How to Fix 'No Suitable Nodes' Error?

Question

I have a site with an image uploader, and whenever a user tries to upload an image, they are getting this error message:

"No suitable nodes are available to serve your request."

I've contacted the hosting company(mosso) and they have said that it is nothing on their end. Any idea what causes this issue, and what I can do to fix it?

Answer 1

I'm pretty sure it's a problem for your hosting company, as it has something to do with clustered servers.

Answer 2

You need to implement a progress bar of some sort. They have their idle timeout set low enough that uploads fail without some constant feedback.

Answer 3

There are several reasons that you might receive the "no suitable nodes" error regarding requests. A fuller discussion of this problem is at http://nosuitablenodes.com. Here's a summary:

First, this is an error message from a load balancer used to direct traffic to available backend servers for your site. It means no backend resources are available to produce the content requested. This is a default message basically meaning the site is currently unavailable.

Think about your site's resources. Static HTML? Scripting language that creates the page content on the fly? DB-backed website? At each level there are resources that can cause a load balancer (that produced the error message) to time out and return this message.

What can you do? (The real question!)

First, contact the system administrator for your site. The system administrator with access to the load balancer will be able to pinpoint the service that is causing the error condition.

As the site owner you can do a few things to remedy this condition yourself. Add more resources behind the load balancer (for hosted sites, this may be beyond your control) If you are not in control of the resources (i.e., you are using a hosting provider): Determine the actual cause and then for:

1. Web Server) Optimize the configuration to support more connections
2. File system/server) Move static content to a CDN, using byte-code caching in your scripting engine to reduces disk reads
3. Scripting engine) Optimize scripting engine to use byte-code caching
4. Database) optimize queries or move to a dedicated database instance
5. Remote resources) minimize dependencies on remote resources, or optimize them, if possible

Answer 4

It is a very annoying issue. Make sure to join the others and vote for solving the problem at the new Rackspace Cloud's issue list: http://feedback.rackspacecloud.com/forums/71021-product-feedback/suggestions/997177-eliminate-the-dreaded-no-suitable-nodes-error?ref=title