Specifying the retention period

Anders Håål anders.haal at ingby.com
Wed Sep 10 12:32:55 CEST 2014


This looks like a bug. Could you please report it on 
http://gforge.ingby.com/gf/project/bischeck/tracker/ in the Bugs 
tracker. You need a account but its just a sign up and you get an email 
confirmation.
Can you try to use maxcount for purging instead as a work around? Just 
calculate your maxcount based on the scheduling interval you use.
Anders

On 09/10/2014 12:17 PM, Rahul Amaram wrote:
> Following up on the earlier topic, I am seeing the below errors related
> to cache purge. Any idea on what might be causing this? I don't see any
> other errors in log related to metrics.
>
> 2014-09-10 12:12:00.001 ; INFO ; DefaultQuartzScheduler_Worker-5 ;
> com.ingby.socbox.bischeck.configuration.CachePurgeJob ; CachePurge
> purging 180
> 2014-09-10 12:12:00.003 ; INFO ; DefaultQuartzScheduler_Worker-5 ;
> com.ingby.socbox.bischeck.configuration.CachePurgeJob ; CachePurge
> executed in 1 ms
> 2014-09-10 12:12:00.003 ; ERROR ; DefaultQuartzScheduler_Worker-5 ;
> org.quartz.core.JobRunShell ; Job DailyMaintenance.CachePurge threw an
> unhandled Exception: java.lang.NullPointerException: null
>          at
> com.ingby.socbox.bischeck.cache.provider.redis.LastStatusCache.trim(LastStatusCache.java:1250)
>
>          at
> com.ingby.socbox.bischeck.configuration.CachePurgeJob.execute(CachePurgeJob.java:140)
>
>
> 2014-09-10 12:12:00.003 ; ERROR ; DefaultQuartzScheduler_Worker-5 ;
> org.quartz.core.ErrorLogger ; Job (DailyMaintenance.CachePurge threw an
> exception.org.quartz.SchedulerException: Job threw an unhandled exception.
>          at org.quartz.core.JobRunShell.run(JobRunShell.java:224)
>          at
> org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:557)
>
> Caused by: java.lang.NullPointerException: null
>          at
> com.ingby.socbox.bischeck.cache.provider.redis.LastStatusCache.trim(LastStatusCache.java:1250)
>
>          at
> com.ingby.socbox.bischeck.configuration.CachePurgeJob.execute(CachePurgeJob.java:140)
>
>
> Here is my cache configuration:
>
>      <cache>
>        <aggregate>
>          <method>avg</method>
>          <useweekend>true</useweekend>
>          <retention>
>            <period>H</period>
>            <offset>720</offset>
>          </retention>
>          <retention>
>            <period>D</period>
>            <offset>30</offset>
>          </retention>
>        </aggregate>
>
>        <purge>
>          <offset>30</offset>
>          <period>D</period>
>        </purge>
>      </cache>
>
> Regards,
> Rahul.
> On Monday 08 September 2014 08:39 PM, Anders Håål wrote:
>> Great if you can make a debian package, and I understand that you can
>> not commit. The best thing would be integrated to our build process
>> where we use ant.
>>
>> if the purging is based on time then it could happen that data is
>> removed from the cache since the logic is based on time relative to
>> now. To avoid it you should increase the purge time before you start
>> bischeck. And just a comment on your last sentence Redis TTl is never
>> used :)
>> Anders
>>
>> On 09/08/2014 02:09 PM, Rahul Amaram wrote:
>>> I would be more than happy to give you guys a testimonial. However, we
>>> have just taken this live and would like to see its performance before I
>>> give a testimonial.
>>>
>>> Also, if time permits, I'll try to bundle this for Debian (I'm a Debian
>>> maintainer). I can't commit on a timeline right away though :).
>>>
>>> Also, just to make things explicitly clear. I understand that the below
>>> service item ttl has nothing to do with Redis TTL. But If I stop my
>>> bischeck server for a day or two, then would any of my metrics get lost?
>>> Or would I have to increase th Redis TTL for this.
>>>
>>> Regards,
>>> Rahul.
>>>
>>> On Monday 08 September 2014 04:09 PM, Anders Håål wrote:
>>>> Glad that it clarified how to configure the cache section. I will make
>>>> a blog post on this in the mean time, until we have a updated
>>>> documentation. I agree with you that the structure of the
>>>> configuration is a bit "heavy", so ideas and input is appreciated.
>>>>
>>>> Regarding redis ttl, this is a redis feature we do not use. The ttl
>>>> mentioned in my mail is managed by bischeck. Redis ttl on linked list
>>>> do not work on individual nodes in a redis linked list.
>>>>
>>>> Currently the bischeck installer should work for ubuntu, redhat/centos
>>>> and debian. There is currently no plans to make distribution packages
