Re: tomcat gracefull shutdown problem

[Ja kub]

Thx for reply,

Do You think it would be hard to implement it in Tomcat ?
It seems to be quite a useful feature.

Regards
Jakub



On Tue, Jan 14, 2014 at 3:26 PM, Daniel Mikusa wrote:

> On Jan 13, 2014, at 7:48 PM, Ja kub  wrote:
>
> > I modified conf/context.xml 
> > I hoped tomcat would wait 60 seconds for request to end.
>
> No, it doesn't do this.  It does not have an option for "graceful" restart
> / shutdown like Apache HTTPD.  If you want that behavior, you could setup a
> proxy in front of Tomcat and use that to either temporarily handle the
> requests (like send them to a maintenance page) or direct them to a
> different Tomcat node (like with a cluster setup).  In this way you can
> slowly drain the requests from your Tomcat server and then safely restart /
> shut it down.
>
> > But there are some problems with spring app, I get
> >
> > HTTP Status 503 - Servlet jsp is currently unavailable:
> >
> > I use tomcat 7.42 64 bit on windows 7
> >
> > steps to reproduce:
>
> As mentioned above, Tomcat doesn't really have a graceful shutdown option,
> at least not like HTTPD has graceful restart / shutdown options.
>
> Tomcat has two shutdown options.  The first is a controlled shutdown (kill
> -15 or the shutdown port) and this nicely gives applications deployed to
> Tomcat the chance to clean up.  This is normally what happens when you use
> the shutdown script.  The second is a kill -9, which just ends the process
> immediately.
>
> Dan
>
> >
> > use app from https://github.com/spring-projects/spring-petclinic
> >
> > git clone https://github.com/SpringSource/spring-petclinic.git
> >
> > to VetController class add:
> >
> >@RequestMapping("/vets/{delay}")
> >public String showVetListDelayed(@PathVariable int delay, Map > Object> model) {
> >// Here we are returning an object of type 'Vets' rather than a
> > collection of Vet objects
> >// so it is simpler for Object-Xml mapping
> >Vets vets = new Vets();
> >vets.getVetList().addAll(this.clinicService.findVets());
> >model.put("vets", vets);
> >try {
> > Thread.sleep(1000*delay);
> > } catch (InterruptedException e) {
> > // TODO Auto-generated catch block
> > e.printStackTrace();
> > } catch (Exception e) {
> > e.printStackTrace();
> > }
> >System.err.println("woken up ---");
> >return "vets/vetList";
> >}
> > mvn clean install
> >
> > // copy from target to webapps
> >
> > go to
> > http://localhost:8080/petclinic/vets/5
> > hit ctrl C
> >
> > app sleeps,  wait until
> > System.err.println("woken up ---"); executes 
> > but browser gets error.
> >
> > below is console log:
> >
> > Hibernate: select distinct vet0_.id as id1_5_0_, specialty2_.id as
> > id1_2_1_, vet0_.first_
> > specialty2_.name as name2_2_1_, specialtie1_.vet_id as vet1_5_0__,
> > specialtie1_.specialt
> > join vet_specialties specialtie1_ on vet0_.id=specialtie1_.vet_id left
> > outer join special
> > alty2_.id order by vet0_.last_name, vet0_.first_name
> > Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardServer await
> > INFO: A valid shutdown command was received via the shutdown port.
> Stopping
> > the Server in
> > Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
> > INFO: Pausing ProtocolHandler ["http-apr-8080"]
> > Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
> > INFO: Pausing ProtocolHandler ["ajp-apr-8009"]
> > Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardService
> > stopInternal
> > INFO: Stopping service Catalina
> > Jan 14, 2014 1:20:16 AM org.apache.catalina.core.StandardWrapper unload
> > INFO: Waiting for 1 instance(s) to be deallocated for Servlet [petclinic]
> > woken up ---
> > INFO  XmlWebApplicationContext - Closing WebApplicationContext for
> > namespace 'petclinic-s
> > ]; parent: Root WebApplicationContext
> > INFO  XmlWebApplicationContext - Closing Root WebApplicationContext:
> > startup date [Tue Ja
> > INFO  AnnotationMBeanExporter - Unregistering JMX-exposed beans on
> shutdown
> > INFO  EhCacheManagerFactoryBean - Shutting down EhCache CacheManager
> > INFO  LocalContainerEntityManagerFactoryBean - Closing JPA
> > EntityManagerFactory for persi
> > Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
> > clearReferencesJdbc
> > SEVERE: The web application [/petclinic] registered the JDBC driver
> > [org.hsqldb.jdbc.JDBC
> > plication was stopped. To prevent a memory leak, the JDBC Driver has been
> > forcibly unregi
> > Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
> > clearReferencesThrea
> > SEVERE: The web application [/petclinic] appears to have started a thread
> > named [PoolClea
> > p it. This is very likely to create a memory leak.
> > Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol stop
> > INFO: Stopping ProtocolHandler ["http-apr-8080"]
> > Jan 14, 2014 1:20:22 AM org.apache.coyote.Abstrac

