I am currently using Jetty 9.1.4 on Windows.
When I deploy the war file without hot deployment config, and then restart the Jetty service. During that 5-10 seconds starting process, all client connections to my Jetty server are waiting for the server to finish loading. Then clients will be able to view the contents.
Now with hot deployment config on, the default Jetty 404 error page shows within that 5-10 second loading interval.
Is there anyway I can make the hot deployment has the same behavior as the complete restart - clients connections will wait instead seeing the 404 error page ?
Unfortunately this does not seem to be possible currently after talking with the Jetty developers on IRC #jetty.
One solution I will try to use are two Jetty instances with a loadbalancing reverse proxy (e.g. nginx) before them and taking one instance down for deployment.
Of course this will instantly lead to new requirements (session persistence/sharing) which need to be handled. So in conclusion: much work to do in the Java world for zero downtime on deployments.
Edit: I will try this, seems like a simple enough solution http://rafaelsteil.com/zero-downtime-deploy-script-for-jetty/ Github: https://github.com/rafaelsteil/jetty-zero-downtime-deploy
Related
We have been maintaining a project internally which has both web and mobile application platform. The backend of the project is developed in Django 1.9 (Python 3.4) and deployed in AWS.
The server stack consists of Nginx, Gunicorn, Django and PostgreSQL. We use Redis based cache server to serve resource intensive heavy queries. Our AWS resources include:
t1.medium EC2 (2 core, 4 GB RAM)
PostgreSQL RDS with one additional read-replica.
Right now Gunicorn is set to create 5 workers (by following the 2*n+1 rule). Load wise, there are like 20-30 mobile users making requests in every minute and there are 5-10 users checking the web panel every hour. So I would say, not very much load.
Now this setup works alright for 80% days. But when something goes wrong (for example, we detect a bug in the live system and we had to switch off the server for maintenance for few hours. In the mean time, the mobile apps have a queue of requests ready in their app. So when we make the backend live, a lot of users hit the system at the same time.), the server stops behaving normally and started responding with 504 gateway timeout error.
Surprisingly every time this happened, we found the server resources (CPU, Memory) to be free by 70-80% and the connection pool in the databases are mostly free.
Any idea where the problem is? How to debug? If you have already faced a similar issue, please share the fix.
Thank you,
I am using Coldfusion MX8 server and one of the scheduled task was running from 2 years but now suddenly from 01/12/2014 scheduled tasks are not running. When i browsed the file in browser then the file is running successfully without error.
I am not sure is there any updatation or license expiration problem. I am aware that mid of this year Adobe closed the support for coldfusion 8.
The first most common problem of this problem is external to the server. When you say you browsed to the file and it worked in a browser, it is very important to know if that test was performed on the server desktop. Knowing that you can browse to the file from your desktop or laptop is of small value.
The most common source of issues like this is a change in the DNS or network stack that is interfereing with resolution. For example, if the internal DNS serving your DMZ suddenly starts serving the "external" address - suddenly your server can't browse to your domain. Or if the IP served by the server for the domain in question goes from being 127.0.0.1 to some other IP that the server can't acces correctly due to reverse proxy or LB or some other rule. Finally, sometimes the Apache or IIS is altered so that an IP that previously was serviced (127.0.0.1 being the most common example) now does not respond.
If it is something intrinsic to the scheduler service then Frank's advice is pretty good - especially look for "proxy schduler" entries in the log - they can give you good clues. I would also log results of a scheduled task to a file. Then check the file. If it exists then your scheduled tasks ARE running - they are just not succeeding. Good luck!
I've seen the cf scheduling service crash in CF8. The rest of CF is unaffected.
Have you tried restarting the server?
Here are your concerns:
Your File (works since you tested it manually).
Your Scheduled Task (failed).
Your Coldfusion Application (Service) (any changes here)?
Your Server (what about here).
To test your problem create a duplicate task and schedule it. Leave the other one in place (maybe set your new one to run earlier). Use the same file too. See if it completes.
If it doesn't then you have a larger problem. Since the Coldfusion Server sits atop of the JVM there could be something happening there. Things just don't stop working unless something got corrupted or you got compromised. If you hardened your server by rearranging/renaming the file structure to make it more secure...It would break your task.
