[ovirt-users] Tunable parameters in ovirt engine
Hari Prasanth Loganathan
hariprasanth.l at msystechnologies.com
Thu Mar 8 11:34:34 UTC 2018
This is the only error message we received from ab.
I googled it and found that it is due to the connection drop. So It would
be Great, If you could check my Apache server configuration I shared in the
thread and let me know your thoughts on this.
Thanks,
Hari
On Thu, Mar 8, 2018 at 4:56 PM, Juan Hernández <jhernand at redhat.com> wrote:
> But other than those SSL error messages, are the connections really
> failing? Can you share the results reported by "ab"?
>
>
> On 03/08/2018 12:16 PM, Hari Prasanth Loganathan wrote:
>
>> No Juan, It is not working with any benchmark / application tool. It fails
>> with the same error SSL handshake failed (5).
>>
>> Could you let me know the configuration of Apache web server is correct?
>>
>> Thanks,
>> Hari
>>
>> On Thu, Mar 8, 2018 at 1:08 AM, Juan Hernández <jhernand at redhat.com>
>> wrote:
>>
>> If you are still having problems I am inclined to think that it is a
>>> client issue. For example, I'd try to remove the "-k" option from the
>>> "ab"
>>> command. If you use keep alive the server may decide anyhow to close the
>>> connection after certain number of requests, even if the client asks to
>>> keep it alive. Some clients don't handle that perfectly, "ab" may have
>>> that
>>> problem. If that makes the SSL error messages disappear then I think you
>>> can safely ignore them, and restore the "-k" option, if you want.
>>>
>>> On 03/07/2018 07:30 PM, Hari Prasanth Loganathan wrote:
>>>
>>> Thanks Juan for your response. Appreciate it.
>>>> But for some reason still, I am facing the same SSL handshake failed
>>>> (5).
>>>> Could you please check this configuration and let me know the issue in
>>>> my
>>>> ovirt engine environment.
>>>>
>>>> *Configuration of Apache server:*
>>>>
>>>>
>>>> 1) httpd version,
>>>>
>>>> # httpd -v
>>>> Server version: Apache/2.4.6 (CentOS)
>>>> Server built: Oct 19 2017 20:39:16
>>>>
>>>> 2) I checked the status using the following command,
>>>>
>>>> # systemctl status httpd -l
>>>> ● httpd.service - The Apache HTTP Server
>>>> Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled;
>>>> vendor
>>>> preset: disabled)
>>>> Active: active (running) since Wed 2018-03-07 23:46:32 IST; 1min
>>>> 55s
>>>> ago
>>>> Docs: man:httpd(8)
>>>> man:apachectl(8)
>>>> Process: 4351 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited,
>>>> status=0/SUCCESS)
>>>> Main PID: 4359 (httpd)
>>>> Status: "Total requests: 264; Current requests/sec: 0.1; Current
>>>> traffic: 204 B/sec"
>>>> CGroup: /system.slice/httpd.service
>>>> ├─4359 /usr/sbin/httpd -DFOREGROUND
>>>> ├─4360 /usr/sbin/httpd -DFOREGROUND
>>>> ├─4362 /usr/sbin/httpd -DFOREGROUND
>>>> ├─5100 /usr/sbin/httpd -DFOREGROUND
>>>> ├─5386 /usr/sbin/httpd -DFOREGROUND
>>>> ├─5415 /usr/sbin/httpd -DFOREGROUND
>>>> └─5416 /usr/sbin/httpd -DFOREGROUND
>>>>
>>>> 3) Since the httpd is pointing to the path :
>>>> /usr/lib/systemd/system/httpd.service
>>>>
>>>> vi /usr/lib/systemd/system/httpd.service
>>>>
>>>> [Unit]
>>>> Description=The Apache HTTP Server
>>>> After=network.target remote-fs.target nss-lookup.target
>>>> Documentation=man:httpd(8)
>>>> Documentation=man:apachectl(8)
>>>>
>>>> [Service]
>>>> Type=notify
>>>> EnvironmentFile=/etc/sysconfig/httpd
>>>> ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND
>>>> ExecReload=/usr/sbin/httpd $OPTIONS -k graceful
>>>> ExecStop=/bin/kill -WINCH ${MAINPID}
>>>> # We want systemd to give httpd some time to finish gracefully, but
>>>> still
>>>> want
>>>> # it to kill httpd after TimeoutStopSec if something went wrong during
>>>> the
>>>> # graceful stop. Normally, Systemd sends SIGTERM signal right after the
>>>> # ExecStop, which would kill httpd. We are sending useless SIGCONT here
>>>> to
>>>> give
>>>> # httpd time to finish.
