Today when creating a follower index via the put follow API, or via an
auto-follow pattern, it is not possible to specify settings overrides
for the follower index. Instead, we copy all of the leader index
settings to the follower. Yet, there are cases where a user would want
some different settings on the follower index such as the number of
replicas, or allocation settings. This commit addresses this by allowing
the user to specify settings overrides when creating follower index via
manual put follower calls, or via auto-follow patterns. Note that not
all settings can be overrode (e.g., index.number_of_shards) so we also
have detection that prevents attempting to override settings that must
be equal between the leader and follow index. Note that we do not even
allow specifying such settings in the overrides, even if they are
specified to be equal between the leader and the follower
index. Instead, the must be implicitly copied from the leader index, not
explicitly set by the user.
CCR follower stats can return information for persistent tasks that are in the process of being cleaned up. This is problematic for tests where CCR follower indices have been deleted, but their persistent follower task is only cleaned up asynchronously afterwards. If one of the following tests then accesses the follower stats, it might still get the stats for that follower task.
In addition, some tests were not cleaning up their auto-follow patterns, leaving orphaned patterns behind. Other tests cleaned up their auto-follow patterns. As always the same name was used, it just depended on the test execution order whether this led to a failure or not. This commit fixes the offensive tests, and will also automatically remove auto-follow-patterns at the end of tests, like we do for many other features.
Closes #48700
This commit adds two APIs that allow to pause and resume
CCR auto-follower patterns:
// pause auto-follower
POST /_ccr/auto_follow/my_pattern/pause
// resume auto-follower
POST /_ccr/auto_follow/my_pattern/resume
The ability to pause and resume auto-follow patterns can be
useful in some situations, including the rolling upgrades of
cluster using a bi-directional cross-cluster replication scheme
(see #46665).
This committ adds a new active flag to the AutoFollowPattern
and adapts the AutoCoordinator and AutoFollower classes so
that it stops to fetch remote's cluster state when all auto-follow
patterns associate to the remote cluster are paused.
When an auto-follower is paused, remote indices that match the
pattern are just ignored: they are not added to the pattern's
followed indices uids list that is maintained in the local cluster
state. This way, when the auto-follow pattern is resumed the
indices created in the remote cluster in the meantime will be
picked up again and added as new following indices. Indices
created and then deleted in the remote cluster will be ignored
as they won't be seen at all by the auto-follower pattern at
resume time.
This commit adds functionality so that aliases that are manipulated on
leader indices are replicated by the shard follow tasks to the follower
indices. Note that we ignore write indices. This is due to the fact that
follower indices do not receive direct writes so the concept is not
useful.
This commit introduces the forget follower API. This API is needed in cases that
unfollowing a following index fails to remove the shard history retention leases
on the leader index. This can happen explicitly through user action, or
implicitly through an index managed by ILM. When this occurs, history will be
retained longer than necessary. While the retention lease will eventually
expire, it can be expensive to allow history to persist for that long, and also
prevent ILM from performing actions like shrink on the leader index. As such, we
introduce an API to allow for manual removal of the shard history retention
leases in this case.
(a restore needs to be complete, which happens in the background and
by default the ccr put follow api doesn't wait for this)
(this was a recent change and the pr that added this docs test,
did not include this change)
Relates to #37917
This commit modifies the put follow index action to use a
CcrRepository when creating a follower index. It routes
the logic through the snapshot/restore process. A
wait_for_active_shards parameter can be used to configure
how long to wait before returning the response.
* Add ccr follow info api
This api returns all follower indices and per follower index
the provided parameters at put follow / resume follow time and
whether index following is paused or active.
Closes#37127
* iter
* [DOCS] Edits the get follower info API
* [DOCS] Fixes link to remote cluster
* [DOCS] Clarifies descriptions for configured parameters
For each remote cluster the auto follow coordinator, starts an auto
follower that checks the remote cluster state and determines whether an
index needs to be auto followed. The time since last auto follow is
reported per remote cluster and gives insight whether the auto follow
process is alive.
Relates to #33007
Originates from #35895
The current response format is:
```
{
"pattern1": {
...
},
"pattern2": {
...
}
}
```
The new format is:
```
{
"patterns": [
{
"name": "pattern1",
"pattern": {
...
}
},
{
"name": "pattern2",
"pattern": {
...
}
}
]
}
```
This format is more structured and more friendly for parsing and generating specs.
This is a breaking change, but it is better to do this now while ccr
is still a beta feature than later.
Follow up from #36049
This commit uses the index settings version so that a follower can
replicate index settings changes as needed from the leader.
Co-authored-by: Martijn van Groningen <martijn.v.groningen@gmail.com>
This commit fixes two issues with the CCR API specification:
- remove the CCR stats endpoint, it is not currently implemented
- fix the documentation links
* Changed the auto follow stats to also include follow stats.
* Renamed the auto follow stats api to stats api and changed its url path
from `/_ccr/auto_follow/stats` `/_ccr/stats`.
* Removed `/_ccr/stats` url path for the follow stats api, which makes
the index parameter a required parameter.
* Fixed docs.
This commit is our first introduction to cross-cluster replication
docs. In this commit, we introduce the cross-cluster replication API
docs. We also add skelton docs for additional content that will be added
in a series of follow-up commits.
