* Use `ctx` rather than `context.TODO()` where available
* Further propagation of context
* Use `context.Background()` instead of `context.TODO()` where appropriate in tests
* Further remove `context.TODO` from tests
* Appease linter on parameter order
This commit fixes memory leak in the cache module:
* Cache calls in to create a NewWatcher
* NewWatcher gets registered in the backend
* Cache closes the watcher
* Watcher never gets deleted from the backend
fanout internal structure.
This is a defect in the way watchers are implemented:
closing a watcher should result from it's removal
from the fanout internal circular buffer prefix tree.
Buffer fan out used simple prefix match
in a loop, what resulted in high CPU load
on many connected watchers.
This commit switches to RADIX trees for
prefix matching what reduces CPU load
substantially for 5K+ connected watchers.
* Add resest for buffers to close watchers
and reset buffer the state.
* Add reconnect logic to DynamoDB
* Add tests for cache watchers, make sure
the errors of the cache internal watcher propagate to
external watchers.
This commit expands the usage of the caching layer
for auth server API:
* Introduces in-memory cache that is used to serve all
Auth server API requests. This is done to achieve scalability
on 10K+ node clusters, where each node fetches certificate authorities,
roles, users and join tokens. It is not possible to scale
DynamoDB backend or other backends on 10K reads per seconds
on a single shard or partition. The solution is to introduce
an in-memory cache of the backend state that is always used
for reads.
* In-memory cache has been expanded to support all resources
required by the auth server.
* Experimental `tctl top` command has been introduced to display
common single node metrics.
Replace SQLite Memory Backend with BTree
SQLite in memory backend was suffering from
high tail latencies under load (up to 8 seconds
in 99.9%-ile on load configurations).
This commit replaces the SQLite memory caching
backend with in-memory BTree backend that
brought down tail latencies to 2 seconds (99.9%-ile)
and brought overall performance improvement.
This commit introduces several key changes to
Teleport backend and API infrastructure
in order to achieve scalability improvements
on 10K+ node deployments.
Events and plain keyspace
--------------------------
New backend interface supports events,
pagination and range queries
and moves away from buckets to
plain keyspace, what better aligns
with DynamoDB and Etcd featuring similar
interfaces.
All backend implementations are
exposing Events API, allowing
multiple subscribers to consume the same
event stream and avoid polling database.
Replacing BoltDB, Dir with SQLite
-------------------------------
BoltDB backend does not support
having two processes access the database at the
same time. This prevented Teleport
using BoltDB backend to be live reloaded.
SQLite supports reads/writes by multiple
processes and makes Dir backend obsolete
as SQLite is more efficient on larger collections,
supports transactions and can detect data
corruption.
Teleport automatically migrates data from
Bolt and Dir backends into SQLite.
GRPC API and protobuf resources
-------------------------------
GRPC API has been introduced for
the auth server. The auth server now serves both GRPC
and JSON-HTTP API on the same TLS socket and uses
the same client certificate authentication.
All future API methods should use GRPC and HTTP-JSON
API is considered obsolete.
In addition to that some resources like
Server and CertificateAuthority are now
generated from protobuf service specifications in
a way that is fully backward compatible with
original JSON spec and schema, so the same resource
can be encoded and decoded from JSON, YAML
and protobuf.
All models should be refactored
into new proto specification over time.
Streaming presence service
--------------------------
In order to cut bandwidth, nodes
are sending full updates only when changes
to labels or spec have occured, otherwise
new light-weight GRPC keep alive updates are sent
over to the presence service, reducing
bandwidth usage on multi-node deployments.
In addition to that nodes are no longer polling
auth server for certificate authority rotation
updates, instead they subscribe to event updates
to detect updates as soon as they happen.
This is a new API, so the errors are inevitable,
that's why polling is still done, but
on a way slower rate.
Noah Stride