I have a web app running on php, mysql, apache on a virtual windows server. I want to redesign it so it is scalable (for fun so I can learn new things) on AWS.
I can see how to setup an EC2 and dump it all in there but I want to make it scalable and take advantage of all the cool features on AWS.
I've tried googling but just can't find a simple guide (note - I have no command line experience of Linux)
Can anyone direct me to detailed resources that can lead me through the steps and teach me? Or alternatively, summarise the steps in an answer so I can research based on what you say.
Thanks
AWS is growing and changing all the time, so there aren't a lot of books to help. Amazon offers training that's excellent. I took their three day class on Architecting with AWS that seems to be just what you're looking for.
Of course, not everyone can afford to spend the travel time and money to attend a class. The AWS re:Invent conference in November 2012 had a lot of sessions related to what you want, and most (maybe all) of the sessions have videos available online for free. Building Web Scale Applications With AWS is probably relevant (slides and video available), as is Dissecting an Internet-Scale Application (slides and video available).
A great way to understand these options better is by fiddling with your existing application on AWS. It will be easy to just move it to an EC2 instance in AWS, then start taking more advantage of what's available. The first thing I'd do is get rid of the MySql server on your own machine and use one offered with RDS. Once that's stable, create one or more read replicas in RDS, and change your application to read from them for most operations, reading from the main (writable) database only when you need completely current results.
Does your application keep any data on the web server, other than in the database? If so, get rid of all local storage by moving that data off the EC2 instance. Some of it might go to the database, some (like big files) might be suitable for S3. DynamoDB is a good place for things like session data.
All of the above reduces the load on the web server to just your application code, which helps with scalability. And now that you keep no state on the web server, you can use ELB and Auto-scaling to automatically run multiple web servers (and even automatically launch more as needed) to handle greater load.
Does the application have any long running, intensive operations that you now perform on demand from a web request? Consider not performing the operation when asked, but instead queueing the request using SQS, and just telling the user you'll get to it. Now have long running processes (or cron jobs or scheduled tasks) check the queue regularly, run the requested operation, and email the result (using SES) back to the user. To really scale up, you can move those jobs off your web server to dedicated machines, and again use auto-scaling if needed.
Do you need bigger machines, or perhaps can live with smaller ones? CloudWatch metrics can show you how much IO, memory, and CPU are used over time. You can use provisioned IOPS with EC2 or RDS instances to improve performance (at a cost) as needed, and use difference size instances for more memory or CPU.
All this AWS setup and configuration can be done with the AWS web console, or command-line tools, or SDKs available in many languages (Python's boto library is great). After learning the basics, look into CloudFormation to automate it better (I've written a couple of posts about that so far).
That's a bit of the 10,000 foot high view of one approach. You'll need to discover the details of each AWS service when you try to use them. AWS has good documentation about all of them.
Depending on how you look at it, this is more of a comment than it is an answer, but it was too long to write as a comment.
What you're asking for really can't be answered on SO--it's a huge, complex question. You're basically asking is "How to I design a highly-scalable, durable application that can be deployed on a cloud-based platform?" The answer depends largely on:
The specifics of your application--what does it do and how does it work?
Your tolerance for downtime balanced against your budget
Your present development and deployment workflow
The resources/skill sets you have on-staff to support the application
What your launch time frame looks like.
I run a software consulting company that specializes in consulting on Amazon Web Services architecture. About 80% of our business is investigating and answering these questions for our clients. It's a multi-week long project each time.
However, to get you pointed in the right direction, I'd recommend that you look at Elastic Beanstalk. It's a PaaS-like service that abstracts away the underlying AWS resources, making AWS easier to use for developers who don't have a lot of sysadmin experience. Think of it as "training wheels" for designing an autoscaling application on AWS.
Sorry for the very involved question, but this is something I've been researching for a while now and it is really frustrating me. I feel like in today's age we have a million and one ways to implement services tat are cross-platform (SOAP) and easy to build (thanks to .NET, java, and other frameworks). However, these technologies have been in the community for 5-10 years, but we are (or at least I am) constantly plagued with the same issues:
Identification (Tracking services) - UDDI; e.g., had to remind a co-worker the 3 times this month where a service is at, despite the fact there is a wiki that discusses the service and a PDF version of the same documentation that lives in a repository where we keep our service docs.
Scalability - Out of the box clustering; As organizations, we spend a lot of money on paying our admins just to watch the utilization of our services and make decisions like, does this service need more RAM, more CPU, more interfaces? How do I load balance this?
