Files
neon/control_plane/attachment_service/src/http.rs
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

219 lines
7.3 KiB
Rust

use crate::reconciler::ReconcileError;
use crate::service::Service;
use hyper::{Body, Request, Response};
use hyper::{StatusCode, Uri};
use pageserver_api::models::{TenantCreateRequest, TimelineCreateRequest};
use pageserver_api::shard::TenantShardId;
use std::sync::Arc;
use utils::auth::SwappableJwtAuth;
use utils::http::endpoint::{auth_middleware, request_span};
use utils::http::request::parse_request_param;
use utils::id::TenantId;
use utils::{
http::{
endpoint::{self},
error::ApiError,
json::{json_request, json_response},
RequestExt, RouterBuilder,
},
id::NodeId,
};
use pageserver_api::control_api::{ReAttachRequest, ValidateRequest};
use control_plane::attachment_service::{
AttachHookRequest, InspectRequest, NodeConfigureRequest, NodeRegisterRequest,
TenantShardMigrateRequest,
};
/// State available to HTTP request handlers
#[derive(Clone)]
pub struct HttpState {
service: Arc<crate::service::Service>,
auth: Option<Arc<SwappableJwtAuth>>,
allowlist_routes: Vec<Uri>,
}
impl HttpState {
pub fn new(service: Arc<crate::service::Service>, auth: Option<Arc<SwappableJwtAuth>>) -> Self {
let allowlist_routes = ["/status"]
.iter()
.map(|v| v.parse().unwrap())
.collect::<Vec<_>>();
Self {
service,
auth,
allowlist_routes,
}
}
}
#[inline(always)]
fn get_state(request: &Request<Body>) -> &HttpState {
request
.data::<Arc<HttpState>>()
.expect("unknown state type")
.as_ref()
}
/// Pageserver calls into this on startup, to learn which tenants it should attach
async fn handle_re_attach(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let reattach_req = json_request::<ReAttachRequest>(&mut req).await?;
let state = get_state(&req);
json_response(
StatusCode::OK,
state
.service
.re_attach(reattach_req)
.await
.map_err(ApiError::InternalServerError)?,
)
}
/// Pageserver calls into this before doing deletions, to confirm that it still
/// holds the latest generation for the tenants with deletions enqueued
async fn handle_validate(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let validate_req = json_request::<ValidateRequest>(&mut req).await?;
let state = get_state(&req);
json_response(StatusCode::OK, state.service.validate(validate_req))
}
/// Call into this before attaching a tenant to a pageserver, to acquire a generation number
/// (in the real control plane this is unnecessary, because the same program is managing
/// generation numbers and doing attachments).
async fn handle_attach_hook(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let attach_req = json_request::<AttachHookRequest>(&mut req).await?;
let state = get_state(&req);
json_response(
StatusCode::OK,
state
.service
.attach_hook(attach_req)
.await
.map_err(ApiError::InternalServerError)?,
)
}
async fn handle_inspect(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let inspect_req = json_request::<InspectRequest>(&mut req).await?;
let state = get_state(&req);
json_response(StatusCode::OK, state.service.inspect(inspect_req))
}
async fn handle_tenant_create(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let create_req = json_request::<TenantCreateRequest>(&mut req).await?;
let state = get_state(&req);
json_response(
StatusCode::OK,
state.service.tenant_create(create_req).await?,
)
}
async fn handle_tenant_timeline_create(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let tenant_id: TenantId = parse_request_param(&req, "tenant_id")?;
let create_req = json_request::<TimelineCreateRequest>(&mut req).await?;
let state = get_state(&req);
json_response(
StatusCode::OK,
state
.service
.tenant_timeline_create(tenant_id, create_req)
.await?,
)
}
async fn handle_tenant_locate(req: Request<Body>) -> Result<Response<Body>, ApiError> {
let tenant_id: TenantId = parse_request_param(&req, "tenant_id")?;
let state = get_state(&req);
json_response(StatusCode::OK, state.service.tenant_locate(tenant_id)?)
}
async fn handle_node_register(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let register_req = json_request::<NodeRegisterRequest>(&mut req).await?;
let state = get_state(&req);
state.service.node_register(register_req).await?;
json_response(StatusCode::OK, ())
}
async fn handle_node_configure(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let node_id: NodeId = parse_request_param(&req, "node_id")?;
let config_req = json_request::<NodeConfigureRequest>(&mut req).await?;
if node_id != config_req.node_id {
return Err(ApiError::BadRequest(anyhow::anyhow!(
"Path and body node_id differ"
)));
}
let state = get_state(&req);
json_response(StatusCode::OK, state.service.node_configure(config_req)?)
}
async fn handle_tenant_shard_migrate(mut req: Request<Body>) -> Result<Response<Body>, ApiError> {
let tenant_shard_id: TenantShardId = parse_request_param(&req, "tenant_shard_id")?;
let migrate_req = json_request::<TenantShardMigrateRequest>(&mut req).await?;
let state = get_state(&req);
json_response(
StatusCode::OK,
state
.service
.tenant_shard_migrate(tenant_shard_id, migrate_req)
.await?,
)
}
/// Status endpoint is just used for checking that our HTTP listener is up
async fn handle_status(_req: Request<Body>) -> Result<Response<Body>, ApiError> {
json_response(StatusCode::OK, ())
}
impl From<ReconcileError> for ApiError {
fn from(value: ReconcileError) -> Self {
ApiError::Conflict(format!("Reconciliation error: {}", value))
}
}
pub fn make_router(
service: Arc<Service>,
auth: Option<Arc<SwappableJwtAuth>>,
) -> RouterBuilder<hyper::Body, ApiError> {
let mut router = endpoint::make_router();
if auth.is_some() {
router = router.middleware(auth_middleware(|request| {
let state = get_state(request);
if state.allowlist_routes.contains(request.uri()) {
None
} else {
state.auth.as_deref()
}
}))
}
router
.data(Arc::new(HttpState::new(service, auth)))
.get("/status", |r| request_span(r, handle_status))
.post("/re-attach", |r| request_span(r, handle_re_attach))
.post("/validate", |r| request_span(r, handle_validate))
.post("/attach-hook", |r| request_span(r, handle_attach_hook))
.post("/inspect", |r| request_span(r, handle_inspect))
.post("/node", |r| request_span(r, handle_node_register))
.put("/node/:node_id/config", |r| {
request_span(r, handle_node_configure)
})
.post("/tenant", |r| request_span(r, handle_tenant_create))
.post("/tenant/:tenant_id/timeline", |r| {
request_span(r, handle_tenant_timeline_create)
})
.get("/tenant/:tenant_id/locate", |r| {
request_span(r, handle_tenant_locate)
})
.put("/tenant/:tenant_shard_id/migrate", |r| {
request_span(r, handle_tenant_shard_migrate)
})
}