Re: [openstack-dev] [nova] Question about boot-from-volume instance and flavor

2015-03-04 Thread Alex Xu
2015-03-04 4:45 GMT+08:00 Jay Pipes jaypi...@gmail.com:

 On 03/03/2015 01:10 AM, Rui Chen wrote:

 Hi all,

 When we boot instance from volume, we find some ambiguous description
 about flavor root_gb in operations guide,
 http://docs.openstack.org/openstack-ops/content/flavors.html

 /Virtual root disk size in gigabytes. This is an ephemeral disk the base
 image is copied into. You don't use it when you boot from a persistent
 volume. /
 /The 0 size is a special case that uses the native base image size as
 the size of the ephemeral root volume./
 /
 /
 'You don't use it(root_gb) when you boot from a persistent volume.'
 It means that we need to set the root_gb to 0 or not? I don't know.


 Hi Rui, I agree the documentation -- and frankly, the code in Nova -- is
 confusing around this area.

  But I find out that the root_gb will been added into local_gb_used of
 compute_node so that it will impact the next scheduling. Think about a
 use case, the local_gb of compute_node is 10, boot instance from volume
 with the root_gb=5 flavor, in this case, I can only boot 2
 boot-from-volume instances on the compute_nodes, although these
 instances don't use the local disk of compute_nodes.

 I find a patch that try to fix this issue,
 https://review.openstack.org/#/c/136284/

 I want to know that which solution is better for you?

 Solution #1: boot instance from volume with the root_gb=0 flavor.
 Solution #2: add some special logic in order to correct the disk usage,
 like patch #136284


 Solution #2 is a better idea, IMO. There should not be any magic setting
 for root_gb that needs to be interpreted both by the user and the Nova code
 base.

 The issue with the 136284 patch is that it is trying to address the
 problem in the wrong place, IMHO.


Emm.I'm thinking of one case. There two flavors, one with root_gb=0,
another one with root_gb=10. And user choice different flavor will pay
different money.
If user choice the flavor with root_gb=10, and then boot from volume...then
user still need pay the extra money. That's good strange. Or say we should
let the bill system to distinguish the instance is boot from volume or not.
Or say we just tell user you make wrong choice... For this case, should we
choice
solution #1?



 Best,
 -jay

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Re: [openstack-dev] [nova] Question about boot-from-volume instance and flavor

2015-03-04 Thread Lingxian Kong
The option1 is a bad idea, IMO. Think about so many extra_specs in the
flavor today, you really don't want create another dozen of flavor
with root_gb=0 just for booting from volume.

For the billing concern, it really should be taken into account, but
it's not the business of OpenStack, IMHO.

I agree with Jay, option 2 will be good.

2015-03-05 13:58 GMT+08:00 Alex Xu sou...@gmail.com:


 2015-03-04 4:45 GMT+08:00 Jay Pipes jaypi...@gmail.com:

 On 03/03/2015 01:10 AM, Rui Chen wrote:

 Hi all,

 When we boot instance from volume, we find some ambiguous description
 about flavor root_gb in operations guide,
 http://docs.openstack.org/openstack-ops/content/flavors.html

 /Virtual root disk size in gigabytes. This is an ephemeral disk the base
 image is copied into. You don't use it when you boot from a persistent
 volume. /
 /The 0 size is a special case that uses the native base image size as
 the size of the ephemeral root volume./
 /
 /
 'You don't use it(root_gb) when you boot from a persistent volume.'
 It means that we need to set the root_gb to 0 or not? I don't know.


 Hi Rui, I agree the documentation -- and frankly, the code in Nova -- is
 confusing around this area.

 But I find out that the root_gb will been added into local_gb_used of
 compute_node so that it will impact the next scheduling. Think about a
 use case, the local_gb of compute_node is 10, boot instance from volume
 with the root_gb=5 flavor, in this case, I can only boot 2
 boot-from-volume instances on the compute_nodes, although these
 instances don't use the local disk of compute_nodes.

 I find a patch that try to fix this issue,
 https://review.openstack.org/#/c/136284/

 I want to know that which solution is better for you?

 Solution #1: boot instance from volume with the root_gb=0 flavor.
 Solution #2: add some special logic in order to correct the disk usage,
 like patch #136284


 Solution #2 is a better idea, IMO. There should not be any magic setting
 for root_gb that needs to be interpreted both by the user and the Nova code
 base.

