I'm new to using AWS EBS and ECS, so please bear with me if I ask questions that might be obvious for others. To the issue:
I've got a single-container Node/Express application that runs on EBS. The local docker container works as expected. On EBS, I can access one endpoint of the API and get the expected output. For the second endpoint, which runs longer (around 10-15 seconds) I get no response and run after 60 seconds into a time out: "504 Gateway Time-out".
I wonder how I would approach debugging this as I can't connect to the container directly? Currently there isn't any debugging functionality in the code included either as I'm not sure what the best node approach for a EBS container is - any recommendations are highly appreciated.
Thank you in advance!
You can see the EC2 instances running on EBS in your AWS, and you can choose to give them IP addresses in your EBS options. That will let you SSH directly into them if you need to.
Otherwise check the keepAliveTimeout field in your server (the value returned by app.listen() of you're using express).
I got a decent number of 504s when my Node server timeout was less than my load balancer timeout.
Your application takes longer than expected (> 60 seconds) to respond, so either nginx or the Load Balancer terminates your request.
See my answer here
Related
I am working on AWS lambda functions (NodeJS) that connects to a MongoDB server running on EC2 Instance.
Lambda function is place in a VPC-1 and MongoDB server (EC2 Instance) is in VPC-2.
We have setup VPC peering between VPC-1 and VPC-2
The lambda function is intermittently throwing timeout error. It works 50% of the time and 50% of the time, it's throwing timeout error.
Note: The MongoDB is running on an EC2 Instance is specially setup for the development of this project. It does not get any additional traffic.
Also, another component of this project developed in NodeJS again running from another EC2 instance can communicate with the MongoDB server without any timeout issues.
Could someone help me in understanding the possible cause of the timeout issues?
Thanks in advance.
Hope below article might solve your problem:
To fix: Increase the timeout setting/memory on the configuration page of your Lambda function
For nodejs async related issues, please refer below link:
AWS Lambda: Task timed out
Lambda timeouts can best be described as
The amount of time that Lambda allows a function to run before stopping it. The default is 3 seconds. The maximum allowed value is 900 seconds.
Within the console you can increase this timeout to a greater number.
When you click on the Lambda function there will be a monitoring tab. From here you should be able to see execution time of Lambda functions. You might find that its always close to the bar.
I'd recommend increasing the timeout a bit higher than you anticipate it needs then reviewing these metrics. Once you have a baseline adjust this timeout value again
I have a set of lambda functions that processes messages on an SQS stack. They take data sets, process them and store the results in an RDS MySQL database, which it connects to via VPC. Both the Lambda functions and the RDS database are in the same availability zone.
This has been working for the last couple of months without any issues, but early this morning (2019-01-12) at 01:00 I started seeing lambda timeouts and messages being moved into the dead letter queue.
I've done some troubleshooting and confirmed the reason for the timeouts is the inability for Lambda to establish a connection to the database server.
The RDS server is public, but locked down to allow access only through VPC and 2 public IPs.
I've taken the following steps so far to try and resolve the issue:
Given the lambda service role admin rights to rule out IAM issues
Unassigned VPC from the lambda functions and opened up RDC inbound access from 0.0.0.0/0 to rule out VPC issues.
Restarted the RDS hosts, the good ol' off'n'on again.
Used serverless to invoke the lambda functions locally with test data (worked). My local machine connects to the public RDS IP, not through VPC.
Changed the runtime environment from 3.6 to 3.7
It doesn't appear to be a code issue, as it's been working flawlessly for the past couple of months and I can invoke locally without issue and my Elastic Beanstalk instance, which sits on the same VPC subnet continues to connect through VPC without issue.
Here's the code I'm using to connect:
connectionString = 'mysql+pymysql://{0}:{1}#{2}/{3}'.format(os.environ['DB_USER'], os.environ['DB_PASSWORD'], os.environ['DB_HOST'], os.environ['DB_SCHEMA'])
engine = create_engine(connectionString, poolclass=NullPool)
with engine.connect() as con: <--- breaking here
meta = MetaData(engine, reflect=True) <-- never gets to here
I double checked the connection string & user accounts, both are correct/working locally.
If someone could point me in the right direction, I'd be grateful!
My first guess is that you've hit a connection limit on the RDS database. Because Lambdas can be executed concurrently (this could easily be the case if there were suddenly a lot of messages in your SQS queue), and each execution opens a new connection to your DB, the connection pool can get saturated.
If this is the case, you can set a concurrent execution limit on your Lambda function to prevent this.
A side note - it is not recommended to use a database with a persistent connection in a serverless architecture exactly for this reason. AFAIK, AWS is working on a better solution to use RDS from Lambda, but it's not available yet.
