* Fix xDS deadlock due to syncLoop termination.
This fixes an issue where agentless xDS streams can deadlock permanently until
a server is restarted. When this issue occurs, no new proxies are able to
successfully connect to the server.
Effectively, the trigger for this deadlock stems from the following return
statement:
https://github.com/hashicorp/consul/blob/v1.18.0/agent/proxycfg-sources/catalog/config_source.go#L199-L202
When this happens, the entire `syncLoop()` terminates and stops consuming from
the following channel:
https://github.com/hashicorp/consul/blob/v1.18.0/agent/proxycfg-sources/catalog/config_source.go#L182-L192
Which results in the `ConfigSource.cleanup()` function never receiving a
response and holding a mutex indefinitely:
https://github.com/hashicorp/consul/blob/v1.18.0/agent/proxycfg-sources/catalog/config_source.go#L241-L247
Because this mutex is shared, it effectively deadlocks the server's ability to
process new xDS streams.
----
The fix to this issue involves removing the `chan chan struct{}` used like an
RPC-over-channels pattern and replacing it with two distinct channels:
+ `stopSyncLoopCh` - indicates that the `syncLoop()` should terminate soon. +
`syncLoopDoneCh` - indicates that the `syncLoop()` has terminated.
Splitting these two concepts out and deferring a `close(syncLoopDoneCh)` in the
`syncLoop()` function ensures that the deadlock above should no longer occur.
We also now evict xDS connections of all proxies for the corresponding
`syncLoop()` whenever it encounters an irrecoverable error. This is done by
hoisting the new `syncLoopDoneCh` upwards so that it's visible to the xDS delta
processing. Prior to this fix, the behavior was to simply orphan them so they
would never receive catalog-registration or service-defaults updates.
* Add changelog.
* Adding explicit MPL license for sub-package
This directory and its subdirectories (packages) contain files licensed with the MPLv2 `LICENSE` file in this directory and are intentionally licensed separately from the BSL `LICENSE` file at the root of this repository.
* Adding explicit MPL license for sub-package
This directory and its subdirectories (packages) contain files licensed with the MPLv2 `LICENSE` file in this directory and are intentionally licensed separately from the BSL `LICENSE` file at the root of this repository.
* Updating the license from MPL to Business Source License
Going forward, this project will be licensed under the Business Source License v1.1. Please see our blog post for more details at <Blog URL>, FAQ at www.hashicorp.com/licensing-faq, and details of the license at www.hashicorp.com/bsl.
* add missing license headers
* Update copyright file headers to BUSL-1.1
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* Update copyright file headers to BUSL-1.1
* Update copyright file headers to BUSL-1.1
* Update copyright file headers to BUSL-1.1
* Update copyright file headers to BUSL-1.1
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---------
Co-authored-by: hashicorp-copywrite[bot] <110428419+hashicorp-copywrite[bot]@users.noreply.github.com>
Receiving an "acl not found" error from an RPC in the agent cache and the
streaming/event components will cause any request loops to cease under the
assumption that they will never work again if the token was destroyed. This
prevents log spam (#14144, #9738).
Unfortunately due to things like:
- authz requests going to stale servers that may not have witnessed the token
creation yet
- authz requests in a secondary datacenter happening before the tokens get
replicated to that datacenter
- authz requests from a primary TO a secondary datacenter happening before the
tokens get replicated to that datacenter
The caller will get an "acl not found" *before* the token exists, rather than
just after. The machinery added above in the linked PRs will kick in and
prevent the request loop from looping around again once the tokens actually
exist.
For `consul-dataplane` usages, where xDS is served by the Consul servers
rather than the clients ultimately this is not a problem because in that
scenario the `agent/proxycfg` machinery is on-demand and launched by a new xDS
stream needing data for a specific service in the catalog. If the watching
goroutines are terminated it ripples down and terminates the xDS stream, which
CDP will eventually re-establish and restart everything.
For Consul client usages, the `agent/proxycfg` machinery is ahead-of-time
launched at service registration time (called "local" in some of the proxycfg
machinery) so when the xDS stream comes in the data is already ready to go. If
the watching goroutines terminate it should terminate the xDS stream, but
there's no mechanism to re-spawn the watching goroutines. If the xDS stream
reconnects it will see no `ConfigSnapshot` and will not get one again until
the client agent is restarted, or the service is re-registered with something
changed in it.
This PR fixes a few things in the machinery:
- there was an inadvertent deadlock in fetching snapshot from the proxycfg
machinery by xDS, such that when the watching goroutine terminated the
snapshots would never be fetched. This caused some of the xDS machinery to
get indefinitely paused and not finish the teardown properly.
- Every 30s we now attempt to re-insert all locally registered services into
the proxycfg machinery.
- When services are re-inserted into the proxycfg machinery we special case
"dead" ones such that we unilaterally replace them rather that doing that
conditionally.
Prior to this PR, servers / agents would panic and crash if an ingress
or api gateway were configured to use a discovery chain that both:
1. Referenced a peered service
2. Had a mesh gateway mode of local
This could occur, because code for handling upstream watches was shared
between both connect-proxy and the gateways. As a short-term fix, this
PR ensures that the maps are always initialized for these gateway services.
This PR also wraps the proxycfg execution and service
registration calls with recover statements to ensure that future issues
like this do not put the server into an unrecoverable state.
Adds a user-configurable rate limiter to proxycfg snapshot delivery,
with a default limit of 250 updates per second.