So going back: if your test schedule works then determine what is different between the two. Note you have logging capabilities. Logging abilities for CF8
If you are not directly incharge of maintaining this server, then I would recommend asking around and see if there was recent maintenance, if so, what was done to the server?
I have an Apache2 and Django (mod_wsgi) setup that provides a RESTful API. I have a set of automated tests for this, that executes ~1000 API requests (pure http GET/POST/PUT/DELETE) in sequential order.
The problem is, for every 80 requests or so, I get a strange lag/timeout for exactly 5s or 10s. See timestamp examples here:
Request 1: 2013-08-30T03:49:20.915
Response 1: 2013-08-30T03:49:30.940
Request 2: 2013-08-30T03:50:32.559
Response 2: 2013-08-30T03:50:37.597
I can't figure out why this happens. I have an apache config with KeepAlive Off (recommended setup setting for Django) but otherwise standard install for Ubuntu 12.04 LTS.
I'm running the tests from the same server where the webserver is, I first thought this was some kind of DNS cache thing, but I've added the hostname I'm requesting to /etc/hosts but the problem persists.
The system is idle and have lots of cpu and mem when this lag/timeouts happens.
The lag is not specific to a certain request (URL), it seems kinda random.
Considering that it's always exactly to the millisecond 5s or 10s, it feels like this is some specific setting somewhere causing this.
In case it provides some insight, watch my talk from PyCon US.
http://lanyrd.com/2013/pycon/scdyzk/
The talk deals with things like process churn and startup costs. One thing you shouldn't do is set maximum requests if you don't really need it.
Also consider trying New Relic to help diagnose where the issue is. That will save a lot of guessing if it is a web application of backend service infrastructure issue.
As far as seeing how such monitoring can help, watch another one of my PyCon talks.
http://lanyrd.com/2012/pycon/spcdg/
This was a DNS issue, adding the domainname I used locally to /etc/hosts actually solved the problem. I just hadn't reboot the server for the changes to take effect, thought restarting networking would take care of that, but apparently not.
In my project, I use Django and heroku to deploy it. In Heroku, I use uWSGI server (with asynchronous mode), database is MySQL (on AWS RDS). I used 7 dyno for scaling django app
When I run stress test with 600 request/second, timeout is 30 second.
My server return > 50% with timeouts request.
Any ideas can help me improve my server performance?
If your async setup is right (and this is the hardest part), well your only solution is adding more dynos. If you are not sure about django+async (or if you have not done any particular customization to make them work together), you have probably a screwed up setup (no concurrency at all).
Take in account that uWSGI async mode could means dozens of different setup (gevent, ugreen, callbacks, greenlets...), so some detail on your configuration could help.
Afternoon all,
We have a group of four BizTalk servers: two orchestration hosts and two adapter hosts. We have a number of orchestrations exposed as web services, and for the purposes of this question, it is important to note that these web services are hosted on the adapter servers, and run under the BizTalkServerIsolatedHost host instance.
This morning, we started seeing odd errors on both of the adapter servers when SOAP calls came into the web services, like this:
The Messaging Engine failed to
register the adapter for “SOAP” for
the receive location blahblahblah.
Please verify that the receive
location exists, and that the isolated
adapter runs under an account that has
access to the BizTalk databases.
We restarted IIS on both servers, which fixed the errors on ONE server, but the other server continued to fail. The errors continued after a reboot as well.
After chasing our tails for a while, we eventually discovered that the BizTalkServerIsolatedHost host instance on the still-failing server was gone. Just... gone. These applications have been in production for months. Everything had been working swimmingly through the morning, until this just happened.
I don't want to muddy the waters, because I think the problems are unrelated, but in the interest of providing enough information, this problem exactly coincided with a problem in our load-balancing network hardware. The load balancer, which provides a single URL to consumers, and round-robins between the two adapter servers, just stopped working. This problem has not been resolved, so I don't know what happened, but it certainly made troubleshooting more interesting...
So, I have two questions:
Has anyone seen this before, where a host instance disappears?
We cannot find anything in the event viewer or anywhere else that says the host instance was deleted. Is this logged somewhere?
Thanks,
Jason