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    Collect OpenTelemetry Netflow Receiver logs

    Supported in:

    This document explains how to ingest OpenTelemetry Netflow Receiver logs to Google Security Operations using Google Cloud Storage V2.

    The OpenTelemetry Netflow Receiver is an open-source component that listens for netflow, sflow, and IPFIX UDP traffic and converts it to OpenTelemetry log records. This enables network traffic monitoring and analysis, including protocol identification, traffic volume analysis, port usage tracking, and byte/packet statistics.

    Before you begin

    Make sure that you have the following prerequisites:

    • A Google SecOps instance
    • A GCP project with Cloud Storage API enabled
    • Permissions to create and manage GCS buckets
    • Permissions to manage IAM policies on GCS buckets
    • Permissions to create Cloud Run services, Pub/Sub topics, and Cloud Scheduler jobs
    • Network devices capable of sending netflow, sflow, or IPFIX data
    • Access to configure network device export settings

    Create Google Cloud Storage bucket

    1. Go to the Google Cloud Console .
    2. Select your project or create a new one.
    3. In the navigation menu, go to Cloud Storage > Buckets.
    4. Click Create bucket.

    5. Provide the following configuration details:

      Setting Value
      Name your bucket Enter a globally unique name (for example, netflow-logs-bucket )
      Location type Choose based on your needs (Region, Dual-region, Multi-region)
      Location Select the location (for example, us-central1 )
      Storage class Standard (recommended for frequently accessed logs)
      Access control Uniform (recommended)
      Protection tools Optional: Enable object versioning or retention policy

    6. Click Create.

    The Cloud Run function needs a service account with permissions to write to GCS bucket and be invoked by Pub/Sub.

    1. In the GCP Console, go to IAM & Admin > Service Accounts.
    2. Click Create Service Account.
    3. Provide the following configuration details:
      • Service account name: Enter netflow-collector-sa
      • Service account description: Enter Service account for Cloud Run function to collect netflow logs
    4. Click Create and Continue.
    5. In the Grant this service account access to projectsection, add the following roles:
      1. Click Select a role.
      2. Search for and select Storage Object Admin.
      3. Click + Add another role.
      4. Search for and select Cloud Run Invoker.
      5. Click + Add another role.
      6. Search for and select Cloud Functions Invoker.
    6. Click Continue.
    7. Click Done.

    These roles are required for:

    • Storage Object Admin: Write logs to GCS bucket and manage state files
    • Cloud Run Invoker: Allow Pub/Sub to invoke the function
    • Cloud Functions Invoker: Allow function invocation

    Grant IAM permissions on GCS bucket

    Grant the service account write permissions on the GCS bucket:

    1. Go to Cloud Storage > Buckets.
    2. Click on your bucket name (for example, netflow-logs-bucket ).
    3. Go to the Permissionstab.
    4. Click Grant access.
    5. Provide the following configuration details:
      • Add principals: Enter the service account email (for example, netflow-collector-sa@PROJECT_ID.iam.gserviceaccount.com )
      • Assign roles: Select Storage Object Admin
    6. Click Save.

    Create Pub/Sub topic

    Create a Pub/Sub topic that Cloud Scheduler will publish to and the Cloud Run function will subscribe to.

    1. In the GCP Console, go to Pub/Sub > Topics.
    2. Click Create topic.
    3. Provide the following configuration details:
      • Topic ID: Enter netflow-trigger
      • Leave other settings as default
    4. Click Create.

    Create Cloud Run function to collect netflow logs

    The Cloud Run function will run an OpenTelemetry Collector that receives netflow data and exports it to GCS.

    1. In the GCP Console, go to Cloud Run.
    2. Click Create service.
    3. Select Function(use an inline editor to create a function).

    4. In the Configuresection, provide the following configuration details:

      Setting Value
      Service name netflow-collector
      Region Select region matching your GCS bucket (for example, us-central1 )
      Runtime Select Python 3.12or later

    5. In the Trigger (optional)section:

      1. Click + Add trigger.
      2. Select Cloud Pub/Sub.
      3. In Select a Cloud Pub/Sub topic, choose the Pub/Sub topic netflow-trigger .
      4. Click Save.

