Nextjs 404s on buildManifest across multiple EC2 instances

user_2780176 0
Viewed 1127

Context: I have a simple Next.js and KeystoneJS app. I've made duplicate deployments on 2 AWS EC2 instances. Each instance also has an Nginx reverse proxy routing port 80 to 3000 (my apps port). The 2 instances are also behind an application load balancer.

Problem: When routing to my default url, my application attempts to fetch the buildManifest for the nextjs application. This, however, 404s most of the time.

My Guess: Because the requests are coming in so close together, my load balancer is routing the second request for the buildManifest to the other instance. Since I did a separate yarn build on that instance, the build ids are different, and therefore it is not fetching the correct build. This request 404s and my site is broken.

My Question: Is there a way to ensure that all requests made from instance A get routed to instance A? Or is there a better way to do my builds on each instance such that their ids are the same? Is this a use case for Docker?

keystonejs next.js amazon-web-services amazon-ec2 load-balancing
2 Answers

I have had a similar problem with our load balancer and specifying a custom build id seems to have fixed it. Here's the dedicated issue and this is how my next.config.js looks like now:

const execSync = require("child_process").execSync;

const lastCommitCommand = "git rev-parse HEAD";

module.exports = {
  async generateBuildId() {
    return execSync(lastCommitCommand).toString().trim();
  },
};
user_113172260
user_100490170
Related