Fixes#4582
When a target cluster gateway is exposed as a hostname rather than with a fixed IP address, the service mirror controller fails to create mirror services and gateway mirrors for that gateway. This is because we only look at the IP field of the gateway service.
We make two changes to address this problem:
First, when extracting the gateway spec from a gateway that has a hostname instead of an IP address, we do a DNS lookup to resolve that hostname into an IP address to use in the mirror service endpoints and gateway mirror endpoints.
Second, we schedule a repair job on a regular (1 minute) to update these endpoint objects. This has the effect of re-resolving the DNS names every minute to pick up any changes in DNS resolution.
Signed-off-by: Alex Leong <alex@buoyant.io>
This change modifies the linkerd-gateway component to use the inbound
proxy, rather than nginx, for gateway. This allows us to detect loops and
propagate identity through the gateway.
This change also cleans up port naming to `mc-gateway` and `mc-probe`
to resolve conflicts with Kubernetes validation.
---
* proxy: v2.99.0
The proxy can now operate as gateway, routing requests from its inbound
proxy to the outbound proxy, without passing the requests to a local
application. This supports Linkerd's multicluster feature by adding a
`Forwarded` header to propagate the original client identity and assist
in loop detection.
---
* Add loop detection to inbound & TCP forwarding (linkerd/linkerd2-proxy#527)
* Test loop detection (linkerd/linkerd2-proxy#532)
* fallback: Unwrap errors recursively (linkerd/linkerd2-proxy#534)
* app: Split inbound/outbound constructors into components (linkerd/linkerd2-proxy#533)
* Introduce a gateway between inbound and outbound (linkerd/linkerd2-proxy#540)
* gateway: Add a Forwarded header (linkerd/linkerd2-proxy#544)
* gateway: Return errors instead of responses (linkerd/linkerd2-proxy#547)
* Fail requests that loop through the gateway (linkerd/linkerd2-proxy#545)
* inject: Support config.linkerd.io/enable-gateway
This change introduces a new annotation,
config.linkerd.io/enable-gateway, that, when set, enables the proxy to
act as a gateway, routing all traffic targetting the inbound listener
through the outbound proxy.
This also removes the nginx default listener and gateway port of 4180,
instead using 4143 (the inbound port).
* proxy: v2.100.0
This change modifies the inbound gateway caching so that requests may be
routed to multiple leaves of a traffic split.
---
* inbound: Do not cache gateway services (linkerd/linkerd2-proxy#549)
There are a few notable things happening in this PR:
- the probe manager has been decoupled from the cluster_watcher. Now its only responsibility is to watch for mirrored gateways beeing created and to probe them. This means that probes are initiated for all gateways no matter whether there are mirrored services being paired
- the number of paired services is derived from the existing services in the cluster rather than being published as a metric by the prober
- there are no events being exchanged between the cluster watcher and the probe manager
Signed-off-by: Zahari Dichev <zaharidichev@gmail.com>
Unit tests that exercise most of the code in cluster_watcher.go. Essentially the whole cluster mirroring machinary can be tought of as a function that takes remote cluster state, local cluster state, and modification events and as a result it either modifies local cluster state or issues new events onto the queue. This is what these tests are trying to model. I think this covers a lot of the logic there. Any suggestions for other edge cases are welcome.
Signed-off-by: Zahari Dichev <zaharidichev@gmail.com>
Alex Leong
Oliver Gould
Zahari Dichev