Embracing AS3: Foundations
Many F5 teams are on the North American leg of the F5 Academy BIG-IP Next Roadshow, where we are sharing the BIG-IP story, where we're going with it, and then diving into some hands-on labs with the attendees. I got to attend in person in Kansas City, St. Louis, Cincinnati, and Columbus, and talked with customers at all stages of the automation journey. Some haven't automated much of anything. Some have been using a variety of on-/off-box scripts, and some are all-in, baby! AS3 is a critical component of BIG-IP Next, but it has also been around for several years for BIG-IP and can be learned and implemented ahead of your transition to BIG-IP Next. So over the next three weeks, I'm going to host a five-part live-stream series on AS3 Foundations. There are a lot of resources I'll link to and key in on during the event for reference and further study. Here are the shows I'm doing with descriptions: Beyond Imperatives—What the heck is AS3? (Dec 4@ 9am PST) In this first episode, I'll cover the history of automation on BIG-IP, the differences between imperative and declarative models, and the basics of AS3 from data structure and systems architecture perspectives. Top 10 Features to Know in the VSCode F5 Extension (Dec 7@ 12pm PST) Next, special guest Ben Novak, author of the F5 Extension for VSCode, will join me to dig into the features most important to know and learn to use for understanding how to take stock BIG-IP configurations and turn applications into declarations. Migrating and Deploying Applications in VSCode (Dec 14@ 12pm PST) In this episode, armed with the knowledge I learned from Ben in the last episode, I'll finally get to the brass tacks of AS3! I'll review diagnostics and migrate several applications from standard configuration to AS3 declarations and deploy a few. For migrating active workloads, I'll discuss the steps necessary to reduce transition impact. Creating New Apps and Using Shared Objects (Dec 18@ 9am PST) I've always tried to alter existing things before creating new things with tech, and this is no different. Now that I have a few migrations under my belt, I'll attack a net-new application and I'll look at shared objects and how and when to use them. Best Practices (Dec 21@ 12pm PST) Finally, I'll close this series with a look at several best practices when working with AS3. The conclusion to this series, though, is hopefully just the stepping off point for everyone new to AS3, and we'll be able to continue the conversation right here on DevCentral.
AS3 Best Practice
Introduction AS3 is a declarative API that uses JSON key-value pairs to describe a BIG-IP configuration. From virtual IP to virtual server, to the members, pools, and nodes required, AS3 provides a simple, readable format in which to describe a configuration. Once you've got the configuration, all that's needed is to POST it to the BIG-IP, where the AS3 extension will happily accept it and execute the commands necessary to turn it into a fully functional, deployed BIG-IP configuration. If you are new to AS3, start reading the following references: Products - Automation and orchestration toolchain(f5.com; Product information) Application Services 3 Extension Documentation(clouddocs; API documentation and guides) F5 Application Services 3 Extension(AS3) (GitHub; Source repository) This article describes some considerations in order to efficiently deploy the AS3 configurations. Architecture In the TMOS space, the services that AS3 provides are processed by a daemon named 'restnoded'. It relies on the existing BIG-IP framework for deploying declarations. The framework consists of httpd, restjavad and icrd_child as depicted below (the numbers in parenthesis are listening TCP port numbers). These processes are also used by other services. For example, restjavad is a gateway for all the iControl REST requests, and is used by a number of services on BIG-IP and BIG-IQ. When an interaction between any of the processes fails, AS3 operation fails. The failures stem from lack of resources, timeouts, data exceeding predefined thresholds, resource contention among the services, and more. In order to complete AS3 operations successfully, it is advised to follow the Best Practice outlined below. Best Practice Your single source of truth is your declaration Refrain from overwriting the AS3-deployed BIG-IP configurations by the other means such as TMSH, GUI or iControl REST calls. Since you started to use the AS3 declarative model, the source of truth for your device's configurations is in your declaration, not the BIG-IP configuration files. Although AS3 tries to weigh BIG-IP locally stored configurations as much as it can do, discrepancy between the declaration and the current configuration on BIG-IP may cause the AS3 to perform less efficiently or error unexpectedly. When you wish to change a section of a tenant (e.g., pool name change), modify the declaration and submit