## Problem
In our experience running the system so far, almost all of the "hang
compute" situations are due to the compute (postgres) pointing at the
wrong pageservers. We currently mainly rely on the promethesus exporter
(PGExporter) running on PG to detect and report any down time, but these
can be unreliable because the read and write probes the PGExporter runs
do not always generate pageserver requests due to caching, even though
the real user might be experiencing down time when touching uncached
pages.
We are also about to start disk-wiping node pool rotation operations in
prod clusters for our pageservers, and it is critical to have a
convenient way to monitor the impact of these node pool rotations so
that we can quickly respond to any issues. These metrics should provide
very clear signals to address this operational need.
## Summary of changes
Added a pair of metrics to detect issues between postgres' PageStream
protocol (e.g. get_page_at_lsn, get_base_backup, etc.) communications
with pageservers:
* On the compute node (compute_ctl), exports a counter metric that is
incremented every time postgres requests a configuration refresh.
Postgres today only requests these configuration refreshes when it
cannot connect to a pageserver or if the pageserver rejects its request
by disconnecting.
* On the pageserver, exports a counter metric that is incremented every
time it receives a PageStream request that cannot be handled because the
tenant is not known or if the request was routed to the wrong shard
(e.g. secondary).
### How I plan to use metrics
I plan to use the metrics added here to create alerts. The alerts can
fire, for example, if these counters have been continuously increasing
for over a certain period of time. During rollouts, misrouted requests
may occasionally happen, but they should soon die down as
reconfigurations make progress. We can start with something like raising
the alert if the counters have been increasing continuously for over 5
minutes.
## How is this tested?
New integration tests in
`test_runner/regress/test_hadron_ps_connectivity_metrics.py`
Co-authored-by: William Huang <william.huang@databricks.com>
## Problem
We have been dealing with a number of issues with the SC compute
notification mechanism. Various race conditions exist in the
PG/HCC/cplane/PS distributed system, and relying on the SC to send
notifications to the compute node to notify it of PS changes is not
robust. We decided to pursue a more robust option where the compute node
itself discovers whether it may be pointing to the incorrect PSs and
proactively reconfigure itself if issues are suspected.
## Summary of changes
To support this self-healing reconfiguration mechanism several pieces
are needed. This PR adds a mechanism to `compute_ctl` called "refresh
configuration", where the compute node reaches out to the control plane
to pull a new config and reconfigure PG using the new config, instead of
listening for a notification message containing a config to arrive from
the control plane. Main changes to compute_ctl:
1. The `compute_ctl` state machine now has a new State,
`RefreshConfigurationPending`. The compute node may enter this state
upon receiving a signal that it may be using the incorrect page servers.
2. Upon entering the `RefreshConfigurationPending` state, the background
configurator thread in `compute_ctl` wakes up, pulls a new config from
the control plane, and reconfigures PG (with `pg_ctl reload`) according
to the new config.
3. The compute node may enter the new `RefreshConfigurationPending`
state from `Running` or `Failed` states. If the configurator managed to
configure the compute node successfully, it will enter the `Running`
state, otherwise, it stays in `RefreshConfigurationPending` and the
configurator thread will wait for the next notification if an incorrect
config is still suspected.
4. Added various plumbing in `compute_ctl` data structures to allow the
configurator thread to perform the config fetch.
The "incorrect config suspected" notification is delivered using a HTTP
endpoint, `/refresh_configuration`, on `compute_ctl`. This endpoint is
currently not called by anyone other than the tests. In a follow up PR I
will set up some code in the PG extension/libpagestore to call this HTTP
endpoint whenever PG suspects that it is pointing to the wrong page
servers.
## How is this tested?
Modified `test_runner/regress/test_change_pageserver.py` to add a
scenario where we use the new `/refresh_configuration` mechanism instead
of the existing `/configure` mechanism (which requires us sending a full
config to compute_ctl) to have the compute node reload and reconfigure
its pageservers.
I took one shortcut to reduce the scope of this change when it comes to
testing: the compute node uses a local config file instead of pulling a
config over the network from the HCC. This simplifies the test setup in
the following ways:
* The existing test framework is set up to use local config files for
compute nodes only, so it's convenient if I just stick with it.
* The HCC today generates a compute config with production settings
(e.g., assuming 4 CPUs, 16GB RAM, with local file caches), which is
probably not suitable in tests. We may need to add another test-only
endpoint config to the control plane to make this work.
The config-fetch part of the code is relatively straightforward (and
well-covered in both production and the KIND test) so it is probably
fine to replace it with loading from the local config file for these
integration tests.
In addition to making sure that the tests pass, I also manually
inspected the logs to make sure that the compute node is indeed
reloading the config using the new mechanism instead of going down the
old `/configure` path (it turns out the test has bugs which causes
compute `/configure` messages to be sent despite the test intending to
disable/blackhole them).
