Switched memory usage reporting to use CGroup metrics by default for Linux consumption (#11114)

* Removed feature flag driven metric reporting code.
* Add release notes.

Author: kshyju

release_notes.md

@@ -17,3 +17,4 @@
 - Improvements to coldstart pipeline (#11102).
 - Update Python Worker Version to [4.38.0](https://github.com/Azure/azure-functions-python-worker/releases/tag/4.38.0)
 - Only start the Diagnostic Events flush logs timer when events are present, preventing unnecessary flush attempts (#11100).
+- Switched memory usage reporting to use CGroup metrics by default for Linux consumption (#11114)

src/WebJobs.Script.WebHost/Metrics/LinuxContainerLegionMetricsPublisher.cs

@@ -24,7 +24,6 @@ public sealed class LinuxContainerLegionMetricsPublisher : IMetricsPublisher, ID
         private readonly TimeSpan _timerStartDelay = TimeSpan.FromSeconds(2);
         private readonly IOptionsMonitor<StandbyOptions> _standbyOptions;
         private readonly IDisposable _standbyOptionsOnChangeListener;
-        private readonly IDisposable _hostingConfigOptionsOnChangeListener;
         private readonly IEnvironment _environment;
         private readonly ILogger _logger;
         private readonly IServiceProvider _serviceProvider;
@@ -37,7 +36,6 @@ public sealed class LinuxContainerLegionMetricsPublisher : IMetricsPublisher, ID
         private Timer _processMonitorTimer;
         private Timer _metricsPublisherTimer;
         private bool _initialized = false;
-        private bool _isCGroupMemoryMetricsEnabled = false;
 
         public LinuxContainerLegionMetricsPublisher(IEnvironment environment, IOptionsMonitor<StandbyOptions> standbyOptions,
             IOptions<LinuxConsumptionLegionMetricsPublisherOptions> options, ILogger<LinuxContainerLegionMetricsPublisher> logger,
@@ -72,21 +70,10 @@ public LinuxContainerLegionMetricsPublisher(IEnvironment environment, IOptionsMo
             {
                 Start();
             }
-
-            _hostingConfigOptionsOnChangeListener = _hostingConfigOptions.OnChange(OnHostingConfigOptionsChanged);
         }
 
         private IMetricsLogger MetricsLogger => _metricsLogger ??= _serviceProvider.GetRequiredService<IMetricsLogger>();
 
-        private void OnHostingConfigOptionsChanged(FunctionsHostingConfigOptions newOptions)
-        {
-            if (newOptions.IsCGroupMemoryMetricsEnabled != _isCGroupMemoryMetricsEnabled)
-            {
-                _logger.LogInformation("CGroup memory metrics enabled: {Enabled}", newOptions.IsCGroupMemoryMetricsEnabled);
-                _isCGroupMemoryMetricsEnabled = newOptions.IsCGroupMemoryMetricsEnabled;
-            }
-        }
-
         public void Initialize()
         {
             _process = Process.GetCurrentProcess();
@@ -189,16 +176,7 @@ private void OnProcessMonitorTimer(object state)
         {
             try
             {
-                long memoryUsageInBytes;
-                if (_hostingConfigOptions.CurrentValue.IsCGroupMemoryMetricsEnabled)
-                {
-                    memoryUsageInBytes = CgroupMemoryUsageHelper.GetMemoryUsageInBytes(_logger);
-                }
-                else
-                {
-                    _process.Refresh();
-                    memoryUsageInBytes = _process.WorkingSet64;
-                }
+                long memoryUsageInBytes = CgroupMemoryUsageHelper.GetMemoryUsageInBytes(_logger);
 
                 if (memoryUsageInBytes != 0)
                 {
@@ -258,7 +236,6 @@ public void Dispose()
 
             _metricsTracker.OnDiagnosticEvent -= OnMetricsDiagnosticEvent;
             _standbyOptionsOnChangeListener?.Dispose();
-            _hostingConfigOptionsOnChangeListener?.Dispose();
         }
 
         internal class Metrics

src/WebJobs.Script.WebHost/Metrics/LinuxContainerMetricsPublisher.cs

@@ -38,7 +38,6 @@ public sealed class LinuxContainerMetricsPublisher : IMetricsPublisher, IDisposa
         private readonly TimeSpan _timerStartDelay = TimeSpan.FromSeconds(2);
         private readonly IOptionsMonitor<StandbyOptions> _standbyOptions;
         private readonly IDisposable _standbyOptionsOnChangeListener;
-        private readonly IDisposable _hostingConfigOptionsOnChangeListener;
         private readonly string _requestUri;
         private readonly IEnvironment _environment;
         private readonly IOptionsMonitor<FunctionsHostingConfigOptions> _hostingConfigOptions;
@@ -66,7 +65,6 @@ public sealed class LinuxContainerMetricsPublisher : IMetricsPublisher, IDisposa
         private int _errorCount = 0;
         private string _stampName;
         private bool _initialized = false;
-        private bool _isCGroupMemoryMetricsEnabled = false;
 
