Has you may know, Web sites hosted under Microsoft Azure Web Sites service are by default configure to timeout after idling 20 minutes (idleTimeout) and the application pool to restart every 29 hours (periodicRestart). This cause the web site to be slow for the first user accessing it.
I would like to know if the new "Always On" setting available on standard mode will prevent both situation from happening.
I found a few articles mentioning the feature, they are all very clear that the idle timeout will be avoided but none of them explicitly talks about the periodic restart:
One of the other useful Web Site features that we are introducing
today is a feature we call “Always On”. When Always On is enabled on
a site, Windows Azure will automatically ping your Web Site regularly
to ensure that the Web Site is always active and in a warm/running
state. This is useful to ensure that a site is always responsive (and
that the app domain or worker process has not paged out due to lack of
external HTTP requests).
http://weblogs.asp.net/scottgu/archive/2014/01/16/windows-azure-staging-publishing-support-for-web-sites-monitoring-improvements-hyper-v-recovery-manager-ga-and-pci-compliance.aspx
Also the Azure Documentation is not very explicit:
Always On - By default, web sites are unloaded if they have been idle
for some period of time. This lets the system conserve resources. You
can enable the Always On setting for a site in Standard mode if the
site needs to be loaded all the time. Because continuous web jobs may
not run reliably if Always On is disabled, you should enable Always On
when you have continuous web jobs running on the site.
http://www.windowsazure.com/en-us/documentation/articles/web-sites-configure/
Yes both of them will be prevented.
The default 29 hours periodicRestart was never on Azure Websites. That feature is an IIS feature that was enforced by WAS and was designed to run on a server level meaning restart all the worker processes on an IIS server. Both these things (WAS and IIS Server) don't apply to Azure Websites as WAS was the process management component of IIS and that was very specific to one box setup. Azure Websites uses a different process management component that doesn't have periodicRestart.
Related
We have a site that keeps falling to sleep, which causes an error due to the time-sensitivity of our sporadic requests.
I've seen how there is an "Always On" setting in the old Azure console, but it doesn't appear to apply to the new interface:
How to prevent an Azure website from going to sleep?
Where is this setting now, or how do I do the equivalent?
Here's what I see:
There's a couple of options. One of those is to use Traffic Manager Endpoint Monitoring which keeps calling your app so it doesn't recycle. Or is automatically started again when it does.
According to the blog post Windows Azure WebSites and Cloud Services Slow on First Request you can "include a script with your package, which is configured to run as a startup script, every time the role is restarted."
REM *** Prevent the IIS app pools from shutting down due to being idle.
%windir%\system32\inetsrv\appcmd set config -section:applicationPools -applicationPoolDefaults.processModel.idleTimeout:00:00:00
REM *** Prevent IIS app pool recycles from recycling on the default schedule of 1740 minutes (29 hours).
%windir%\system32\inetsrv\appcmd set config -section:applicationPools -applicationPoolDefaults.recycling.periodicRestart.time:00:00:00
How to proceed with the configuration can be found under "Avoid automatic recycle of Azure Cloud Services Web Role" of that post.
Check the Cloud Service availability on Azure portal.
Ensure that all role instances are in a Ready state. If they are not,
refer to the troubleshooting blade.
RDP into the role instance and check the IIS process (w3wp.exe) in
Task Manager is running.
If the w3wp.exe process does not show in Task Manager, go to IIS
Manager and restart the application.
Check the http response code you get in the browser. 50x errors are
application-related issues, refer to the troubleshooting blade.
Check that the default ports 80 (for http) and 443 (for https) are
accessible. Use TELNET or TCPING to ensure that the w3wp.exe process
is listening on it.
If your web application is accessible locally but not externally, it
could be a network-related issue.
You may want to refer this as well.
I've got an ASP.NET MVC site hosted as an Azure Web App and I've noticed that once the site has been idle for a while, when hitting it the application reverts to a deployed state.
Now traditionally, I would solve this problem by setting the Idle Timeout of the application pool in IIS to 0. However, given that I don't have ready access to do this with an Azure Web App I'm struggling to find the equivalent.
I did try the "Always On" setting which appears to be what I'm looking for, however it seemed to make absolutely no difference unfortunately.
Always On. By default, web apps are unloaded if they are idle for some
period of time. This lets the system conserve resources. In Basic or
Standard mode, you can enable Always On to keep the app loaded all the
time. If your app runs continuous web jobs, you should enable Always
On, or the web jobs may not run reliably.
From https://learn.microsoft.com/en-us/azure/app-service-web/web-sites-configure
Make sure you're running in the right price tier (Basic / Standard).
I have a NodeJS server running on an Azure free website. The server has a websocket module installed. Each connected user will cache some data with an object so that anyone else who connects can retrieve cached data from this object. The problem I am experiencing is that the server doesn't seem to keep this object around for very long. I can access the data with in for some time, but if I try later in the day, it's just gone.
Is Azure shutting down the server because it is experiencing no activity, causing the object to be deallocated? Does NodeJS deallocate objects if they aren't used after some time?
Azure Websites, as Ben pointed out in his answer, will evict idle websites. This is especially true with free/shared tiers, since your website is sharing resources with several other tenants on the same VM instances. But even with basic and standard tiers, there may be a need to evict your website (especially since you can have many of your own websites running within a single hosting plan).
With basic/standard tier websites, you have the ability to enable Always On. You'll see this option under the Configure tab:
Once you enable this, your website should remain loaded.
