Transparent proxies typically cannot dial upstreams in remote
datacenters. However, if their upstream configures a redirect to a
remote DC then the upstream targets will be in another datacenter.
In that sort of case we should use the WAN address for the passthrough.
Due to timing, a transparent proxy could have two upstreams to dial
directly with the same address.
For example:
- The orders service can dial upstreams shipping and payment directly.
- An instance of shipping at address 10.0.0.1 is deregistered.
- Payments is scaled up and scheduled to have address 10.0.0.1.
- The orders service receives the event for the new payments instance
before seeing the deregistration for the shipping instance. At this
point two upstreams have the same passthrough address and Envoy will
reject the listener configuration.
To disambiguate this commit considers the Raft index when storing
passthrough addresses. In the example above, 10.0.0.1 would only be
associated with the newer payments service instance.
Transparent proxies can set up filter chains that allow direct
connections to upstream service instances. Services that can be dialed
directly are stored in the PassthroughUpstreams map of the proxycfg
snapshot.
Previously these addresses were not being cleaned up based on new
service health data. The list of addresses associated with an upstream
service would only ever grow.
As services scale up and down, eventually they will have instances
assigned to an IP that was previously assigned to a different service.
When IP addresses are duplicated across filter chain match rules the
listener config will be rejected by Envoy.
This commit updates the proxycfg snapshot management so that passthrough
addresses can get cleaned up when no longer associated with a given
upstream.
There is still the possibility of a race condition here where due to
timing an address is shared between multiple passthrough upstreams.
That concern is mitigated by #12195, but will be further addressed
in a follow-up.
set -euo pipefail
unset CDPATH
cd "$(dirname "$0")"
for f in $(git grep '\brequire := require\.New(' | cut -d':' -f1 | sort -u); do
echo "=== require: $f ==="
sed -i '/require := require.New(t)/d' $f
# require.XXX(blah) but not require.XXX(tblah) or require.XXX(rblah)
sed -i 's/\brequire\.\([a-zA-Z0-9_]*\)(\([^tr]\)/require.\1(t,\2/g' $f
# require.XXX(tblah) but not require.XXX(t, blah)
sed -i 's/\brequire\.\([a-zA-Z0-9_]*\)(\(t[^,]\)/require.\1(t,\2/g' $f
# require.XXX(rblah) but not require.XXX(r, blah)
sed -i 's/\brequire\.\([a-zA-Z0-9_]*\)(\(r[^,]\)/require.\1(t,\2/g' $f
gofmt -s -w $f
done
for f in $(git grep '\bassert := assert\.New(' | cut -d':' -f1 | sort -u); do
echo "=== assert: $f ==="
sed -i '/assert := assert.New(t)/d' $f
# assert.XXX(blah) but not assert.XXX(tblah) or assert.XXX(rblah)
sed -i 's/\bassert\.\([a-zA-Z0-9_]*\)(\([^tr]\)/assert.\1(t,\2/g' $f
# assert.XXX(tblah) but not assert.XXX(t, blah)
sed -i 's/\bassert\.\([a-zA-Z0-9_]*\)(\(t[^,]\)/assert.\1(t,\2/g' $f
# assert.XXX(rblah) but not assert.XXX(r, blah)
sed -i 's/\bassert\.\([a-zA-Z0-9_]*\)(\(r[^,]\)/assert.\1(t,\2/g' $f
gofmt -s -w $f
done
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.
The duo of `makeUpstreamFilterChainForDiscoveryChain` and `makeListenerForDiscoveryChain` were really hard to reason about, and led to concealing a bug in their branching logic. There were several issues here:
- They tried to accomplish too much: determining filter name, cluster name, and whether RDS should be used.
- They embedded logic to handle significantly different kinds of upstream listeners (passthrough, prepared query, typical services, and catch-all)
- They needed to coalesce different data sources (Upstream and CompiledDiscoveryChain)
Rather than handling all of those tasks inside of these functions, this PR pulls out the RDS/clusterName/filterName logic.
This refactor also fixed a bug with the handling of [UpstreamDefaults](https://www.consul.io/docs/connect/config-entries/service-defaults#defaults). These defaults get stored as UpstreamConfig in the proxy snapshot with a DestinationName of "*", since they apply to all upstreams. However, this wildcard destination name must not be used when creating the name of the associated upstream cluster. The coalescing logic in the original functions here was in some situations creating clusters with a `*.` prefix, which is not a valid destination.
Fixes an issue described in #10132, where if two DCs are WAN federated
over mesh gateways, and the gateway in the non-primary DC is terminated
and receives a new IP address (as is commonly the case when running them
on ephemeral compute instances) the primary DC is unable to re-establish
its connection until the agent running on its own gateway is restarted.
This was happening because we always preferred gateways discovered by
the `Internal.ServiceDump` RPC (which would fail because there's no way
to dial the remote DC) over those discovered in the federation state,
which is replicated as long as the primary DC's gateway is reachable.
This will behave the way we handle SNI and SPIFFE IDs, where the default
partition is excluded.
Excluding the default ensures that don't attempt to compare default.dc2
to dc2 in OSS.
This commit updates mesh gateway watches for cross-partitions
communication.
* Mesh gateways are keyed by partition and datacenter.
* Mesh gateways will now watch gateways in partitions that export
services to their partition.
* Mesh gateways in non-default partitions will not have cross-datacenter
watches. They are not involved in traditional WAN federation.
Previously the datacenter of the gateway was the key identifier, now it
is the datacenter and partition.
When dialing services in other partitions or datacenters we now watch
the appropriate partition.
These methods only called a single function. Wrappers like this end up making code harder to read
because it adds extra ways of doing things.
We already have many helper functions for constructing these types, we don't need additional methods.