So...
I was changing security groups and it was having no effect on the RDS host, at one point I removed all access and I could still connect, which is crazy. At this point I started to think the outage on Friday night put the underlying RDS host into a weird state. I put the Security Groups back to the way they should be, stopped & started (restart had no effect) the RDS host and everything started to work again.
Very frustrating, but happy it's finally resolved.
I have a very simple piece of code written in node.js which runs on Kubernetes and AWS. The app just does POST/GET request to create and get data from other services. service1-->service2->service3
Service1 get post request and call service2, service2 calls postgres DB (using sequlize) and create a new row and then call service3, service3 get data from the DB and returns the response to service2, service2 returns the response to service1.
Most of the times it works, but once in 4-5 attempts + concurrency, it dropped and I got a timeout. the problem is that the service1 receives the response back (according to the logs and network traces) but it seems that the connection was dropped somewhere between the services and I got a timeout (ESOCKETTIMEDOUT).
I've tried to use to replace request.js with node-fetch
I've tried to use NewRelic/Elastic APM
I've tried to use node -prof and analyze it with node --prof-process with no conclusions.
Is it possible Kubernetes drops my connection?
Hard to tell without debugging but since some connections are getting dropped when you add more load + concurrency it's likely that you need more replicas on your Kubernetes deployments and possibly adjusts the Resources on your container pod specs.
If this turns out to be the case you can also configure an HPA (Horizontal Pod Autoscaler) to handle your load.
We have a setup with several RESTful APIs on the same VM in Azure.
The websites run in Kestrel on IIS.
They are protected by the azure application gateway with firewall.
We now have requests that would run for at least 20 minutes.
The request run the full length uninterrupted on Kestrel (Visible in the logs) but the sender either get "socket hang up" after exactly 5 minutes or run forever even if the request finished in kestrel. The request continue in Kestrel even if the connection was interrupted for the sender.
What I have done:
Wrote a small example application that returns after a set amount of
seconds to exclude our websites being the problem.
Ran the request in the VM (to localhost): No problems, response was received.
Ran the request within Azure from one to another VM: Request ran forever.
Ran the request from outside of Azure: Request terminates after 5 minutes
with "socket hang up".
Checked set timeouts: Kestrel: 50m , IIS: 4000s, ApplicationGateway-HttpSettings: 3600
Request were tested with Postman,
Is there another request or connection timeout hidden somewhere in Azure?
We now have requests that would run for at least 20 minutes.
This is a horrible architecture and it should be rewritten to be async. Don't take this personally, it is what it is. Consider returning a 202 Accepted with a Location header to poll for the result.
You're most probably hitting the Azure SNAT layer timeout —
Change it under the Configuration blade for the Public IP.
So I ran into something like this a little while back:
For us the issue was probably the timeout like the other answer suggests but the solution was (instead of increasing timeout) to add PGbouncer in front of our postgres database to manage the connections and make sure a new one is started before the timeout fires.
Not sure what your backend connection looks like but something similar (backend db proxy) could work to give you more ability to tune connection / reconnection on your side.
For us we were running AKS (azure Kubernetes service) but all azure public ips obey the same rules that cause issues similar to this one.
While it isn't an answer I know there are also two types of public IP addresses, one of them is considered 'basic' and doesn't have the same configurability, could be something related to the difference between basic and standard public ips / load balancers?
I have setup 2 instance under aws load balancer. I have deployed node.js web services + mongodb in both instance. load balancer works fine with web services.
But, Problem is I have one timer service (node.js service only). the behavior of this timer is updating my mongodb based on some calculation.
My problem is, I must need to run this timer service (timer.js) at only one aws instance (out of 2) at same time. and expected that if one aws instance goes down then timer service at other instance will come up.
i know elb not providing this kind of facility.Can any one please help me to make it done ?
Condition : At a time only one timer service must be run with amazon load balancer.
Thanks.
You would have to implement this yourself using a locking algorithm using a shared data store that supports atomic operations
Alternatively, consider starting a "timer" server in an Auto Scale Group of Min:1, Max: 1 so Amazon keeps it running. This instance can be a t2.micro which is very cheap. It can either run the job itself, or just make an http request to your load balancer to run the job at the desired internal. If you so that, only one of your servers will run each job
Wouldn't it make more sense to handle this like any other "service" that needs to keep running?
upstart service
running node.js server using upstart causes 'terminated with status 127' on 'ubuntu 10.04'
This guy had a bad path in his file but his upstart script looks okay
monit
Node.js (sudo) and monit