COVID-19 Response: Supplement to the BIG-IP APM and BIG-IP Edge Client Operations Guides
In the new F5 VPN for Business Continuity guide published to AskF5, you can learn how to: License and provision many new BIG-IP Network Access VPN users. Ensure seamless and secure BIG-IP APM Network Access VPN service any time. Troubleshoot problems when your BIG-IP Network Access VPN is not functioning optimally. The F5 VPN for Business Continuity guide includes the following chapters: Chapter 1: Contents Chapter 2: What is Network Access VPN? Chapter 3: Licensing and provisioning Network Access VPN Chapter 4: Optimizing Network Access VPN Chapter 5: Securing Network Access VPN Chapter 6: Troubleshooting Network Access VPNThe Power of F5 and NGINX
NGINX Controller 3.0 released Since the NGINX acquisition, F5 and NGINX have been integrating teams, listening to customers, and planning our first release as a unified company. Now, we have introduced NGINX Controller 3.0, which allows you to manage apps and services across a variety of deployment models, including multi-cloud scenarios. NGINX Controller 3.0 shifts from an infrastructure-centric to an application-centric design, improving developer productivity and accelerating time-to-market for new applications. In this article, learn about core NGINX concepts and explore new NGINX documentation on AskF5. Core NGINX concepts Putting your Apps First (5 mins) Load Balancing in a Multi-Cloud World (4 mins) Managing a Real Time API (4 mins) Simplifying the Move to Microservices (5 mins) Putting your Apps First (5 mins) Learn how an app-centric delivery platform can increase collaboration, decrease risk, and help you move with speed. Load Balancing in a Multi-Cloud World (4 mins) Explore considerations for deploying your applications to multiple clouds. Managing a Real Time API (4 mins) Learn the benefits of a lightweight API management platform. Simplifying the Move to Microservices (5 mins) Learn about options to successfully deploy microservices and see our six-point checklist to help you determine if you’re ready for a service mesh. New NGINX documentation on AskF5 As the F5 and NGINX engineering teams are releasing products together, engineers from both Support teams and AskF5 are combining forces to produce new documentation. For example, if you want to deploy your BIG-IP LTM system with HTTP load balancing to two NGINX proxies in AWS, see Quick deployment: BIG-IP LTM system with HTTP load balancing to two NGINX Plus web servers in AWS. More NGINX articles on AskF5: K74544015: Removing nginx/<version> from HTTP response headers K82655201: Host OS swap space must be disabled in NGINX Controller 2.8.0 and later K24214052: NGINX Controller 2.0.0 installation fails when the host OS locale is not UTF-8 K64001240: Enabling NGINX Controller Agent debug logging K06962163: Resetting the Admin account password on the NGINX Controller system K30389284: Backing up and restoring the NGINX Controller system K10640269: Setting nginx-controller as the default Kubernetes namespaceK51798430: Using the proxy_headers_hash_max_size and proxy_headers_hash_bucket_size directives K03453121: Basic Authentication on the health check request K21528053: [crit] message in error.log says '24: Too many open files' K43542013: NGINX returns status '400 Request Header Or Cookie Too Large' or '414 Request-URI Too Large' K48373902: [warn] message in error log: an upstream response is buffered to a temporary file while reading upstream K84508595: Different SSL protocols for different servers K18050039: Enabling client certificate authentication for NGINX K95305552: How to download or update the GeoIP2 database K68914062: Displaying a custom 502 response page K13912623: Configuring a default 'catchall' server K04600350: Using a common set of directives in the NGINX Plus configuration K46613025: High Availability solutions available for NGINX Plus in Azure K42497190: NGINX versions that support Lightweight M2M protocol K53631303: Capturing HTTP headers of a request in a log file K95324441: modsec_audit.log dramatically increasing What new NGINX topics would you like to see on AskF5? Leave your suggestions in the comments.
