Files
neon/test_runner/regress/test_broken_timeline.py
John Spray b6ec11ad78 control_plane: generalize attachment_service to handle sharding (#6251)
## Problem

To test sharding, we need something to control it. We could write python
code for doing this from the test runner, but this wouldn't be usable
with neon_local run directly, and when we want to write tests with large
number of shards/tenants, Rust is a better fit efficiently handling all
the required state.

This service enables automated tests to easily get a system with
sharding/HA without the test itself having to set this all up by hand:
existing tests can be run against sharded tenants just by setting a
shard count when creating the tenant.

## Summary of changes

Attachment service was previously a map of TenantId->TenantState, where
the principal state stored for each tenant was the generation and the
last attached pageserver. This enabled it to serve the re-attach and
validate requests that the pageserver requires.

In this PR, the scope of the service is extended substantially to do
overall management of tenants in the pageserver, including
tenant/timeline creation, live migration, evacuation of offline
pageservers etc. This is done using synchronous code to make declarative
changes to the tenant's intended state (`TenantState.policy` and
`TenantState.intent`), which are then translated into calls into the
pageserver by the `Reconciler`.

Top level summary of modules within
`control_plane/attachment_service/src`:
- `tenant_state`: structure that represents one tenant shard.
- `service`: implements the main high level such as tenant/timeline
creation, marking a node offline, etc.
- `scheduler`: for operations that need to pick a pageserver for a
tenant, construct a scheduler and call into it.
- `compute_hook`: receive notifications when a tenant shard is attached
somewhere new. Once we have locations for all the shards in a tenant,
emit an update to postgres configuration via the neon_local `LocalEnv`.
- `http`: HTTP stubs. These mostly map to methods on `Service`, but are
separated for readability and so that it'll be easier to adapt if/when
we switch to another RPC layer.
- `node`: structure that describes a pageserver node. The most important
attribute of a node is its availability: marking a node offline causes
tenant shards to reschedule away from it.

This PR is a precursor to implementing the full sharding service for
prod (#6342). What's the difference between this and a production-ready
controller for pageservers?
- JSON file persistence to be replaced with a database
- Limited observability.
- No concurrency limits. Marking a pageserver offline will try and
migrate every tenant to a new pageserver concurrently, even if there are
thousands.
- Very simple scheduler that only knows to pick the pageserver with
fewest tenants, and place secondary locations on a different pageserver
than attached locations: it does not try to place shards for the same
tenant on different pageservers. This matters little in tests, because
picking the least-used pageserver usually results in round-robin
placement.
- Scheduler state is rebuilt exhaustively for each operation that
requires a scheduler.
- Relies on neon_local mechanisms for updating postgres: in production
this would be something that flows through the real control plane.

