"feature_name": "tasks",
"indices": [
".tasks"
]
}
],
"indices": [
".tasks",
"test1",
"test2"
]
```
Co-authored-by: William Brafford <william.brafford@elastic.co>
* Adding new page for restore snapshot API.
* Improving test cases, lots of edits, and streamlining content.
* Incorporating review suggestions and feedback.
* Specify `index alias` vs `alias`
* Change parameter order
* Provide clarity around regular expression
* Add link to SLM parameters
* Split sentences in example
* Adding link to master node page.
* Adding get snapshot status API docs.
* Adding more fields and a link to the new page.
* Adding missing spaces in TESTRESPONSES
* Adding more parameters and making some edits.
* Marking snapshot as optional
* Marking repository as optional
* Add data type for stats
* Add data type for shard_stats
* Incorporating review feedback.
* Lots of review feedback incorporated.
* Fixing tests to unbreak CI builds.
* Changing indices to index.
* Adding page for get snapshot API.
* Adding values for state and cleaning up some other formatting.
* Adding missing forward slash to GET request.
* Updating values for start_time and end_time in TESTRESPONSE.
* Swap "return" for "retrieve"
* Swap "return" for "retrieve" 2
* Change .snapshot to .response
* Adding response parameters and incorporating edits from review.
* Update response example to include repository info
* Change dash to underscore
* Add data type for snapshot in response
* Incorporating review comments and adding missing response definitions.
* Minor rewording in description.
* Adding create index snapshot API page.
* Condense API description.
* Remove parameter from query.
* Add POST method and remove `-name` from the snapshot variable.
* Expand description of `<snapshot>`.
* Add data streams to introduction and expand the overall description.
* Add support for data streams.
* Add support for data streams.
* Add data stream and reference for "point-in-time view".
* Add data streams.
* Change `my_backup` to `my_repository`.
* Add description of boolean options for `wait_for_completion` parameter.
* Change command --> response
* Clarify `indices` parameter description
* Update `ignore-unavailable` parameter description
* Reword example description
* Remove "index" from API name
* Incorporating review comments from James R.
* Adding a much better request + response
* Clarify `include_global_state` description
* Incorporating additional edits.
* Changing my_backup to my_repository in example.
* Update snippet test to avoid failures
* Update TESTRESPONSE snippets
* Remove errant space
* Removing the parameter per reviewer comments
Changes:
* Adds API reference docs for the delete snapshot repo API.
* Corrects an error in the delete snapshot repo API spec. Comma-separated
repository names are not supported.
* Relocates the existing delete snapshot repo API example docs.