Tools and facilities to troubleshoot HTTP/3 over QUIC with the BIG-IP system
Introduction This article is for engineers who are troubleshooting issues related to HTTP/3 over QUIC as you deploy this new technology on your BIG-IP system. As you perform your troubleshooting tasks, the BIG-IP system provides you a set of useful tools along with other third party software to identify the root cause of issues and even tune HTTP/3 performance to maximize your system's potential. Overview of HTTP/3 and QUIC HTTP/3 is the next version of the HTTP protocol after HTTP/2. The most significant change in HTTP/3 from its predecessors is that it uses the UDP protocol instead of TCP. HTTP/3 uses a new Internet transport protocol, QUIC uses streams at the transport layer and provides TCP-like congestion control and loss recovery. One major improvement QUIC provides is it combines the typical 3-way TCP handshake with TLS 1.3's handshake. This improves the time required to establish a connection. Hence, you may see QUIC as providing the functions previously provided by TCP, TLS, and HTTP/2 as shown in the following diagram: For an overview of HTTP/3 over QUIC with the BIG-IP system, refer to K60235402: Overview of the BIG-IP HTTP/3 and QUIC profiles. Available tools and facilties Beginning in BIG-IP 15.1.0.1, HTTP/3 over QUIC (client-side only) is available as an experimental feature on the BIG-IP system. Beginning in BIG-IP 16.1.0, BIG-IP supports QUIC and HTTP/3. In addition to that feature, there are tools and facilities that are available to help you troubleshoot issues you might encounter. Install an HTTP/3 command line client Use a browser that supports QUIC Review statistics on your BIG-IP system Enable QUIC debug logging on the BIG-IP system Perform advanced troubleshooting with Packet Tracing Use the NetLog feature from the Chromium Project to capture a NetLog dump. Use the tcpdump command and Wireshark to capture and analyze traffic. Use the qlog trace system database key on the BIG-IP system. Important: For BIG-IP versions prior to 16.1.0 that are in the experimental stages, it is important that you note in your troubleshooting, the version of the ietf draft that your client and server implements. For example, in the Hello packets between the client and server, version negotiation is performed to ensure that client and server agree to a QUIC version that is mutually supported. In BIG-IP 15.1.0.1, the HTTP/3 and QUIC profiles in the BIG-IP system are experimental implementations of draft-ietf-quic-http-24 and draft-ietf-quic-transport-24 respectively. You need to consider this when configuring the Alt-Svc header in HTTP/3 discovery. For some browsers such as those from the Chromium project, Chrome canary, Microsoft Edge canary and Opera, when starting these browsers from the command line, you need to provide the QUIC version it implements. For example, for Chrome canary, you run the following command: chrome.exe --enable-quic --quic-version=h3-25. Only implementations of the final, published RFC can identify themselves ash3. Until such an RFC exists, implementations must not identify themselves using theh3string. 1. Install an HTTP/3 command line client Keep in mind that HTTP/3 over QUIC runs on UDP instead of TCP. By default, browsers always initiate a connection to the server using the traditional TCP handshake which will not work with a QUIC server listening for UDP packets. You therefore need to configure HTTP/3 discovery on your BIG-IP system. This can be done by using the HTTP Alternative Services concept which can be implemented either by inserting the Alt-Svc header or via DNS as a HTTPSVC DNS resource record. To insert the Alt-Svc header, refer to K16240003: Configuring HTTP/3 discovery for BIG-IP virtual server. As you troubleshoot your HTTP/3 discovery implementation, you can use a command line tool that does not come with the overhead of HTTP/3 discovery. Following are two popular tools that you can install on your client system: The picoquic client The curl client where you have the option to use either the ntcp2 or quiche software libraries. 2. Use a browser that supports QUIC At this time, browsers by default, still do not support QUIC and do not send the server UDP packets to establish a QUIC connection. The following browsers which are in development support it: Firefox Nightly Chrome Canary (Chromium Project) Microsoft Edge Canary (Chromium Project) Opera (Chromium Project) Note that for browsers from the Chromium project, you need to specify the QUIC ietf version that the browser supports when you launch it. For example, for Chrome, run the following command: chrome.exe --enable-quic --quic-version=h3-25. In most browsers today, you can quickly view the HTTP information exchanged by using the built-in developer tool. To open the tool, select F12 after your browser opens and access any site that supports QUIC. Select the Network tab and under the Protocol column, look at h3-<draft_version> . If the Protocol column is not there, you may have to right click the toolbar to add it. Note: Only implementations of the final, published RFC can identify themselves as h3. Until such an RFC exists, implementations must not identify themselves using the h3 string. Click the name of the HTTP request and you can see that the site returns the Alt-Svc header indicating that it supports HTTP/3 with its ietf draft version. 