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[openstack-dev] [nova] reset key pair during rebuilding

0 votes

Hi nova developers,

This mail is proposed to reconsider the key pair resetting of instance. The
nova queens PTG discuss is here: https://etherpad.openstack.org/p/nova-ptg-
queens L498. And there are now two proposals.

  1. SPEC 1: https://review.openstack.org/#/c/375221/ started by me
    (liuyulong) since sep 2016.

    This spec will allow setting the new key_name for the instance during
    rebuild API. That’s a very simple and well-understood approach:

  • Make consistent with rebuild API properties, such as name, imageRef,
    metadata, adminPass etc.
  • Rebuild API is something like recreating, this is the right way to
    do key pair updating. For keypair-login-only VM, this is the key point.
  • This does not involve to other APIs like reboot/unshelve etc.
  • Easy to use, only one API.

By the way, here is the patch (https://review.openstack.org/#/c/379128/)
which has implemented this spec. And it stays there more than one year too.

  1. SPEC 2 : https://review.openstack.org/#/c/506552/ propose by Kevin_zheng.

This spec supposed to add a new updating API for one instance’s key pair.
This one has one foreseeable advantage for this is to do instance running
key injection.

But it may cause some issues:

  • This approach needs to update the instance key pair first (one step,
    API call). And then do a reboot/rebuild or any actions causing the vm
    restart (second step, another API call). Firstly, this is waste, it use two
    API calls. Secondly, if updating key pair was done, and the reboot was not.
    That may result an inconsistent between instance DB key pair and guest VM
    inside key. Cloud user may confused to choose which key should be used to
    login.
  • For the second step (reboot), there is a strong constraint is that
    cloud-init config needs to be set to running-per-booting. But if a cloud
    platform all images are set cloud-init to per-deployment. In order to
    achieve this new API goal, the entire cloud platform images need updating.
    This will cause a huge upgrading work for entire cloud platform images.
    They need to change all the images cloud-init config from
    running-per-deployment to running-every-boot. But that still can not solve
    the inconsistent between DB keypair and guest-key. For instance, if the
    running VM is based on a running-once-cloud-init image: 1. create image
    from this VM; 2. change the keypair of the new VM; 3. reboot still can not
    work because of the old config of per-deployment-running.
  • For another second step (rebuild), if they have to rebuild, or rebuild
    is the only one way to deployment new key, we are going back to rebuild
    SPEC 1. Two steps for keypair updating are not good. Why don’t directly
    using SPEC 1?
  • Another perspective to think about this is that SPEC 2 is expanding
    the functionality of reboot. What about one day user want to change
    password/name/personality at a reboot?
  • Cloud user may still have questions: why key pair can not be updated
    during rebuilding ? Why name/image/personality can?
  • If new API does not supporting running injection, the DB keypair and
    guest keypair are inconsistent if cloud user forget a rebuiding, reboot,
    unshelving API call.

In conclusion, IMHO SPEC 1 is the reasonable way to set key pair for
rebuild API. It’s simple and easy.

SPEC 2 can be used for future running key injection. And it is still a way
for reboot API to deploy the new key. But the its disadvantages are as
stated above.

There already has some discuss [1] about this with Matt and Kevin.

Sincerely hope to receive your opinion. Feel free to ping me at IRC
openstack-nova, my nick is liuyulong. Thank you very much.

[1] http://eavesdrop.openstack.org/irclogs/%23openstack-nova/
%23openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07


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asked Sep 28, 2017 in openstack-dev by liuyulong.xa_at_gmai (280 points)   1

9 Responses

0 votes

Hi,

FYI, we are going to use the existing PUT /servers/{serveruuid} API,
adding the 'key
name' field.

On Sat, Sep 23, 2017 at 9:58 PM, LIU Yulong liuyulong.xa@gmail.com wrote:

Hi nova developers,

This mail is proposed to reconsider the key pair resetting of instance.
The nova queens PTG discuss is here: https://etherpad.opensta
ck.org/p/nova-ptg-queens L498. And there are now two proposals.

  1. SPEC 1: https://review.openstack.org/#/c/375221/ started by me
    (liuyulong) since sep 2016.

    This spec will allow setting the new key_name for the instance during
    rebuild API. That’s a very simple and well-understood approach:

  • Make consistent with rebuild API properties, such as name, imageRef,
    metadata, adminPass etc.
  • Rebuild API is something like recreating, this is the right way to
    do key pair updating. For keypair-login-only VM, this is the key point.
  • This does not involve to other APIs like reboot/unshelve etc.
  • Easy to use, only one API.