    6. In the Authenticationsection:

      1. Select Require authentication.
      2. Check Identity and Access Management (IAM).

    7. Scroll down and expand Containers, Networking, Security.

    8. Go to the Securitytab:

      • Service account: Select the service account netflow-collector-sa

    9. Go to the Containerstab:

      1. Click Variables & Secrets.
      2. Click + Add variablefor each environment variable:
      Variable Name Example Value Description
      GCS_BUCKET
      		netflow-logs-bucket GCS bucket name
      GCS_PREFIX
      		netflow Prefix for log files
      NETFLOW_PORT
      		2055 Port for netflow receiver
      NETFLOW_SCHEME
      		netflow Scheme type: netflow, sflow, or ipfix
      NETFLOW_SOCKETS
      		4 Number of UDP sockets
      NETFLOW_WORKERS
      		8 Number of decoder workers

    10. In the Variables & Secretssection, scroll down to Requests:

      • Request timeout: Enter 600 seconds (10 minutes)

    11. Go to the Settingstab:

      • In the Resourcessection:
        • Memory: Select 1 GiBor higher
        • CPU: Select 2

    12. In the Revision scalingsection:

      • Minimum number of instances: Enter 1
      • Maximum number of instances: Enter 10

    13. Click Create.

    14. Wait for the service to be created (1-2 minutes).

    15. After the service is created, the inline code editorwill open automatically.

    Add function code

    1. Enter mainin the Entry pointfield.

    2. In the inline code editor, create three files:

      • main.py:
        import 
  
 functions_framework 
 from 
  
 google.cloud 
  
 import 
  storage 
 
 import 
  
 json 
 import 
  
 os 
 import 
  
 subprocess 
 import 
  
 tempfile 
 import 
  
 signal 
 import 
  
 time 
 from 
  
 datetime 
  
 import 
 datetime 
 , 
 timezone 
 # Initialize Storage client 
 storage_client 
 = 
  storage 
 
 . 
  Client 
 
 () 
 # Environment variables 
 GCS_BUCKET 
 = 
 os 
 . 
 environ 
 . 
 get 
 ( 
 'GCS_BUCKET' 
 ) 
 GCS_PREFIX 
 = 
 os 
 . 
 environ 
 . 
 get 
 ( 
 'GCS_PREFIX' 
 , 
 'netflow' 
 ) 
 NETFLOW_PORT 
 = 
 os 
 . 
 environ 
 . 
 get 
 ( 
 'NETFLOW_PORT' 
 , 
 '2055' 
 ) 
 NETFLOW_SCHEME 
 = 
 os 
 . 
 environ 
 . 
 get 
 ( 
 'NETFLOW_SCHEME' 
 , 
 'netflow' 
 ) 
 NETFLOW_SOCKETS 
 = 
 os 
 . 
 environ 
 . 
 get 
 ( 
 'NETFLOW_SOCKETS' 
 , 
 '4' 
 ) 
 NETFLOW_WORKERS 
 = 
 os 
 . 
 environ 
 . 
 get 
 ( 
 'NETFLOW_WORKERS' 
 , 
 '8' 
 ) 
 # Global process handle 
 collector_process 
 = 
 None 
 def 
  
 create_collector_config 
 (): 
  