3. Review statistics on your BIG-IP system The statistics facility on the BIG-IP system displays the system's QUIC traffic processing. On the Configuration utility, go to Local Traffic > Virtual Servers. Select the name of your virtual server and select the Statistics tab. In the Profiles section, select the HTTP/3 and QUIC profiles associated with the virtual server. Alternatively, you can view the statistics from the TMOS shell (tmsh) utility using the following command syntax: tmsh show ltm profile http3 <http3_profile_name> tmsh show ltm profile quic <quic_profile_name> 4. Enable QUIC debug logging on the BIG-IP system You can use the sys db variable tmm.quic.log.level to adjust the verbosity of the QUIC log level to the /var/log/ltm file. Type the following command to see the list of values. tmsh list sys db tmm.quic.log.level value-range sys db tmm.quic.log.level { default-value "Critical" value-range "Critical Error Warning Notice Info Debug" } For example: tmsh modify sys db tmm.quic.log.level value debug 5. Perform advanced troubleshooting with Packet Tracing a. Use the NetLog feature from the Chromium Project to capture a NetLog dump. NetLog is an event logging mechanism for Chrome’s network stack to help debug problems and analyze performance not just for HTTP/3 over QUIC traffic but also HTTP/1.1 and HTTP/2. This feature is available only in browsers from the Chromium project, such as Google Chrome, Opera and Microsoft Edge. The feature provides detailed client side logging including SSL handshake and HTTP content without having to perform decryption or run any commands on your BIG-IP system. To start capturing, open a new tab on your browser and go to, for example, chrome://net-export (Chromium only). For a step by step guide, refer to How to capture a NetLog dump. Once you have your NetLog dump, you can view and analyze it by navigating to netlog-viewer (Chromium only). To analyze QUIC traffic, on the left panel, select Events. In the Description column, identify the URL you requested. For QUIC SSL handshake events, select QUIC_SESSION. For HTTP content, select URL_REQUEST. For example, in the following NetLog dump, the connection failed at the beginning because the client and server could not negotiate a common QUIC version. b. Use the tcpdump command and Wireshark to capture and analyze traffic. The tcpdump command and Wireshark are both essential tools when you need to examine any communication at the packet level. To generate captures and the SSL secrets required to decrypt them, follow the procedure in K05822509: Decrypting HTTP/3 over QUIC with Wireshark. Keep your Wireshark version updated at all times as Wireshark's ability to decode QUIC packets continue to evolve as we speak. c. Use the qlog traces on the BIG-IP system. The BIG-IP qlog trace facility provides you another tool to troubleshoot QUIC communications. By enabling a database variable, the system logs packets and other events to /var/log/trace<TMM_number>.qlog files. qlog is a standardized structured logging format for QUIC and is basically a well-defined JSON file with specified event names and associated data that allows you to use tools like qvis for visualization. Note that the payload is not logged. The qlog trace files are compliant to the IETF schema specified in draft-marx-qlog-main-schema-01. To capture and analyze qlog trace files on your BIG-IP system, perform the following procedure: Capturing qlog trace files on the BIG-IP system Login to the BIG-IP command line. Enable qlogging by typing the following command: tmsh modify sys db quic.qlogging value enable Reproduce the issue you are troubleshooting by initiating QUIC traffic to your virtual server. Disable qlogging by typing the following command: tmsh modify sys db quic.qlogging value disable Note: This step will log required closing json content to the trace files, terminate the trace logging gracefully and is required before you view the files. Sanitizing the qlog trace files Before loading the trace files onto a graphical visualization tool, you first need to sanitize the json content. The tools attempt to fix some common json errors but there may be cases where you need to manually correct some json syntax errors by adding closing braces or commas. Note: Knowledge of different json constructs such as objects, arrays and members may be required when you fix the json files. You can use any of the available online tools such as the following: Json Formatter Fixjson freeformatter Important: Even as the payload information such as IP addresses, or HTTP content are not included in the trace files, you should exercise caution when uploading content to online tools. F5 is not responsible for the privacy and security of your data when you use the third party software listed in this procedure. Alternatively, you can