```test
2024-09-24T18:53:29.573650Z INFO http request{otel.name=/refresh_configuration http.method=POST}: serving /refresh_configuration POST request
2024-09-24T18:53:29.573689Z INFO configurator_main_loop: compute node suspects its configuration is out of date, now refreshing configuration
2024-09-24T18:53:29.573706Z INFO configurator_main_loop: reloading config.json from path: /workspaces/hadron/test_output/test_change_pageserver_using_refresh[release-pg16]/repo/endpoints/ep-1/spec.json
PG:2024-09-24 18:53:29.574 GMT [52799] LOG: received SIGHUP, reloading configuration files
PG:2024-09-24 18:53:29.575 GMT [52799] LOG: parameter "neon.extension_server_port" cannot be changed without restarting the server
PG:2024-09-24 18:53:29.575 GMT [52799] LOG: parameter "neon.pageserver_connstring" changed to "postgresql://no_user@localhost:15008"
...
```
Co-authored-by: William Huang <william.huang@databricks.com>
## Problem
There has been some inconsistencies of providing tenant config via
`tenant_create` and via other tenant config APIs due to how the
properties are processed: in `tenant_create`, the test framework calls
neon-cli and therefore puts those properties in the cmdline. In other
cases, it's done via the HTTP API by directly serializing to a JSON.
When using the cmdline, the program only accepts serde bool that is
true/false.
## Summary of changes
Convert Python bool into `true`/`false` when using neon-cli.
Signed-off-by: Alex Chi Z <chi@neon.tech>
NB: effectively a no-op in the neon env since the handling is config
gated
in storcon
## Problem
When a pageserver suffers from a local disk/node failure and restarts,
the storage controller will receive a re-attach call and return all the
tenants the pageserver is suppose to attach, but the pageserver will not
act on any tenants that it doesn't know about locally. As a result, the
pageserver will not rehydrate any tenants from remote storage if it
restarted following a local disk loss, while the storage controller
still thinks that the pageserver have all the tenants attached. This
leaves the system in a bad state, and the symptom is that PG's
pageserver connections will fail with "tenant not found" errors.
## Summary of changes
Made a slight change to the storage controller's `re_attach` API:
* The pageserver will set an additional bit `empty_local_disk` in the
reattach request, indicating whether it has started with an empty disk
or does not know about any tenants.
* Upon receiving the reattach request, if this `empty_local_disk` bit is
set, the storage controller will go ahead and clear all observed
locations referencing the pageserver. The reconciler will then discover
the discrepancy between the intended state and observed state of the
tenant and take care of the situation.
To facilitate rollouts this extra behavior in the `re_attach` API is
guarded by the `handle_ps_local_disk_loss` command line flag of the
storage controller.
---------
Co-authored-by: William Huang <william.huang@databricks.com>
- Add ComputeSpec flag `offload_lfc_interval_seconds` controlling
whether LFC should be offloaded to endpoint storage. Default value
(None) means "don't offload".
- Add glue code around it for `neon_local` and integration tests.
- Add `autoprewarm` mode for `test_lfc_prewarm` testing
`offload_lfc_interval_seconds` and `autoprewarm` flags in conjunction.
- Rename `compute_ctl_lfc_prewarm_requests_total` and
`compute_ctl_lfc_offload_requests_total` to
`compute_ctl_lfc_prewarms_total`
and `compute_ctl_lfc_offloads_total` to reflect we count prewarms and
offloads, not `compute_ctl` requests of those.
Don't count request in metrics if there is a prewarm/offload already
ongoing.
https://github.com/neondatabase/cloud/issues/19011
Resolves: https://github.com/neondatabase/cloud/issues/30770
## Problem
`test_runner` integration tests should support gRPC.
Touches #11926.
## Summary of changes
* Enable gRPC for Pageservers, with dynamic port allocations.
* Add a `grpc` parameter for endpoint creation, plumbed through to
`neon_local endpoint create`.
No tests actually use gRPC yet, since computes don't support it yet.
- Add optional `?mode=fast|immediate` to `/terminate`, `fast` is
default. Immediate avoids waiting 30
seconds before returning from `terminate`.
- Add `TerminateMode` to `ComputeStatus::TerminationPending`
- Use `/terminate?mode=immediate` in `neon_local` instead of `pg_ctl
stop` for `test_replica_promotes`.
- Change `test_replica_promotes` to check returned LSN
- Annotate `finish_sync_safekeepers` as `noreturn`.
https://github.com/neondatabase/cloud/issues/29807
## Problem
Currently the `logger` library throws annoying deprecation warnings:
```python
DeprecationWarning: The 'warn' method is deprecated, use 'warning' instead
```
## Summary of changes
This small PR resolves the annoying deprecation warnings by migrating to
`.warning` as suggested.
Signed-off-by: Emmanuel Ferdman <emmanuelferdman@gmail.com>
Corrects the postgres extension s3 gateway address to
be not just a domain name but a full base URL.
To make the code more readable, the option is renamed
to "remote_ext_base_url", while keeping the old name
also accessible by providing a clap argument alias.