---------

Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
2024-01-17 18:01:08 +00:00

233 lines
9.5 KiB
Python

import concurrent.futures
import os
from typing import List, Tuple
import pytest
from fixtures.log_helper import log
from fixtures.neon_fixtures import (
Endpoint,
NeonEnv,
NeonEnvBuilder,
wait_for_last_flush_lsn,
)
from fixtures.pg_version import PgVersion
from fixtures.types import TenantId, TimelineId
# Test restarting page server, while safekeeper and compute node keep
# running.
def test_local_corruption(neon_env_builder: NeonEnvBuilder):
env = neon_env_builder.init_start()
env.pageserver.allowed_errors.extend(
[
".*get_value_reconstruct_data for layer .*",
".*could not find data for key.*",
".*is not active. Current state: Broken.*",
".*will not become active. Current state: Broken.*",
".*failed to load metadata.*",
".*load failed.*load local timeline.*",
".*layer loading failed permanently: load layer: .*",
]
)
tenant_timelines: List[Tuple[TenantId, TimelineId, Endpoint]] = []
for _ in range(3):
tenant_id, timeline_id = env.neon_cli.create_tenant()
endpoint = env.endpoints.create_start("main", tenant_id=tenant_id)
with endpoint.cursor() as cur:
cur.execute("CREATE TABLE t(key int primary key, value text)")
cur.execute("INSERT INTO t SELECT generate_series(1,100), 'payload'")
wait_for_last_flush_lsn(env, endpoint, tenant_id, timeline_id)
endpoint.stop()
tenant_timelines.append((tenant_id, timeline_id, endpoint))
# Stop the pageserver -- this has to be not immediate or we need to wait for uploads
env.pageserver.stop()
# Leave the first timeline alone, but corrupt the others in different ways
(tenant0, timeline0, pg0) = tenant_timelines[0]
log.info(f"Timeline {tenant0}/{timeline0} is left intact")
(tenant1, timeline1, pg1) = tenant_timelines[1]
metadata_path = f"{env.pageserver.workdir}/tenants/{tenant1}/timelines/{timeline1}/metadata"
with open(metadata_path, "w") as f:
f.write("overwritten with garbage!")
log.info(f"Timeline {tenant1}/{timeline1} got its metadata spoiled")
(tenant2, timeline2, pg2) = tenant_timelines[2]
timeline_path = f"{env.pageserver.workdir}/tenants/{tenant2}/timelines/{timeline2}/"
for filename in os.listdir(timeline_path):
if filename.startswith("00000"):
# Looks like a layer file. Corrupt it
p = f"{timeline_path}/{filename}"
size = os.path.getsize(p)
with open(p, "wb") as f:
f.truncate(0)
f.truncate(size)
log.info(f"Timeline {tenant2}/{timeline2} got its local layer files spoiled")
env.pageserver.start()
# Un-damaged tenant works
pg0.start()
assert pg0.safe_psql("SELECT COUNT(*) FROM t")[0][0] == 100
# Tenant with corrupt local metadata works: remote storage is authoritative for metadata
pg1.start()
assert pg1.safe_psql("SELECT COUNT(*) FROM t")[0][0] == 100
# Second timeline will fail during basebackup, because the local layer file is corrupt.
# It will fail when we try to read (and reconstruct) a page from it, ergo the error message.
# (We don't check layer file contents on startup, when loading the timeline)
#
# This will change when we implement checksums for layers
with pytest.raises(Exception, match="get_value_reconstruct_data for layer ") as err:
pg2.start()
log.info(
f"As expected, compute startup failed for timeline {tenant2}/{timeline2} with corrupt layers: {err}"
)
def test_create_multiple_timelines_parallel(neon_simple_env: NeonEnv):
env = neon_simple_env
tenant_id, _ = env.neon_cli.create_tenant()
with concurrent.futures.ThreadPoolExecutor(max_workers=4) as executor:
futures = [
executor.submit(
env.neon_cli.create_timeline, f"test-create-multiple-timelines-{i}", tenant_id
)
for i in range(4)
]
for future in futures:
future.result()
def test_timeline_init_break_before_checkpoint(neon_env_builder: NeonEnvBuilder):
env = neon_env_builder.init_start()
pageserver_http = env.pageserver.http_client()
env.pageserver.allowed_errors.extend(
[
".*Failed to process timeline dir contents.*Timeline has no ancestor and no layer files.*",
".*Timeline got dropped without initializing, cleaning its files.*",
]
)
tenant_id = env.initial_tenant
timelines_dir = env.pageserver.timeline_dir(tenant_id)
old_tenant_timelines = env.neon_cli.list_timelines(tenant_id)
initial_timeline_dirs = [d for d in timelines_dir.iterdir()]
# Introduce failpoint during timeline init (some intermediate files are on disk), before it's checkpointed.
pageserver_http.configure_failpoints(("before-checkpoint-new-timeline", "return"))