By the way, here is the patch (https://review.openstack.org/#/c/379128/)
which has implemented this spec. And it stays there more than one year too.

  1. SPEC 2 : https://review.openstack.org/#/c/506552/ propose by
    Kevin_zheng.

This spec supposed to add a new updating API for one instance’s key pair.
This one has one foreseeable advantage for this is to do instance running
key injection.

But it may cause some issues:

  • This approach needs to update the instance key pair first (one step,
    API call). And then do a reboot/rebuild or any actions causing the vm
    restart (second step, another API call). Firstly, this is waste, it use two
    API calls. Secondly, if updating key pair was done, and the reboot was not.
    That may result an inconsistent between instance DB key pair and guest VM
    inside key. Cloud user may confused to choose which key should be used to
    login.
  • For the second step (reboot), there is a strong constraint is that
    cloud-init config needs to be set to running-per-booting. But if a cloud
    platform all images are set cloud-init to per-deployment. In order to
    achieve this new API goal, the entire cloud platform images need updating.
    This will cause a huge upgrading work for entire cloud platform images.
    They need to change all the images cloud-init config from
    running-per-deployment to running-every-boot. But that still can not solve
    the inconsistent between DB keypair and guest-key. For instance, if the
    running VM is based on a running-once-cloud-init image: 1. create image
    from this VM; 2. change the keypair of the new VM; 3. reboot still can not
    work because of the old config of per-deployment-running.
  • For another second step (rebuild), if they have to rebuild, or
    rebuild is the only one way to deployment new key, we are going back to
    rebuild SPEC 1. Two steps for keypair updating are not good. Why don’t
    directly using SPEC 1?
  • Another perspective to think about this is that SPEC 2 is expanding
    the functionality of reboot. What about one day user want to change
    password/name/personality at a reboot?
  • Cloud user may still have questions: why key pair can not be updated
    during rebuilding ? Why name/image/personality can?
  • If new API does not supporting running injection, the DB keypair and
    guest keypair are inconsistent if cloud user forget a rebuiding, reboot,
    unshelving API call.

In conclusion, IMHO SPEC 1 is the reasonable way to set key pair for
rebuild API. It’s simple and easy.

SPEC 2 can be used for future running key injection. And it is still a way
for reboot API to deploy the new key. But the its disadvantages are as
stated above.

There already has some discuss [1] about this with Matt and Kevin.

Sincerely hope to receive your opinion. Feel free to ping me at IRC
openstack-nova, my nick is liuyulong. Thank you very much.

[1] http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23openstack-
nova.2017-09-22.log.html#t2017-09-22T14:05:07


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responded Sep 25, 2017 by Zhenyu_Zheng (2,800 points)   6 6
0 votes

On 9/23/2017 8:58 AM, LIU Yulong wrote:
Hi nova developers,

This mail is proposed to reconsider the key pair resetting of instance.
The nova queens PTG discuss is here:
https://etherpad.openstack.org/p/nova-ptg-queens
https://etherpad.openstack.org/p/nova-ptg-queens L498. And there are
now two proposals.

  1. SPEC 1: https://review.openstack.org/#/c/375221/
    https://review.openstack.org/#/c/375221/ started by me (liuyulong)
    since sep 2016.

       This spec will allow setting the new key_name for the instance
    during rebuild API. That’s a very simple and well-understood approach:

  • Make consistent with rebuild API properties, such as name, imageRef,
    metadata, adminPass etc.
  • Rebuild API is something like recreating, this is the right way to
    do key pair updating. For keypair-login-only VM, this is the key point.
  • This does not involve to other APIs like reboot/unshelve etc.

This was one of the issues I brought up in IRC, is that if we just
implemented this for the rebuild API, then someone could also ask that
we do it for things like reboot, cold migrate/resize, unshelve, etc.
Anything that involves re-creating the guest.

  • Easy to use, only one API.

Until someone says we should also do it for the other APIs, as noted above.

By the way, here is the patch (https://review.openstack.org/#/c/379128/
https://review.openstack.org/#/c/379128/) which has implemented this
spec. And it stays there more than one year too.

It's been open because the spec was never approved. Just a procedural issue.

  1. SPEC 2 : https://review.openstack.org/#/c/506552/
    https://review.openstack.org/#/c/506552/ propose by Kevin_zheng.

This spec supposed to add a new updating API for one instance’s key
pair. This one has one foreseeable advantage for this is to do instance
running key injection.