>>>> like rpm or deb. I know op5 (www.op5.com) that bundles Bischeck make a
>>>> bischeck rpm. It would be super if there is any one that like to do
>>>> this for the project.
>>>> When it comes to packaging we have done a bit of work to create docker
>>>> containers, but its still experimental.
>>>>
>>>> I also encourage you, if you think bischeck support your monitoring
>>>> effort, to write a small testimony that we can put on the site.
>>>> Regards
>>>> Anders
>>>>
>>>> On 09/08/2014 11:30 AM, Rahul Amaram wrote:
>>>>> Thanks Anders. This explains precisely why my data was getting purged
>>>>> after 16 hours (30 values per hour * 1 hours = 480). It would be great
>>>>> if you could update the documentation with this info. The entire setup
>>>>> and configuration itself takes time to get a hold on and detailed
>>>>> documentation would be very helpful.
>>>>>
>>>>> Also, another quick question? Right now, I believe the Redis TTL is
>>>>> set
>>>>> to 2000 seconds. Does this mean that if I don't receive data for a
>>>>> particular serviceitem (or service or host) for a 2000 seconds, the
>>>>> data
>>>>> related to it is lost?
>>>>>
>>>>> Also, any plans for bundling this with distributions such as Debian?
>>>>>
>>>>> Regards,
>>>>> Rahul.
>>>>>
>>>>>
>>>>> On Monday 08 September 2014 02:04 PM, Anders Håål wrote:
>>>>>> Hi Rahul,
>>>>>> Thanks for the question and feedback on the documentation. Great to
>>>>>> hear that you think Bischeck is awesome. If you do not understand how
>>>>>> it works by reading the documentation you are probably not alone, and
>>>>>> we should consider it a documentation bug.
>>>>>>
>>>>>> In 1.0.0 we introduce the concept that you asking about and it really
>>>>>> two different independent features.
>>>>>>
>>>>>> Lets start with cache purging.
>>>>>> Collected monitoring data, metrics, are kept in the cache (redis from
>>>>>> 1.0.0) as a linked lists. There is one linked list per service
>>>>>> definition, like host1-service1-serviceitem1.  Prior to 1.0.0 all the
>>>>>> linked lists had the same size that was defined with the property
>>>>>> lastStatusCacheSize. But in 1.0.0 we made that configurable so it
>>>>>> could be defined per service definition.
>>>>>> To enable individual cache configurations we added a section called
>>>>>> <cache> in the serviceitem section of the bischeck.xml. Like many
>>>>>> other configuration options in 1.0.0 the cache section could have the
>>>>>> specific values or point to a template that could be shared.
>>>>>> To manage the size of the cache , or to be more specific the linked
>>>>>> list size, we defined the <purge> section. The purge section can have
>>>>>> two different configurations. The first is defining the max size of
>>>>>> the cache linked list.
>>>>>> <cache>
>>>>>>   <purge>
>>>>>>    <maxcount>1000</maxcount>
>>>>>>   </purge>
>>>>>> </cache>
>>>>>>
>>>>>> The second options is to define the “time to live” for the metrics in
>>>>>> the cache.
>>>>>> <cache>
>>>>>>   <purge>
>>>>>>    <offset>10</offset>
>>>>>>    <period>D</period>
>>>>>>   </purge>
>>>>>> </cache>
>>>>>> In the above example we set the time to live to 10 days. So any
>>>>>> metrics older then this period will be removed. The period can have
>>>>>> the following values:
>>>>>> H - hours
>>>>>> D - days
>>>>>> W - weeks
>>>>>> Y - year
>>>>>>
>>>>>> The two option are mutual exclusive. You have to chose one for each
>>>>>> serviceitem or cache template.
>>>>>>
>>>>>> If no cache directive is define for a serviceitem the property
>>>>>> lastStatusCacheSize will be used. It's default value is 500.
>>>>>>
>>>>>> Hopefully this explains the cache purging.
>>>>>>
>>>>>> The next question was related to aggregations which has nothing to do
>>>>>> with purging, but it's configured in the same <cache> section. The
>>>>>> idea with aggregations was to create an automatic way to aggregate
>>>>>> metrics on the level of an hour, day, week and month. The aggregation
>>>>>> functions current supported is average, max and min.
>>>>>> Lets say you have a service definition of the format
>>>>>> host1-service1-serviceitem1. When you  enable an average (avg)
>>>>>> aggregation you will automatically get the following new service
>>>>>> definitions
>>>>>> host1-service1/H/avg-serviceitem1
>>>>>> host1-service1/D/avg-serviceitem1
>>>>>> host1-service1/W/avg-serviceitem1
>>>>>> host1-service1/M/avg-serviceitem1
>>>>>>
>>>>>> The configuration you need to achive the above average
>>>>>> aggregations is:
>>>>>> <cache>
>>>>>>   <aggregate>
>>>>>>     <method>avg</method>
>>>>>>   </aggregate>
>>>>>> </cache>
>>>>>>
>>>>>> If you like to combine it with the above descibed purging your
>>>>>> configuration would look like:
>>>>>> <cache>
>>>>>>   <aggregate>
>>>>>>     <method>avg</method>
>>>>>>   </aggregate>
>>>>>>
>>>>>>   <purge>
>>>>>>    <offset>10</offset>
>>>>>>    <period>D</period>
>>>>>>   </purge>
>>>>>> </cache>
>>>>>>
>>>>>> The new aggregated service definitions,
>>>>>> host1-service1/H/avg-serviceitem1, etc, will have their own cache
>>>>>> entries and can be used in threshold configurations and virtual
>>>>>> services like any other service definitions. For example in a
>>>>>> threshold hours section we could define
>>>>>>
>>>>>> <hours hoursID="2">
>>>>>>
>>>>>>   <hourinterval>
>>>>>>     <from>09:00</from>
>>>>>>     <to>12:00</to>
>>>>>> <threshold>host1-service1/H/avg-serviceitem1[0]*0.8</threshold>
>>>>>>   </hourinterval>
>>>>>>   ...
>>>>>>
>>>>>> This would mean that we use the average value for
>>>>>> host1-service1-serviceitem1  for the period of the last hour.
>>>>>> Aggregations are calculated hourly, daily, weekly and monthly.
>>>>>>
>>>>>> By default weekends metrics are not included in the aggrgation
>>>>>> calculation. This can be enabled by setting the
>>>>>> <useweekend>true</useweekend>:
>>>>>>
>>>>>> <cache>
>>>>>>   <aggregate>
>>>>>>     <method>avg</method>
>>>>>>     <useweekend>true</useweekend>
>>>>>>   </aggregate>
>>>>>>   ….
>>>>>> </cache>
>>>>>>
>>>>>> This will create aggregated service definitions with the following
>>>>>> name standard:
>>>>>> host1-service1/H/avg/weekend-serviceitem1
>>>>>> host1-service1/D/avg/weekend-serviceitem1
>>>>>> host1-service1/W/avg/weekend-serviceitem1
>>>>>> host1-service1/M/avg/weekend-serviceitem1
>>>>>>
>>>>>> You can also have multiple entries like:
>>>>>> <cache>
>>>>>>   <aggregate>
>>>>>>     <method>avg</method>
>>>>>>     <useweekend>true</useweekend>
>>>>>>   </aggregate>
>>>>>>   <aggregate>
>>>>>>     <method>max</method>
>>>>>>   </aggregate>
>>>>>>   ….
>>>>>> </cache>
>>>>>>
>>>>>> So how long time will the aggregated values be kept in the cache? By
>>>>>> default we save
>>>>>> Hour aggregation for 25 hours
>>>>>> Daily aggregations for 7 days
>>>>>> Weekly aggregations for 5 weeks
>>>>>> Monthly aggregations for 1 month
>>>>>>
>>>>>> These values can be override but they can not be lower then the
>>>>>> default. Below you have an example where we save the aggregation for
>>>>>> 168 hours, 60 days and 53 weeks.
>>>>>> <cache>
>>>>>>   <aggregate>
>>>>>>     <method>avg</method>
>>>>>>     <useweekend>true</useweekend>
>>>>>>     <retention>
>>>>>>       <period>H</period>
>>>>>>       <offset>168</offset>
>>>>>>     </retention>
>>>>>>     <retention>
>>>>>>      <period>D</period>
>>>>>>       <offset>60</offset>
>>>>>>     </retention>
>>>>>>     <retention>
>>>>>>       <period>W</period>
>>>>>>       <offset>53</offset>
>>>>>>     </retention>
>>>>>> </aggregate>
>>>>>>   ….
>>>>>> </cache>
>>>>>>
>>>>>> I hope this makes it a bit less confusing. What is clear to me is
>>>>>> that
>>>>>> we need to improve the documentation in this area.
>>>>>>
>>>>>> Looking forward to your feedback.
>>>>>> Anders
>>>>>>
>>>>>> On 09/08/2014 06:02 AM, Rahul Amaram wrote:
>>>>>>> Hi,
>>>>>>> I am trying to setup the bischeck plugin for our organization. I
>>>>>>> have
>>>>>>> configured most part of it except for the cache retention period.
>>>>>>> Here
>>>>>>> is what I want - I want to store every value which has been
>>>>>>> generated
>>>>>>> during the past 1 month. The reason being my threshold is currently
>>>>>>> calculated as the average of the metric value during the past 4
>>>>>>> weeks at
>>>>>>> the same time of the day.
>>>>>>>
>>>>>>> So, how do I define the cache template for this? If I don't
>>>>>>> define any
>>>>>>> cache template, for how many days is the data kept?
>>>>>>> Also, how does the aggregrate function work and and what does the
>>>>>>> purge
>>>>>>> Maxitems signify?
>>>>>>>
>>>>>>> I've gone through the documentation but it wasn't clear. Looking
>>>>>>> forward
>>>>>>> to a response.
>>>>>>>
>>>>>>> Bischeck is one awesome plugin. Keep up the great work.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Rahul.
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>


-- 

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<http://www.bischeck.org>

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