Monitoring - error logging, etc; I can't count how many times I have to set up tracing on services in order to see why a bug is happening that only seems to affect one customer, or have to code logic into the service to serialize exceptions, log exceptions to dbs, fail gracefully, etc.
Deployment - easy to deploy; none of this deploying DLLs to 5 load balanced servers
Each one of these problems requires some type of custom solution implemented by the organization. Documentation and UDDIs for #1. Virtualization and load balancing hardware / software for #2. Tracing, writing exceptions to databases / logs, etc for #3. Custom deployment software for #4. I work for a mid-sized organization. I can't even imagine how a company the size of Sun, Google, or Microsoft would tackle these dilemmas.
Maybe my vision is unrealistic, but I dream of having a Framework per se that lives on top of a server cluster that manages all of the above. I was ecstatic to read about Microsoft's AppFabric since it really seems to extend some of the functionality of BizTalk to WCF service implementors: Caching, Hosting, Monitoring, etc. However, from what I've seen, I still don't feel it lives up to my dream for an all-in-one solution that assists the developer and organization in writing services that are scaled across clusters easily, deployed into the cluster easily, and identifiable, possibly even version-able.
So, I don't mean this post to be about my dream. I do actually have a question. For starters, is my dream / want completely unrealistic? Furthermore, what solutions are there available that attempt to solve these problems without confining us to a new and more proprietary way (BizTalk) of developing services? An lastly, in concern to a complete SOA / ESB solution, where do we see the most potential in the market right now or in the future?
I think that you are talking about different kinds of problems here.
1). Developers who don't read documentation. This is an endemic problem, not limited to SOA - just look at some questions on StackOverflow. At least the developer is asking you whether there is a service, rather then just duplicating logic in their own code. I don't see any technical solution to these kinds of problems, you've already provided good registries and documentation, but some developers prefer to talk to people. Maybe, even, this is actually a good thing - human interaction has value above the technical content of the interaction. Or maybe, you're too nice: "No, I won't answer that question, look it up."
2). Scaling. There are technologies addressing this issue. (Disclaimer I work for IBM, who sell some, so I'll reference these - I'm not intending to imply that IBM are the only vendor with solutions in this space.) There are products such as this that can provision a new machine, install a software stack and add it to a cluster to address workload changes. Then at a finer grained level of control in the Java EE world the Application Server can dynamically shape traffic and adjust clusters. See WebSphere Virtual Enterprise
3). Monitoring. I don't "get" what you expect here. In all likelyhood such tricky bugs will require application level trace. For some problems such as finding memory leaks and performance bottlenecks there are very good tools, at least in the Java EE world.
4). I can't speak to the .Net world, but I'd say that Java EE app servers do a reasonable job of deploying the apps across clusters smoothly, and in the cases where we use JNI and need DLLs deploying then we can use products such as the Tivoli stack I mention to manage this.
So, in summary, I do think that vendors are trying to address these issues. And I don't think your life would be simpler without SOA. Imagine instead the same problems applied to myriad separate, independent applications.
Here's my two cents.
I've been a developer at a company that used SOA incorrectly. The worst solution they implemented was field level validation of form elements on a desktop app using SOA. To perform acceptably these require very low latency. A 2-4 second wait to change to a new field gets old fast. The service ran over the network on a biztalk server. Everyone hated it.
If you're going to do this you really need to spend a lot of time dealing with network latency, service failure, timing, and timeout issues.
Don't get carried away and think SOA is the solution to every problem. Used at a high level it's great, used at a low level it makes your applications fragile, slow, and impossible to debug.
If you talk to IBM or one of the big SOA vendors, they got a products that cover each scenario.
Identification (Tracking services) - UDDI; e.g., had to remind a co-worker the 3 times this month where a service is at, despite the fact there is a wiki that discusses the service and a PDF version of the same documentation that lives in a repository where we keep our service docs.
Registry and Repository server. Nice thing is that it does governance (promotion, demotion, versioning, approval) and your ESB typically does a "lookup" for the latest and greatest against the register server.
Scalability - Out of the box clustering; As organizations, we spend a lot of money on paying our admins just to watch the utilization of our services and make decisions like, does this service need more RAM, more CPU, more interfaces? How do I load balance this?
Transaction monitoring software like IBM Tivoli Composite Application Manager for SOA. Basically, it tracks things from a horizontal point of view and to see if there is a service disruption from a end user/end app point of view.
As far as your clustering.... you have to pick good middleware and architecture. Personally speaking, get stuff that is "cloud" ready. App Servers with NoSQL connected by MOM.