download and install any of the following command line tools on your client device: jsonlint-php jsonlint-py jsonlint-cli Loading and analyzing the qlog trace files with a visualization tool When you have sanitized your json trace files, upload them to a visualization tool for analysis. For example, you can use the following tool available for free. qvis QUIC and HTTP/3 visualization toolsuite The visualization tool can provide you graphical representations of the sequence of messages, congestion information and qlog stats for troubleshooting. For example, the following screenshot, illustrates a sequence diagram of the SSL handshake. Important: Even as payload information such as IP addresses, or HTTP content are not included in the trace files, you should exercise caution when uploading content to online tools. F5 is not responsible for the privacy and security of your data when you use the third party software listed in this procedure. Summary As you use the tools described in this article, you notice that each one helps you troubleshoot issues at the different OSI layers. The built-in developer tools in each browser provide a quick and easy way to view HTTP content but do not let you see the details of the protocol, as do the NetLog tool and Wireshark. However, viewing qlog traces on the qvis graphical tool provides you high level trends and statistics that packet captures do not show. Using the appropriate tool with the right troubleshooting methodology maximizes the potential of HTTP/3 and QUIC for your organization.Upgrade your BIG-IP systems for more secure apps
Keeping your BIG-IP software up to date ensures you have access to advanced capabilities and higher-quality, more secure releases. At a minimum, F5 recommends implementing BIG-IP 14.1.0 across your BIG-IP fleet.BIG-IP 15.1.0 and 16.0.0 will reward you with the most advanced BIG-IP functionality, including new protocol support and security capabilities. Walkthrough Videos For a walkthrough of three common upgrade scenarios, watch the following videos: Performing a software upgrade on a BIG-IP system (standalone) Updating BIG-IP HA systems with a point release Upgrading BIG-IP VIPRION vCMP systems Automation For information about upgrading with the assistance of automation, watch DevCentral Connects: Automating Software Updates with BIG-IQ or Ansible. Official Training F5 has temporarily, and until further notice, made the following training available for free: BIG-IP Fundamentals: Upgrading a BIG-IP System --- For more information about upgrading, refer to the F5 page on BIG-IP upgrade.Next Quarterly Security Notification is October 19, 2022
F5 discloses security vulnerabilities and security exposures for F5 products in a Quarterly Security Notification (QSN). On the day of the last QSN, Aug 3, 2022, F5 announced that the next QSN will occur Wednesday October 19, 2022. QSN dates are published in advance so that customers can schedule updates and business operations ahead of the public disclosure date. K67091411: Guidance for Quarterly Security Notifications includes steps you can take before and after a QSN, such as scheduling maintenance windows in advance, saving a UCS archive backup file, and planning for any upgrades that may be required.K67091411 also includes links to articles detailing additional security best practices.Upgrade your BIG-IQ system: Videos and procedures
AskF5 published a new series of videos and procedures to take you through the BIG-IQ upgrade process. Videos Watch the playlist here: In this playlist, you'll find the following videos: Preparing for a BIG-IQ upgrade Part 1: Checking the BIG-IQ DCD configuration (1:38) Part 2: Downloading and uploading files (2:23) Part 3: Running the pre-upgrade check tool (4:43) Part 4: Ensuring you have multiple DCDs (1:17) Upgrading the BIG-IQ and DCDs Part 5: Upgrading the BIG-IQ system (3:20) Part 6: Upgrading the secondary system (2:21) Completing the post-upgrade process Part 7: Adding back the secondary BIG-IQ system (1:28) Part 8: Re-importing the devices and services (2:37) Part 9: (VMware) Installing the certificate (1:37) Procedures To review the written procedures, refer to K51342220: Upgrading the BIG-IQ videos and procedures.AskF5's new BIG-IP upgrade guide
AskF5 published the new BIG-IP upgrade guideto help you through the BIG-IP upgrade process.At a minimum, F5 recommends that you upgrade your BIG-IP appliances to at least version 14.1.x and your BIG-IP VE systems to at least version 15.1.x. Because F5 customers use a variety of configurations and tools, there are many upgrade scenarios. In this new Operations Guide, you'll find the following topics: Prepare to upgrade Chapter 1: Guide introduction and contents Chapter 2: Choosinga BIG-IP upgrade version Chapter 3: Preparingto upgrade the BIG-IP system BIG-IP hardware and VE platforms BIG-IP systems Chapter 4: Upgradinga standalone BIG-IPsystem Chapter 5: Upgradinga standalone BIG-IPsystem using the TMOS Shell VIPRION BIG-IP systems Chapter 6: Upgradinga VIPRION HA pair Chapter 7:UpgradingBIG-IP VIPRION vCMP systems Other BIG-IP vCMP systems Chapter 8: