Oct 6, 2013

Follow-up to post on healthcare.gov & state ACA site issues

My post from Friday seemed to have resonated—I think the reaction to it speaks to the dearth of quality reporting on the technology side of the healthcare.gov story that can tease out and interpret implementation issues accurately and give them the proportional weight. It can be hard for the people on the inside and close to the problem to judge what the root cause is in the midst of an ongoing incident. For outside observers not versed in the language of software and systems engineering, it can be even more difficult to gauge the relevance of new facts.

The story of the weekend so far seems to be that the system appears to be stabilizing somewhat (more reports of successful account creations and enrollments), and that the administrators are planning to take the site down for maintenance during off-peak hours (i.e., wee hours of the night). I want to focus on the latter for a moment.

Let’s demystify that classic tech site euphemism, “down for maintenance”. (As if there is a chamber of ball bearings that needs greasing …) There is usually only one reason to take a site down for maintenance: the database. Almost any other component of a web application—load balancers, frontend HTTP servers, caches, application servers—can be swapped-in more or less at any time with minimal or no disruption of existing traffic; perhaps at worst some in-flight requests are disrupted. This applies to hardware or software deployments. If you hear about administrators “adding capacity” or “deploying bug fixes”, with the notable exception of databases (and even just a certain database role at that), that can almost always be accomplished in a way that’s totally transparent to any users. So to me, being down for maintenance speaks to a change to the database.

The reason you would take a site down due to the database is for a schema migration. “Schema migration” means that the way the data is being stored has changed, either due to new business requirements, optimizations (such as “denormalization”, in which pre-computed values are stored for better performance), or other system-level compatibility requirements. Because data storage is so critical to the system and the potential for lost or inconsistent data so damaging, schema migrations typically cannot be performed while the system continues to process requests. (There are some exceptions, such as when the new schema version introduces no incompatibilities with existing application code.) Further, a migration typically involves data being transformed from the old schema version to the new, or indexes being built or rebuild, which can take a non-trivial amount of time, as a function of the size of the data set. Usually the maintenance window will be scaled to the estimated time needed to migrate the data, with padding to check that it went well and to run load and consistency tests.

There are other possibilities for the site being down, such as bringing a new master database online. Quick aside, many sites generally have a single master database—or several with data siloed amongst them—and any changes, including schema migrations or replacing them with new, higher-capacity (in terms of CPU, physical memory, and/or size or performance of storage devices) servers, must be managed exceedingly carefully, in order to avoid data loss or inconsistency. There may be one or more standby or secondary databases, which serve as additional capacity for “read-only” queries—in other words, queries that don’t change the underlying data. But secondary databases can in general be treated like the other components mentioned above, and any operational changes to them can be performed while the site is online.

My suspicion is that as healthcare.gov and the state-based marketplace sites went live earlier in the week, and the access patterns due to user traffic were discovered (and which can be hard, but not impossible, to test for in advance), a systematic flaw in the database architecture was discovered, and the site engineers made a determination that a schema migration was the best course of action for alleviating persistent poor response times and related errors.

As I said in my prior post, I still believe that we will largely forget the stories of healthcare.gov being down and the problems people have had signing up in short order. Part of me hesitated to even write these posts in the first place because in the long run this story won’t really matter. Again, people have until December 15th of this year to enroll for coverage beginning in 2014. If the White House, HHS, and CMS doesn’t have their act together by, say, Thanksgiving, then, yeah, there is a problem. That’s not an excuse for these agencies not delivering on expectations they themselves set, even as they warned about inevitable bugs. Save the hang-wringing and outrage for the Republicans who shut down the government while this was being rolled out.

Oct 4, 2013

healthcare.gov and ACA marketplace sites from the perspective of a software engineer

Full disclosure: my wife works at the Centers for Medicare and Medicaid Services (and this post is entirely my views, not hers), I worked on the president’s re-election campaign, and politically, I wish to see the PPACA law in general and the new marketplaces specifically succeed.

This has been an important week in the history of health care in the United States and for technology professionals working in government and on related services. Here are some thoughts on healthcare.gov and the state-based marketplace websites from my perspective as someone who was been developing and deploying web-based software applications for many years and who has experience with large systems and high-traffic sites.

As I write this there is a weird mixture of angst, elation, anticipation, control-freakery, sympathetic embarassment, hope, and generalized anxiety about healthcare.gov and the state-based marketplace sites among supporters of Obamacare and also among left-leaning technologists. On the one hand, affordable health insurance is now available to any American; on the other, availability doesn’t necessarily mean you can get it, due to errors during the sign-up process on healthcare.gov and the state-based marketplace sites which have been widely reported. There is a sense that, while this is primarily a technology problem to be fixed, the political problem is larger and may risk the implementation and success of the overall law—if enough people perceive the marketplace sites to be broken, support for the law—already tenuous according to some polls—will erode, and the law’s opponents’ argument that implementation needs to be delayed or even defunded will be persuasive.

