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Prevent a crash loop caused by upstream changes #237

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07bd11f
Merge pull request #238 from sunnylovestiramisu/module-update-master
k8s-ci-robot Dec 21, 2023
0ec40d8
Prevent a crash loop caused by upstream changes
ejweber Dec 19, 2023
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44 changes: 7 additions & 37 deletions cmd/livenessprobe/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,10 +23,8 @@ import (
"net"
"net/http"
"os"
"sync"
"time"

"google.golang.org/grpc"
"k8s.io/klog/v2"

"k8s.io/component-base/featuregate"
Expand Down Expand Up @@ -62,7 +60,7 @@ func (h *healthProbe) checkProbe(w http.ResponseWriter, req *http.Request) {
ctx, cancel := context.WithTimeout(req.Context(), *probeTimeout)
defer cancel()

conn, err := acquireConnection(ctx, h.metricsManager)
conn, err := connlib.Connect(*csiAddress, h.metricsManager, connlib.WithTimeout(*probeTimeout))
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(err.Error()))
Expand Down Expand Up @@ -92,37 +90,6 @@ func (h *healthProbe) checkProbe(w http.ResponseWriter, req *http.Request) {
klog.V(5).InfoS("Health check succeeded")
}

// acquireConnection wraps the connlib.Connect but adding support to context
// cancelation.
func acquireConnection(ctx context.Context, metricsManager metrics.CSIMetricsManager) (conn *grpc.ClientConn, err error) {

var m sync.Mutex
var canceled bool
ready := make(chan bool)
go func() {
conn, err = connlib.Connect(*csiAddress, metricsManager)

m.Lock()
defer m.Unlock()
if err != nil && canceled && conn != nil {
conn.Close()
}

close(ready)
}()

select {
case <-ctx.Done():
m.Lock()
defer m.Unlock()
canceled = true
return nil, ctx.Err()

case <-ready:
return conn, err
}
}

func main() {
fg := featuregate.NewFeatureGate()
logsapi.AddFeatureGates(fg)
Expand Down Expand Up @@ -151,10 +118,13 @@ func main() {
}

metricsManager := metrics.NewCSIMetricsManager("" /* driverName */)
csiConn, err := acquireConnection(context.Background(), metricsManager)
csiConn, err := connlib.Connect(*csiAddress, metricsManager, connlib.WithTimeout(5*time.Minute))
if err != nil {
// connlib should retry forever so a returned error should mean
// the grpc client is misconfigured rather than an error on the network
// It is not possible to configure connlib to never timeout while acquiring a connection.
// If we allow it to timeout too quickly, livenessprobe may enter a crash loop and it may
// become impossible for a liveness probe on the CSI plugin to ever succeed. Set a five
// minute timeout (the maximum exponential backoff time) so livenessprobe at least waits
// long enough for a crashing CSI plugin to restart.
klog.ErrorS(err, "Failed to establish connection to CSI driver")
klog.FlushAndExit(klog.ExitFlushTimeout, 1)
}
Expand Down
2 changes: 1 addition & 1 deletion go.mod
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,6 @@ require (
github.com/golang/mock v1.6.0
github.com/kubernetes-csi/csi-lib-utils v0.16.0
github.com/kubernetes-csi/csi-test/v5 v5.2.0
google.golang.org/grpc v1.60.1
k8s.io/component-base v0.29.0
k8s.io/klog/v2 v2.110.1
)
Expand Down Expand Up @@ -46,6 +45,7 @@ require (
golang.org/x/sys v0.14.0 // indirect
golang.org/x/text v0.14.0 // indirect
google.golang.org/genproto/googleapis/rpc v0.0.0-20231106174013-bbf56f31fb17 // indirect
google.golang.org/grpc v1.60.1 // indirect
google.golang.org/protobuf v1.31.0 // indirect
gopkg.in/inf.v0 v0.9.1 // indirect
gopkg.in/yaml.v2 v2.4.0 // indirect
Expand Down