UpgradingBIG-IP vCMP systems (non-VIPRION) BIG-IP cloud platforms BIG-IP on AWS Chapter 9: Upgrading aBIG-IP VE instance on AWS using the f5-aws-migrate.py script BIG-IP on Microsoft Azure Chapter 10: Upgradinga BIG-IP Azure VM using the Azure portal to deploy an ARM template Chapter 11: Upgradinga BIG-IP Azure VM using Terraform to deploy an ARM template Chapter 12: Upgradinga BIG-IP Azure VM using Ansible to deploy an ARM template BIG-IP on GCP Chapter 13: Upgrading a BIG-IP GCP VM using Terraform Automation Chapter 14: UsingF5 Modules for Ansible to upgrade BIG-IP system software Send Feedback This guide is a work in progress; request the upgrade scenarios you want to see in this guide. Use the feedback or survey button at the bottom of any guide page, or email TellAskF5@f5.com. Related Content For supported paths and general considerations, refer toK13845: Overview of supported BIG-IP upgrade paths and an upgrade planning reference.Part 3: Monitoring the health of BIG-IP APM network access PPP connections with a periodic iCall handler
In this part, you monitor the health of PPP connections on the BIG-IP APM system by monitoring the frequency of a particular log message in the/var/log/apmfile. In this log file, when the system is under high CPU load, you may observe different messages indicating users' VPN connections are disconnecting. For example: You observe multiple of the following messages where the PPP tunnel is started and closed immediately: Mar 13 13:57:57 hostname.example notice tmm3[16095]: 01490505:5: /Common/accessPolicy_policy:Common:ee6e0ce7: PPP tunnel 0x5604775f7000 (ID: 2c4507ea) started. Mar 13 13:57:57 hostname.example notice tmm3[16095]: 01490505:5: /Common/accessPolicy_policy:Common:ee6e0ce7: PPP tunnel 0x560478482000 (ID: acf63e47) closed. You observe an unusually high rate of log messages indicating users' APM sessions terminated due to various reasons in a short span of time. Mar 13 14:01:10 hostname.com notice tmm3[16095]: 01490567:5: /Common/AccessPolicy_policy:Common:a7cf25d9: Session deleted due to user inactivity. You observe an unusually high rate of log messages indicating different user apm session IDs are attempting to reconnect to network access, VPN. Mar 13 12:18:13 hostname notice tmm1[16095]: 01490549:5: /Common/AP_policy:Common:2c321803: Assigned PPP Dynamic IPv4: 10.10.1.20 ID: 033d0635 Tunnel Type: VPN_TUNNELTYPE_TLS NA Resource: /Common/AP_policy_na_res Client IP: 172.2.2.2 – Reconnect In this article, you monitor theReconnectmessage in the last example because it indicates that the VPN connection terminated and the client system still wants to reconnect. When this happens for several users and repeatedly, it usually indicates that the issue is not related to the client side. The next question is, what is an unusually high rate of reconnect messages, taking into account the fact that some reconnects may be due to reasons on the client side and not due to high load on the system. You can create a periodic iCall handler to run a script once every minute. Each time the script runs, it uses grep to find the total number of Reconnect log messages that happened over the last 3 minutes for example. When the average number of entries per minute exceeds a configured threshold, the system can take appropriate action. The following describes the procedures: Creating an iCall script to monitor the rate of reconnect messages Creating a periodic iCall handler to run the iCall script once a minute Testing the implementation using logger 1. Creating an iCall script to monitor the rate of reconnect messages The example script uses the following values: Periodic handler interval 1 minute: This runs the script once a minute to grep the number of reconnect messages logged in the last 3.0 minutes. Period 3.0 minutes: The script greps for the Reconnect messages logged in the last three minutes. Critical threshold value 4: When the average number of Reconnect messages per minute exceeds four or a total of 12 in the last three minutes, the system logs a critical message in the/var/log/apmfile. Alert threshold value 7: When the average number of Reconnect messages per minute exceeds seven or a total of 21 in the last three minutes, the system logs an alert message and requires immediate action. Emergency threshold 10: When the BIG-IP system is logging 10 Reconnect messages or more every minute for the last three minutes or a total of 30 messages, the system logs an emergency message, indicating the system is unusable. You should reconfigure these values at the top of the script according to the behavior and set up of your environment. By performing the count over an interval of three minutes or longer, it reduces the possibility of high number of reconnects due to one-off spikes. Procedure Perform the following procedure to create the script to monitor CPU statistics and log an alert message in the/var/log/ltmfile when traffic exceeds a CPU threshold value. To create an iCall script, perform the following procedure: Log in to tmsh. Enter the following command to create the script in the vi editor: create sys icall