 """Create OpenTelemetry Collector configuration.""" 
 timestamp 
 = 
 datetime 
 . 
 now 
 ( 
 timezone 
 . 
 utc 
 ) 
 . 
 strftime 
 ( 
 '%Y%m 
 %d 
 _%H%M%S' 
 ) 
 file_path 
 = 
 f 
 "/tmp/netflow_ 
 { 
 timestamp 
 } 
 .ndjson" 
 config 
 = 
 { 
 'receivers' 
 : 
 { 
 'netflow' 
 : 
 { 
 'scheme' 
 : 
 NETFLOW_SCHEME 
 , 
 'hostname' 
 : 
 '0.0.0.0' 
 , 
 'port' 
 : 
 int 
 ( 
 NETFLOW_PORT 
 ), 
 'sockets' 
 : 
 int 
 ( 
 NETFLOW_SOCKETS 
 ), 
 'workers' 
 : 
 int 
 ( 
 NETFLOW_WORKERS 
 ), 
 'queue_size' 
 : 
 5000 
 } 
 }, 
 'processors' 
 : 
 { 
 'batch' 
 : 
 { 
 'timeout' 
 : 
 '10s' 
 , 
 'send_batch_size' 
 : 
 1000 
 } 
 }, 
 'exporters' 
 : 
 { 
 'file' 
 : 
 { 
 'path' 
 : 
 file_path 
 , 
 'format' 
 : 
 'json' 
 } 
 }, 
 'service' 
 : 
 { 
 'pipelines' 
 : 
 { 
 'logs' 
 : 
 { 
 'receivers' 
 : 
 [ 
 'netflow' 
 ], 
 'processors' 
 : 
 [ 
 'batch' 
 ], 
 'exporters' 
 : 
 [ 
 'file' 
 ] 
 } 
 }, 
 'telemetry' 
 : 
 { 
 'logs' 
 : 
 { 
 'level' 
 : 
 'info' 
 } 
 } 
 } 
 } 
 config_path 
 = 
 '/tmp/otel-config.yaml' 
 with 
 open 
 ( 
 config_path 
 , 
 'w' 
 ) 
 as 
 f 
 : 
 import 
  
 yaml 
 yaml 
 . 
 dump 
 ( 
 config 
 , 
 f 
 ) 
 return 
 config_path 
 , 
 file_path 
 def 
  
 upload_to_gcs 
 ( 
 file_path 
 ): 
  
 """Upload netflow logs to GCS.""" 
 if 
 not 
 os 
 . 
 path 
 . 
 exists 
 ( 
 file_path 
 ) 
 or 
 os 
 . 
 path 
 . 
 getsize 
 ( 
 file_path 
 ) 
 == 
 0 
 : 
 print 
 ( 
 f 
 "No data to upload from 
 { 
 file_path 
 } 
 " 
 ) 
 return 
 bucket 
 = 
 storage_client 
 . 
  bucket 
 
 ( 
 GCS_BUCKET 
 ) 
 timestamp 
 = 
 datetime 
 . 
 now 
 ( 
 timezone 
 . 
 utc 
 ) 
 . 
 strftime 
 ( 
 '%Y%m 
 %d 
 _%H%M%S' 
 ) 
 object_key 
 = 
 f 
 " 
 { 
 GCS_PREFIX 
 } 
 /netflow_ 
 { 
 timestamp 
 } 
 .ndjson" 
 blob 
 = 
 bucket 
 . 
 blob 
 ( 
 object_key 
 ) 
 blob 
 . 
  upload_from_filename 
 
 ( 
 file_path 
 , 
 content_type 
 = 
 'application/x-ndjson' 
 ) 
 print 
 ( 
 f 
 "Uploaded 
 { 
 os 
 . 
 path 
 . 
 getsize 
 ( 
 file_path 
 ) 
 } 
 bytes to gs:// 
 { 
 GCS_BUCKET 
 } 
 / 
 { 
 object_key 
 } 
 " 
 ) 
 def 
  
 signal_handler 
 ( 
 signum 
 , 
 frame 
 ): 
  
 """Handle shutdown signals.""" 
 global 
 collector_process 
 if 
 collector_process 
 : 
 print 
 ( 
 "Shutting down collector..." 
 ) 
 collector_process 
 . 
  terminate 
 
 () 
 collector_process 
 . 
 wait 
 ( 
 timeout 
 = 
 10 
 ) 
 @functions_framework 
 . 
 cloud_event 
 def 
  
 main 
 ( 
 cloud_event 
 ): 
  
