## Problem
`test_storage_controller_node_deletion` sometimes failed because shards
were moving around during timeline creation, and neon_local isn't
tolerant of that. The movements were unexpected because the shards had
only just been created.
This was a regression from #9916Closes: #10383
## Summary of changes
- Make this test use multiple AZs -- this makes the storage controller's
scheduling reliably stable
Why this works: in #9916 , I made a simplifying assumption that we would
have multiple AZs to get nice stable scheduling -- it's much easier,
because each tenant has a well defined primary+secondary location when
they have an AZ preference and nodes have different AZs. Everything
still works if you don't have multiple AZs, but you just have this quirk
that sometimes the optimizer can disagree with initial scheduling, so
once in a while a shard moves after being created -- annoying for tests,
harmless IRL.
Rename the safekeeper scheduling policy "disabled" to "pause".
A rename was requested in
https://github.com/neondatabase/neon/pull/10400#discussion_r1916259124,
as the "disabled" policy is meant to be analogous to the "pause" policy
for pageservers.
Also simplify the `SkSchedulingPolicyArg::from_str` function, relying on
the `from_str` implementation of `SkSchedulingPolicy`. Latter is used
for the database format as well, so it is quite stable. If we ever want
to change the UI, we'll need to duplicate the function again but this is
cheap.
Implementing the last missing endpoint of #9981, this adds support to
set the scheduling policy of an individual safekeeper, as specified in
the RFC. However, unlike in the RFC we call the endpoint
`scheduling_policy` not `status`
Closes#9981.
As for why not use the upsert endpoint for this: we want to have the
safekeeper upsert endpoint be used for testing and for deploying new
safekeepers, but not for changes of the scheduling policy. We don't want
to change any of the other fields when marking a safekeeper as
decommissioned for example, so we'd have to first fetch them only to
then specify them again. Of course one can also design an endpoint where
one can omit any field and it doesn't get modified, but it's still not
great for observability to put everything into one big "change something
about this safekeeper" endpoint.
## Problem
For large deployments, the `control/v1/tenant` listing API can time out
transmitting a monolithic serialized response.
## Summary of changes
- Add `limit` and `start_after` parameters to listing API
- Update storcon_cli to use these parameters and limit requests to 1000
items at a time
## Problem
We want to do a more robust job of scheduling tenants into their home
AZ: https://github.com/neondatabase/neon/issues/8264.
Closes: https://github.com/neondatabase/neon/issues/8969
## Summary of changes
### Scope
This PR combines prioritizing AZ with a larger rework of how we do
optimisation. The rationale is that just bumping AZ in the order of
Score attributes is a very tiny change: the interesting part is lining
up all the optimisation logic to respect this properly, which means
rewriting it to use the same scores as the scheduler, rather than the
fragile hand-crafted logic that we had before. Separating these changes
out is possible, but would involve doing two rounds of test updates
instead of one.
### Scheduling optimisation
`TenantShard`'s `optimize_attachment` and `optimize_secondary` methods
now both use the scheduler to pick a new "favourite" location. Then
there is some refined logic for whether + how to migrate to it:
- To decide if a new location is sufficiently "better", we generate
scores using some projected ScheduleContexts that exclude the shard
under consideration, so that we avoid migrating from a node with
AffinityScore(2) to a node with AffinityScore(1), only to migrate back
later.
- Score types get a `for_optimization` method so that when we compare
scores, we will only do an optimisation if the scores differ by their
highest-ranking attributes, not just because one pageserver is lower in
utilization. Eventually we _will_ want a mode that does this, but doing
it here would make scheduling logic unstable and harder to test, and to
do this correctly one needs to know the size of the tenant that one is
migrating.
- When we find a new attached location that we would like to move to, we
will create a new secondary location there, even if we already had one
on some other node. This handles the case where we have a home AZ A, and
want to migrate the attachment between pageservers in that AZ while
retaining a secondary location in some other AZ as well.