Re: tomcat gracefull shutdown problem

[Daniel Mikusa]

On Jan 13, 2014, at 7:48 PM, Ja kub  wrote:

> I modified conf/context.xml 
> I hoped tomcat would wait 60 seconds for request to end.

No, it doesn't do this.  It does not have an option for "graceful" restart / 
shutdown like Apache HTTPD.  If you want that behavior, you could setup a proxy 
in front of Tomcat and use that to either temporarily handle the requests (like 
send them to a maintenance page) or direct them to a different Tomcat node 
(like with a cluster setup).  In this way you can slowly drain the requests 
from your Tomcat server and then safely restart / shut it down.

> But there are some problems with spring app, I get
> 
> HTTP Status 503 - Servlet jsp is currently unavailable:
> 
> I use tomcat 7.42 64 bit on windows 7
> 
> steps to reproduce:

As mentioned above, Tomcat doesn't really have a graceful shutdown option, at 
least not like HTTPD has graceful restart / shutdown options.  

Tomcat has two shutdown options.  The first is a controlled shutdown (kill -15 
or the shutdown port) and this nicely gives applications deployed to Tomcat the 
chance to clean up.  This is normally what happens when you use the shutdown 
script.  The second is a kill -9, which just ends the process immediately.

Dan

> 
> use app from https://github.com/spring-projects/spring-petclinic
> 
> git clone https://github.com/SpringSource/spring-petclinic.git
> 
> to VetController class add:
> 
>@RequestMapping("/vets/{delay}")
>public String showVetListDelayed(@PathVariable int delay, Map Object> model) {
>// Here we are returning an object of type 'Vets' rather than a
> collection of Vet objects
>// so it is simpler for Object-Xml mapping
>Vets vets = new Vets();
>vets.getVetList().addAll(this.clinicService.findVets());
>model.put("vets", vets);
>try {
> Thread.sleep(1000*delay);
> } catch (InterruptedException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> } catch (Exception e) {
> e.printStackTrace();
> }
>System.err.println("woken up ---");
>return "vets/vetList";
>}
> mvn clean install
> 
> // copy from target to webapps
> 
> go to
> http://localhost:8080/petclinic/vets/5
> hit ctrl C
> 
> app sleeps,  wait until
> System.err.println("woken up ---"); executes 
> but browser gets error.
> 
> below is console log:
> 
> Hibernate: select distinct vet0_.id as id1_5_0_, specialty2_.id as
> id1_2_1_, vet0_.first_
> specialty2_.name as name2_2_1_, specialtie1_.vet_id as vet1_5_0__,
> specialtie1_.specialt
> join vet_specialties specialtie1_ on vet0_.id=specialtie1_.vet_id left
> outer join special
> alty2_.id order by vet0_.last_name, vet0_.first_name
> Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardServer await
> INFO: A valid shutdown command was received via the shutdown port. Stopping
> the Server in
> Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
> INFO: Pausing ProtocolHandler ["http-apr-8080"]
> Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
> INFO: Pausing ProtocolHandler ["ajp-apr-8009"]
> Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardService
> stopInternal
> INFO: Stopping service Catalina
> Jan 14, 2014 1:20:16 AM org.apache.catalina.core.StandardWrapper unload
> INFO: Waiting for 1 instance(s) to be deallocated for Servlet [petclinic]
> woken up ---
> INFO  XmlWebApplicationContext - Closing WebApplicationContext for
> namespace 'petclinic-s
> ]; parent: Root WebApplicationContext
> INFO  XmlWebApplicationContext - Closing Root WebApplicationContext:
> startup date [Tue Ja
> INFO  AnnotationMBeanExporter - Unregistering JMX-exposed beans on shutdown
> INFO  EhCacheManagerFactoryBean - Shutting down EhCache CacheManager
> INFO  LocalContainerEntityManagerFactoryBean - Closing JPA
> EntityManagerFactory for persi
> Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
> clearReferencesJdbc
> SEVERE: The web application [/petclinic] registered the JDBC driver
> [org.hsqldb.jdbc.JDBC
> plication was stopped. To prevent a memory leak, the JDBC Driver has been
> forcibly unregi
> Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
> clearReferencesThrea
> SEVERE: The web application [/petclinic] appears to have started a thread
> named [PoolClea
> p it. This is very likely to create a memory leak.
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol stop
> INFO: Stopping ProtocolHandler ["http-apr-8080"]
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol stop
> INFO: Stopping ProtocolHandler ["ajp-apr-8009"]
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol destroy
> INFO: Destroying ProtocolHandler ["http-apr-8080"]
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol destroy
> INFO: Destroying ProtocolHandler ["ajp-apr-8009"]
> 
> 
> Regards
> Jakub