 """ 
 Cloud Run function to run OpenTelemetry Collector for netflow collection. 
 Args: 
 cloud_event: CloudEvent object containing Pub/Sub message 
 """ 
 global 
 collector_process 
 if 
 not 
 GCS_BUCKET 
 : 
 print 
 ( 
 'Error: GCS_BUCKET environment variable not set' 
 ) 
 return 
 try 
 : 
 # Set up signal handlers 
 signal 
 . 
 signal 
 ( 
 signal 
 . 
 SIGTERM 
 , 
 signal_handler 
 ) 
 signal 
 . 
 signal 
 ( 
 signal 
 . 
 SIGINT 
 , 
 signal_handler 
 ) 
 # Create collector configuration 
 config_path 
 , 
 file_path 
 = 
 create_collector_config 
 () 
 print 
 ( 
 f 
 "Created collector config at 
 { 
 config_path 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "Netflow receiver listening on 
 { 
 NETFLOW_SCHEME 
 } 
 ://0.0.0.0: 
 { 
 NETFLOW_PORT 
 } 
 " 
 ) 
 # Start OpenTelemetry Collector 
 collector_process 
 = 
 subprocess 
 . 
 Popen 
 ( 
 [ 
 '/otelcol-contrib' 
 , 
 '--config' 
 , 
 config_path 
 ], 
 stdout 
 = 
 subprocess 
 . 
 PIPE 
 , 
 stderr 
 = 
 subprocess 
 . 
 PIPE 
 , 
 text 
 = 
 True 
 ) 
 print 
 ( 
 f 
 "Started OpenTelemetry Collector (PID: 
 { 
 collector_process 
 . 
 pid 
 } 
 )" 
 ) 
 # Run for collection period (e.g., 5 minutes) 
 collection_time 
 = 
 300 
 print 
 ( 
 f 
 "Collecting netflow data for 
 { 
 collection_time 
 } 
 seconds..." 
 ) 
 start_time 
 = 
 time 
 . 
 time 
 () 
 while 
 time 
 . 
 time 
 () 
 - 
 start_time 
< collection_time 
 : 
 if 
 collector_process 
 . 
 poll 
 () 
 is 
 not 
 None 
 : 
 stdout 
 , 
 stderr 
 = 
 collector_process 
 . 
 communicate 
 () 
 print 
 ( 
 f 
 "Collector exited unexpectedly" 
 ) 
 print 
 ( 
 f 
 "STDOUT: 
 { 
 stdout 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "STDERR: 
 { 
 stderr 
 } 
 " 
 ) 
 break 
 time 
 . 
 sleep 
 ( 
 10 
 ) 
 # Stop collector 
 if 
 collector_process 
 . 
 poll 
 () 
 is 
 None 
 : 
 print 
 ( 
 "Stopping collector..." 
 ) 
 collector_process 
 . 
  terminate 
 
 () 
 collector_process 
 . 
 wait 
 ( 
 timeout 
 = 
 10 
 ) 
 # Upload collected data 
 upload_to_gcs 
 ( 
 file_path 
 ) 
 # Cleanup 
 if 
 os 
 . 
 path 
 . 
 exists 
 ( 
 file_path 
 ): 
 os 
 . 
 remove 
 ( 
 file_path 
 ) 
 if 
 os 
 . 
 path 
 . 
 exists 
 ( 
 config_path 
 ): 
 os 
 . 
 remove 
 ( 
 config_path 
 ) 
 print 
 ( 
 "Netflow collection completed successfully" 
 ) 
 except 
 Exception 
 as 
 e 
 : 
 print 
 ( 
 f 
 'Error during netflow collection: 
 { 
 str 
 ( 
 e 
 ) 
 } 
 ' 
 ) 
 if 
 collector_process 
 and 
 collector_process 
 . 
 poll 
 () 
 is 
 None 
 : 
 collector_process 
 . 
  terminate 
 