- A unit test is added for
https://github.com/neondatabase/neon/issues/8969, which is implicitly
fixed by reworking optimisation to use the same scheduling scores as
scheduling.
## Problem
Currently, if we want to move a secondary there isn't a neat way to do
that: we just have migration API for the attached location, and it is
only clean to use that if you've manually created a secondary via
pageserver API in the place you're going to move it to.
Secondary migration API enables:
- Moving the secondary somewhere because we would like to later move the
attached location there.
- Move the secondary location because we just want to reclaim some disk
space from its current location.
## Summary of changes
- Add `/migrate_secondary` API
- Add `tenant-shard-migrate-secondary` CLI
- Add tests for above
## Problem
We would sometimes fail to retry compute notifications:
1. Try and send, set compute_notify_failure if we can't
2. On next reconcile, reconcile() fails for some other reason (e.g.
tried to talk to an offline node), and we fail the `result.is_ok() &&
must_notify` condition around the re-sending.
Closes: https://github.com/neondatabase/cloud/issues/22612
## Summary of changes
- Clarify the meaning of the reconcile result: it should be Ok(()) if
configuring attached location worked, even if secondary or detach
locations cannot be reached.
- Skip trying to talk to secondaries if they're offline
- Even if reconcile fails and we can't send the compute notification (we
can't send it because we're not sure if it's really attached), make sure
we save the `compute_notify_failure` flag so that subsequent reconciler
runs will try again
- Add a regression test for the above
## Problem
Typical deployments of neon have some tenants that stay in use
continuously, and a background churning population of tenants that are
created and then fall idle, and are configured to Detached state.
Currently, this churn of short lived tenants results in an
ever-increasing memory footprint.
Closes: https://github.com/neondatabase/neon/issues/9712
## Summary of changes
- At startup, filter to only load shards that don't have Detached policy
- In process_result, check if a tenant's shards are all Detached and
observed=={}, and if so drop them from memory
- In tenant_location_conf and other tenant mutators, load the tenants'
shards on-demand if they are not present
## Problem
The observed state removal may race with the inline updates of the
observed state done from `Service::node_activate_reconcile`.
This was intended to work as follows:
1. Detaches while the node is unavailable remove the entry from the
observed state.
2. `Service::node_activate_reconcile` diffs the locations returned
by the pageserver with the observed state and detaches in-line
when required.
## Summary of changes
This PR removes step (1) and lets background reconciliations
deal with the mismatch between the intent and observed state.
A follow up will attempt to remove `Service::node_activate_reconcile`
altogether.
Closes https://github.com/neondatabase/neon/issues/10253
Add a `safekeepers` subcommand to `storcon_cli` that allows listing the
safekeepers.
```
$ curl -X POST --url http://localhost:1234/control/v1/safekeeper/42 --data \
'{"active":true, "id":42, "created_at":"2023-10-25T09:11:25Z", "updated_at":"2024-08-28T11:32:43Z","region_id":"neon_local","host":"localhost","port":5454,"http_port":0,"version":123,"availability_zone_id":"us-east-2b"}'
$ cargo run --bin storcon_cli -- --api http://localhost:1234 safekeepers
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.38s
Running `target/debug/storcon_cli --api 'http://localhost:1234' safekeepers`
+----+---------+-----------+------+-----------+------------+
| Id | Version | Host | Port | Http Port | AZ Id |
+==========================================================+
| 42 | 123 | localhost | 5454 | 0 | us-east-2b |
+----+---------+-----------+------+-----------+------------+
```
Also:
* Don't return the raw `SafekeeperPersistence` struct that contains the
raw database presentation, but instead a new
`SafekeeperDescribeResponse` struct.
* The `SafekeeperPersistence` struct leaves out the `active` field on
purpose because we want to deprecate it and replace it with a
`scheduling_policy` one.