script vpn_reconnect_script 3. Enter the following script into the definition stanza in the editor: This script counts the average number of entries/min the Reconnect message is logged in /var/log/apm over a period of 3 minutes. definition { #log file to grep errormsg set apm_log "/var/log/apm" #This is the string to grep for. set errormsg "Reconnect" #num of entries = grep $errormsg $apm_log | grep $hourmin | wc -l #When (num of entries < crit_threshold), no action #When (crit_threshold <= num of entries < alert_threshold), log crtitical message. #When (alert_threshold <= num of entries < emerg_threshold), log alert message. #When (emerg_threhold <= num of entries log emerg message set crit_threshold 4 set alert_threshold 7 set emerg_threshold 10 #Number of minutes to take average of. E.g. Every 1.0, 2.0, 3.0, 4.0... minutes set period 3.0 #Set this to 1 to log to /var/tmp/scriptd.out. Set to 0 to disable. set DEBUG 0 set total 0 puts "\n[clock format [clock seconds] -format "%b %e %H:%M:%S"] Running script..." for {set i 1} {$i <= $period} {incr i} { set hourmin [clock format [clock scan "-$i minute"] -format "%b %e %H:%M:"] set errorcode [catch {exec grep $errormsg $apm_log | grep $hourmin | wc -l} num_entries] if{$errorcode} { set num_entries 0 } if {$DEBUG} {puts "DEBUG: $hourmin \"$errormsg\" logged $num_entries times."} set total [expr {$total + $num_entries}] } set average [expr $total / $period] set average [format "%.1f" $average] if{$average < $crit_threshold} { if {$DEBUG} {puts "DEBUG: $hourmin \"$errormsg\" logged $average times on average. Below all threshold. No action."} exit } if{$average < $alert_threshold} { if {$DEBUG} {puts "DEBUG: $hourmin \"$errormsg\" logged $average times on average. Reached critical threshold $crit_threshold. Log Critical msg."} exec logger -p local1.crit "01490266: \"$errormsg\" logged $average times on average in last $period mins. >= critical threshold $crit_threshold." exit } if{$average < $emerg_threshold} { if {$DEBUG} {puts "DEBUG: $hourmin \"$errormsg\" logged $average times on average. Reached alert threshold $alert_threshold. Log Alert msg."} exec logger -p local1.alert "01490266: \"$errormsg\" logged $average times on average in last $period mins. >= alert threshold $alert_threshold." exit } if {$DEBUG} {puts "DEBUG: $hourmin \"$errormsg\" logged $average times on average in last $period mins. Log Emerg msg"} exec logger -p local1.emerg "01490266: \"$errormsg\" logged $average times on average in last $period mins. >= emerg threshold $emerg_threshold." exit } 4. Configure the variables in the script as needed and exit the editor by entering the following command: :wq! y 5. Run the following command to list the contents of the script: list sys icall script vpn_reconnect_script 2. Creating a periodic iCall handler to run the script In this example, you create the iCall handler to run the script once a minute. You can increase this interval to once every two minutes or longer. However, you should consider this value together with theperiodvalue of the script in the previous procedure to ensure that you're notified on any potential issues early. Procedure Perform the following procedure to create the periodic handler that runs the script once a minute. To create an iCall periodic handler, perform the following procedure: Log in to tmsh. Enter the following command to create a periodic handler: create sys icall handler periodic vpn_reconnect_handler interval 60 script vpn_reconnect_script 3. Run the following command to list the handler: list sys icall handler periodic vpn_reconnect_handler 4. You can start and stop the handler by using the following command syntax: <start|stop> sys icall handler periodic vpn_reconnect_handler 3. Testing the implementation using logger You can use theloggercommand to log test messages to the/var/log/apmfile to test your implementation. To do so, run the following command the required number of times to exceed the threshold you set: Note: The following message must contain the keyword that you are searching for in the script. In this case, the keyword is Reconnect. logger -p local1.notice "01490549:5 Assigned PPP Dynamic IPv4: 10.10.1.20 ID: 033d0635 Tunnel Type: VPN_TUNNELTYPE_TLS NA Resource: /Common/AP_policy_na_res Client IP: 172.2.2.2 - Reconnect" Follow the/var/tmp/scriptd.outand/var/log/apm file entries to verify your implementation is working correctly. Conclusion This article lists three use cases for using iCall to monitor the health of your BIG-IP APM system. The examples mainly log the appropriate messages in the log files. You can extend the examples to monitor more parameters and also perform different kinds of actions such as calling another script (Bash, Perl, and so on) to send an email notification or perform remedial action.Using iCall to monitor BIG-IP APM network access VPN
