Memory Management - BETA

Note

Using F5 BIG-IP Telemetry Streaming Memory Monitor is supported as of BIG-IP TS 1.35.

F5 BIG-IP Telemetry Streaming v1.35 and later allows you to specify memory usage limit.

Overview of the “memoryMonitor” property of Controls class

The “memoryMonitor” property of Controls class is where you define your memory usage limits.

Property	Required	Description
interval	No	Defines how often Memory Monitor should check memory usage. The acceptable values are default (the default), or aggressive (forces Memory Monitor to check memory usage more often).
logFrequency	No	Defines how often Memory Monitor should log memory usage data. The default value set to 10 seconds. The minimal value is 1.
logLevel	No	Defines the logging level Memory Monitor should use to log memory usage data. The acceptable values are verbose, debug (the default), info or error
memoryThresholdPercent	No	Defines the threshold value for memory usage. Once limit is exceeded the data processing will be temporarily ceased until the level returns below the threshold. The default value set to 90. The minimal value is 1 and the maximum 100.
osFreeMemory	No	Defines the threshold value for OS free memory. Once amount of OS free memory becomes below the threshold value then data processing will be temporarily ceased until the level returns above the threshold. The default value set to 30 MB. The minimal value is 1.
provisionedMemory	No	Defines the total amount of memory available for application. The allowed amount of memory is calculated by multiplying provisionedMemory and memoryThresholdPercent. The default is 1400 MB. The minimal value is 1 and maximum 1400.
thresholdReleasePercent	No	Defines amount of memory (in %) once memory utilization is equal or below that value the data processing will be enabled. The default value set to 90. The minimal value is 1 and the maximum 100. For more info see How to avoid processing state “flapping” behavior.

For example, your declaration could add the following snippet, which contains Memory Monitor configuration:

{
    ...
     "controls": {
         "class": "Controls",
         "memoryMonitor": {
             "interval": "aggressive",
             "logFrequency": 60,
             "logLevel": "debug",
             "memoryThresholdPercent": 80,
             "osFreeMemory": 100,
             "provisionedMemory": 500,
             "thresholdReleasePercent": 95
         }
     }
 }

memoryThresholdPercent as part of Controls and “memoryMonitor”

F5 BIG-IP Telemetry Streaming v1.35 and later allows to specify memoryThresholdPercent twice:

{
    ...
     "controls": {
         "class": "Controls",
         "memoryThresholdPercent": 80,
         "memoryMonitor": {
             "logLevel": "debug",
             "memoryThresholdPercent": 90,
             "provisionedMemory": 500
         }
     }
 }

For this particular case the property controls/memoryMonitor/memoryThresholdPercent with value 90**% has more priority than **controls/memoryThresholdPercent with value 80**% and as result the last one will be ignored. If the property **controls/memoryMonitor/memoryThresholdPercent would not be specified then controls/memoryThresholdPercent would be used. In other words - whenever controls/memoryMonitor/memoryThresholdPercent specified then controls/memoryThresholdPercent ignored despite the value.

{
    ...
     "controls": {
         "class": "Controls",
         "memoryMonitor": {
             "logLevel": "debug",
             "memoryThresholdPercent": 90,
             "provisionedMemory": 500
         }
     }
 }

Memory Monitor will be configured with memoryThresholdPercent set to **90**%.

Using the “memoryMonitor” property of Controls class

The good starting point of using memoryMonitor may looks like following:

{
    ...
     "controls": {
         "class": "Controls",
         "memoryMonitor": {
             "memoryThresholdPercent": 90
         }
     }
 }

Simply limit memory usage by applying 90% threshold.