Yep. If there aren't any requests to the app pool, Azure Websites stops your application. That means anything in memory is lost. You can set up a cron job or scheduled task to ping your web app to avoid the app pool timing out due to inactivity.
EDIT: Or, as David Makogon pointed out,
With basic/standard tier websites, you have the ability to enable Always On. You'll see this option under the Configure tab:
I have created a WCF service which i have hosted in IIS. When I start the service in IIS, the Service do not started until I browse my Service.svc file.
Application pool gets recycled after a specific interval, then when the Service is restarted I again need to go and browse the Service.svc file.
I have set this Service as Default bt it does not work and results the same.
Is there any way to automatic browse my Service.svc file when the Service is started or restarted.
This is a general annoyance with IIS. It launches worker processes to perform website processing which don't (always) start until the website has been requested. The workaround I've used in the past is to hit a page outside of my web application to launch the IIS worker process so it is available when I need it. Be careful though there are some nuances to the app pools that can make this more complicated than it needs to be.
I have a problem with timeouts in IIS. In the web.config the session timeout was set to 60 minutes but after 20 minutes the session ends.
This problem only occurs in IIS7 and not in IIS5.
After some investigation, I discovered it was due to the application pool's timeout. If the App Pool is left 20 minutes without doing anything, IIS ends the session.
If the application is using the defaultAppPool this always happens but if I change the App Pool to the classic .NET App Pool, the timeout does not occur.
Both modes have idle timeout but only in the DefaultAppPool this occurs.
Why is this?
What is the difference between be a Classic .NET AppPool and DefaultAppPool?
What is the difference in the pipeline, between Classic and Integrated?
IIS7 has some major changes to better support WCF and one of the key pieces is the new integrated application pool. This session from PDC talks about some of these challenges from the perspective of making WCF services perform better: http://channel9.msdn.com/pdc2008/TL38/
This page has a good overview of IIS7 architecture: http://learn.iis.net/page.aspx/101/introduction-to-iis7-architecture/.
I've included some of the key information from this article on the purpose of the two different kinds of app pools below:
Integrated application pool mode
When an application pool is in
Integrated mode, you can take
advantage of the integrated
request-processing architecture of IIS
and ASP.NET. When a worker process in
an application pool receives a
request, the request passes through an
ordered list of events. Each event
calls the necessary native and managed
modules to process portions of the
request and to generate the response.
There are several benefits to running
application pools in Integrated mode.
First the request-processing models of
IIS and ASP.NET are integrated into a
unified process model. This model
eliminates steps that were previously
duplicated in IIS and ASP.NET, such as
authentication. Additionally,
Integrated mode enables the
availability of managed features to
all content types.
Classic application pool mode
When an application pool is in Classic
mode, IIS 7.0 handles requests as in
IIS 6.0 worker process isolation mode.
ASP.NET requests first go through
native processing steps in IIS and are
then routed to Aspnet_isapi.dll for
processing of managed code in the
managed runtime. Finally, the request
is routed back through IIS to send the
response. This separation of the IIS
and ASP.NET request-processing models
results in duplication of some
processing steps, such as
authentication and authorization.
Additionally, managed code features,
such as forms authentication, are only
available to ASP.NET applications or
applications for which you have script
mapped all requests to be handled by
aspnet_isapi.dll. Be sure to test your
existing applications for
compatibility in Integrated mode
before upgrading a production
environment to IIS 7.0 and assigning
applications to application pools in
Integrated mode. You should only add
an application to an application pool
in Classic mode if the application
fails to work in Integrated mode. For
example, your application might rely
on an authentication token passed from
IIS to the managed runtime, and, due
to the new architecture in IIS 7.0,
the process breaks your application.
The classic pool processes the requests in the app pool by using seperate processing pipelinesfor IIS and ISAPI. integrated uses an integrated pipeline, IIS and ASP.NET a(better performance) takes advantage of the improved features of IIS 7.0 using only the one process.
Good practise is to create a new application pool for each application, then configure sepeerately according to application requirements.
Classic mode follows the steps below :
1.The incoming HTTP request is received through the IIS core.
2.The request is processed through ISAPI.
3.The request is processed through ASP.NET.
4.The request passes back through ISAPI.
5.The request passes back through the IIS core where the HTTP response finally is delivered
Integrated mode uses:
1.The incoming HTTP request is received through the IIS core and ASP.NET.
2.The appropriate handler executes the request and delivers the HTTP response
Increase the session timeout in web.config as per
remember increasing this causes the application to consume more resource, eg memory
I think your question has the answer in it. IIS 6 and 7 have a concept of Application Pool timeout, this is different from session timeout.
What is the difference between modes ... already addressed. I'm uncertain about how your questions regarding pipelines and differences in modes relate to your problem - the timeouts.
Some perspective: Idle timeout won't occur on a web site with any traffic. You've probably got a problem that only occurs in a QA site or your dev box. The idle timeout setting exists to save resources on your dev box and $5/month hosting companies with lots of underused web sites (e.g. my blog). You probably do not want idle timeout on a public site.
Session timeout - set in web config, if a user doesn't hit the server, their session times out.
Idle timeout Noone touches the web server at all for 20 minutes, so shut down to save resources. In IIS 6, this is on the performance tab of the app pool - and is easy to disable. In IIS 7, you can set in in application pool advanced settings or in the processModel element. I don't run as much IIS 7 as IIS 6, but it looks like removing the element from web.config, or setting to 0, gets infinite idle timeout.
The DefaultAppPool ignores settings for session timeout in web.config, but ASPNet App Pool will use the settings in web.config.