Monitoring - error logging, etc; I can't count how many times I have to set up tracing on services in order to see why a bug is happening that only seems to affect one customer, or have to code logic into the service to serialize exceptions, log exceptions to dbs, fail gracefully, etc.
Enterprise standards for your developers and for your vendors. Integration of all business and system events into a single dashboard. (Most companies spilt them). This is done already at most enterprise shops.
Deployment - easy to deploy; none of this deploying DLLs to 5 load balanced servers
Ahh.. Microsoft IIS Web Deployment Tool 2.0. You can sync 100s of MS servers by just updating the master. It's really easy.
I just saw a demo of electric cloud and it was very interesting, but it is expensive.
Pro: Excellent features
- extract the secret sauce from my builds and make them more standardized with reusable steps
- parallelize the build to speed it up and use my build farm more effectively
- restart the build from any step
- integrate test automation and promotion (perhaps even deployment into production) with good logging, auditing and reporting
Con: enterprise sized price tag
I feel like I could probably use STAF, maven and hudson with some plugin development to do most (but not all) of what these tools offer, but it would require a lot of customization and feels like beating my clothes against rocks instead of paying for a washing machine.
Does anyone have opinions to share about these options and what aspects of the environment makes one choice fit better than another?
At my last company, we deployed both the commander and accelerator. At my current company, we are planning on doing the same thing.
My last company did about 70 builds per day. The build time was 12 hours. The total build time was reduced to about 3 hours using accelerator. We started the deployment building only the very latest release and its incoming streams. We used commander to follow a continuous integration (CI) model - the same "recipe" was used to do both the CI and nightly builds with the CI builds using some different options. The number of nightly build failures dropped down to near 0 and the velocity of development increased significantly. At that point, all we heard from development was "ME NEXT"!!! The ROI for this was incredible.
Yes you can develop some of this using hudson or cruisecontrol, but as you indicated you'll be missing a lot of functionality and end up spending spending time customizing and supporting this environment.
Feel free to contact me if you'd like to discuss this more.
I do not have experience with BuildForge.
We started our 20 team program with Jenkins and Incredibuild, however, this didn't scale as well as we had hoped. Many of our teams would check in the day or two before the end of a sprint (yes, a behavioral issue) and Jenkins would get overwhelmed. A build without IncrediBuild would take ~90mins and with ~12mins. This does not include the wait time teams would face since Jenkins builds in a serial manner (queue).
We moved to Electric Commander + Accelerator and saw our build times decrease to ~5mins. The biggest benefit, however, was running parallel builds. Teams don't have to wait any more for their build to start. We use EC's schedules for each team and our build is much more modular/maintainable (written in perl).
Be warned, their dashboard is not like Jenkins. This was a common complaint from our teams. There are ways to run EC from Jenkins (so you get the Jenkins dashboard with the EC speed) though.
tl;dr Electric Cloud is great if you need to scale.
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We are finishing up our web application and planning for deployment. Very important aspect of deployment to production is monitoring the health of the system. Having a small team of developers/support makes it very critical for us to get the early notifications of potential problems and resolve them before they have impact on users.
Using Nagios seams like a good option, but wanted to get more opinions on what are the best monitoring tools/practices for web application in general and specifically for Django app? Also would welcome recommendations on what should be monitored aside from the obvious CPU, memory, disk space, database connectivity.
Our web app is written in Django, we are running on Linux (Ubuntu) under Apache + Fast CGI with PostgreSQL database.
EDIT
We have a completely virtualized environment under Linode.
EDIT
We are using django-logging so we have a way separate info, errors, critical issues, etc.
Nagios is good, it's good to maybe have system testing (Selenium) running regularily.
Edit: Hyperic and Groundwork also look interesting.
There is probably a test suite system that can keep pressure testing everything as well for you. I can't remember the name off the top of my head, maybe someone can mention one below.
Other things I like to do:
The best motto for infrastructure is always fix, detect, repair. Get it up, get to the root of it, and cure/prevent it if you can.
Since a system exists at many levels, we should test at many levels:
Edit: Have all errors or warnings posted directly to your case manager via email. That way you can track occurrences in one place.
1) Connection : monitor your internet connectivity from the server and from the outside. Log this somewhere
2) Server : monitor all the processes that you need to to ensure they are running and not pinning the server. Use a HP Server or something equivalent with hardware failure notification that it can do from a bios level. Notify and log if they are.
3) Software : Identify the key software that always needs to be running. Set the performance levels if any and then monitor them. Nagios should be able to help with this. On windows it can be a bit more. When an exception occurs, you should be able to run a script from it to restart processes automatically. My dream system is allowing me to interact with servers via SMS if the server sees it as an exception that I have to either permit, or one that will happen automatically unless I cancel by sms. One day..