 () 
 raise
      • requirements.txt:
       functions-framework==3.*
google-cloud-storage==2.*
PyYAML==6.*
      • Dockerfile:
        FROM 
  
 python:3.12-slim 
 # Install OpenTelemetry Collector Contrib 
 RUN 
  
apt-get  
update && 
apt-get  
install  
-y  
wget && 
 \ 
  
wget  
https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v0.144.0/otelcol-contrib_0.144.0_linux_amd64.deb && 
 \ 
  
dpkg  
-i  
otelcol-contrib_0.144.0_linux_amd64.deb && 
 \ 
  
rm  
otelcol-contrib_0.144.0_linux_amd64.deb && 
 \ 
  
apt-get  
clean # Set working directory 
 WORKDIR 
  
 /app 
 # Copy requirements and install 
 COPY 
  
requirements.txt  
. RUN 
  
pip  
install  
--no-cache-dir  
-r  
requirements.txt # Copy function code 
 COPY 
  
main.py  
. # Expose netflow port 
 EXPOSE 
  
 2055/udp 
 # Run function 
 CMD 
  
 [ 
 "functions-framework" 
 , 
  
 "--target=main" 
 , 
  
 "--port=8080" 
 ]

    3. Click Deployto save and deploy the function.

    4. Wait for deployment to complete (3-5 minutes).

    Configure network devices to send netflow data

    Configure your network devices (routers, switches, firewalls) to export netflow, sflow, or IPFIX data to the Cloud Run function.

    Get Cloud Run function external IP

    1. In the GCP Console, go to Cloud Run > Services.
    2. Click on the function name netflow-collector .
    3. Copy the URLdisplayed at the top (for example, https://netflow-collector-xxxxx-uc.a.run.app ).
    4. Extract the hostname from the URL.

    5. Use nslookup or dig to resolve the IP address:

       nslookup  
netflow-collector-xxxxx-uc.a.run.app

    • Example: Cisco router netflow configuration

       ! Configure netflow exporter
  flow exporter OTEL-EXPORTER
  destination <CLOUD_RUN_IP>
  transport udp 2055
  source <INTERFACE>
  export-protocol netflow-v9

  ! Configure flow monitor
  flow monitor OTEL-MONITOR
  exporter OTEL-EXPORTER
  record netflow ipv4 original-input

  ! Apply to interface
  interface GigabitEthernet0/0
  ip flow monitor OTEL-MONITOR input
  ip flow monitor OTEL-MONITOR output

    • Example: Generic netflow configuration

      For most network devices, configure the following settings:

      • Netflow version: NetFlow v5, v9, or IPFIX
      • Collector IP: Cloud Run function IP address
      • Collector port: 2055 (or configured port)
      • Protocol: UDP
      • Active timeout: 60 seconds (recommended)
      • Inactive timeout: 15 seconds (recommended)

    Create Cloud Scheduler job

    Cloud Scheduler will publish messages to the Pub/Sub topic at regular intervals, triggering the Cloud Run function.

    1. In the GCP Console, go to Cloud Scheduler.
    2. Click Create Job.

    3. Provide the following configuration details:

      Setting Value
      Name netflow-collector-hourly
      Region Select same region as Cloud Run function
      Frequency 0 * * * * (every hour, on the hour)
      Timezone Select timezone (UTC recommended)
      Target type Pub/Sub
      Topic Select the Pub/Sub topic netflow-trigger
      Message body {} (empty JSON object)

    4. Click Create.

    Schedule frequency options

    Choose frequency based on log volume and latency requirements:

    Frequency Cron Expression Use Case
    Every 5 minutes
    		 */5 * * * * High-volume, low-latency
    Every 15 minutes
    		 */15 * * * * Medium volume
    Every hour
    		 0 * * * * Standard (recommended)
    Every 6 hours
    		 0 */6 * * * Low volume, batch processing

    Test the integration

    1. In the Cloud Schedulerconsole, find the job netflow-collector-hourly .
    2. Click Force runto trigger the job manually.
    3. Wait a few seconds.
    4. Go to Cloud Run > Services.
    5. Click on the function name netflow-collector .
    6. Click the Logstab.

