Prior to #13244, connect proxies and gateways could only be configured by an
xDS session served by the local client agent.
In an upcoming release, it will be possible to deploy a Consul service mesh
without client agents. In this model, xDS sessions will be handled by the
servers themselves, which necessitates load-balancing to prevent a single
server from receiving a disproportionate amount of load and becoming
overwhelmed.
This introduces a simple form of load-balancing where Consul will attempt to
achieve an even spread of load (xDS sessions) between all healthy servers.
It does so by implementing a concurrent session limiter (limiter.SessionLimiter)
and adjusting the limit according to autopilot state and proxy service
registrations in the catalog.
If a server is already over capacity (i.e. the session limit is lowered),
Consul will begin draining sessions to rebalance the load. This will result
in the client receiving a `RESOURCE_EXHAUSTED` status code. It is the client's
responsibility to observe this response and reconnect to a different server.
Users of the gRPC client connection brokered by the
consul-server-connection-manager library will get this for free.
The rate at which Consul will drain sessions to rebalance load is scaled
dynamically based on the number of proxies in the catalog.
This is the OSS portion of enterprise PR 2339.
It improves our handling of "irrecoverable" errors in proxycfg data sources.
The canonical example of this is what happens when the ACL token presented by
Envoy is deleted/revoked. Previously, the stream would get "stuck" until the
xDS server re-checked the token (after 5 minutes) and terminated the stream.
Materializers would also sit burning resources retrying something that could
never succeed.
Now, it is possible for data sources to mark errors as "terminal" which causes
the xDS stream to be closed immediately. Similarly, the submatview.Store will
evict materializers when it observes they have encountered such an error.
Previously, public referred to gRPC services that are both exposed on
the dedicated gRPC port and have their definitions in the proto-public
directory (so were considered usable by 3rd parties). Whereas private
referred to services on the multiplexed server port that are only usable
by agents and other servers.
Now, we're splitting these definitions, such that external/internal
refers to the port and public/private refers to whether they can be used
by 3rd parties.
This is necessary because the peering replication API needs to be
exposed on the dedicated port, but is not (yet) suitable for use by 3rd
parties.
This is the OSS portion of enterprise PR 1994
Rather than directly interrogating the agent-local state for HTTP
checks using the `HTTPCheckFetcher` interface, we now rely on the
config snapshot containing the checks.
This reduces the number of changes required to support server xDS
sessions.
It's not clear why the fetching approach was introduced in
931d167ebb.
OSS port of enterprise PR 1822
Includes the necessary changes to the `proxycfg` and `xds` packages to enable
Consul servers to configure arbitrary proxies using catalog data.
Broadly, `proxycfg.Manager` now has public methods for registering,
deregistering, and listing registered proxies — the existing local agent
state-sync behavior has been moved into a separate component that makes use of
these methods.
When an xDS session is started for a proxy service in the catalog, a goroutine
will be spawned to watch the service in the server's state store and
re-register it with the `proxycfg.Manager` whenever it is updated (and clean
it up when the client goes away).
Fixes#11876
This enforces that multiple xDS mutations are not issued on the same ADS connection at once, so that we can 100% control the order that they are applied. The original code made assumptions about the way multiple in-flight mutations were applied on the Envoy side that was incorrect.
When a wildcard xDS type (LDS/CDS/SRDS) reconnects from a delta xDS stream,
prior to envoy `1.19.0` it would populate the `ResourceNamesSubscribe` field
with the full list of currently subscribed items, instead of simply omitting it
to infer that it wanted everything (which is what wildcard mode means).
This upstream issue was filed in envoyproxy/envoy#16063 and fixed in
envoyproxy/envoy#16153 which went out in Envoy `1.19.0` and is fixed in later
versions (later refactored in envoyproxy/envoy#16855).
This PR conditionally forces LDS/CDS to be wildcard-only even when the
connected Envoy requests a non-wildcard subscription, but only does so on
versions prior to `1.19.0`, as we should not need to do this on later versions.
This fixes the failure case as described here: #11833 (comment)
Co-authored-by: Huan Wang <fredwanghuan@gmail.com>
Fixes#10563
The `resourceVersion` map was doing two jobs prior to this PR. The first job was
to track what version of every resource we know envoy currently has. The
second was to track subscriptions to those resources (by way of the empty
string for a version). This mostly works out fine, but occasionally leads to
consul removing a resource and accidentally (effectively) unsubscribing at the
same time.
The fix separates these two jobs. When all of the resources for a subscription
are removed we continue to track the subscription until envoy explicitly
unsubscribes
Updates to a cluster will clear the associated endpoints, and updates to
a listener will clear the associated routes. Update the incremental xDS
logic to account for this implicit cleanup so that we can finish warming
the clusters and listeners.
Fixes#10379
This adds support for the Incremental xDS protocol when using xDS v3. This is best reviewed commit-by-commit and will not be squashed when merged.
Union of all commit messages follows to give an overarching summary:
xds: exclusively support incremental xDS when using xDS v3
Attempts to use SoTW via v3 will fail, much like attempts to use incremental via v2 will fail.
Work around a strange older envoy behavior involving empty CDS responses over incremental xDS.
xds: various cleanups and refactors that don't strictly concern the addition of incremental xDS support
Dissolve the connectionInfo struct in favor of per-connection ResourceGenerators instead.
Do a better job of ensuring the xds code uses a well configured logger that accurately describes the connected client.
xds: pull out checkStreamACLs method in advance of a later commit
xds: rewrite SoTW xDS protocol tests to use protobufs rather than hand-rolled json strings
In the test we very lightly reuse some of the more boring protobuf construction helper code that is also technically under test. The important thing of the protocol tests is testing the protocol. The actual inputs and outputs are largely already handled by the xds golden output tests now so these protocol tests don't have to do double-duty.
This also updates the SoTW protocol test to exclusively use xDS v2 which is the only variant of SoTW that will be supported in Consul 1.10.
xds: default xds.Server.AuthCheckFrequency at use-time instead of construction-time
Freddy