I have a Tomcat web app running on AWS. I would like to have several instances of it instead of only one, mainly to avoid down-time in case of problems on one instance. I need a concept of a "leader instance" because some operations should not be carried out by all instances but only one of them. Does Spring Cloud support leadership election and quorum out of the box?
P.S. I would like to avoid the obvious ZooKeeper, if possible.
There is some preliminary work going on in spring-cloud-cluster. It is not released (or supported) yet. You have your choice of implementation, currently: zookeeper, redis or hazelcast. Other implementations shouldn't be hard to do either.
Related
I need some advice on what type of EC2 instance to use for Rocket.Chat development.
The languages and technologies we will work with are Node.js, Express, mongoDB, etc., using docker.
Team members are about 10 people.
This is not our main work and not all members do work always, and not at the same time.
Projects will be API development ,for example, connecting Zapier to Rocket.Chat, making a chatbot platform through BotHub API, integrating Rocket.Chat with other services.
Thanks for the help.
I would strongly recommend you to go through this link to see which Instance Type suits your needs.
In case you are still not sure about it, you can always start with a general-purpose m5.large type. Keep a close eye on CloudWatch metrics to check the CPU Utilization. If you think that the system is unutilized, you can downgrade to a t2 instance and in case the system is overutilized, you can change the instance type to m4.x or c4 instances and so on.
If your application is RAM intensive, a better starting point would be to choose r5/r4 instances.
We have a spring boot application running in physical boxes. Planning to migrate to EKS (AWS). We have hazelcast used for multiple purposes listed below.
Is it possible to use hazelcast itself in AWS to make use of the same features.?
Or should I used any other technology than using hazelcast itself ?
Hazelcast is used for:
1. Master Election (of machines)
2. Caching (To keep some files sometimes and mainly to websocket messages and to transmit those whenever required)
Master Election :
It is used to pick any one machine out of 4 boxes, to do a particular job until next restart/re-deploy.
Hazelcast version used : com.hazelcast.hazelcast : 3.4.2
Reference : what algorithm hazelcast uses to find the master node
Note : Previously I mentioned as leader (actually it's master in the case of Hazelcast)
A. You need to upgrade to a more recent version, preferably 3.12.5, as the later versions have more capabilities in terms of features than their predecessors.
B. From what I could understand, you need a distributed lock so that when acquired, no other application or thread or member can perform the operation defined within the lock boundary. Check out here: https://docs.hazelcast.org/docs/3.12.5/manual/html-single/index.html#lock
Using Hazelcast as a distributed system for its features is agnostic to the underlying platform, EKS or AWS direct or on-prem. Once a cluster is formed, you may want to look at Hazelcast as a service with all the distributed features listed in ref manual.
For caching, definitely yes. A lot of folks use it that way. Hazelcast is very well integrated with all Kubernetes environments.
For leader election, I'm not sure I understand your use case and what you'd like to do in EKS. In Kubernetes, you usually focus more on the container/pod level, not the machine itself. So, to keep the leader election between pods, then yes, you can use Hazelcast, not problem with that.
My company is currently evaluating hyperledger(fabric) and we're using it for our POC. It looks very promising and we're targeting rolling out to production in next few months.
We're targeting AWS as our production environment.
However, we're struggling to find good tutorial/practices/recommendations about operating hyperledger network in such environment.
I'm aware that Cello is aiming to solve/ease deploying/monitoring hyperledger network but i also read that its not production ready yet. Question is, should we even consider looking at Cello at this point?
If not, what are our alternatives? Docker swarm, kubernetes?
I also didn't find information about recommended instance types. I understand this is application and AWS specific but what are the minimal system requirements
(memory&CPU&network) for example for 'peer' node (our application is not network intensive, nor a lot of transactions will be submitted per hour/day, only few of them per day).
Another question is where to create those instances on AWS from geographical&decentralization point of view. Does it make sense all of them to be created in same region? Or, we must create instances running in different regions?
Tnx a lot.
Igor.
yes, look at Cello.. if nothing else it will help you see the aws deployment model.
really nothing special..
design the desired system, peers, orderer, gateways, etc..
then decide who many ec2 instance u need to support that.
as for WHERE (region).. depends on where the connecting application is and what kind of fault tolerance you need for your business model.
one of the businesses I am working with wants a minimum of 99.99999 % availability. so, multi-region is critical. its just another ec2 instance with sockets open from different hosts..
aws doesn't provide much in terms of support for hyperledger. they have some templates which allow you to setup the VMs initially, but that's stuff you can do yourself as well.
you are right, the documentation is very light and most of the time confusing. I got to the point where I can start from scratch with a brand new VM and got everything ready and deploy my own network definition and chaincode and have the scripts to do that.
IBM cloud has much better support for hyperledger however. you can design your network visually, you can download your connection profiles, deploy and instantiate chaincode, create and join channels, handle certificates, pretty much everything you need to run and support such a network. It's light years ahead of AWS. They even have a full CI / CD pipepline that you could replicate for your own project. if you look at their marbles demo, you'll see what i mean.
Cello is definitely worth looking at, with the caveat that it's incubation meaning, not real yet, not production ready and not really useful until it becomes a fully fledged product.
I have created a django app that contains c++ for some of the views as well as a java library. How would I deploy this app? What kind of hosting service allows for multiple languages? I have looked at EC2, GAE, and several platforms (like heroku) but I can't seem to find a definitive solution.
I have never deployed anything to the web so a simple explanation would be much appreciated.
PaaS stuff is probably not your best bet. If you want the scalability and associated buzzwords(muh 99.9999999999% availability because my servers are hosted in a parallel dimension without electrical storms, power outages, hurricanes, earthquakes, or nuclear holocausts) that comes with hosting your application on a huge web company's platform, check out IaaS(Infrastructure as a service) systems like Google's Compute Engine or AWS. With these you just get a virtual server (or servers), running your Linux distro of choice, and you can install and run whatever you please on them without being constrained to a specific platform like App Engine or Heroku(where you have to basically write your app to specifically run on that platform). If you plan on consuming a ton of bandwidth/resources from the get-go, you will almost certainly get a better deal using a dedicated server(s) from a small company.
Interested in what specifically you are executing C++ for in a Django view. Image/video processing?
Well. Deployment is not really something where a simple explanation helps much.
First I would check what the requirements to the operating system are (compilers, dependencies,…). That will maybe reduce the options quickly.
I guess that with a setup containing C++ & Java artifacts, the usual PaaS (GaE, Heroku,…) offerings will not be sufficient because they define the stack. And a mixture of Python/C++/Java is rather uncommon I'd say.
Choosing an IaaS offering (EC2, …) may be an option. There you can run your whole self-defined stack and have the possibility of easier scaling.
Hosting the application on your own server(s) is also always possible. Check your data protection regulations to find out if it's not even a requirement.
There are a lot of ways to get the Django application to run. The Django documentation has some information about deployment. If you have certain special requirements, uwsgi may be a good application server.
You may also want a web server in front of the application. Possibilities range from using uwsgi's built-in http server or using e.g. Nginx with uwsgi.
All in all every component of the whole "deployment" has hundereds of bells and whistels and it's not easy to give advice without knowing specific requirements and properties of the system itself. You'll also probably need a database you have to deploy.
But before deploying it to the web, it's also important to have a solid build process to assemble all the parts. And not only on the development machine. With three languages involved this should be the first step solve. If it easily and automagically deploys in a development environment, moving it to a server is easier.
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.