Default behavior when the “memoryMonitor” property not configured

If the memoryMonitor property is not specified, then default values will be used. It is equal to following declaration:

{
    ...
     "controls": {
         "class": "Controls",
         "memoryMonitor": {
             "interval": "default",
             "logFrequency": 10,
             "logLevel": "debug",
             "memoryThresholdPercent": 90,
             "osFreeMemory": 30,
             "provisionedMemory": 1400,
             "thresholdReleasePercent": 90
         }
     }
 }

Default behavior when no active components configured

Let’s say your declaration look like following:

{
     "class": "Telemetry",
     "controls": {
         "class": "Controls",
         "memoryMonitor": {
             "interval": "default",
             "logFrequency": 10,
             "logLevel": "debug",
             "memoryThresholdPercent": 90,
             "osFreeMemory": 30,
             "provisionedMemory": 1400,
             "thresholdReleasePercent": 90
         }
     },
     "listener": {
         "class": "Telemetry_Listener",
         "enable": false
     }
 }

Once declaration applied F5 BIG-IP Telemetry Streaming checks if there are any active components enabled at all. For that declaration Memory Monitor will be disabled because there are no active components.

How to avoid processing state “flapping” behavior

Once limits defined by memoryThresholdPercent exceeding the data processing will be temporarily ceased until levels return below the threshold. F5 BIG-IP Telemetry Streaming allows to specify a recovery state once reached will enable data processing. thresholdReleasePercent is amount of memory (in %) once memory utilization is equal or below that value the data processing will be enabled.

Let’s say your declaration look like following:

{
     "class": "Telemetry",
     "controls": {
         "class": "Controls",
         "memoryMonitor": {
             "memoryThresholdPercent": 90,
             "provisionedMemory": 1000,
             "thresholdReleasePercent": 90
         }
     },
     "listener": {
         "class": "Telemetry_Listener",
         "enable": false
     }
 }

provisionedMemory set to 1000 MB and the threshold value is provisionedMemory * memoryThresholdPercent = 1000 MB * 90% = 900 MB. Once memory usage exceeded 900 MB the data processing will be temporarily ceased until levels return below thresholdReleasePercent. The recovery limit calculated using following formula: threshold * thresholdReleasePercent, where threshold = provisionedMemory * memoryThresholdPercent. In our example it will be 900 MB * 90% = 810 MB. Once memory usage returns below or equal to 810 MB the data processing will be enabled and back to its activity.

Note

It is not recommended to set thresholdReleasePercent to 100 because it may result in flapping behavior: processing state will switch its states rapidly without a delay.

Runtime Configuration options - BETA

The “runtime” property of Controls class is where you define your runtime configuration.

Note

Using F5 BIG-IP Telemetry Streaming runtime is supported as of BIG-IP TS 1.35 (currently experimental).

Important

RUNTIME CONFIGURATION OPTIONS SHOULD BE USED ONLY WHEN YOU ARE OBSERVING/EXPERIENCING MEMORY USAGE ISSUES

Property	Required	Description
enableGC	No	EXPERIMENTAL: Enables the built-in Garbage Collector and makes it available for F5 BIG-IP Telemetry Streaming to clean up freed memory blocks. The default is false.
maxHeapSize	No	EXPERIMENTAL: Defines the upper limit of V8’s heap size that allows F5 BIG-IP Telemetry Streaming to utilize more memory before being killed due to a Heap-Out-Of-Memory error. The default value set to 1400 MB. The minimal value is 1400 MB.

Important

Changes in the runtime’s configuration may require the restnoded service to be restarted. F5 BIG-IP Telemetry Streaming will schedule the restnoded restart when changes in configuration are made.

The good starting point of using runtime may looks like following:

{
     "class": "Telemetry",
     "controls": {
         "class": "Controls",
         "runtime": {
             "enableGC": true
         }
     }
 }

It enables the garbage collection function that F5 BIG-IP Telemetry Streaming will use to free memory.

Declaration with all runtime properties specified:

{
     "class": "Telemetry",
     "controls": {
         "class": "Controls",
         "runtime": {
             "enableGC": false,
             "maxHeapSize": 1400
         }
     }
 }