Part of https://github.com/neondatabase/neon/issues/9981
## Problem
It is unreliable for the control plane to infer the AZ for computes from
where the tenant is currently attached, because if a tenant happens to
be in a degraded state or a release is ongoing while a compute starts,
then the tenant's attached AZ can be a different one to where it will
run long-term, and the control plane doesn't check back later to restart
the compute.
This can land in parallel with
https://github.com/neondatabase/neon/pull/9947
## Summary of changes
- Thread through the preferred AZ into the compute hook code via the
reconciler
- Include the preferred AZ in the body of compute hook notifications
This adds an API to the storage controller to list safekeepers
registered to it.
This PR does a `diesel print-schema > storage_controller/src/schema.rs`
because of an inconsistency between up.sql and schema.rs, introduced by
[this](2c142f14f7)
commit, so there is some updates of `schema.rs` due to that. As a
followup to this, we should maybe think about running `diesel
print-schema` in CI.
Part of #9981
## Problem
We saw the drain/fill operations not drain fast enough in ap-southeast.
## Summary of changes
These are some quick changes to speed it up:
* double reconcile concurrency - this is now half of the available
reconcile bandwidth
* reduce the waiter polling timeout - this way we can spawn new
reconciliations faster
## Problem
Cplane and storage controller tenant config changes are not additive.
Any change overrides all existing tenant configs. This would be fine if
both did client side patching, but that's not the case.
Once this merges, we must update cplane to use the PATCH endpoint.
## Summary of changes
### High Level
Allow for patching of tenant configuration with a `PATCH
/v1/tenant/config` endpoint.
It takes the same data as it's PUT counterpart. For example the payload
below will update `gc_period` and unset `compaction_period`. All other
fields are left in their original state.
```
{
"tenant_id": "1234",
"gc_period": "10s",
"compaction_period": null
}
```
### Low Level
* PS and storcon gain `PATCH /v1/tenant/config` endpoints. PS endpoint
is only used for cplane managed instances.
* `storcon_cli` is updated to have separate commands for
`set-tenant-config` and `patch-tenant-config`
Related https://github.com/neondatabase/cloud/issues/21043
## Problem
We saw a tenant get stuck when it had been put into Pause scheduling
mode to pin it to a pageserver, then it was left idle for a while and
the control plane tried to detach it.
Close: https://github.com/neondatabase/neon/issues/9957
## Summary of changes
- When changing policy to Detached or Secondary, set the scheduling
policy to Active.
- Add a test that exercises this
- When persisting tenant shards, set their `generation_pageserver` to
null if the placement policy is not Attached (this enables consistency
checks to work, and avoids leaving state in the DB that could be
confusing/misleading in future)
## Problem
Sharded tenants should be run in a single AZ for best performance, so
that computes have AZ-local latency to all the shards.
Part of https://github.com/neondatabase/neon/issues/8264
## Summary of changes
- When we split a tenant, instead of updating each shard's preferred AZ
to wherever it is scheduled, propagate the preferred AZ from the parent.
- Drop the check in `test_shard_preferred_azs` that asserts shards end
up in their preferred AZ: this will not be true again until the
optimize_attachment logic is updated to make this so. The existing check
wasn't testing anything about scheduling, it was just asserting that we
set preferred AZ in a way that matches the way things happen to be
scheduled at time of split.
Before this PR, the storcon_cli didn't have a way to show the
tenant-wide information of the TenantDescribeResponse.
Sadly, the `Serialize` impl for the tenant config doesn't skip on
`None`, so, the output becomes a bit bloated.
Maybe we can use `skip_serializing_if(Option::is_none)` in the future.
=> https://github.com/neondatabase/neon/issues/9983
## Problem
I was touching `test_storage_controller_node_deletion` because for AZ
scheduling work I was adding a change to the storage controller (kick
secondaries during optimisation) that made a FIXME in this test defunct.
While looking at it I also realized that we can easily fix the way node
deletion currently doesn't use a proper ScheduleContext, using the
iterator type recently added for that purpose.