    7. Verify the function executed successfully. Look for:

       Started OpenTelemetry Collector (PID: ...)
Netflow receiver listening on netflow://0.0.0.0:2055
Collecting netflow data for 300 seconds...
Uploaded ... bytes to gs://netflow-logs-bucket/netflow/netflow_YYYYMMDD_HHMMSS.ndjson
Netflow collection completed successfully

    8. Go to Cloud Storage > Buckets.

    9. Click on the bucket name netflow-logs-bucket .

    10. Navigate to the prefix folder netflow/ .

    11. Verify that a new .ndjson file was created with the current timestamp.

    If you see errors in the logs:

    • Collector exited unexpectedly: Check netflow receiver configuration
    • No data to upload: Verify network devices are sending netflow data to the correct IP and port
    • Permission denied: Check service account has Storage Object Admin role
    • Port binding error: Ensure port 2055 is not already in use

    Google SecOps uses a unique service account to read data from your GCS bucket. You must grant this service account access to your bucket.

    1. Go to SIEM Settings > Feeds.
    2. Click Add New Feed.
    3. Click Configure a single feed.
    4. In the Feed namefield, enter a name for the feed (for example, OpenTelemetry Netflow Logs ).
    5. Select Google Cloud Storage V2as the Source type.
    6. Select NETFLOW_OTELas the Log type.

    7. Click Get Service Account. A unique service account email will be displayed. For example:

       chronicle-12345678@chronicle-gcp-prod.iam.gserviceaccount.com

    8. Copy this email address for use in the next step.

    9. Click Next.

    10. Specify values for the following input parameters:

      • Storage bucket URL: Enter the GCS bucket URI with the prefix path:

         gs://netflow-logs-bucket/netflow/

      • Source deletion option: Select the deletion option according to your preference:

        • Never: Never deletes any files after transfers (recommended for testing).
        • Delete transferred files: Deletes files after successful transfer.

        • Delete transferred files and empty directories: Deletes files and empty directories after successful transfer.

      • Maximum File Age: Include files modified in the last number of days (default is 180 days)

      • Asset namespace: The asset namespace

      • Ingestion labels: The label to be applied to the events from this feed

    11. Click Next.

    12. Review your new feed configuration in the Finalizescreen, and then click Submit.

    The Google SecOps service account needs Storage Object Viewerrole on your GCS bucket.

    1. Go to Cloud Storage > Buckets.
    2. Click on the bucket name netflow-logs-bucket .
    3. Go to the Permissionstab.
    4. Click Grant access.
    5. Provide the following configuration details:
      • Add principals: Paste the Google SecOps service account email
      • Assign roles: Select Storage Object Viewer
    6. Click Save.

    UDM mapping table

    The following table shows how OpenTelemetry Netflow Receiver log fields map to Google SecOps UDM fields:

    OpenTelemetry Field UDM Field Description
    source.address
    		principal.ip Source IP address
    source.port
    		principal.port Source port number
    destination.address
    		target.ip Destination IP address
    destination.port
    		target.port Destination port number
    network.transport
    		network.ip_protocol Transport protocol (tcp, udp)
    network.type
    		network.ip_version IP version (ipv4, ipv6)
    flow.io.bytes
    		network.sent_bytes Total bytes transferred
    flow.io.packets
    		network.sent_packets Total packets transferred
    flow.type
    		metadata.product_log_id Flow type (NETFLOW_V5, NETFLOW_V9, SFLOW_5, IPFIX)
    flow.start
    		metadata.event_timestamp Flow start time
    flow.end
    		network.session_duration Flow end time
    flow.sampler_address
    		intermediary.ip Netflow exporter IP address
    flow.tcp_flags
    		network.tcp_flags TCP flags

    Need more help? Get answers from Community members and Google SecOps professionals.

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