It is natural for technologists to go into crisis mode and immediately start triaging problems and brainstorming solutions. They are smart and want to help and believe they can fix things. This is a totally appropriate attitude, and their nervous feelings are valid. The people implementing the marketplace sites have all the problems of developing large-scale, integrated, enterprise software, plus delivering a high-quality consumer experience. I think we should also have some perspective on what’s happening, and I would caution against panic. There are a number of things to bear in mind:

Architecture. Caveat: I don’t have direct experience with the marketplace sites, only second-hand knowledge about how they’re implemented. That said, I know some details. The main thing to understand is there is no one, single Obamacare site—there is healthcare.gov, which is home to the federal marketplace and a portal to the state-based marketplaces, and there are the 20+ state-based sites. The federal marketplace is for all Americans for whom their states either chose not to implement their own marketplace or their site isn’t ready yet.

The user interface, or frontend, of healthcare.gov is quite interesting. It’s design has been compared favorably with top commercial sites. It was implemented using modern web development techniques, working well across browsers and on mobile devices. We used similar techniques on the president’s campaign: generate static files from templates with Jekyll, serve them from behind a CDN (Akamai, in the case of healthcare.gov). This gives you a very fast, low-latency user experience that’s very durable in the face of high-traffic loads. Dave Cole has written about the process by which the frontend was developed, it’s fascinating to read if you have any experience with how government sites have typically been built. And you’ll notice, no one has complained about being able to access the site itself. healthcare.gov itself has been up continuously since October 1st. It’s submitting forms back to the server that’s been the issue.

About the backend server: having a great frontend experience means little if you can’t complete a transaction with the service. (Although, not nothing—many important informational consumer resources reside on the frontend and have been wholly unaffected by the reported outages.) People may not realize that a major part of PPACA was the streamlining the rules surrounding Medicaid eligibility. healthcare.gov serves then as a portal, routing people to the appropriate resource they need to help them get covered. This means not only sending you to your state-based marketplace site if your state has one, but directing you to Medicaid instead of the marketplaces, if you are eligible, or determining that you meet requirements for a subsidy on the marketplace. In order to do these things, the system verifies your identity, income, and other personal data with new and existing government databases. In other words, so that it may route you to the correct entity that will be offering or providing you health insurance, healthcare.gov looks up your information online (i.e., during the course of a request-response cycle with the site). The architecture of healthcare.gov is an example of both the challenges of integration—different software services working together—and distributed systems—independent systems that may or may not be available or meeting certain service-level agreements or standards.

An alternative to an online lookup of personal data or account creation would be to store the request for later processing. This is commonly referred to as queuing. It turns an online process into an offline one: the system goes from being synchronous—waiting for a response from another system after making a request to it—to asychronous—not waiting for the response and arranging to check the result somehow later. This is not a trivial change, as people who have implemented these systems will know. It requires a fairly fundamental redesign of the flow of the software, the application of business rules, and how certain operational details are carried out. However, it is now widely established pattern for system development. For example, when you buy a ticket from an airline reservation site, and wait for your credit card to be processed and the whole transaction to complete, that is an example of a synchronous, or online, system (internally, the system may very well be composed of asynchronous services, but the frontend interface that the user interacts with presents a synchronous experience). When you place an order with Amazon, on the other hand, you receive a response almost immediately (“thank you for your order!”). If there is a problem with your order—your card is expired, or was declined—you later receive a notification, usually an email, asking you to update your payment info. That is an example of an asynchronous system. Why does this matter? Asynchrous, distributed systems have components that are de-coupled—if one fails, it doesn’t necessarily bring the rest down with that. You have to design your system to be resilient for such failures, but it enables you to do things such as quickly store the contents of a form submission and acknowledge the user with a thank-you message when the system that looks up personal data or creates new accounts is down. This introduces operational complexity: you must have a functioning queue system, you must have programs that process the queue, they need to be monitored and errors have to be handled appropriately (since there is no online user that can respond to them), and notification systems like email that are out-of-band of the website may need to be employed (in case you need to ask the user to come back and provide more information).

I don’t know to what extent healthcare.gov was designed with the challenges of distributed systems in mind, but moving toward more asynchronous data flows where possible will alleviate some of the poor user experiences we’ve seen reported. It will also free them up to still take in a high volume of requests while independently working to fix bugs in the transactional or informational data services.

Errors, user experience, and expectations. In the reports about problems users have experienced with healthcare.gov and the state-based marketplace sites, we’ve seen screenshots and descriptions of ugly error messages. The quality of the healthcare.gov frontend, with its attractive design that’s more like a retail site than a government site, I think has primed users for an overall experience reflective of that design. They expect the under-the-hood to be as good as the hood appears. Ugly error messages, and disappointment at not being able to complete the sign-up process, frustrate expectations that were set by the site itself, and by its champions, myself included, who encouraged people to go to the site on day 1.

The ugly error messages have for the most part been replaced with friendlier views, and we know that the backend engineers are working to fix the sign-up process. A way to handle expectations at this point for site users might be to remind them, at the point of a system error or maintenance page, that they have until December 15th to enroll for coverage beginning January 1st, 2014, and until March 31st to enroll for coverage in 2014. Another mechanism to reassure a frustrated user that couldn’t sign up might be a simple form that collect email addresses to be notified when the system is back online.

