daemon: Init endpoint queue during validation

[christarazi]

See commit msgs.

Fixes: #13398

Fix bug where events cannot be enqueued during endpoint restoration

[christarazi]

test-me-please

[pchaigno]

LGTM!

[pchaigno]

These error messages also happen in v1.8 CI.

[christarazi]

CI passed and code owner approval. Pushing to resolve typo referenced above:

commit 6435f18a44a6354e1fec57dccf44a5333def349e
Author: Chris Tarazi <chris@isovalent.com>
Date:   Sun Oct 18 14:32:14 2020 -0700

    fixup! endpoint: Add function to initialize event queue
    
    Signed-off-by: Chris Tarazi <chris@isovalent.com>

diff --git a/pkg/endpoint/manager.go b/pkg/endpoint/manager.go
index c241d4300..8472f0459 100644
--- a/pkg/endpoint/manager.go
+++ b/pkg/endpoint/manager.go
@@ -172,9 +172,9 @@ func (e *Endpoint) Unexpose(mgr endpointManager) <-chan struct{} {
 
 // InitEventQueue initializes the endpoint's event queue. Note that this
 // function does not begin processing events off the queue, as that's left up
-// to the caller when should call Expose in order to allow other subsystems to
-// access the endpoint. This function assumes that the endpoint ID has already
-// been allocated!
+// to the caller to call Expose in order to allow other subsystems to access
+// the endpoint. This function assumes that the endpoint ID has already been
+// allocated!
 //
 // Having this be a separate function allows us to prepare
 // the event queue while the endpoint is being validated (during restoration)

[rolinh]

@christarazi Backporting this PR to v1.8 leads to a deadlock situation when some endpoints are being deleted on restore (thanks @aanm for digging and finding out!):

goroutine 682 [chan receive, 3 minutes]:
github.com/cilium/cilium/pkg/eventqueue.(*EventQueue).WaitToBeDrained(...)
	/go/src/github.com/cilium/cilium/pkg/eventqueue/eventqueue.go:312
github.com/cilium/cilium/pkg/endpoint.(*Endpoint).Delete(0xc000aa2c00, 0x27fab80, 0xc0007be000, 0x27fb700, 0xc000acc6c0, 0x2876de0, 0xc0000aea80, 0x430101, 0x0, 0x0, ...)
	/go/src/github.com/cilium/cilium/pkg/endpoint/endpoint.go:2194 +0x10f9
github.com/cilium/cilium/daemon/cmd.(*Daemon).deleteEndpointQuiet(...)
	/go/src/github.com/cilium/cilium/daemon/cmd/endpoint.go:674
github.com/cilium/cilium/daemon/cmd.(*Daemon).regenerateRestoredEndpoints.func2(0xc0007be000, 0xc001027f94, 0xc000aa2c00)
	/go/src/github.com/cilium/cilium/daemon/cmd/state.go:302 +0x7c
created by github.com/cilium/cilium/daemon/cmd.(*Daemon).regenerateRestoredEndpoints
	/go/src/github.com/cilium/cilium/daemon/cmd/state.go:296 +0x8a0

A 1.8 specific version of this PR seems to be required.

[christarazi]

Removing needs-backport/1.8 for now until the investigation of the potential regression is complete.