Introduction During peak periods, when a large number of users are connected to network access VPN, it is important to monitor your BIG-IP APM system's resource (CPU, memory, and license) usage and performance to ensure that the system is not overloaded and there is no impact on user experience. If you are a BIG-IP administrator, iCall is a tool perfectly suited to do this for you. iCall is a Tcl-based scripting framework that gives you programmability in the control plane, allowing you to script and run Tcl and TMOS Shell (tmsh) commands on your BIG-IP system based on events. For a quick introduction to iCall, refer to iCall - All New Event-Based Automation System. Overview This article is made up of three parts that describe how to use and configure iCall in the following use cases to monitor some important BIG-IP APM system statistics: Part 1: Monitoring access sessions and CCU license usage of the system using a triggered iCall handler Part 2: Monitoring the CPU usage of the system using a periodic iCall handler. Part 3: Monitoring the health of BIG-IP APM network access VPN PPP connections with a periodic iCall handler. In all three cases, the design consists of identifying a specific parameter to monitor. When the value of the parameter exceeds a configured threshold, an iCall script can perform a set of actions such as the following: Log a message to the /var/log/apm file at the appropriate severity: emerg: System is unusable alert: Action must be taken immediately crit: Critical conditions You may then have another monitoring system to pick up these messages and respond to them. Perform a remedial action to ease the load on the BIG-IP system. Run a script (Bash, Perl, Python, or Tcl) to send an email notification to the BIG-IP administrator. Run the tcpdump or qkview commands when you are troubleshooting an issue. When managing or troubleshooting iCall scripts and handler, you should take into consideration the following: You use the Tcl language in the editor in tmsh to edit the contents of scripts and handlers. For example: create sys icall script <name of script> edit sys icall script <name of script> The puts command outputs entries to the /var/tmp/scriptd.out file. For example: puts "\n[clock format [clock seconds] -format "%b %d %H:%M:%S"] Running script..." You can view the statistics for a particular handler using the following command syntax: show sys icall handler <periodic | perpetual | triggered> <name of handler> Series 1: Monitoring access sessions and CCU license usage with a triggered iCall handler You can view the number of currently active sessions and current connectivity sessions usage on your BIG-IP APM system by entering the tmsh show apm license command. You may observe an output similar to the following: -------------------------------------------- Global Access License Details: -------------------------------------------- total access sessions: 10.0M current active sessions: 0 current established sessions: 0 access sessions threshold percent: 75 total connectivity sessions: 2.5K current connectivity sessions: 0 connectivity sessions threshold percent: 75 In the first part of the series, you use iCall to monitor the number of current access sessions and CCU license usage by performing the following procedures: Modifying database DB variables to log a notification when thresholds are exceed. Configuring user_alert.conf to generate an iCall event when the system logs the notification. Creating a script to respond when the license usage reaches its threshold. Creating an iCall triggered handler to handle the event and run an iCall script Testing the implementation using logger 1. Modifying database variables to log a notification when thresholds are exceeded. The tmsh show apm license command displays the access sessions threshold percent and access sessions threshold percent values that you can configure with database variables. The default values are 75. For more information, refer to K62345825: Configuring the BIG-IP APM system to log a notification when APM sessions exceed a configured threshold. When the threshold values are exceeded, you will observe logs similar to the following in /var/log/apm: notice tmm1[<pid>]: 01490564:5: (null):Common:00000000: Global access license usage is 1900 (76%) of 2500 total. Exceeded 75% threshold of total license. notice tmm2[<pid>]: 01490565:5: 00000000: Global concurrent connectivity license usage is 393 (78%) of 500 total. Exceeded 75% threshold of total license. Procedure: Run the following commands to set the threshold to 95% for example: tmsh modify /sys db log.alertapmaccessthreshold value 95 tmsh modify /sys db log.alertapmconnectivitythreshold value 95 Whether to set the alert threshold at 90% or 95%, depends on your specific environment, specifically how fast the usage increases over a period of time. 2. Configuring user_alert.conf to generate an iCall event when the system logs the notification You can configure the /config/user_alert.conf file to run a command or script based on a syslog message. In this step, edit the user_alert.conf file with your favorite editor, so that the file contains the following stanza. alert <name> "<string in syslog to match to trigger event>" { <command to run> } For more information on configuring the /config/user_alert.conf file, refer to K14397: Running a command or custom script based