>>>> KillSignal=SIGCONT
>>>> PrivateTmp=true
>>>>
>>>> [Install]
>>>> WantedBy=multi-user.target
>>>>
>>>>
>>>> 4) As per the above command I found the env file is available
>>>> '/etc/sysconfig/httpd'
>>>>
>>>> vi /etc/sysconfig/httpd
>>>>
>>>> #
>>>> # This file can be used to set additional environment variables for
>>>> # the httpd process, or pass additional options to the httpd
>>>> # executable.
>>>> #
>>>> # Note: With previous versions of httpd, the MPM could be changed by
>>>> # editing an "HTTPD" variable here. With the current version, that
>>>> # variable is now ignored. The MPM is a loadable module, and the
>>>> # choice of MPM can be changed by editing the configuration file
>>>> /etc/httpd/conf.modules.d/00-mpm.conf
>>>> #
>>>>
>>>> #
>>>> # To pass additional options (for instance, -D definitions) to the
>>>> # httpd binary at startup, set OPTIONS here.
>>>> #
>>>> #OPTIONS=
>>>>
>>>> #
>>>> # This setting ensures the httpd process is started in the "C" locale
>>>> # by default. (Some modules will not behave correctly if
>>>> # case-sensitive string comparisons are performed in a different
>>>> # locale.)
>>>> #
>>>> LANG=C
>>>>
>>>>
>>>> 5) As per the above command, I found that the conf fileis available in
>>>> the
>>>> path : /etc/httpd/conf.modules.d/00-mpm.conf
>>>>
>>>> vi /etc/httpd/conf.modules.d/00-mpm.conf
>>>>
>>>> # Select the MPM module which should be used by uncommenting exactly
>>>> # one of the following LoadModule lines:
>>>>
>>>> # prefork MPM: Implements a non-threaded, pre-forking web server
>>>> # See: http://httpd.apache.org/docs/2.4/mod/prefork.html
>>>> #LoadModule mpm_prefork_module modules/mod_mpm_prefork.so
>>>>
>>>> # worker MPM: Multi-Processing Module implementing a hybrid
>>>> # multi-threaded multi-process web server
>>>> # See: http://httpd.apache.org/docs/2.4/mod/worker.html
>>>> #
>>>> LoadModule mpm_worker_module modules/mod_mpm_worker.so
>>>>
>>>> # event MPM: A variant of the worker MPM with the goal of consuming
>>>> # threads only for connections with active processing
>>>> # See: http://httpd.apache.org/docs/2.4/mod/event.html
>>>> #
>>>> #LoadModule mpm_event_module modules/mod_mpm_event.so
>>>>
>>>> <IfModule mpm_worker_module>
>>>> ServerLimit 1000
>>>> MaxRequestWorkers 1000
>>>> </IfModule>
>>>>
>>>>
>>>>
>>>> As per your comment, I enabled the 'LoadModule mpm_worker_module
>>>> modules/mod_mpm_worker.so' with the ServerLimit and MaxRequestWorkers as
>>>> 1000 still I am facing the issue for the following command in apache
>>>> benchmark test.
>>>>
>>>> Completed 100 requests
>>>> SSL handshake failed (5).
>>>> SSL handshake failed (5).
>>>> SSL handshake failed (5).
>>>> SSL handshake failed (5).
>>>> SSL handshake failed (5).
>>>> SSL handshake failed (5).
>>>>
>>>>
>>>> NOTE : It always scales when I have concurrent request below 400
>>>>
>>>> What is wrong in this apache configuration, why SSL handshake is failing
>>>> for concurrent request above 400 ?