This addresses a problem observed in our load testing of Consul
Dataplane where updating a "global" resource such as a wildcard
intention or the proxy-defaults config entry could starve the Raft or
Memberlist goroutines of CPU time, causing general cluster instability.
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.
This is the OSS portion of enterprise PRs 1904, 1905, 1906, 1907, 1949,
and 1971.
It replaces the proxycfg manager's direct dependency on the agent cache
with interfaces that will be implemented differently when serving xDS
sessions from a Consul server.
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).
OSS portion of enterprise PR 1857.
This removes (most) references to the `cache.UpdateEvent` type in the
`proxycfg` package.
As we're going to be direct usage of the agent cache with interfaces that
can be satisfied by alternative server-local datasources, it doesn't make
sense to depend on this type everywhere anymore (particularly on the
`state.ch` channel).
We also plan to extract `proxycfg` out of Consul into a shared library in
the future, which would require removing this dependency.
Aside from a fairly rote find-and-replace, the main change is that the
`cache.Cache` and `health.Client` types now accept a callback function
parameter, rather than a `chan<- cache.UpdateEvents`. This allows us to
do the type conversion without running another goroutine.
This commit extracts all the kind-specific logic into handler types, and
keeps the generic parts on the state struct. This change should make it
easier to add new kinds, and see the implementation of each kind more
clearly.
These two new struct types will allow us to make polymorphic handler for each kind, instad of
having all the logic for each proxy kind on the state struct.
* Implements a simple, tcp ingress gateway workflow
This adds a new type of gateway for allowing Ingress traffic into Connect from external services.
Co-authored-by: Chris Piraino <cpiraino@hashicorp.com>
This is like a Möbius strip of code due to the fact that low-level components (serf/memberlist) are connected to high-level components (the catalog and mesh-gateways) in a twisty maze of references which make it hard to dive into. With that in mind here's a high level summary of what you'll find in the patch:
There are several distinct chunks of code that are affected:
* new flags and config options for the server
* retry join WAN is slightly different
* retry join code is shared to discover primary mesh gateways from secondary datacenters
* because retry join logic runs in the *agent* and the results of that
operation for primary mesh gateways are needed in the *server* there are
some methods like `RefreshPrimaryGatewayFallbackAddresses` that must occur
at multiple layers of abstraction just to pass the data down to the right
layer.
* new cache type `FederationStateListMeshGatewaysName` for use in `proxycfg/xds` layers
* the function signature for RPC dialing picked up a new required field (the
node name of the destination)
* several new RPCs for manipulating a FederationState object:
`FederationState:{Apply,Get,List,ListMeshGateways}`
* 3 read-only internal APIs for debugging use to invoke those RPCs from curl
* raft and fsm changes to persist these FederationStates
* replication for FederationStates as they are canonically stored in the
Primary and replicated to the Secondaries.
* a special derivative of anti-entropy that runs in secondaries to snapshot
their local mesh gateway `CheckServiceNodes` and sync them into their upstream
FederationState in the primary (this works in conjunction with the
replication to distribute addresses for all mesh gateways in all DCs to all
other DCs)
* a "gateway locator" convenience object to make use of this data to choose
the addresses of gateways to use for any given RPC or gossip operation to a
remote DC. This gets data from the "retry join" logic in the agent and also
directly calls into the FSM.
* RPC (`:8300`) on the server sniffs the first byte of a new connection to
determine if it's actually doing native TLS. If so it checks the ALPN header
for protocol determination (just like how the existing system uses the
type-byte marker).
* 2 new kinds of protocols are exclusively decoded via this native TLS
mechanism: one for ferrying "packet" operations (udp-like) from the gossip
layer and one for "stream" operations (tcp-like). The packet operations
re-use sockets (using length-prefixing) to cut down on TLS re-negotiation
overhead.
* the server instances specially wrap the `memberlist.NetTransport` when running
with gateway federation enabled (in a `wanfed.Transport`). The general gist is
that if it tries to dial a node in the SAME datacenter (deduced by looking
at the suffix of the node name) there is no change. If dialing a DIFFERENT
datacenter it is wrapped up in a TLS+ALPN blob and sent through some mesh
gateways to eventually end up in a server's :8300 port.
* a new flag when launching a mesh gateway via `consul connect envoy` to
indicate that the servers are to be exposed. This sets a special service
meta when registering the gateway into the catalog.
* `proxycfg/xds` notice this metadata blob to activate additional watches for
the FederationState objects as well as the location of all of the consul
servers in that datacenter.
* `xds:` if the extra metadata is in place additional clusters are defined in a
DC to bulk sink all traffic to another DC's gateways. For the current
datacenter we listen on a wildcard name (`server.<dc>.consul`) that load
balances all servers as well as one mini-cluster per node
(`<node>.server.<dc>.consul`)
* the `consul tls cert create` command got a new flag (`-node`) to help create
an additional SAN in certs that can be used with this flavor of federation.
* Proxy Config Manager
This component watches for local state changes on the agent and ensures that each service registered locally with Kind == connect-proxy has it's state being actively populated in the cache.
This serves two purposes:
1. For the built-in proxy, it ensures that the state needed to accept connections is available in RAM shortly after registration and likely before the proxy actually starts accepting traffic.
2. For (future - next PR) xDS server and other possible future proxies that require _push_ based config discovery, this provides a mechanism to subscribe and be notified about updates to a proxy instance's config including upstream service discovery results.
* Address review comments
* Better comments; Better delivery of latest snapshot for slow watchers; Embed Config
* Comment typos
* Add upstream Stringer for funsies
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