## Problem
The initial implementation of the validate API treats the in-memory
generations as authoritative.
- This is true when only one storage controller is running, but if a
rogue controller was running that hadn't been shut down properly, and
some pageserver requests were routed to that bad controller, it could
incorrectly return valid=true for stale generations.
- The generation in the main in-memory map gets out of date while a live
migration is in flight, and if the origin location for the migration
tries to do some deletions even though it is in AttachedStale (for
example because it had already started compaction), these might be
wrongly validated + executed.
## Summary of changes
- Continue to do the in-memory check: if this returns valid=false it is
sufficient to reject requests.
- When valid=true, do an additional read from the database to confirm
the generation is fresh.
- Revise behavior for validation on missing shards: this used to always
return valid=true as a convenience for deletions and shard splits, so
that pageservers weren't prevented from completing any enqueued
deletions for these shards after they're gone. However, this becomes
unsafe when we consider split brain scenarios. We could reinstate this
in future if we wanted to store some tombstones for deleted shards.
- Update test_scrubber_physical_gc to cope with the behavioral change:
they must now explicitly flush the deletion queue before splits, to
avoid tripping up on deletions that are enqueued at the time of the
split (these tests assert "scrubber deletes nothing", which check fails
if the split leaves behind some remote objects that are legitimately
GC'able)
- Add `test_storage_controller_validate_during_migration`, which uses
failpoints to create a situation where incorrect generation validation
during a live migration could result in a corruption
The rate of validate calls for tenants is pretty low: it happens as a
consequence deletions from GC and compaction, which are both
concurrency-limited on the pageserver side.
We currently do not record safekeepers in the storage controller
database. We want to migrate timelines across safekeepers eventually, so
start recording the safekeepers on deploy.
Cc: #8698
Implement the timeline specific `archival_config` endpoint also in the
storage controller.
It's mostly a copy-paste of the detach handler: the task is the same: do
the same operation on all shards.
Part of #8088.
## Problem
We have been naughty and curl-ed storcon to fix-up drains and fills.
## Summary of changes
Add support for starting/cancelling drain/fill operations via
`storcon_cli`.
## Problem
https://github.com/neondatabase/neon/pull/8588 implemented the mechanism
for storage controller
leadership transfers. However, there's no tests that exercise the
behaviour.
## Summary of changes
1. Teach `neon_local` how to handle multiple storage controller
instances. Each storage controller
instance gets its own subdirectory (`storage_controller_1, ...`).
`storage_controller start|stop` subcommands
have also been extended to optionally accept an instance id.
2. Add a storage controller proxy test fixture. It's a basic HTTP server
that forwards requests from pageserver
and test env to the currently configured storage controller.
3. Add a test which exercises storage controller leadership transfer.
4. Finally fix a couple bugs that the test surfaced
Per #8674, disallow node configuration while drain/fill are ongoing.
Implement it by adding a only-http wrapper
`Service::external_node_configure` which checks for operation existing
before configuring.
Additionally:
- allow cancelling drain/fill after a pageserver has restarted and
transitioned to WarmingUp
Fixes: #8674
Part of #8128, followed by #8502.
## Problem
Currently we lack mechanism to alert unhealthy `scan_metadata` status if
we start running this scrubber command as part of a cronjob. With the
storage controller client introduced to storage scrubber in #8196, it is
viable to set up alert by storing health status in the storage
controller database.
We intentionally do not store the full output to the database as the
json blobs potentially makes the table really huge. Instead, only a
health status and a timestamp recording the last time metadata health
status is posted on a tenant shard.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
## Problem
We are missing the step-down primitive required to implement rolling
restarts of the storage controller.
## Summary of changes
Add `/control/v1/step_down` endpoint which puts the storage controller
into a state where it rejects
all API requests apart from `/control/v1/step_down`, `/status` and
`/metrics`. When receiving the request,
storage controller cancels all pending reconciles and waits for them to
exit gracefully. The response contains
a snapshot of the in-memory observed state.
Related:
* https://github.com/neondatabase/cloud/issues/14701
* https://github.com/neondatabase/neon/issues/7797
* https://github.com/neondatabase/neon/pull/8310
## Problem
After a shard split, the pageserver leaves the ancestor shard's content
in place. It may be referenced by child shards, but eventually child
shards will de-reference most ancestor layers as they write their own
data and do GC. We would like to eventually clean up those ancestor
layers to reclaim space.
## Summary of changes
- Extend the physical GC command with `--mode=full`, which includes
cleaning up unreferenced ancestor shard layers
- Add test `test_scrubber_physical_gc_ancestors`
- Remove colored log output: in testing this is irritating ANSI code
spam in logs, and in interactive use doesn't add much.
- Refactor storage controller API client code out of storcon_client into
a `storage_controller/client` crate
- During physical GC of ancestors, call into the storage controller to
check that the latest shards seen in S3 reflect the latest state of the
tenant, and there is no shard split in progress.
Currently storage controller does not support forwarding timeline detach
ancestor requests to pageservers. Add support for forwarding `PUT
.../:tenant_id/timelines/:timeline_id/detach_ancestor`. Implement the
support mostly as is, because the timeline detach ancestor will be made
(mostly) idempotent in future PR.