>>>>
>>>> Thanks,
>>>> Hari
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Wed, Mar 7, 2018 at 9:20 PM, Juan Hernández <jhernand at redhat.com>
>>>> wrote:
>>>>
>>>> It means that with the default configuration the Apache web server can't
>>>>
>>>>> serve more than 256 concurrent connections. This applies to any
>>>>> application
>>>>> that uses Apache as the web frontend, not just to oVirt. If you want to
>>>>> change that you have to change the MaxRequestWorkers and ServerLimit
>>>>> parameters, as explained here:
>>>>>
>>>>> https://httpd.apache.org/docs/2.4/mod/mpm_common.html#m
>>>>> axrequestworkers
>>>>>
>>>>> So, go to your oVirt engine machine and create a
>>>>> /etc/httpd/conf.d/my.conf
>>>>> file with this content:
>>>>>
>>>>> MaxRequestWorkers 1000
>>>>> ServerLimit 1000
>>>>>
>>>>> Then restart the Apache server:
>>>>>
>>>>> # systemctl restart httpd
>>>>>
>>>>> Then your web server should be able to handle 1000 concurrent requests,
>>>>> and you will probably start to find other limits, like the amount of
>>>>> memory
>>>>> and CPU that those 1000 Apache child processes will consume, the number
>>>>> of
>>>>> threads in the JBoss application server, the number of connections to
>>>>> the
>>>>> database, etc.
>>>>>
>>>>> Let me insist a bit that if you base your benchmark solely on the
>>>>> number
>>>>> of concurrent requests or connections that the server can handle you
>>>>> may
>>>>> end up with meaningless results, as a real world application can/should
>>>>> use
>>>>> the server much better than that.
>>>>>
>>>>> On 03/07/2018 04:33 PM, Hari Prasanth Loganathan wrote:
>>>>>
>>>>> With the default configuration of the web server it is impossible to
>>>>>
>>>>>> handle
>>>>>> more than 256 *connections* simultaneously. I guess that "ab" is
>>>>>> opening a
>>>>>> connection for each concurrent request, so when you reach request 257
>>>>>> the
>>>>>> web server will just reject the connection, there is nothing that the
>>>>>> JBoss
>>>>>> can do about it; you have to increase the number of connections
>>>>>> supported
>>>>>> by the web server.
>>>>>>
>>>>>> *So Does it mean that oVirt cannot serve more than 257 request? *
>>>>>>
>>>>>> My question is, If its possible How to scale this and what is the
>>>>>> configuration we need to change?
>>>>>>
>>>>>> Also, we are taking a benchmark in using oVirt, So I need to find the
>>>>>> maximum possible oVirt request. So please let me know the
>>>>>> configuration
>>>>>> tuning for oVirt to achieve maximum concurrent request.
>>>>>>
>>>>>> Thanks,
>>>>>> Hari
>>>>>>
>>>>>> On Wed, Mar 7, 2018 at 7:25 PM, Juan Hernández <jhernand at redhat.com>
>>>>>> wrote:
>>>>>>
>>>>>> With the default configuration of the web server it is impossible to
>>>>>>
>>>>>> handle more than 256 *connections* simultaneously. I guess that "ab"
>>>>>>> is
>>>>>>> opening a connection for each concurrent request, so when you reach
>>>>>>> request
>>>>>>> 257 the web server will just reject the connection, there is nothing
>>>>>>> that
>>>>>>> the JBoss can do about it; you have to increase the number of
>>>>>>> connections
>>>>>>> supported by the web server.
>>>>>>>
>>>>>>> Or else you may want to re-consider why you want to use 1000
>>>>>>> simultaneous
>>>>>>> connections. It may be OK for a performance test, but there are
>>>>>>> better
>>>>>>> ways
>>>>>>> to squeeze performance. For example, you could consider using HTTP
>>>>>>> pipelining, which is much more friendly for the server than so many
>>>>>>> connections. This is what we use when we need to send a large number
>>>>>>> of
>>>>>>> requests from other systems. There are examples of how to do that
>>>>>>> with
>>>>>>> the
>>>>>>> Python and Ruby SDKs here:
>>>>>>>
>>>>>>> Python:
>>>>>>>
>>>>>>> https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/
>>>>>>> examples/asynchronous_inventory.py
>>>>>>>
>>>>>>> Ruby:
>>>>>>>
>>>>>>> https://github.com/oVirt/ovirt-engine-sdk-ruby/blob/master/
>>>>>>> sdk/examples/asynchronous_inventory.rb
>>>>>>>
>>>>>>>
>>>>>>> On 03/07/2018 02:43 PM, Hari Prasanth Loganathan wrote:
>>>>>>>
>>>>>>> Hi Juan,
>>>>>>>
>>>>>>>
>>>>>>>> Thanks for the response.
>>>>>>>>
>>>>>>>> I agree web server can handle only limited number of concurrent
>>>>>>>> requests.
