4 Commits (32515c77f28dd1dcb0e6f010a36a523a29ea6ec3)

Author	SHA1	Message	Date
Derek Menteer	0ac8ae6c3b	Fix xDS deadlock due to syncLoop termination. (#20867) ... * 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.	8 months ago
Ashwin Venkatesh	797e42dc24	Watch the ProxyTracker from xDS controller (#18611)	1 year ago
John Murret	0e606504bc	NET-4944 - wire up controllers with proxy tracker (#18603) ... Co-authored-by: github-team-consul-core <github-team-consul-core@hashicorp.com>	1 year ago
Dan Upton	7a55de375c	xds: don't attempt to load-balance sessions for local proxies (#15789) ... Previously, we'd begin a session with the xDS concurrency limiter regardless of whether the proxy was registered in the catalog or in the server's local agent state. This caused problems for users who run `consul connect envoy` directly against a server rather than a client agent, as the server's locally registered proxies wouldn't be included in the limiter's capacity. Now, the `ConfigSource` is responsible for beginning the session and we only do so for services in the catalog. Fixes: https://github.com/hashicorp/consul/issues/15753	2 years ago