with pytest.raises(Exception, match="before-checkpoint-new-timeline"):
_ = pageserver_http.timeline_create(PgVersion.NOT_SET, tenant_id, TimelineId.generate())
# Restart the page server
env.pageserver.restart(immediate=True)
# Creating the timeline didn't finish. The other timelines on tenant should still be present and work normally.
new_tenant_timelines = env.neon_cli.list_timelines(tenant_id)
assert (
new_tenant_timelines == old_tenant_timelines
), f"Pageserver after restart should ignore non-initialized timelines for tenant {tenant_id}"
timeline_dirs = [d for d in timelines_dir.iterdir()]
assert (
timeline_dirs == initial_timeline_dirs
), "pageserver should clean its temp timeline files on timeline creation failure"
# The "exit" case is for a reproducer of issue 6007: an unclean shutdown where we can't do local fs cleanups
@pytest.mark.parametrize("exit_or_return", ["return", "exit"])
def test_timeline_init_break_before_checkpoint_recreate(
neon_env_builder: NeonEnvBuilder, exit_or_return: str
):
env = neon_env_builder.init_configs()
env.start()
pageserver_http = env.pageserver.http_client()
env.pageserver.allowed_errors.extend(
[
".*Failed to process timeline dir contents.*Timeline has no ancestor and no layer files.*",
".*Timeline got dropped without initializing, cleaning its files.*",
".*Failed to load index_part from remote storage, failed creation?.*",
]
)
env.neon_cli.create_tenant(env.initial_tenant)
tenant_id = env.initial_tenant
timelines_dir = env.pageserver.timeline_dir(tenant_id)
old_tenant_timelines = env.neon_cli.list_timelines(tenant_id)
initial_timeline_dirs = [d for d in timelines_dir.iterdir()]
# Some fixed timeline ID (like control plane does)
timeline_id = TimelineId("1080243c1f76fe3c5147266663c9860b")
# Introduce failpoint during timeline init (some intermediate files are on disk), before it's checkpointed.
failpoint = "before-checkpoint-new-timeline"
pattern = failpoint
if exit_or_return == "exit":
# in reality a read error happens, but there are automatic retries which now fail because pageserver is dead
pattern = "Connection aborted."
pageserver_http.configure_failpoints((failpoint, exit_or_return))
with pytest.raises(Exception, match=pattern):
_ = pageserver_http.timeline_create(env.pg_version, tenant_id, timeline_id)
# Restart the page server (with the failpoint disabled)
env.pageserver.restart(immediate=True)
# Creating the timeline didn't finish. The other timelines on tenant should still be present and work normally.
new_tenant_timelines = env.neon_cli.list_timelines(tenant_id)
assert (
new_tenant_timelines == old_tenant_timelines
), f"Pageserver after restart should ignore non-initialized timelines for tenant {tenant_id}"
timeline_dirs = [d for d in timelines_dir.iterdir()]
assert (
timeline_dirs == initial_timeline_dirs
), "pageserver should clean its temp timeline files on timeline creation failure"
# creating the branch should have worked now
new_timeline_id = TimelineId(
pageserver_http.timeline_create(env.pg_version, tenant_id, timeline_id)["timeline_id"]
)
assert timeline_id == new_timeline_id
def test_timeline_create_break_after_uninit_mark(neon_env_builder: NeonEnvBuilder):
env = neon_env_builder.init_start()
pageserver_http = env.pageserver.http_client()
tenant_id = env.initial_tenant
timelines_dir = env.pageserver.timeline_dir(tenant_id)
old_tenant_timelines = env.neon_cli.list_timelines(tenant_id)
initial_timeline_dirs = [d for d in timelines_dir.iterdir()]
# Introduce failpoint when creating a new timeline uninit mark, before any other files were created
pageserver_http.configure_failpoints(("after-timeline-uninit-mark-creation", "return"))
with pytest.raises(Exception, match="after-timeline-uninit-mark-creation"):
_ = pageserver_http.timeline_create(PgVersion.NOT_SET, tenant_id, TimelineId.generate())
# Creating the timeline didn't finish. The other timelines on tenant should still be present and work normally.
# "New" timeline is not present in the list, allowing pageserver to retry the same request
new_tenant_timelines = env.neon_cli.list_timelines(tenant_id)
assert (
new_tenant_timelines == old_tenant_timelines
), f"Pageserver after restart should ignore non-initialized timelines for tenant {tenant_id}"
timeline_dirs = [d for d in timelines_dir.iterdir()]
assert (
timeline_dirs == initial_timeline_dirs
), "pageserver should clean its temp timeline files on timeline creation failure"