         public LinuxContainerMetricsPublisher(IEnvironment environment, IOptionsMonitor<StandbyOptions> standbyOptions, ILogger<LinuxContainerMetricsPublisher> logger, HostNameProvider hostNameProvider, IOptionsMonitor<FunctionsHostingConfigOptions> functionsHostingConfigOptions, HttpClient httpClient = null)
         {
@@ -95,17 +93,6 @@ public LinuxContainerMetricsPublisher(IEnvironment environment, IOptionsMonitor<
             {
                 Start();
             }
-
-            _hostingConfigOptionsOnChangeListener = _hostingConfigOptions.OnChange(OnHostingConfigOptionsChanged);
-        }
-
-        private void OnHostingConfigOptionsChanged(FunctionsHostingConfigOptions newOptions)
-        {
-            if (newOptions.IsCGroupMemoryMetricsEnabled != _isCGroupMemoryMetricsEnabled)
-            {
-                _logger.LogInformation("CGroup memory metrics enabled: {Enabled}", newOptions.IsCGroupMemoryMetricsEnabled);
-                _isCGroupMemoryMetricsEnabled = newOptions.IsCGroupMemoryMetricsEnabled;
-            }
         }
 
         private void OnStandbyOptionsChange()
@@ -278,16 +265,7 @@ private void OnProcessMonitorTimer(object state)
         {
             try
             {
-                long memoryUsageInBytes;
-                if (_hostingConfigOptions.CurrentValue.IsCGroupMemoryMetricsEnabled)
-                {
-                    memoryUsageInBytes = CgroupMemoryUsageHelper.GetMemoryUsageInBytes(_logger);
-                }
-                else
-                {
-                    _process.Refresh();
-                    memoryUsageInBytes = _process.WorkingSet64;
-                }
+                long memoryUsageInBytes = CgroupMemoryUsageHelper.GetMemoryUsageInBytes(_logger);
 
                 if (memoryUsageInBytes != 0)
                 {
@@ -339,7 +317,6 @@ public void OnFunctionCompleted(string functionName, string invocationId)
         public void Dispose()
         {
             _standbyOptionsOnChangeListener?.Dispose();
-            _hostingConfigOptionsOnChangeListener?.Dispose();
             _processMonitorTimer?.Dispose();
             _metricsPublisherTimer?.Dispose();
             _httpClient?.Dispose();

src/WebJobs.Script/Config/FunctionsHostingConfigOptions.cs

@@ -78,22 +78,6 @@ internal bool SwtIssuerEnabled
             }
         }
 
-        /// <summary>
-        /// Gets or sets a value indicating whether to use cgroup memory metrics for reporting memory usage.
-        /// </summary>
-        internal bool IsCGroupMemoryMetricsEnabled
-        {
-            get
-            {
-                return GetFeatureAsBooleanOrDefault(ScriptConstants.FeatureFlagEnableCGroupMemoryMetrics, false);
-            }
-
-            set
-            {
-                _features[ScriptConstants.FeatureFlagEnableCGroupMemoryMetrics] = value ? "1" : "0";
-            }
-        }
-
         /// <summary>
         /// Gets or sets a string delimited by '|' that contains a list of admin APIs that are allowed to
         /// be invoked internally by platform components.

src/WebJobs.Script/ScriptConstants.cs

@@ -142,7 +142,6 @@ public static class ScriptConstants
         public const string FeatureFlagDisableOrderedInvocationMessages = "DisableOrderedInvocationMessages";
         public const string FeatureFlagEnableAzureMonitorTimeIsoFormat = "EnableAzureMonitorTimeIsoFormat";
         public const string FeatureFlagEnableTestDataSuppression = "EnableTestDataSuppression";
-        public const string FeatureFlagEnableCGroupMemoryMetrics = "EnableCGroupMemoryMetrics";
         public const string HostingConfigDisableLinuxAppServiceDetailedExecutionEvents = "DisableLinuxExecutionDetails";
         public const string HostingConfigDisableLinuxAppServiceExecutionEventLogBackoff = "DisableLinuxLogBackoff";
         public const string FeatureFlagEnableLegacyDurableVersionCheck = "EnableLegacyDurableVersionCheck";

test/WebJobs.Script.Tests/Configuration/FunctionsHostingConfigOptionsTest.cs

@@ -76,7 +76,6 @@ public static IEnumerable<object[]> PropertyValues
                 yield return [nameof(FunctionsHostingConfigOptions.IsDotNetInProcDisabled), "DotNetInProcDisabled=0", false];
 
                 yield return [nameof(FunctionsHostingConfigOptions.IsTestDataSuppressionEnabled), "EnableTestDataSuppression=1", true];
-                yield return [nameof(FunctionsHostingConfigOptions.IsCGroupMemoryMetricsEnabled), "EnableCGroupMemoryMetrics=1", true];
 
 #pragma warning restore SA1011 // Closing square brackets should be spaced correctly
 #pragma warning restore SA1010 // Opening square brackets should be spaced correctly