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 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
931d167ebb2300839b218d08871f22323c60175d.
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).
Prior to this PR for the envoy xDS golden tests in the agent/xds package we
were hand-creating a proxycfg.ConfigSnapshot structure in the proper format for
input to the xDS generator. Over time this intermediate structure has gotten
trickier to build correctly for the various tests.
This PR proposes to switch to using the existing mechanism for turning a
structs.NodeService and a sequence of cache.UpdateEvent copies into a
proxycfg.ConfigSnapshot, as that is less error prone to construct and aligns
more with how the data arrives.
NOTE: almost all of this is in test-related code. I tried super hard to craft
correct event inputs to get the golden files to be the same, or similar enough
after construction to feel ok that i recreated the spirit of the original test
cases.
The gist here is that now we use a value-type struct proxycfg.UpstreamID
as the map key in ConfigSnapshot maps where we used to use "upstream
id-ish" strings. These are internal only and used just for bidirectional
trips through the agent cache keyspace (like the discovery chain target
struct).
For the few places where the upstream id needs to be projected into xDS,
that's what (proxycfg.UpstreamID).EnvoyID() is for. This lets us ALWAYS
inject the partition and namespace into these things without making
stuff like the golden testdata diverge.
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
Previously SAN validation for prepared queries was broken because we
validated against the name, namespace, and datacenter for prepared
queries.
However, prepared queries can target:
- Services with a name that isn't their own
- Services in multiple datacenters
This means that the SpiffeID to validate needs to be based on the
prepared query endpoints, and not the prepared query's upstream
definition.
This commit updates prepared query clusters to account for that.
- The TestNodeService helper created services with the fixed name "web",
and now that name is overridable.
- The discovery chain snapshot didn't have prepared query endpoints so
the endpoints tests were missing data for prepared queries
These changes ensure that the identity of services dialed is
cryptographically verified.
For all upstreams we validate against SPIFFE IDs in the format used by
Consul's service mesh:
spiffe://<trust-domain>/ns/<namespace>/dc/<datacenter>/svc/<service>
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
Dan Upton