azure: set default of cloudstorage.azure.try.timeout to 0

This setting was previously set to 1m to deflake the TestAzureFaultInjection
unit test, but unfortunately this also led to production backup flakes in the
azure backup roachtest. Instead of reenabling this setting, we should to teach
the resuming reader to time out hanging reads (reference issue #159098)

Epic: none

Release note: none

Author: msbutler

pkg/cloud/azure/azure_storage.go

@@ -55,7 +55,7 @@ var tryTimeout = settings.RegisterDurationSetting(
 	settings.ApplicationLevel,
 	"cloudstorage.azure.try.timeout",
 	"the timeout for individual retry attempts in Azure operations",
-	60*time.Second)
+	0)
 
 var reuseSession = settings.RegisterBoolSetting(
 	settings.ApplicationLevel,

pkg/cloud/azure/azure_storage_test.go

@@ -176,6 +176,9 @@ func TestAzureFaultInjection(t *testing.T) {
 	conf, err := cloud.ExternalStorageConfFromURI(uri, username.RootUserName())
 	require.NoError(t, err)
 
+	settings := cluster.MakeTestingClusterSettings()
+	tryTimeout.Override(context.Background(), &settings.SV, time.Minute)
+
 	args := cloud.EarlyBootExternalStorageContext{
 		IOConf:          base.ExternalIODirConfig{},
 		Settings:        cluster.MakeTestingClusterSettings(),

pkg/cmd/roachtest/tests/backup_fixtures.go

@@ -181,7 +181,6 @@ func (bd *backupDriver) prepareCluster(ctx context.Context) {
 				"kv.snapshot_rebalance.max_rate":                    "256 MiB",
 				"server.debug.default_vmodule":                      "s3_storage=2",
 				"cloudstorage.s3.client_retry_token_bucket.enabled": "false",
-				"cloudstorage.azure.try.timeout":                    "0s",
 			},
 		))
 }