--

Re: tomcat gracefull shutdown problem

[Ja kub]

even with unloadDelay="6" in conf/context.xml
probably Servlet jsp is undeployed before spring servlet, and when spring
servlet wants to use it to render jsp -  it is already undeployed (and
results in : HTTP Status 503 - Servlet jsp is currently unavailable)

question is
how to make Servlet jsp undeployed as last servlet,
afaik there is no priority opposite to
100 deciding when servlet is undeployed.
is there any solution in tomcat ?
can we prevent tomcat from unloading servlets for some time ?
can we tell tomcat to stop accept new requests ?

Regards
Jakub


On Tue, Jan 14, 2014 at 1:48 AM, Ja kub  wrote:

> I modified conf/context.xml 
> I hoped tomcat would wait 60 seconds for request to end.
> But there are some problems with spring app, I get
>
> HTTP Status 503 - Servlet jsp is currently unavailable:
>
> I use tomcat 7.42 64 bit on windows 7
>
> steps to reproduce:
>
> use app from https://github.com/spring-projects/spring-petclinic
>
> git clone https://github.com/SpringSource/spring-petclinic.git
>
> to VetController class add:
>
> @RequestMapping("/vets/{delay}")
> public String showVetListDelayed(@PathVariable int delay, Map Object> model) {
> // Here we are returning an object of type 'Vets' rather than a
> collection of Vet objects
> // so it is simpler for Object-Xml mapping
> Vets vets = new Vets();
> vets.getVetList().addAll(this.clinicService.findVets());
> model.put("vets", vets);
> try {
> Thread.sleep(1000*delay);
> } catch (InterruptedException e) {
> // TODO Auto-generated catch block
>  e.printStackTrace();
> } catch (Exception e) {
> e.printStackTrace();
>  }
> System.err.println("woken up ---");
> return "vets/vetList";
> }
>
> mvn clean install
>
> // copy from target to webapps
>
> go to
> http://localhost:8080/petclinic/vets/5
> hit ctrl C
>
> app sleeps,  wait until
> System.err.println("woken up ---"); executes 
> but browser gets error.
>
> below is console log:
>
> Hibernate: select distinct vet0_.id as id1_5_0_, specialty2_.id as
> id1_2_1_, vet0_.first_
>  specialty2_.name as name2_2_1_, specialtie1_.vet_id as vet1_5_0__,
> specialtie1_.specialt
> join vet_specialties specialtie1_ on vet0_.id=specialtie1_.vet_id left
> outer join special
> alty2_.id order by vet0_.last_name, vet0_.first_name
> Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardServer await
> INFO: A valid shutdown command was received via the shutdown port.
> Stopping the Server in
> Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
> INFO: Pausing ProtocolHandler ["http-apr-8080"]
> Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
> INFO: Pausing ProtocolHandler ["ajp-apr-8009"]
> Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardService
> stopInternal
> INFO: Stopping service Catalina
> Jan 14, 2014 1:20:16 AM org.apache.catalina.core.StandardWrapper unload
> INFO: Waiting for 1 instance(s) to be deallocated for Servlet [petclinic]
> woken up ---
> INFO  XmlWebApplicationContext - Closing WebApplicationContext for
> namespace 'petclinic-s
> ]; parent: Root WebApplicationContext
> INFO  XmlWebApplicationContext - Closing Root WebApplicationContext:
> startup date [Tue Ja
> INFO  AnnotationMBeanExporter - Unregistering JMX-exposed beans on shutdown
> INFO  EhCacheManagerFactoryBean - Shutting down EhCache CacheManager
> INFO  LocalContainerEntityManagerFactoryBean - Closing JPA
> EntityManagerFactory for persi
> Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
> clearReferencesJdbc
> SEVERE: The web application [/petclinic] registered the JDBC driver
> [org.hsqldb.jdbc.JDBC
> plication was stopped. To prevent a memory leak, the JDBC Driver has been
> forcibly unregi
> Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
> clearReferencesThrea
> SEVERE: The web application [/petclinic] appears to have started a thread
> named [PoolClea
> p it. This is very likely to create a memory leak.
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol stop
> INFO: Stopping ProtocolHandler ["http-apr-8080"]
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol stop
> INFO: Stopping ProtocolHandler ["ajp-apr-8009"]
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol destroy
> INFO: Destroying ProtocolHandler ["http-apr-8080"]
> Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol destroy
> INFO: Destroying ProtocolHandler ["ajp-apr-8009"]
>
>
> Regards
> Jakub
>

