You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

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.		9 months ago
..
internal	Add `consul snapshot decode` command (#20824)	9 months ago
proxy-snapshot	Run copyright after running deep-copy as part of the Makefile/CI (#18741)	1 year ago
proxy-tracker	Fix xDS deadlock due to syncLoop termination. (#20867)	9 months ago
exports.go	mesh: sidecar proxy controller improvements (#19083)	1 year ago