But it may cause some issues:

  • This approach needs to update the instance key pair first (one step,
    API call). And then do a reboot/rebuild or any actions causing the
    vm restart (second step, another API call). Firstly, this is waste,
    it use two API calls. Secondly, if updating key pair was done, and
    the reboot was not. That may result an inconsistent between instance
    DB key pair and guest VM inside key. Cloud user may confused to
    choose which key should be used to login.
  1. I don't think multiple API calls is a problem. Any GUI or
    orchestration tool can stitch these APIs together for what appears to be
    a single operation for the end user. Furthermore, with multiple options
    about what to do after the instance.key_name is updated, something like
    a GUI could present the user with the option to picking if they want to
    reboot or rebuild after the key is updated.

  2. An orchestrator or GUI would make sure that both APIs are called. For
    a user that is updating the key_name, they should realize they need to
    make another API call to enable it. This would all be in the API
    reference documentation, CLI help, etc, that anyone doing this should
    read and understand.

  • For the second step (reboot), there is a strong constraint is that
    cloud-init config needs to be set to running-per-booting. But if a
    cloud platform all images are set cloud-init to per-deployment. In
    order to achieve this new API goal, the entire cloud platform images
    need updating. This will cause a huge upgrading work for entire
    cloud platform images. They need to change all the images cloud-init
    config from running-per-deployment to running-every-boot. But that
    still can not solve the inconsistent between DB keypair and
    guest-key. For instance, if the running VM is based on a
    running-once-cloud-init image: 1. create image from this VM; 2.
    change the keypair of the new VM; 3. reboot still can not work
    because of the old config of per-deployment-running.

This is per-cloud configuration, and as such it should be documented
with the cloud documentation. I can't say what is more "normal" for
OpenStack clouds to be doing with cloud-init here, that would be a good
question for the operators community (I've cross posted to the ops ML).

  • For another second step (rebuild), if they have to rebuild, or
    rebuild is the only one way to deployment new key, we are going back
    to rebuild SPEC 1. Two steps for keypair updating are not good. Why
    don’t directly using SPEC 1?

Because of the points made above, which are if I can simply reboot my
instance to use the new keypair rather than rebuild it, that is much
better. Plus then it doesn't just limit us to rebuild, but the new key
could also be used after unshelving or cold migrating the instance.

  • Another perspective to think about this is that SPEC 2 is expanding
    the functionality of reboot. What about one day user want to change
    password/name/personality at a reboot?

Kevin's spec does not propose any change to the reboot (or rebuild) APIs.

  • Cloud user may still have questions: why key pair can not be updated
    during rebuilding ? Why name/image/personality can?
  • If new API does not supporting running injection, the DB keypair and
    guest keypair are inconsistent if cloud user forget a rebuiding,
    reboot, unshelving API call.

This is the same as the point made above, which I replied to, but anyone
calling the native APIs should be reading the docs and understanding
what they do. If they don't want that level of detail, use a GUI or
orchestration tool.

In conclusion, IMHO SPEC 1 is the reasonable way to set key pair for
rebuild API. It’s simple and easy.

SPEC 2 can be used for future running key injection. And it is still a
way for reboot  API to deploy the new key. But the its disadvantages are
as stated above.

There already has some discuss [1] about this with Matt and Kevin.

Sincerely hope to receive your opinion. Feel free to ping me at IRC
openstack-nova, my nick is liuyulong. Thank you very much.

[1]
http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07


OpenStack Development Mailing List (not for usage questions)
Unsubscribe: OpenStack-dev-request@lists.openstack.org?subject:unsubscribe
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Thanks for at starting this discussion in the mailing list and
summarizing the concerns with both approaches.

--

Thanks,

Matt


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responded Sep 27, 2017 by mriedemos_at_gmail.c (15,720 points)   2 4 10
0 votes

On Wed, Sep 27, 2017 at 10:29 AM, Matt Riedemann mriedemos@gmail.com
wrote:

On 9/23/2017 8:58 AM, LIU Yulong wrote:

Hi nova developers,

This mail is proposed to reconsider the key pair resetting of instance.
The nova queens PTG discuss is here: https://etherpad.openstack.org
/p/nova-ptg-queens https://etherpad.openstack.org/p/nova-ptg-queens L498.
And there are now two proposals.

  1. SPEC 1: https://review.openstack.org/#/c/375221/ <
    https://review.openstack.org/#/c/375221/ started by me (liuyulong)
    since sep 2016.

