My Java application is built around an embedded database which stores db data directly to disk. I understand that Heroku by default is built on an ephemeral filesystem and anything stored in it will be removed when dynos restart or just don't stick.
What is the workaround to make such an application available and deployed in Heroku?
I understand that Heroku by default is built on an ephemeral filesystem
This isn't "by default". It's fundamental to Heroku's architecture and cannot be changed. Heroku is designed to be trivially horizontally scalable, and part of that design is that state should exist apart from any one dyno. Dynos are disposable.
What is the workaround to make such an application available and deployed in Heroku?
As far as I know, none exists. Either change how you save your data or choose another host.
(You might be able to mount a shared persistent filesystem on your dynos, but that's awkward and undermines Heroku's architecture. I don't advise it. None of Heroku's offical addons provides a persistent filesystem, and a quick search finds a few blog posts outlining attempts but I don't see any successes.)
Related
I have been using heroku for previous 4-5 years, and most recently got to work on Infra as code and i was wondering which technology/methodology Heroku uses for sniping dynos or workers, I have tried searching online whether its LXC or something else but was not able to find any answer. Thanks
Heroku uses LXC:
Each application on the Heroku platform runs within its own isolated environment and cannot interact with other applications or areas of the system. This restrictive operating environment is designed to prevent security and stability issues. These self-contained environments isolate processes, memory, and the file system using LXC while host-based firewalls restrict applications from establishing local network connections.
Source: https://www.heroku.com/policy/security
Can someone explain me why we need the Atlas?
If I have Heroku which gives an easier access to cloud (PaaS), then why we need MongoDB Atlas?
Some sources say that we can connect Heroku with Atlas, but why we need that? And can please someone explain me the difference, because it seems I do not understand it completely.
Will be very thankful to everyone. Articles will also be good.
Heroku is a PAAS where you can deploy your applications. Multiple languages are supported and the development experience is great (deploy from Git or using Docker, plenty of examples and documentation).
Typically your application needs a data store to persist the data, Heroku offers few options (ie Postgres) but no more MongoDB. An alternative is to use Atlas where you can define your MongoDB cluster and databases.
Both Heroku and Atlas have a free-tier so you can run both the application and the database without cost. As your database grows you might need to buy a different subscription, this applies to Heroku too if you require more resources or for example no downtime (Heroku Free tier sends the Dyno to sleep after 30 min inactivity).
A good article to use Heroku with Atlas is Detaching from mLab
I'm new using heroku and I will pick 4 instances of 2X dynos and I worry about AFAIK there is no share data between dynos.
So my question is, is there a way to save data in all redis(https://addons.heroku.com/rediscloud#250) instances(located on each dynos)
Your confusion stems from assuming that Redis runs locally on each dyno. When you use an add-on such as Redis Cloud, Redis is external to all dynos and is run on sperate servers that are operated by the service provider (Redis Labs in this case).
As long as all your dynos belong to the same app (which appears to be the case), all of them will share the same add-ons, Redis Cloud included. While your app will run distributed across these dynos, all of its connections will be opened to the same Redis database (defined by the `REDISCLOUD_URL' env var) and will therefore be able to share the data in it.
The app I am currently hosting on Heroku allows users to submit photos. Initially, I was thinking about storing those photos on the filesystem, as storing them in the database is apparently bad practice.
However, it seems there is no permanent filesystem on Heroku, only an ephemeral one. Is this true and, if so, what are my options with regards to storing photos and other files?
It is true. Heroku allows you to create cloud apps, but those cloud apps are not "permanent" - they are instances (or "slugs") that can be replicated multiple times on Amazon's EC2 (that's why scaling is so easy with Heroku). If you were to push a new version of your app, then the slug will be recompiled, and any files you had saved to the filesystem in the previous instance would be lost.
Your best bet (whether on Heroku or otherwise) is to save user submitted photos to a CDN. Since you are on Heroku, and Heroku uses AWS, I'd recommend Amazon S3, with optionally enabling CloudFront.
This is beneficial not only because it gets around Heroku's ephemeral "limitation", but also because a CDN is much faster, and will provide a better service for your webapp and experience for your users.