4) Remote Power : Ensure Remote power-reset capabilities are in your hand. You might want to schedule weekly reboots if you ever use windows for anything.
5) Business Logic Testing : Have regularly running scripts testing the workflow of your system. Selenium can probably achieve some of this, but I like logging the results as well to say this ran at this time and these files had errors. If possible anywhere, have the system monitor itself through your scripts.
6) Backups : Make a backup that you can set and forget. If you can get things into virtual machines it would be ideal as you can scale, move, or deploy any part of your infrastructure anywhere. I have had instances where I moved a dead server onto my laptop, let it run in vmware while I fixed a problem.
Monitoring the number of connections to your Web server and your database is another good thing to track. Chances are if one shoots through the roof, something is starving for resources and the site is about to go down.
Also make sure you have a regular request for a URL that is a reasonable end-to-end test of the system. If your site supports search, then have nagios execute a search - that should make sure the search index is healthy, the Web server and the database server.
Also, make sure that your applications sends you email anytime your users see an error, or there is an unhandled exception. That way you know how the application is failing in the field.
If I had to pick one type of testing it would be to test the end-user functionality of the system. The important thing to consider is the user. While testing things like database availability, server up-time, etc, are all important, testing work-flows through your system via a remote UI testing system covers all these bases. If you know that the critical parts of your system are available to the end-user, then you know your system is prolly Ok.
Identify the important work-flows in your system. For example, if you wrote an eCommerce site you might identify a work-flow of "search for a product, put product in shopping cart, and purchase product".
Prioritize the work-flows, and build out higher-priority tests first. You can always add additional tests after you roll out to production.
Build UI tests using one of the available UI testing frameworks. There are a number of free and commercial UI testing frameworks that can be run in an automated fashion. Build a core set of tests first that address critical work-flows.
Setup at least one remote location from which to run tests. You want to test every aspect of your system, which means testing it remotely. Is the internet connection up? Is the web server running? Is the connection to the database server working? Etc, etc. If you test remotely you make sure you system is available to the outside world which means it is most likely working end-to-end. You can also run these tests internally, but I think it is critical to run them externally.
Make sure your solution includes both reporting and notification. If one of your critical work-flow tests fails, you want someone to know about it to fix the problem ASAP. If a non-critical task fails, perhaps you only want reporting so that you can fix problems out-of-band.
This end-user testing should not eliminate monitoring of system in your data-center, but I want to reiterate that end-user testing is the most important type of testing you can do for a web application.
Ahhh, monitoring. How I love thee and your vibrations at 3am.
Essentially, you need a way to inspect the internal state of your application, both at a specific moment, as well as over spans of time (the latter is very important for detecting problems before they occur). Another way to think of it is as glorified unit-testing.
We have our own (very nice) monitoring system, so I can't comment on Nagios or other apps. Our use case is similar to yours, though (cgi app on apache).
Add a logging.monitor() type method, which will log information to disk. This should support, at the least, logging simple numbers and dicts of numbers (the key=>value association can be incredibly handy).
Have a process that scrapes the monitoring logs and stores them into a database.
Have a process that takes the database information, checks them against rules, and sends out alerts. Keep in mind that somethings can be flaky. Just because you got a 404 once doesn't mean the app it down.
Have a way to mute alerts (very useful for maintenance or to read your email).
Thats all pretty high level. The important thing is that you have a history of the state of the application over time. From this, you can then create rules (perhaps just raw sql queries you put into a config somewhere), that say "If the queries per second doubled, send a SlashDotted alert", or "if 50% of responses are 404, send an alert". It also bedazzles management because you can quantify any comment about whether its up, down, fast, or slow.
Things to monitor include (others probably mentioned these as well): http status, port accessible, http load, database load, open connection, query latency, server accessibility (ssh, ping), queries per second, number of worker processes, error percentage, error rate.
Simple end-to-end tests are also very handy, though they can be brittle. Its best to keep them simple, but you should have one that tries to touch core pieces of the app (caching, database, authentication).
I use Munin and Monit, and have been very happy with both of them.
Internal logging is fine and dandy but when your whole app goes down or your box/enviro crashes you need an outside check too. http://www.pingdom.com/ has been very reliable for me.
My only other advice is I wouldnt spent too much time on this. my best example is twitter, how much energy did they put into the system being able to half-die instead of just investing that time and energy into throwing more hardware / scaling it out.
Chances are what ends up taking you down, your logging and health systems will have missed anyway.