it. Keep the number of applications in one tenant to a minimum AS3 processes each tenant separately.Having too many applications (virtual servers) in a single tenant (partition) results in a lengthy poll when determining the current configuration. In extreme cases (thousands of virtuals), the action may time out. When you want to deploy a thousand or more applications on a single device, consider chunking the work for AS3 by spreading the applications across multiple tenants (say, 100 applications per tenant). AS3 tenant access behavior behaves as BIG-IP partition behavior.A non-Common partition virtual cannot gain access to another partition's pool, and in the same way, an AS3 application does not have access to a pool or profile in another tenant.In order to share configuration across tenants, AS3 allows configuration of the "Shared" application within the "Common" tenant.AS3 avoids race conditions while configuring /Common/Shared by processing additions first and deletions last, as shown below.This dual process may cause some additional delay in declaration handling. Overwrite rather than patching (POSTing is a more efficient practice than PATCHing) AS3 is a stateless machine and is idempotent. It polls BIG-IP for its full configuration, performs a current-vs-desired state comparison, and generates an optimal set of REST calls to fill the differences.When the initial state of BIG-IP is blank, the poll time is negligible.This is why initial configuration with AS3 is often quicker than subsequent changes, especially when the tenant contains a large number of applications. AS3 provides the means to partially modify using PATCH (seeAS3 API Methods Details), but do not expect PATCH changes to be performant.AS3 processes each PATCH by (1) performing a GET to obtain the last declaration, (2) patching that declaration, and (3) POSTing the entire declaration to itself.A PATCH of one pool member is therefore slower than a POST of your entire tenant configuration.If you decide to use PATCH,make sure that the tenant configuration is a manageable size. Note: Using PATCH to make a surgical change is convenient, but using PATCH over POST breaks the declarative model. Your declaration should be your single source of truth.If you include PATCH, the source of truth becomes "POST this file, then apply one or more PATCH declarations." Get the latest version AS3 is evolving rapidly with new features that customers have been wishing for along with fixes for known issues. Visitthe AS3 section of the F5 Networks Github.Issuessection shows what features and fixes have been incorporated. For BIG-IQ, check K54909607: BIG-IQ Centralized Management compatibility with F5 Application Services 3 Extension and F5 Declarative Onboarding for compatibilities with BIG-IQ versions before installation. Use administrator Use a user with the administrator role when you submit your declaration to a target BIG-IP device. Your may find your role insufficient to manipulate BIG-IP objects that are included in your declaration. Even one authorized item will cause the entire operation to fail and role back. See the following articles for more on BIG-IP user and role. Manual Chapter : User Roles (12.x) Manual Chapter : User Roles (13.x) Manual Chapter : User Roles (14.x) Prerequisites and Requirements(clouddocs AS3 document) Use Basic Authentication for a large declaration You can choose either Basic Authentication (HTTP Authorization header) or Token-Based Authentication (F5 proprietary X-F5-Auth-Token) for accessing BIG-IP. While the Basic Authentication can be used any time, a token obtained for the Token-Based Authentication expires after 1,200 seconds (20 minutes). While AS3 does re-request a new token upon expiry, it requires time to perform the operation, which may cause AS3 to slow down. Also, the number of tokens for a user is limited to 100 (since 13.1), hence if you happen to have other iControl REST players (such as BIG-IQ or your custom iControl REST scripts) using the Token-Based Authentication for the same user, AS3 may not be able to obtain the next token, and your request will fail. See the following articles for more on the Token-Based Authentication. Demystifying iControl REST Part 6: Token-Based Authentication(DevCentral article). iControl REST Authentication Token Management(DevCentral article) Authentication and Authorization(clouddocs AS3 document) Choose the best window for deployment AS3 (restnoded daemon) is a Control Plane process. It competes against other Control Plane processes such as monpd and iRules LX (node.js) for CPU/memory resources. AS3 uses the iControl REST framework for manipulating the BIG-IP resources. This implies that its operation is impacted by any processes that use httpd (e.g., GUI), restjavad, icrd_child and mcpd. If you have resource-hungry processes that run periodically (e.g., avrd), you may want to run your AS3 declaration during some other time window. See