Files
neon/control_plane/Cargo.toml
John Spray 61d661a6c3 pageserver: generation number fetch on startup and use in /attach (#5163)
## Problem

- #5050 

Closes: https://github.com/neondatabase/neon/issues/5136

## Summary of changes

- A new configuration property `control_plane_api` controls other
functionality in this PR: if it is unset (default) then everything still
works as it does today.
- If `control_plane_api` is set, then on startup we call out to control
plane `/re-attach` endpoint to discover our attachments and their
generations. If an attachment is missing from the response we implicitly
detach the tenant.
- Calls to pageserver `/attach` API may include a `generation`
parameter. If `control_plane_api` is set, then this parameter is
mandatory.
- RemoteTimelineClient's loading of index_part.json is generation-aware,
and will try to load the index_part with the most recent generation <=
its own generation.
- The `neon_local` testing environment now includes a new binary
`attachment_service` which implements the endpoints that the pageserver
requires to operate. This is on by default if running `cargo neon` by
hand. In `test_runner/` tests, it is off by default: existing tests
continue to run with in the legacy generation-less mode.

Caveats:
- The re-attachment during startup assumes that we are only re-attaching
tenants that have previously been attached, and not totally new tenants
-- this relies on the control plane's attachment logic to keep retrying
so that we should eventually see the attach API call. That's important
because the `/re-attach` API doesn't tell us which timelines we should
attach -- we still use local disk state for that. Ref:
https://github.com/neondatabase/neon/issues/5173
- Testing: generations are only enabled for one integration test right
now (test_pageserver_restart), as a smoke test that all the machinery
basically works. Writing fuller tests that stress tenant migration will
come later, and involve extending our test fixtures to deal with
multiple pageservers.
- I'm not in love with "attachment_service" as a name for the neon_local
component, but it's not very important because we can easily rename
these test bits whenever we want.
- Limited observability when in re-attach on startup: when I add
generation validation for deletions in a later PR, I want to wrap up the
control plane API calls in some small client class that will expose
metrics for things like errors calling the control plane API, which will
act as a strong red signal that something is not right.

Co-authored-by: Christian Schwarz <christian@neon.tech>
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
2023-09-06 14:44:48 +01:00

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TOML

[package]
name = "control_plane"
version = "0.1.0"
edition.workspace = true
license.workspace = true
[dependencies]
anyhow.workspace = true
clap.workspace = true
comfy-table.workspace = true
git-version.workspace = true
nix.workspace = true
once_cell.workspace = true
postgres.workspace = true
hex.workspace = true
hyper.workspace = true
regex.workspace = true
reqwest = { workspace = true, features = ["blocking", "json"] }
serde.workspace = true
serde_json.workspace = true
serde_with.workspace = true
tar.workspace = true
thiserror.workspace = true
toml.workspace = true
tokio.workspace = true
url.workspace = true
# Note: Do not directly depend on pageserver or safekeeper; use pageserver_api or safekeeper_api
# instead, so that recompile times are better.
pageserver_api.workspace = true
postgres_backend.workspace = true
safekeeper_api.workspace = true
postgres_connection.workspace = true
storage_broker.workspace = true
utils.workspace = true
compute_api.workspace = true
workspace_hack.workspace = true
tracing.workspace = true