## Summary of changes
- A testing-only behavior in storage controller where if a secondary
location isn't yet ready during optimisation, it will be actively
polled.
- Remove workaround in `test_storage_controller_node_deletion` that
previously was needed because optimisation would get stuck on cold
secondaries.
- Update node deletion code to use a `TenantShardContextIterator` and
thereby a proper ScheduleContext
Improves `wait_until` by:
* Use `timeout` instead of `iterations`. This allows changing the
timeout/interval parameters independently.
* Make `timeout` and `interval` optional (default 20s and 0.5s). Most
callers don't care.
* Only output status every 1s by default, and add optional
`status_interval` parameter.
* Remove `show_intermediate_error`, this was always emitted anyway.
Most callers have been updated to use the defaults, except where they
had good reason otherwise.
## Problem
We use a pretty old version of `mypy` 1.3 (released 1.5 years ago), it
produces false positives for `typing.Self`.
## Summary of changes
- Bump `mypy` from 1.3 to 1.13
- Fix new warnings and errors
- Use `typing.Self` whenever we `return self`
## Problem
On Debian 12 (Bookworm), Python 3.11 is the latest available version.
## Summary of changes
- Update Python to 3.11 in build-tools
- Fix ruff check / format
- Fix mypy
- Use `StrEnum` instead of pair `str`, `Enum`
- Update docs
## Problem
Running `pytest.skip(...)` in a test body instead of marking the test
with `@pytest.mark.skipif(...)` makes all fixtures to be initialised,
which is not necessary if the test is going to be skipped anyway.
Also, some tests are unnecessarily skipped (e.g. `test_layer_bloating`
on Postgres 17, or `test_idle_reconnections` at all) or run (e.g.
`test_parse_project_git_version_output_positive` more than on once
configuration) according to comments.
## Summary of changes
- Move `skip_on_postgres` / `xfail_on_postgres` /
`run_only_on_default_postgres` decorators to `fixture.utils`
- Add new `skip_in_debug_build` and `skip_on_ci` decorators
- Replace `pytest.skip(...)` calls with decorators where possible
## Problem
We haven't historically taken this API route where we would onboard a
tenant to the controller in detached state. It worked, but we didn't
have test coverage.
## Summary of changes
- Add a test that onboards a tenant to the storage controller in
Detached mode, and checks that deleting it without attaching it works as
expected.
## Problem
If something goes wrong with a live migration, we currently only have
awkward ways to interrupt that:
- Restart the storage controller
- Ask it to do some other modification/migration on the shard, which we
don't really want.
## Summary of changes
- Add a new `/cancel` control API, and storcon_cli wrapper for it, which
fires the Reconciler's cancellation token. This is just for on-call use
and we do not expect it to be used by any other services.
## Problem
Previously, figuring out how many tenant shards were managed by a
storage controller was typically done by peeking at the database or
calling into the API. A metric makes it easier to monitor, as
unexpectedly increasing shard counts can be indicative of problems
elsewhere in the system.
## Summary of changes
- Add metrics `storage_controller_pageserver_nodes` (updated on node
CRUD operations from Service) and `storage_controller_tenant_shards`
(updated RAII-style from TenantShard)
## Problem
If we migrate A->B, then B->A, and the notification of A->B fails, then
we might have retained state that makes us think "A" is the last state
we sent to the compute hook, whereas when we migrate B->A we should
really be sending a fresh notification in case our earlier failed
notification has actually mutated the remote compute config.
Closes: #9417
## Summary of changes
- Add a reproducer for the bug
(`test_storage_controller_compute_hook_revert`)
- Refactor compute hook code to represent remote state with
`ComputeRemoteState` which stores a boolean for whether the compute has
fully applied the change as well as the request that the compute
accepted.
- The actual bug fix: after sending a compute notification, if we got a
423 response then update our ComputeRemoteState to reflect that we have
mutated the remote state. This way, when we later try and notify for our
historic location, we will properly see that as a change and send the
notification.
