Re: [Condor-users] Is VM_MAX_NUMBER a redundant macro?

[Jaime Frey <jfrey@xxxxxxxxxxx>]

On Jul 12, 2009, at 8:04 PM, Rob wrote:

> I'm using Condor 7.2.4.
>
> I ran into this problem when trying to set the condor_config file  
> for the
> macros VM_MAX_NUMBER and VM_MEMORY, using the hardware
> macros $(NUM_CPUS) and $(MEMORY).
>
> This seemed to work for VM_MAX_NUMBER, but not for VM_MEMORY.
> However, digging a little deeper, it seems that setting VM_MAX_NUMBER
> to just about any value, doesn't affect condor at all.......
>
> Let me explain this with the following three examples:
>
> ----------
> The default setting for this macro is  VM_MAX_NUMBER = $(NUM_CPUS)
> If I set this EXPLICITLY in the condor_config file and then query  
> its value,
> I get this:
>
>     C:\condor\bin> condor_config_val.exe -verbose VM_MAX_NUMBER
>     Not defined: VM_MAX_NUMBER
>
> ----------
> If I set it to a specific number, e.g:   VM_MAX_NUMBER = 2
> I get this:
>
>     C:\condor\bin> condor_config_val.exe -verbose VM_MAX_NUMBER
>     VM_MAX_NUMBER: 2
>          Defined in 'C:\condor\condor_config', line 2171
>
> ----------
> If I set it to a wrong value, e.g.  VM_MAX_NUMBER = "what do I care"
> I get this (without any error message in the log files!)
>
>     C:\condor\bin> condor_config_val.exe -verbose VM_MAX_NUMBER
>     VM_MAX_NUMBER: "what do I care"
>          Defined in 'C:\condor\condor_config', line 2171
>
>
> The absence of an error message in the last example, tells me that
> condor doesn't care at all about the value of VM_MAX_NUMBER.
> Also, in the StartLog there's mentioning of the VM settings, but  
> nothing
> about VM_MAX_NUMBER:
>
> VM_GAHP_VERSION = "0.0.1"
> VM_Type = "vmware"
> VM_Version = "server1.0"
> VM_Memory = 512
> VM_Networking = TRUE
> VM_Networking_Types = "nat,bridge"
> 7/11 14:09:35
> 7/11 14:09:35 VMType('vmware') is supported
> 7/11 14:09:35 The maximum available memory for vm universe is set to  
> 512 MB
> 7/11 14:09:35 VM networking is enabled
> 7/11 14:09:35 Supported networking types are nat,bridge
> 7/11 14:09:36 New machine resource allocated
>
>
>
> Hence my humble conclusion:
>
> Although the explanation in the condor_config file suggests that the  
> macro
> $(NUM_CPUS) can be used to set VM_MAX_NUMBER, this is actually not  
> true.
> $(NUM_CPUS) is not available at startup time and therefore  
> VM_MAX_NUMBER
> becomes by default an empty macro.
>
> The absence of any error message when setting VM_MAX_NUMBER to a wrong
> value, tells me that Condor doesn't care what its value is and  
> therefore it doesn't
> matter at all what value it has!
>
> Is VM_MAX_NUMBER really a redundant macro?
>
>
> (All this contrasts to the way VM_MEMORY is dealt with; if set to a  
> wrong value,
> then there are plenty of error messages in the log files and the VM  
> universe
> won't be available.)


VM_MAX_NUMBER is working properly, though its behavior is a little  
odd. If its value isn't a positive integer, then there's no limit on  
the number of VMs (other than the number of slots). No error is  
written to the log in the event of an invalid value.

The number of additional VMs that can be started is advertised as  
'VM_AvailNum' in the machine ad. In the unlimited case, the value is  
set to 10000.

Thanks and regards,
Jaime Frey
UW-Madison Condor Team