Depending on the technology you're using, your best bet is likely to stream the uploads to S3 (Amazon's storage service). You can interact with S3 with a client library to make it simple to post and retrieve the files. Boto is an example client library for Python - they exist for all popular languages.
Another thing to keep in mind is that Heroku file systems are not shared either. This means you'll have to be putting the file to S3 with the same application as the one handling the upload (instead of say, a worker process). If you can, try to load the upload into memory, never write it to disk and post directly to S3. This will increase the speed of your uploads.
Because Heroku is hosted on AWS, the streams to S3 happen at a very high speed. Keep that in mind when you're developing locally.
I just started learning Ruby on rails and I was wondering what Heroku really is? I know that its a cloud that helps us to avoid using servers? When do we actually use it?
Heroku is a cloud platform as a service. That means you do not have to worry about infrastructure; you just focus on your application.
In addition to what Jonny said, there are a few features of Heroku:
Instant Deployment with Git push - build of your application is performed by Heroku using your build scripts
Plenty of Add-on resources (applications, databases etc.)
Processes scaling - independent scaling for each component of your app without affecting functionality and performance
Isolation - each process (aka dyno) is completely isolated from each other
Full Logging and Visibility - easy access to all logging output from every component of your app and each process (dyno)
Heroku provides very well written tutorial which allows you to start in minutes. Also they provide first 750 computation hours free of charge which means you can have one processes (aka Dyno) at no cost. Also performance is very good e.g. simple web application written in node.js can handle around 60 - 70 requests per second.
Heroku competitors are:
OpenShift by Red Hat
Windows Azure
Amazon Web Services
Google App Engine
VMware
HP Cloud Services
Force.com
It's a cloud-based, scalable server solution that allows you to easily manage the deployment of your Rails (or other) applications provided you subscribe to a number of conventions (e.g. Postgres as the database, no writing to the filesystem).
Thus you can easily scale as your application grows by bettering your database and increasing the number of dynos (Rails instances) and workers.
It doesn't help you avoid using servers, you will need some understanding of server management to effectively debug problems with your platform/app combination. However, while it is comparatively expensive (i.e. per instance when compared to renting a slice on Slicehost or something), there is a free account and it's a rough trade off between whether it's more cost effective to pay someone to build your own solution or take the extra expense.
Heroku Basically provides with webspace to upload your app
If you are uploading a Rails app then you can follow this tutorial
https://github.com/mrkushjain/herokuapp
As I see it, it is a scalable administrated web hosting service, ready to grow in any sense so you don't have to worry about it.
It's not useful for a normal PHP web application, because there are plenty of web hosting services with ftp over there for a simple web without scalability needs, but if you need something bigger Heroku or something similar is what you need.
It is exposed as a service via a command line tool so you can write scripts to automate your deployments. Anyway it is pretty similar to other web hosting services with Git enabled, but Heroku makes it simpler.
That's its thing, to make the administration stuff simpler to you, so it saves you time. But I'm not sure, as I'm just starting with it!
A nice introduction of how it works in the official documentation is:
https://devcenter.heroku.com/articles/how-heroku-works
Per DZone: https://dzone.com/articles/heroku-or-amazon-web-services-which-is-best-for-your-startup
Heroku is a Platform as a Service (PaaS) product based on AWS, and is vastly different from Elastic Compute Cloud. It’s very important to differentiate ‘Infrastructure as a Service’ and ‘Platform as a Service’ solutions as we consider deploying and supporting our application using these two solutions.
Heroku is way simpler to use than AWS Elastic Compute Cloud. Perhaps it’s even too simple. But there’s a good reason for this simplicity. The Heroku platform equips us with a ready runtime environment and application servers. Plus, we benefit from seamless integration with various development instruments, a pre-installed operating system, and redundant servers.
Therefore, with Heroku, we don’t need to think about infrastructure management, unlike with AWS EC2. We only need to choose a subscription plan and change our plan when necessary.
That article does a good job explaining the differences between Heroku and AWS but it looks like you can choose other iaas (infrastructure) providers other than AWS. So ultimately Heroku seems to just simplify the process of using a cloud provider but at a cost.