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https://issues.apache.org/jira/browse/AMBARI-14690?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15112877#comment-15112877
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Sumit Mohanty edited comment on AMBARI-14690 at 1/22/16 9:09 PM:
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Thanks [~gsaha]. The generic way to think about this feature is that Ambari
Agent's default way of querying for system info is not adequate. A simple
reason could be IT not wanting to have Ambari assume that all available
resources can be used or, as mentioned earlier, containers may have a different
mechanism to compute available resources.
Thus it makes sense for the agent to have a configurable mechanism to
infer/read various system resource limits.
Agent uses "scripts" to overwrite some defaults such as hostname (use a
hostname script that gives the agent the hostname). Scripts are not necessarily
the best but its possible to have the script simply cat a file as discussed
above. However, taking in more main-stream and have Ambari read a directory or
file for over-writes to the system info will be great. As suggested earlier,
lets keep names consistent with what we already have. It will make it easier to
add more system info properties in future.
was (Author: sumitmohanty):
Thanks [~gahah]. The generic way to think about this feature is that Ambari
Agent's default way of querying for system info is not adequate. A simple
reason could be IT not wanting to have Ambari assume that all available
resources can be used or, as mentioned earlier, containers may have a different
mechanism to compute available resources.
Thus it makes sense for the agent to have a configurable mechanism to
infer/read various system resource limits.
Agent uses "scripts" to overwrite some defaults such as hostname (use a
hostname script that gives the agent the hostname). Scripts are not necessarily
the best but its possible to have the script simply cat a file as discussed
above. However, taking in more main-stream and have Ambari read a directory or
file for over-writes to the system info will be great. As suggested earlier,
lets keep names consistent with what we already have. It will make it easier to
add more system info properties in future.
> Configurable system resource values for ambari-agent
> ----------------------------------------------------
>
> Key: AMBARI-14690
> URL: https://issues.apache.org/jira/browse/AMBARI-14690
> Project: Ambari
> Issue Type: Improvement
> Components: ambari-agent
> Affects Versions: 2.2.0
> Reporter: Olivér Szabó
> Assignee: Olivér Szabó
> Fix For: 2.2.2
>
> Attachments: AMBARI-14690.patch, AMBARI-14690_v2.patch
>
>
> When an ambari agent starts, host system details are registered into ambari
> server database. These values are calculated by ambari-agents based on
> different files on the hosts (e.g : /proc/meminfo).
> In some cases it isn't a correct behavior: If ambari-agent is in a
> docker-container, it will see the same memory/cpu details. (stack advisor
> also uses these values, its possible stack advisor can recommend a too high
> memory value for some services)
> Solution: Configurable system resources in ambari-agent.ini (if a value does
> not exist or empty, it will use the default behavior)
> {code:java}
> [system_resource]
> processorcount=2
> physicalprocessorcount=2
> memorysize=50000
> memoryfree=50000
> memorytotal=100000
> swapsize=20
> swapfree=20
> ...
> {code}
> In ambari-agent Facter.py set these values, all of the factor info values can
> be redefined in ambari-agent.ini file.
> That means ambari is not responsible to gather these values from the system.
> - use case:
> During 'docker run' , if there is a script which calls 'ambari-agent start',
> before that, some of the memory values can be replaced/inserted into the
> ambari-agent.ini file in that script. (e.g. the user knows that, 4
> ambari-agent containers will be started, with the same services, so the real
> memory needs to be devided by 4 etc.)
> Facter.py is called during ambari-agent start, so if the values will be
> modified later, ambari-agent needs to be restarted.
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