Why Google Cloud Run gettings massive container restart / new instance creation? - node.js

Question

I've been using Google Cloud Run for a year now and the issue with cloud run containers restarts / new container start is from the beginning.
I've hosted Node + MongoDB app in Cloud Run, but cloud run container is restarting frequently. It's getting around 10 - 12 requests / second, couldn't find any performance bottleneck, requests are serving smoothly, sometimes requests are served more than normal time, might be new container instance cold start delay.
The issue I am facing is the HIGH Number of connections to the MONGODB Server. After some research I could find that I've to close mongodb connection on node process exit so I've added a graceful shutdown function.
// Function to terminate the app gracefully:
const gracefulShutdown = async () => {
console.log(`MONGODB CONNECTION CLOSED!`);
await mongoose.connection.close();
};
// This will handle process.exit():
process.on('exit', gracefulShutdown);
// This will handle kill commands, such as CTRL+C:
process.on('SIGINT', gracefulShutdown);
process.on('SIGTERM', gracefulShutdown);
// This will prevent dirty exit on code-fault crashes:
process.on('uncaughtException', gracefulShutdown);
But even after adding this, I couldn't find this graceful shutdown function is invoked while checking logs.
Does google cloud run really signals when the nodejs process in the container crashed?
Is there any way to identity a container restart or new instance creation in cloud run?
Here is the MongoDB connection code
exports.connect = () => {
try {
mongoose
.connect(MONGO.URI, {
useCreateIndex: true,
keepAlive: 1,
useNewUrlParser: true,
useUnifiedTopology: true,
useFindAndModify: false,
})
.then((docs) => {
console.log(`DB Connected`);
})
.catch((err) => {
console.log(`err`, err);
});
return mongoose.connection;
} catch (err) {
console.log(`#### Error Connecting DB`, err);
console.log(`Mongo URI: `, MONGO.URI);
}
};
Sometimes cloud run issues a high number of connections to MONGODB, and hits the connection limit of 1500 connections.
Any suggestions are appreciated! I've been facing this issue for a year now.

Answer 1

You should not start the node process using npm or yarn but directly as CMD ["node", "index.js"] (when you are inside a Docker container using Dockerfile)
Explanation here https://maximorlov.com/process-signals-inside-docker-containers/