Co-authored-by: Vlad Lazar <vlad@neon.tech>
## Problem
We faced the problem of incompatibility of the different components of
different versions.
This should be detected automatically to prevent production bugs.
## Summary of changes
The test for this situation was implemented
Co-authored-by: Alexander Bayandin <alexander@neon.tech>
## Problem
Creation of a timelines during a reconciliation can lead to
unavailability if the user attempts to
start a compute before the storage controller has notified cplane of the
cut-over.
## Summary of changes
Create timelines on all currently attached locations. For the latest
location, we still look
at the database (this is a previously). With this change we also look
into the observed state
to find *other* attached locations.
Related https://github.com/neondatabase/neon/issues/9144
Add wrappers for a few commands that didn't have them before. Move the
logic to generate tenant and timeline IDs from NeonCli to the callers,
so that NeonCli is more purely just a type-safe wrapper around
'neon_local'.
## Problem
We don't have an alert for long running reconciles. Stuck reconciles are
problematic
as we've seen in a recent incident.
## Summary of changes
Add a new metric `storage_controller_reconcile_long_running_total` with
labels: `{tenant_id, shard_number, seq}`.
The metric is removed after the long running reconcile finishes. These
events should be rare, so we won't break
the bank on cardinality.
Related https://github.com/neondatabase/neon/issues/9150
## Problem
If a timeline was deleted right before waiting for LSNs to catch up
before the cut-over,
then we would wait forever.
## Summary of changes
Fix the issue and add a test for timeline deletions mid migration.
Related https://github.com/neondatabase/neon/issues/9144
## Problem
The live migration code waits forever for the compute notification hook,
on the basis that until it succeeds, the compute is probably using the
old location and we shouldn't detach it.
However, if a pageserver stops or restarts in the background, then this
original location might no longer be available, so there is no point
waiting. Waiting is also actively harmful, because it prevents other
reconciliations happening for the tenant shard, such as during an
upgrade where a stuck "drain" migration might prevent the later "fill"
migration from moving the shard back to its original location.
## Summary of changes
- Refactor the notification wait loop into a function
- Add a checks during the loop, for the origin node's cancellation token
and an explicit HTTP request to the origin node to confirm the shard is
still attached there.
Closes: https://github.com/neondatabase/neon/issues/8901
## Problem
These commits are split off from
https://github.com/neondatabase/neon/pull/8971/commits where I was
fixing this to make a better scale test pass -- Vlad also independently
recognized these issues with cloudbench in
https://github.com/neondatabase/neon/issues/9062.
1. The storage controller proxies GET requests to pageservers based on
their intent, not the ground truth of where they're really attached.
2. Proxied requests can race with scheduling to tenants, resulting in
404 responses if the request hits the wrong pageserver.
Closes: https://github.com/neondatabase/neon/issues/9062
## Summary of changes
1. If a shard has a running reconciler, then use the database
generation_pageserver to decide who to proxy the request to
2. If such a request gets a 404 response and its scheduled node has
changed since the request was dispatched.
Part of #7497, closes https://github.com/neondatabase/neon/issues/8890.
## Problem
Since leases are in-memory objects, we need to take special care of them
after pageserver restarts and while doing a live migration. The approach
we took for pageserver restart is to wait for at least lease duration
before doing first GC. We want to do the same for live migration. Since
we do not do any GC when a tenant is in `AttachedStale` or
`AttachedMulti` mode, only the transition from `AttachedMulti` to
`AttachedSingle` requires this treatment.
## Summary of changes
- Added `lsn_lease_deadline` field in `GcBlock::reasons`: the tenant is
temporarily blocked from GC until we reach the deadline. This
information does not persist to S3.
- In `GCBlock::start`, skip the GC iteration if we are blocked by the
lsn lease deadline.