The single most important way to monitor any online site is to monitor externally. The goal should be to monitor your site in a way that most closely reflects how your users use the site. In 99% of cases, as soon as you know that your site is down externally, it's relatively easy to find the root cause. The most important thing is to know as soon as possible that your customers are unable to load your site.
This generally means using an external performance monitoring service. They very from the very low end (mon.itor.us, pingdom) to the high end (Webmetrics, Gomez, Keynote). And as always, you get what you pay for. The things to look for when shopping around for a monitoring service include:
The size and distribution of the monitoring network
Whether or not the monitoring solution is able to monitor your site using a real browser (otherwise you aren't testing your site like a real user would)
The scripting language (to script the transactions against your site)
The support department, to help you along the way, and provide expertise on how to monitor correctly
Good luck!
Web monitoring by IP Patrol or SiteSentry have been useful for us. The second is a bit like site confidence but slightly prettier lol.
Have you thought about monitoring the functionality as well? A script (either in a scripting language like Perl or Pyton or using some tool like WebTest) that talks to your application and does some important steps like logging in, making a purchase, etc is very nice to have.
Aside from what to monitor, which has already been answered, you need to make sure - whatever system you use - that you get only one notification of an error that happens multiple times, on each request. Or your inbox will run out of memory :) Plus, it's plain annoying...
Divide the standby shifts among the support/dev team, so one person does not have to be on call every single evening. That will wear people down. Monitoring is a good thing, but everyone needs to get a chance to have a life once in a while. Your cellphone buzzing at 2AM for a few nights will get very old pretty soon, trust me. And not every developer is used to 24/7 support, so you need to find the balance between using monitoring and abusing monitoring.
Basically, have distinct escalation levels, and if the sky is not falling, define a "serenity now" window at night where smaller escalation levels don't go out.
I've been using Nagios + CruiseControl + Selenium for running high-level tests on mission critical web applications. I got burned pretty hard by a simple jquery error that stopped users from proceding through an online signup form.
http://www.agileatwork.com/the-holy-trinity-of-web-2-0-application-monitoring/
You can take a look at AlertGrid. This web application allows you to filter and forward alerts to your team (worldwide). It has also nice ability to monitor if something did not happen.
To paraphrase Richard Levasseur: ah, monitoring tools, how your imperfections frustrate me. There doesn't seem to be a perfect tool out there; Nagios is pretty easy to set up but the UI is kinda old fashioned and you have to have a daemon running on each server being monitored. Zenoss has a much nicer UI including trend graphs of resource usage, but it uses SNMP so you have to have some familiarity with that to get it working properly, and the documentation is not the best - there are hundreds of pages but it's really hard to find just the info you need to get started.
Friends of mine have also recommended Cacti and Hyperic, but I don't have personal experience with those.
One last thing - one of the other answers suggested running a tool that stresses your site. I wouldn't recommend doing that on your live site unless you have a reliable quiet period when nobody is hitting it; even then you might bring it down unexpectedly. Much better to have a staging server where you can run load tests before putting changes into production.
One of our clients uses Techout (www.techout.com) and is very pleased with the service.
There is no charge for alerts, no matter what kind or how many, and they offer email, voicemail and SMS alerts -- and if something major happens, a phone call from a live person to help you out.
It's all based on service -- you don't install the software and you have a consultant who works with you to determine the best approach for your business. It's one of the most convenient web application monitoring services because they take care of everything.
I would just add that you can predict error likelihood somewhat based on history of past errors and having fixed them. With smaller scale internal testing if you were to graph the frequency and severity of problems that have been corrected to this point you'll have an overview of predictable new problems. If everything has been running error free for some time now, then the two sources of trouble would be recent changes or scalability issues.
From the above it sounds like scalability is your only worry, but I just mention the past-error frequency test because the teams I've been on invariably think they got the last error fixed and there are no more. Until there is.
Changing the line a little bit, something I really think is useful and changed a lot how I monitor my apps is to log javascript exceptions somewhere. There's a very nice implementation that logs that directly from user browsers to Google Analytics.
This is a must for Javascript centered web applications, and can give you results based directly on users browsers what can lead to very unexpected errors (iE and mobile browser are pain)
Disclaimer: My post bellow
http://www.directperformance.com.br/en/javascript-debug-simples-com-google-analytics
For the internet presence monitoring, I would suggest the service that I am working on: Sucuri NBIM (Network-based integrity monitor).
It does availability and integrity checks, looking for changes on your internet presence (sites, DNS, WHOIS, headers, etc) and loss of connectivity. It is free and you can try it out here.