Also provides a very simple and, perhaps, even redundant
unit test to confirm the logic behind parsing of the
corresponding CLI argument.
## Problem
As it is clearly stated in
https://github.com/neondatabase/cloud/issues/26005, using of the short
version of the domain name might work for now, but in the future, we
should get rid of using the `default` namespace and this is where it
will, most likely, break down.
## Summary of changes
The changes adjust the domain name of the extension s3 gateway to use
the proper base url format instead of the just domain name assuming the
"default" namespace and add a new CLI argument name for to reflect the
change and the expectance.
Currently we only have an admin scope which allows a user to bypass the
compute_id check. When the admin scope is provided, validate the
audience of the JWT to be "compute".
Closes: https://github.com/neondatabase/cloud/issues/27614
Signed-off-by: Tristan Partin <tristan@neon.tech>
Service targeted for storing and retrieving LFC prewarm data.
Can be used for proxying S3 access for Postgres extensions like
pg_mooncake as well.
Requests must include a Bearer JWT token.
Token is validated using a pemfile (should be passed in infra/).
Note: app is not tolerant to extra trailing slashes, see app.rs
`delete_prefix` test for comments.
Resolves: https://github.com/neondatabase/cloud/issues/26342
Unrelated changes: gate a `rename_noreplace` feature and disable it in
`remote_storage` so as `object_storage` can be built with musl
## Problem
`TYPE_CHECKING` is used inconsistently across Python tests.
## Summary of changes
- Update `ruff`: 0.7.0 -> 0.11.2
- Enable TC (flake8-type-checking):
https://docs.astral.sh/ruff/rules/#flake8-type-checking-tc
- (auto)fix all new issues
## Problem
Preparation for https://github.com/neondatabase/neon/issues/10851
## Summary of changes
Add walproposer `safekeepers_generations` field which can be set by
prefixing `neon.safekeepers` GUC with `g#n:`. Non zero value (n) forces
walproposer to use generations. In particular, this also disables
implicit timeline creation as timeline will be created by storcon. Add
test checking this. Also add missing infra: `--safekeepers-generation`
flag to neon_local endpoint start + fix `--start-timeout` flag: it
existed but value wasn't used.
## Problem
Previously, Workload was reconfiguring the compute before each run of
writes, which was meant to be a no-op when nothing changed, but was
actually writing extra data due to an issue being fixed in
https://github.com/neondatabase/neon/pull/10696.
The row counts in tests were too low in some cases, these tests were
only working because of those extra writes that shouldn't have been
happening, and moreover were relying on checkpoints happening.
## Summary of changes
- Only reconfigure compute if the attached pageserver actually changed.
If pageserver is set to None, that means controller is managing
everything, so never reconfigure compute.
- Update tests that wrote too few rows.
---------
Co-authored-by: Alexey Kondratov <kondratov.aleksey@gmail.com>
The compute_ctl HTTP server has the following purposes:
- Allow management via the control plane
- Provide an endpoint for scaping metrics
- Provide APIs for compute internal clients
- Neon Postgres extension for installing remote extensions
- local_proxy for installing extensions and adding grants
The first two purposes require the HTTP server to be available outside
the compute.
The Neon threat model is a bad actor within our internal network. We
need to reduce the surface area of attack. By exposing unnecessary
unauthenticated HTTP endpoints to the internal network, we increase the
surface area of attack. For endpoints described in the third bullet
point, we can just run an extra HTTP server, which is only bound to the
loopback interface since all consumers of those endpoints are within the
compute.
Drop logical replication subscribers
before compute starts on a non-main branch.
Add new compute_ctl spec flag: drop_subscriptions_before_start
If it is set, drop all the subscriptions from the compute node
before it starts.
To avoid race on compute start, use new GUC
neon.disable_logical_replication_subscribers
to temporarily disable logical replication workers until we drop the
subscriptions.
Ensure that we drop subscriptions exactly once when endpoint starts on a
new branch.
It is essential, because otherwise, we may drop not only inherited, but
newly created subscriptions.
We cannot rely only on spec.drop_subscriptions_before_start flag,
because if for some reason compute restarts inside VM,
it will start again with the same spec and flag value.
To handle this, we save the fact of the operation in the database
in the neon.drop_subscriptions_done table.
If the table does not exist, we assume that the operation was never
performed, so we must do it.
If table exists, we check if the operation was performed on the current
timeline.
fixes: https://github.com/neondatabase/neon/issues/8790
## 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
Part of https://github.com/neondatabase/neon/issues/8623
## Summary of changes
Removed all aux-v1 config processing code. Note that we persisted it
into the index part file, so we cannot really remove the field from
index part. I also kept the config item within the tenant config, but we
will not read it any more.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
In the passing, rename it to NeonLocalCli, to reflect that the binary
is called 'neon_local'.
Add wrapper for the 'timeline_import' command, eliminating the last
raw call to the raw_cli() function from tests, except for a few in
test_neon_cli.py which are about testing the 'neon_local' iteself. All
the other calls are now made through the strongly-typed wrapper
functions