Unprecedented environmental hostility and limited time. Ever since PPACA was passed, I’ve heard griping about would it take so long for Obamacare to come online. In reality, given the scope of the changes to the regulatory framework for health insurance markets, changes to Medicaid eligibility, and the implementation of the federal and state-based marketplaces, there was a huge amount of work to deliver a major new social insurance program in such a short amount of time. It’s natural that there would be bugs, and the president, HHS, and CMS teams have said as much. Going back, many regulatory and technical fixes to the law have been prevented from being taken up by Congress by the law’s opponents. And now of course the federal government is shutdown due in part to opposition to the law. While little of this hostility is new information to implementers, it is nonetheless remarkable what they were able to achieve in this environment. A suspected denial-of-service attack on New York’s site only compounds the outside forces set against this fledgling program.

State-based marketplaces. It is a joke among Medicaid staff that you’ve seen one state’s Medicaid system, you’ve seen one state’s Medicaid system. 24 states chose to implement their own marketplace. While their sites will share some common services with the federal marketplace, and some large contractors worked on multiple sites, these are independently developed and administered sites with their own architectures, infrastructure, designs, and staff.

Time. My strong belief is that these early problems will be largely forgotten very soon. People will get covered. People are getting enrolled, now, despite the problems. It’s worth remembering what happened during the implementation of Medicare Part D. There were many of the same types of reports, from pharmacies that couldn’t connect to government data services, to seniors that were temporarily unable to receive their benefit. Do we think about those stories now when we think about Part D? Of course not. Part D is just as strong and beloved piece of the social safety net firmament as any other. So it will be with Obamacare.

None of this is to excuse the problems healthcare.gov has had this week. October 1st was a known deadline, major sites have been launched under hostile or constrained circumstances before. But I think if we understand a bit more everything involved, we might not be so quick to condemn or dismiss out of hand.

Aug 22, 2013

The God of ‘SNL’ Will See You Now

Jul 30, 2013
Jun 15, 2013

Ancient Roman Concrete Is About to Revolutionize Modern Architecture

Jun 12, 2013

Announcing gogeos, a spatial data library for Go

Jun 11, 2013

Frank Chimero - Generosity of Perspective

I watched the Apple keynote yesterday where they debuted iOS 7. According to my various feeds, you can have one of three reactions: you’re ecstatic about the new design, you hate it, or you’re reserving judgment.

There is a fourth camp: you don’t give a shit, you just want stuff that works.

Apple started off the iOS 7 portion of the keynote with a self-important video applesplainer about how “design is not joost how it looks, it’s about how it works …”, and then spent nearly the entire rest of the time marveling to themselves about the way it looks.

The Android 4.2 operating system is super, super useful. It has been for a while, going back several versions now. The rich notifications pull-down so you can do things like respond to missed calls with canned texts, skip tracks in the music player, mute your Sonos, etc.; the app switcher with screenshots of the apps as they were when you last used them so it’s easier to get back to them; the gesture keyboard that let’s you slide your finger to type which is great for entering text when you’re holding it with one hand; swipe to delete photos or change Chrome tabs; the deep integration with Google services I use all the time; super-accurate voice recognition; tethering; blah, blah, I’m not going to give you the whole laundry list, you can look up Jelly Bean’s features any where. My point is that I can get a veritable shit ton done with my phone. It makes me very productive. I could not possibly care less about the way it looks aesthetically.

This isn’t about iOS vs. Android—it doesn’t matter to me which one is better. But I’m going to use the one that is currently better, that makes me more productive. The fact is that while Apple and apparently most of its observers guffaw to themselves about how they made fun of the old versions for having virtual leather, iOS hasn’t been even remotely as useful as Android for several years now. Maybe iOS 7 will close that gap a bit. Hard to tell because they were marveling at themselves for implementing parallax (!) for the home screen instead of explaining or showing how will make getting certain things done easier, possible, or less painful. Parallax doesn’t make me more productive.

It’s great that designers can get excited about their craft and a company that values it. I wish they would remember that, to paraphrase some wise words, design is about how it works.

Jun 7, 2013

Star Trek Continues E01 "Pilgrim of Eternity" from Star Trek Continues on Vimeo.

Spent 50 minutes gawking at the faithful set, sound, costume, and lighting design. Bravo.

I think the only remaining question is where does it rank in a list of best TOS episodes?

Jun 3, 2013

How Go uses Go to build itself | Dave Cheney

This post walks through the nine steps of the Go build process, starting with the source and ending with a fully tested Go installation.
Jun 3, 2013

Maria - The MVC Framework for JavaScript Applications

Why no one else chose to write an true MVC framework, I cannot figure. … The MVC architecture has withstood a 30 year test. It has passed that brutal test. … The Squeak classes have been around a long time. They are some of the best lines of code in all the world’s aggregate of software. They are a solid foundation on top of which to build an important application.

—from Peter Michaux’s post announcing Maria

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