>>>>>>>> But Why it is failing with SSL handshake failure for few requests,
>>>>>>>> Can't
>>>>>>>> the JBOSS wait and serve the request? We can spare the delay but not
>>>>>>>> with
>>>>>>>> the request fails. So Is there a configuration in oVirt which can be
>>>>>>>> tuned
>>>>>>>> to achieve this?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Hari
>>>>>>>>
>>>>>>>> On Wed, Mar 7, 2018 at 7:05 PM, Juan Hernández <jhernand at redhat.com
>>>>>>>> >
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>> The first thing you will need to change for such a test is the
>>>>>>>> number
>>>>>>>> of
>>>>>>>>
>>>>>>>> simultaneous connections accepted by the Apache web server: by
>>>>>>>> default
>>>>>>>>
>>>>>>>>> the
>>>>>>>>> max is 256. See the Apache documentation here:
>>>>>>>>>
>>>>>>>>> https://httpd.apache.org/docs/2.4/mod/mpm_common.html#m
>>>>>>>>> axrequestworkers
>>>>>>>>>
>>>>>>>>> In addition I also suggest that you consider using the "worker"
>>>>>>>>> multi-processing module instead of the "prefork", as it usually
>>>>>>>>> works
>>>>>>>>> better when talking to a Java application server, because it
>>>>>>>>> re-uses
>>>>>>>>> connections better.
>>>>>>>>>
>>>>>>>>> On 03/07/2018 02:20 PM, Hari Prasanth Loganathan wrote:
>>>>>>>>>
>>>>>>>>> Hi Team,
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> *Description of problem:*
>>>>>>>>>>
>>>>>>>>>> I am trying to achieve 1000 concurrent request to oVirt. What are
>>>>>>>>>> the
>>>>>>>>>> tunable parameters to achieve this?
>>>>>>>>>>
>>>>>>>>>> I tried to perform the benchmarking for ovirt engine using Apache
>>>>>>>>>> benchmark
>>>>>>>>>> using the same SSO token.
>>>>>>>>>>
>>>>>>>>>> ab -n 1000 -c 500 -k -H "accept: application/json" -H
>>>>>>>>>> "Authorization:
>>>>>>>>>> Bearer SSOTOKEN" https://172.30.56.70/ovirt-engine/
>>>>>>>>>> <https://172.30.56.70/ovirt-engine/api/vms/5440271b-afb3-48b
>>>>>>>>>> b-9ff1-076fc07ebf50/statistics>
>>>>>>>>>>
>>>>>>>>>> When the number of concurrent request is 500, we are getting more
>>>>>>>>>> than
>>>>>>>>>> 100
>>>>>>>>>> failures with the following error,
>>>>>>>>>>
>>>>>>>>>> SSL read failed (1) - closing connection
>>>>>>>>>> 139620982339352:error:
>>>>>>>>>>
>>>>>>>>>> NOTE: It is scaling for concurrent request below 500.
>>>>>>>>>>
>>>>>>>>>> I used the profiler to get the memory and CPU and it seems very
>>>>>>>>>> less,
>>>>>>>>>>
>>>>>>>>>> PID USER PR NI VIRT RES SHR S %CPU %MEM
>>>>>>>>>> TIME+
>>>>>>>>>> COMMAND
>>>>>>>>>> 30413 ovirt 20 0 4226664 882396 6776 S 126.0 23.0
>>>>>>>>>> 27:48.53
>>>>>>>>>> java
>>>>>>>>>>
>>>>>>>>>> Configuration of the machine in which Ovirt is deployed :
>>>>>>>>>>
>>>>>>>>>> RAM - 4GB,
>>>>>>>>>> Hard disk - 100GB,
>>>>>>>>>> core processor - 2,
>>>>>>>>>> OS - Cent7.x.
>>>>>>>>>>
>>>>>>>>>> In which 2GB is allocated to oVirt.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Version-Release number of selected component (if applicable):
>>>>>>>>>>
>>>>>>>>>> 4.2.2
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> How reproducible:
>>>>>>>>>>
>>>>>>>>>> If the number of concurrent requests are above 500, we are easily
>>>>>>>>>> facing
>>>>>>>>>> this issue.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> *Actual results:*
>>>>>>>>>>
>>>>>>>>>> SSL read failed (1) - closing connection
>>>>>>>>>> 139620982339352:error:
>>>>>>>>>>
>>>>>>>>>> *Expected results:*
>>>>>>>>>>
>>>>>>>>>> Request success.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Hari
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> Users mailing list
>>>>>>>>>> Users at ovirt.org
>>>>>>>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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