Cc: #6994
## Problem
In anticipation of later adding a really nice drain+delete API, I
initially only added an intentionally basic `/drop` API that is just
about usable for deleting nodes in a pinch, but requires some ugly
storage controller restarts to persuade it to restart secondaries.
## Summary of changes
I started making a few tiny fixes, and ended up writing the delete
API...
- Quality of life nit: ordering of node + tenant listings in storcon_cli
- Papercut: Fix the attach_hook using the wrong operation type for
reporting slow locks
- Make Service::spawn tolerate `generation_pageserver` columns that
point to nonexistent node IDs. I started out thinking of this as a
general resilience thing, but when implementing the delete API I
realized it was actually a legitimate end state after the delete API is
called (as that API doesn't wait for all reconciles to succeed).
- Add a `DELETE` API for nodes, which does not gracefully drain, but
does reschedule everything. This becomes safe to use when the system is
in any state, but will incur availability gaps for any tenants that
weren't already live-migrated away. If tenants have already been
drained, this becomes a totally clean + safe way to decom a node.
- Add a test and a storcon_cli wrapper for it
This is meant to be a robust initial API that lets us remove nodes
without doing ugly things like restarting the storage controller -- it's
not quite a totally graceful node-draining routine yet. There's more
work in https://github.com/neondatabase/neon/issues/8333 to get to our
end-end state.
## Problem
For some time, we have created tenants with calls to location_conf. The
legacy "POST /v1/tenant" path was only used in some tests.
## Summary of changes
- Remove the API
- Relocate TenantCreateRequest to the controller API file (this used to
be used in both pageserver and controller APIs)
- Rewrite tenant_create test helper to use location_config API, as
control plane and storage controller do
- Update docker-compose test script to create tenants with
location_config API (this small commit is also present in
https://github.com/neondatabase/neon/pull/7947)
## Problem
There's no way to cancel drain and fill operations.
## Summary of changes
Implement HTTP endpoints to allow cancelling of background operations.
When the operationis cancelled successfully, the node scheduling policy will revert to
`Active`.
## Problem
Pageserver restarts cause read availablity downtime for tenants. See
`Motivation` section in the
[RFC](https://github.com/neondatabase/neon/pull/7704).
## Summary of changes
* Introduce a new `NodeSchedulingPolicy`: `PauseForRestart`
* Implement the first take of drain and fill algorithms
* Add a node status endpoint which can be polled to figure out when an
operation is done
The implementation follows the RFC, so it might be useful to peek at it
as you're reviewing.
Since the PR is rather chunky, I've made sure all commits build (with
warnings), so you can
review by commit if you prefer that.
RFC: https://github.com/neondatabase/neon/pull/7704
Related https://github.com/neondatabase/neon/issues/7387
## Problem
As described in #7952, the controller's attempt to reconcile a tenant
before finally deleting it can get hung up waiting for the compute
notification hook to accept updates.
The fact that we try and reconcile a tenant at all during deletion is
part of a more general design issue (#5080), where deletion was
implemented as an operation on attached tenant, requiring the tenant to
be attached in order to delete it, which is not in principle necessary.
Closes: #7952
## Summary of changes
- In the pageserver deletion API, only do the traditional deletion path
if the tenant is attached. If it's secondary, then tear down the
secondary location, and then do a remote delete. If it's not attached at
all, just do the remote delete.
- In the storage controller, instead of ensuring a tenant is attached
before deletion, do a best-effort detach of the tenant, and then call
into some arbitrary pageserver to issue a deletion of remote content.
The pageserver retains its existing delete behavior when invoked on
attached locations. We can remove this later when all users of the API
are updated to either do a detach-before-delete. This will enable
removing the "weird" code paths during startup that sometimes load a
tenant and then immediately delete it, and removing the deletion markers
on tenants.
## Problem
We were matching on `/tenant/:tenant_id` and
`/tenant/:tenant_id/timeline*`, but not non-timeline tenant sub-paths.
There aren't many: this was only noticeable when using the
synthetic_size endpoint by hand.
## Summary of changes
- Change the wildcard from `/tenant/:tenant_id/timeline*` to
`/tenant/:tenant_id/*`
- Add test lines that exercise this
## Problem
Sometimes we have test data in the form of S3 contents that we would
like to run live in a neon_local environment.
## Summary of changes
- Add a storage controller API that imports an existing tenant.
Currently this is equivalent to doing a create with a high generation
number, but in future this would be something smarter to probe S3 to
find the shards in a tenant and find generation numbers.
- Add a `neon_local` command that invokes the import API, and then
inspects timelines in the newly attached tenant to create matching
branches.
## Problem
Some awkwardness in the measured API.
Missing process metrics.
## Summary of changes
Update measured to use the new convenience setup features.
Added measured-process lib.
Added measured support for libmetrics
The binary etc were renamed some time ago, but the path in the source
tree remained "attachment_service" to avoid disruption to ongoing PRs.
There aren't any big PRs out right now, so it's a good time to cut over.
- Rename `attachment_service` to `storage_controller`
- Move it to the top level for symmetry with `storage_broker` & to avoid
mixing the non-prod neon_local stuff (`control_plane/`) with the storage
controller which is a production component.