tomcat gracefull shutdown problem

[Ja kub]

I modified conf/context.xml 
I hoped tomcat would wait 60 seconds for request to end.
But there are some problems with spring app, I get

HTTP Status 503 - Servlet jsp is currently unavailable:

I use tomcat 7.42 64 bit on windows 7

steps to reproduce:

use app from https://github.com/spring-projects/spring-petclinic

git clone https://github.com/SpringSource/spring-petclinic.git

to VetController class add:

@RequestMapping("/vets/{delay}")
public String showVetListDelayed(@PathVariable int delay, Map model) {
// Here we are returning an object of type 'Vets' rather than a
collection of Vet objects
// so it is simpler for Object-Xml mapping
Vets vets = new Vets();
vets.getVetList().addAll(this.clinicService.findVets());
model.put("vets", vets);
try {
Thread.sleep(1000*delay);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
System.err.println("woken up ---");
return "vets/vetList";
}

mvn clean install

// copy from target to webapps

go to
http://localhost:8080/petclinic/vets/5
hit ctrl C

app sleeps,  wait until
System.err.println("woken up ---"); executes 
but browser gets error.

below is console log:

Hibernate: select distinct vet0_.id as id1_5_0_, specialty2_.id as
id1_2_1_, vet0_.first_
 specialty2_.name as name2_2_1_, specialtie1_.vet_id as vet1_5_0__,
specialtie1_.specialt
join vet_specialties specialtie1_ on vet0_.id=specialtie1_.vet_id left
outer join special
alty2_.id order by vet0_.last_name, vet0_.first_name
Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardServer await
INFO: A valid shutdown command was received via the shutdown port. Stopping
the Server in
Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
INFO: Pausing ProtocolHandler ["http-apr-8080"]
Jan 14, 2014 1:20:15 AM org.apache.coyote.AbstractProtocol pause
INFO: Pausing ProtocolHandler ["ajp-apr-8009"]
Jan 14, 2014 1:20:15 AM org.apache.catalina.core.StandardService
stopInternal
INFO: Stopping service Catalina
Jan 14, 2014 1:20:16 AM org.apache.catalina.core.StandardWrapper unload
INFO: Waiting for 1 instance(s) to be deallocated for Servlet [petclinic]
woken up ---
INFO  XmlWebApplicationContext - Closing WebApplicationContext for
namespace 'petclinic-s
]; parent: Root WebApplicationContext
INFO  XmlWebApplicationContext - Closing Root WebApplicationContext:
startup date [Tue Ja
INFO  AnnotationMBeanExporter - Unregistering JMX-exposed beans on shutdown
INFO  EhCacheManagerFactoryBean - Shutting down EhCache CacheManager
INFO  LocalContainerEntityManagerFactoryBean - Closing JPA
EntityManagerFactory for persi
Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
clearReferencesJdbc
SEVERE: The web application [/petclinic] registered the JDBC driver
[org.hsqldb.jdbc.JDBC
plication was stopped. To prevent a memory leak, the JDBC Driver has been
forcibly unregi
Jan 14, 2014 1:20:22 AM org.apache.catalina.loader.WebappClassLoader
clearReferencesThrea
SEVERE: The web application [/petclinic] appears to have started a thread
named [PoolClea
p it. This is very likely to create a memory leak.
Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol stop
INFO: Stopping ProtocolHandler ["http-apr-8080"]
Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol stop
INFO: Stopping ProtocolHandler ["ajp-apr-8009"]
Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol destroy
INFO: Destroying ProtocolHandler ["http-apr-8080"]
Jan 14, 2014 1:20:22 AM org.apache.coyote.AbstractProtocol destroy
INFO: Destroying ProtocolHandler ["ajp-apr-8009"]


Regards
Jakub