- In `TenantManager::upsert_location`, set the lsn_lease_deadline to
`Instant::now() + lsn_lease_length` so the granted leases have a chance
to be renewed before we run GC for the first time after transitioned
from AttachedMulti to AttachedSingle.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
There's currently no way to just start/stop broker from `neon_local`.
This PR
* adds a sub-command
* uses that sub-command from the test suite instead of the pre-existing
Python `subprocess` based approach.
Found this useful during investigation
https://github.com/neondatabase/cloud/issues/16886.
## Problem
It turns out that we can't rely on external orchestration to promptly
route trafic to the new leader. This is downtime inducing.
Forwarding provides a safe way out.
## Safety
We forward when:
1. Request is not one of ["/control/v1/step_down", "/status", "/ready",
"/metrics"]
2. Current instance is in [`LeadershipStatus::SteppedDown`] state
3. There is a leader in the database to forward to
4. Leader from step (3) is not the current instance
If a storcon instance is persisted in the database, then we know that it
is the current leader.
There's one exception: time between handling step-down request and the
new leader updating the
database.
Let's treat the happy case first. The stepped down node does not produce
any side effects,
since all request handling happens on the leader.
As for the edge case, we are guaranteed to always have a maximum of two
running instances.
Hence, if we are in the edge case scenario the leader persisted in the
database is the
stepped down instance that received the request. Condition (4) above
covers this scenario.
## Summary of changes
* Conversion utilities for reqwest <-> hyper. I'm not happy with these,
but I don't see a better way. Open to suggestions.
* Add request forwarding logic
* Update each request handler. Again, not happy with this. If anyone
knows a nice to wrap the handlers, lmk. Me and Joonas tried :/
* Update each handler to maybe forward
* Tweak tests to showcase new behaviour
For control-plane managed tenants, we have the page in the admin console
that lists all tenants on a specific pageserver. But for
storage-controller managed ones, we don't have that functionality for
now.
## Summary of changes
Adds an API that lists all shards on a given node (intention + observed)
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
We want to do AZ aware scheduling, but don't have enough metadata.
## Summary of changes
Introduce a `preferred_az_id` concept for each managed tenant shard.
In a future PR, the scheduler will use this as a soft preference.
The idea is to try and keep the shard attachments within the same AZ.
Under the assumption that the compute was placed in the correct AZ,
this reduces the chances of cross AZ trafic from between compute and PS.
In terms of code changes we:
1. Add a new nullable `preferred_az_id` column to the `tenant_shards`
table. Also include an in-memory counterpart.
2. Populate the preferred az on tenant creation and shard splits.
3. Add an endpoint which allows to bulk-set preferred AZs.
(3) gives us the migration path. I'll write a script which queries the
cplane db in the region and sets the preferred az of all shards with an
active compute to the AZ of said compute. For shards without an active compute,
I'll use the AZ of the currently attached pageserver
since this is what cplane uses now to schedule computes.
## 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
## Problem
- If a reconciler was waiting to be able to notify computes about a
change, but the control plane was waiting for the controller to finish a
timeline creation/deletion, the overall system can deadlock.
- If a tenant shard was migrated concurrently with a timeline
creation/deletion, there was a risk that the timeline operation could be
applied to a non-latest-generation location, and thereby not really be
persistent. This has never happened in practice, but would eventually
happen at scale.
Closes: #8743
## Summary of changes
- Introduce `Service::tenant_remote_mutation` helper, which looks up
shards & generations and passes them into an inner function that may do
remote I/O to pageservers. Before returning success, this helper checks
that generations haven't incremented, to guarantee that changes are
persistent.
- Convert tenant_timeline_create, tenant_timeline_delete, and
tenant_timeline_detach_ancestor to use this helper.
- These functions no longer block on ensure_attached unless the tenant
was never attached at all, so they should make progress even if we can't
complete compute notifications.
This increases the database load from timeline/create operations, but
only with cheap read transactions.