 The issue with the 136284 patch is that it is trying to address the
 problem in the wrong place, IMHO.


 Emm.I'm thinking of one case. There two flavors, one with root_gb=0,
 another one with root_gb=10. And user choice different flavor will pay
 different money.
 If user choice the flavor with root_gb=10, and then boot from volume...then
 user still need pay the extra money. That's good strange. Or say we should
 let the bill system to distinguish the instance is boot from volume or not.
 Or say we just tell user you make wrong choice... For this case, should we
 choice
 solution #1?



 Best,
 -jay

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-- 
Regards!
---
Lingxian Kong

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Re: [openstack-dev] [nova] Question about boot-from-volume instance and flavor

2015-03-03 Thread Jay Pipes

On 03/03/2015 01:10 AM, Rui Chen wrote:

Hi all,

When we boot instance from volume, we find some ambiguous description
about flavor root_gb in operations guide,
http://docs.openstack.org/openstack-ops/content/flavors.html

/Virtual root disk size in gigabytes. This is an ephemeral disk the base
image is copied into. You don't use it when you boot from a persistent
volume. /
/The 0 size is a special case that uses the native base image size as
the size of the ephemeral root volume./
/
/
'You don't use it(root_gb) when you boot from a persistent volume.'
It means that we need to set the root_gb to 0 or not? I don't know.


Hi Rui, I agree the documentation -- and frankly, the code in Nova -- is 
confusing around this area.



But I find out that the root_gb will been added into local_gb_used of
compute_node so that it will impact the next scheduling. Think about a
use case, the local_gb of compute_node is 10, boot instance from volume
with the root_gb=5 flavor, in this case, I can only boot 2
boot-from-volume instances on the compute_nodes, although these
instances don't use the local disk of compute_nodes.

I find a patch that try to fix this issue,
https://review.openstack.org/#/c/136284/

I want to know that which solution is better for you?

Solution #1: boot instance from volume with the root_gb=0 flavor.
Solution #2: add some special logic in order to correct the disk usage,
like patch #136284


Solution #2 is a better idea, IMO. There should not be any magic 
setting for root_gb that needs to be interpreted both by the user and 
the Nova code base.


The issue with the 136284 patch is that it is trying to address the 
problem in the wrong place, IMHO.


Best,
-jay

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Re: [openstack-dev] [nova] Question about boot-from-volume instance and flavor

2015-03-03 Thread Rui Chen
Thank you for reply, @Jay.

+1 for
There should not be any magic setting for root_gb that needs to be
interpreted both by the user and the Nova code base.

I will try to restart the patch 136284 on the other way, like: instance
object.

Best Regards

2015-03-04 4:45 GMT+08:00 Jay Pipes jaypi...@gmail.com:

 On 03/03/2015 01:10 AM, Rui Chen wrote:

 Hi all,

 When we boot instance from volume, we find some ambiguous description
 about flavor root_gb in operations guide,
 http://docs.openstack.org/openstack-ops/content/flavors.html

 /Virtual root disk size in gigabytes. This is an ephemeral disk the base
 image is copied into. You don't use it when you boot from a persistent
 volume. /
 /The 0 size is a special case that uses the native base image size as
 the size of the ephemeral root volume./
 /
 /
 'You don't use it(root_gb) when you boot from a persistent volume.'
 It means that we need to set the root_gb to 0 or not? I don't know.


 Hi Rui, I agree the documentation -- and frankly, the code in Nova -- is
 confusing around this area.

  But I find out that the root_gb will been added into local_gb_used of
 compute_node so that it will impact the next scheduling. Think about a
 use case, the local_gb of compute_node is 10, boot instance from volume
 with the root_gb=5 flavor, in this case, I can only boot 2
 boot-from-volume instances on the compute_nodes, although these
 instances don't use the local disk of compute_nodes.

 I find a patch that try to fix this issue,
 https://review.openstack.org/#/c/136284/

 I want to know that which solution is better for you?

 Solution #1: boot instance from volume with the root_gb=0 flavor.
 Solution #2: add some special logic in order to correct the disk usage,
 like patch #136284


 Solution #2 is a better idea, IMO. There should not be any magic setting
 for root_gb that needs to be interpreted both by the user and the Nova code
 base.

 The issue with the 136284 patch is that it is trying to address the
 problem in the wrong place, IMHO.

 Best,
 -jay

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