the following K articles for alist of processes K89999342 BIG-IP Daemons (12.x) K05645522BIG-IP Daemons (v13.x) K67197865BIG-IP Daemons (v14.x) K14020: BIG-IP ASM daemons (11.x - 15.x) K14462: Overview of BIG-IP AAM daemons (11.x - 15.x) Workarounds If you experience issues such as timeout on restjavad, it is possible that your AS3 operation had resource issues. After reviewing the Best Practice above but still unable to alleviate the problem, you may be able to temporarily fix it by applying the following tactics. Increase the restjavad memory allocation The memory size of restjavad can be increased by the following tmsh sys db commands tmsh modify sys db provision.extramb value <value> tmsh modify sys db restjavad.useextramb value true The provision.extramb db key changes the maximum Java heap memory to (192 + <value> * 8 / 10) MB. The default value is 0. After changing the memory size, you need to restart restjavad. tmsh restart sys service restjavad See the following article for more on the memory allocation: K26427018: Overview of Management provisioning Increase a number of icrd_child processes restjavad spawns a number of icrd_child processes depending on the load. The maximum number of icrd_child processes can be configured from /etc/icrd.conf. Please consult F5 Support for details. See the following article for more on the icrd_child process verbosity: K96840770: Configuring the log verbosity for iControl REST API related to icrd_child Decrease the verbosity levels of restjavad and icrd_child Writing log messages to the file system is not exactly free of charge. Writing unnecessarily large amount of messages to files would increase the I/O wait, hence results in slowness of processes. If you have changed the verbosity levels of restjavad and/or icrd_child, consider rolling back the default levels. See the following article for methods to change verbosity level: K15436: Configuring the verbosity for restjavad logs on the BIG-IP systemHow I did it - "Visualizing Metrics with F5 Telemetry Streaming and Datadog"
In some recent installments of the “How I Did it” series, we’ve taken a look at how F5 Telemetry Streaming, (TS) integrates with third-party analytics providers like Splunk and Elastic.In this article we continue our analytics vendor journey with the latest supported vendor, Datadog. Datadog is an analytics and monitoring platform offered in a Software-as-a-Service (SaaS) model.The platform provides a centralized visibility and monitoring of applications and infrastructure assets.While Datadog typically relies upon its various agents to capture logs and transmit back to the platform, there is an option for sending telemetry over HTTP.This is where F5’s TS comes into play. For the remainder of this article, I'll provide a brief overview of the services required to integrate the BIG-IP with Datadog.Rather than including the step-by-step instructions, I've included a video walkthrough of the configuration process.After all, seeing is believing! Application Services 3 Extension (AS3) There are several resources, (logging profiles, log publishers, iRules, etc.) that must be configured on the BIG-IP to enable remote logging. I utilized AS3 to deploy and manage these resources. I used Postman to apply a single REST API declaration to the AS3 endpoint. Telemetry Streaming (TS) F5's Telemetry Streaming, (TS) service enables the BIG-IP to stream telemetry data to a variety of third-party analytics providers. Aside from the aforementioned resources, configuring TS to stream to a consumer, (Datadog in this instance), is simply a REST call away. Just as I did for AS3, I utilized Postman to post a single declaration to the BIG-IP. Datadog Preparing my Datadog environment to receive telemetry from BIG-IPs via telemetry streaming is extremely simple.I will need to generate an API key which will in turn be used by a telemetry streaming extension to authenticate and access the Datadog platform.Additionally, the TS consumer provides for additional options, (Datadog region, compression settings, etc.) to be configured on the TS side. Dashboard Once my Datadog environment starts to ingest telemetry data from my BIG-IP, I’ll visualize the datausing a custom dashboard.The dashboard, (community-supported and may not be suitable for framing) report various relevant BIG-IP performance metrics and information. F5 BIG-IP Performance Metrics Check it Out Rather than walk you through the entire configuration, how about a movie? Click on the link (image) below for a brief walkthrough demo integrating F5's BIG-IP with Datadog using F5 Telemetry Streaming. Try it Out Liked what you saw? If that's the case, (as I hope it was) try it out for yourself. Checkout F5's CloudDocs for guidance on configuring your BIG-IP(s) with the F5 Automation Toolchain.The various configuration files, (including the above sample dashboards) used in the demo are available on the GitHub solution repository Enjoy!