on a syslog message. In particular, it is important to read the bullet points in the Description section of the article first; for example, the system may not process the user_alert.conf file after system upgrades. In addition, BIG-IP APM messages are not processed by the alertd SNMP process by default. So you will also have to perform the steps described in K51341580: Configuring the BIG-IP system to send BIG-IP APM syslog messages to the alertd process as well. Procedure: Perform the following procedure: Edit the /config/user_alert.conf file to match each error code and generate an iCall event named apm_threshold_event. Per K14397 Note: You can create two separate alerts based on both error codes or alternatively use the text description part of the log message common to both log entries to capture both in a single alert. For example "Exceeded 75% threshold of total license" # cat /config/user_alert.conf alert apm_session_threshold "01490564:" { exec command="tmsh generate sys icall event apm_threshold_event" } alert apm_ccu_threshold "01490565:" { exec command="tmsh generate sys icall event apm_threshold_event" } 2. Run the following tmsh command: edit sys syslog all-properties 3. Replace the include none line with the following: Per K51341580 include " filter f_alertd_apm { match (\": 0149[0-9a-fA-F]{4}:\"); }; log { source(s_syslog_pipe); filter(f_alertd_apm); destination(d_alertd); }; " 3. Creating a script to respond when the license usage reaches its threshold. When the apm session or CCU license usage exceeds your configured threshold, you can use a script to perform a list of tasks. For example, if you had followed the earlier steps to configure the threshold values to be 95%, you can write a script to perform the following actions: Log a syslog alert message to the /var/log/apm file. If you have another monitoring system, it can pick this up and respond as well. Optional: Run a tmsh command to modify the Access profile settings. For example, when the threshold exceeds 95%, you may want to limit users to one apm session each, decrease the apm access profile timeout or both. Changes made only affect new users. Users with existing apm sessions are not impacted. If you are making changes to the system in the script, it is advisable to run an additional tmsh command to stop the handler. When you have responded to the alert, you can manually start the handler again. Note: When automating changes to the system, it is advisable to err on the side of safety by making minimal changes each time and only when required. In this case, after the system reaches the license limit, users cannot login and you may need to take immediate action. Procedure: Perform the following procedure to create the iCall script: 1. Log in to tmsh. 2. Run the following command: create sys icall script threshold_alert_script 3. Enter the following in the editor: Note: The tmsh commands to modify the access policy settings have been deliberately commented out. Uncomment them when required. sys icall script threshold_alert_script { app-service none definition { exec logger -p local1.alert "01490266: apm license usage exceeded 95% of threshold set." #tmsh::modify apm profile access exampleNA max-concurrent-sessions 1 #tmsh::modify apm profile access exampleNA generation-action increment #tmsh::stop sys icall handler triggered threshold_alert_handler } description none events none } 4. Creating an iCall triggered handler to handle the event and run an iCall script In this step, you create a triggered iCall handler to handle the event triggered by the tmsh generate sys icall event command from the earlier step to run the script. Procedure: Perform the following: 1. Log in to tmsh. 2. Enter the following command to create the triggered handler. create sys icall handler triggered threshold_alert_handler script threshold_alert_script subscriptions add { apm_threshold_event { event-name apm_threshold_event } } Note: The event-name field must match the name of the event in the generate sys icall command in /config/user_alert.conf you configured in step 2. 3. Enter the following command to verify the configuration of the handler you created. (tmos)# list sys icall handler triggered threshold_alert_handler sys icall handler triggered threshold_alert_handler { script threshold_alert_script subscriptions { apm_threshold_event { event-name apm_threshold_event } } } 5. Testing the implementation using logger You can use theloggercommand to log test messages to the/var/log/apmfile to test your implementation. To do so, run the following command: Note: The message below must contain the keyword that you are searching for in the script. In this example, the keyword is01490564or01490565. logger -p local1.notice "01490564:5: (null):Common:00000000: Global access license usage is 1900 (76%) of 2500 total. Exceeded 75% threshold of total license." logger -p local1.notice "01490565:5: 00000000: Global concurrent connectivity license usage is 393 (78%) of 500 total. Exceeded 75% threshold of total license." Follow the /var/log/apm file to verify your implementation is working correctly.
