[jboss-as7-dev] Domain mode server launch command

[John O'Hara]

I think the launch-command-prefix is probably more suitable, as 
ModelCombiner already does a good job at defining which java command to run.

atm I can not think of a use case for a launch-command-suffix element

re [1] - I noticed this up after I sent the email

On 08/14/2012 06:03 PM, Brian Stansberry wrote:
> That's along the lines of what I was thinking for the "different user
> account" case.
>
> Something to think about is whether "java" should be in the
> launch-command[1] value (with a default value of just "java".) If not
> it's really a launch-command-prefix, and then is there a use case for
> launch-command-suffix?
>
> I think using a separate child element for this instead of an attribute
> is better.
>
> Another question is whether it makes sense to allow this to be
> configured at the server-group level, with servers by default inheriting
> that config. My vote is "no." KISS. If there is demand for doing it at
> the server-group level, we'll here about it and can add it later.
>
> As for validation, I doubt we can do much there. I think this would be
> an advanced feature where users are going to have to be careful and test
> things.
>
> [1] Note our schema uses lower case names with "-" as a separator, not
> camel case. So "launch-command" not "launchCommand".
>
> On 8/14/12 11:49 AM, John O'Hara wrote:
>> When running AS7 in a domain, we need to be able to bind each host to
>> explicit numa nodes when the process is launched. We need to be able to
>> insert a numa command before the java command for each server process
>> that is launched by the HostController. The numa command needs to be
>> configurable for each host, i.e. we might want to bind hosts to
>> different numa nodes or the same numa node.
>>
>> Another use case that I am aware of is running the server process under
>> a different user account to the HostController, e.g. prefixing the java
>> command with something like "sudo joe java"
>>
>> Having thought about our use case and a use case where the host should
>> start start under a different account , a possible solution could be to
>> modify the AS config schema to allow a generic "launch command" for each
>> server entity, so that the host.xml would look something like;
>>
>>             <server name="server-one" group="main-server-group"
>> launchCommand="numactl --membind 0 --cpubind 0"/>
>>             <server name="server-two" group="main-server-group"
>> auto-start="true" launchCommand="numactl --membind 1 --cpubind 1">
>>                 <!-- server-two avoids port conflicts by incrementing the
>> ports in
>>                      the default socket-group declared in the server-group
>> -->
>>                 <socket-bindings port-offset="150"/>
>>             </server>
>>             <server name="server-three" group="main-server-group"
>> auto-start="true" launchCommand="sudo joe">
>>                 <!-- server-two avoids port conflicts by incrementing the
>> ports in
>>                      the default socket-group declared in the server-group
>> -->
>>                 <socket-bindings port-offset="150"/>
>>             </server>
>>
>> If a launchCommand attribute was defined for a server, you could parse
>> the attribute value and add the parsed commands to the ProcessBuilder
>> before the java command.
>>
>> The main difficulty would be validating any commands added in
>> launchCommand attribute, not sure how problematic this would be?
>>
>> Regards,
>>
>> John
>>
>


-- 
John O'Hara
johara at redhat.com

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