    This spec will allow setting the new key_name for the instance during
    rebuild API. That’s a very simple and well-understood approach:

  • Make consistent with rebuild API properties, such as name, imageRef,
    metadata, adminPass etc.
  • Rebuild API is something like recreating, this is the right way to
    do key pair updating. For keypair-login-only VM, this is the key
    point.
  • This does not involve to other APIs like reboot/unshelve etc.

This was one of the issues I brought up in IRC, is that if we just
implemented this for the rebuild API, then someone could also ask that we
do it for things like reboot, cold migrate/resize, unshelve, etc. Anything
that involves re-creating the guest.

IMHO, rebuild has its own meaning is that we are going to recreate a VM.
So those inputs such as name, key, password should have a chance to be
reset in this rebuild interface. Unlike reboot, cold migrate/resize,
unshelve, those actions does not have such potential implication. If
anything else involved, you are expanding those actions (reboot, cold
migrate/resize, unshelve).

  • Easy to use, only one API.
    >

Until someone says we should also do it for the other APIs, as noted above.

This could not be acceptable. Other APIs does not have such recreating
background. For rebuild, you are going to renew an instance, so those
params for instance creation should have chance to be reset.

By the way, here is the patch (https://review.openstack.org/#/c/379128/ <
https://review.openstack.org/#/c/379128/) which has implemented this
spec. And it stays there more than one year too.

It's been open because the spec was never approved. Just a procedural
issue.

  1. SPEC 2 : https://review.openstack.org/#/c/506552/ <
    https://review.openstack.org/#/c/506552/ propose by Kevin_zheng.

This spec supposed to add a new updating API for one instance’s key pair.
This one has one foreseeable advantage for this is to do instance running
key injection.

But it may cause some issues:

  • This approach needs to update the instance key pair first (one step,
    API call). And then do a reboot/rebuild or any actions causing the
    vm restart (second step, another API call). Firstly, this is waste,
    it use two API calls. Secondly, if updating key pair was done, and
    the reboot was not. That may result an inconsistent between instance
    DB key pair and guest VM inside key. Cloud user may confused to
    choose which key should be used to login.
  1. I don't think multiple API calls is a problem. Any GUI or orchestration
    tool can stitch these APIs together for what appears to be a single
    operation for the end user. Furthermore, with multiple options about what
    to do after the instance.key_name is updated, something like a GUI could
    present the user with the option to picking if they want to reboot or
    rebuild after the key is updated.

We provided a discontinuous API, so we should take responsibilities for
it. This inconsistent between instance DB key pair and guest VM inside can
stay there. So GUI or orchestration tool can not be a reasonable support.
More API calls may cause more problems. What if the GUI or orchestration
tool user/developer forget the second API? What if the first API failed,
should the retry all the APIs? Which key should be used to login if first
API succeed and the second not succeed/not response? What if the second API
failed? They confused again and again.

  1. An orchestrator or GUI would make sure that both APIs are called. For a
    user that is updating the key_name, they should realize they need to make
    another API call to enable it. This would all be in the API reference
    documentation, CLI help, etc, that anyone doing this should read and
    understand.
  • For the second step (reboot), there is a strong constraint is that
    > cloud-init config needs to be set to running-per-booting. But if a
    > cloud platform all images are set cloud-init to per-deployment. In
    > order to achieve this new API goal, the entire cloud platform images
    > need updating. This will cause a huge upgrading work for entire
    > cloud platform images. They need to change all the images cloud-init
    > config from running-per-deployment to running-every-boot. But that
    > still can not solve the inconsistent between DB keypair and
    > guest-key. For instance, if the running VM is based on a
    > running-once-cloud-init image: 1. create image from this VM; 2.
    > change the keypair of the new VM; 3. reboot still can not work
    > because of the old config of per-deployment-running.
    >

This is per-cloud configuration, and as such it should be documented with
the cloud documentation. I can't say what is more "normal" for OpenStack
clouds to be doing with cloud-init here, that would be a good question for
the operators community (I've cross posted to the ops ML).

This upgrading issue could make a result that rebuild become the only
way to apply new key to VM.

  • For another second step (rebuild), if they have to rebuild, or
    > rebuild is the only one way to deployment new key, we are going back
    > to rebuild SPEC 1. Two steps for keypair updating are not good. Why
    > don’t directly using SPEC 1?
    >

Because of the points made above, which are if I can simply reboot my
instance to use the new keypair rather than rebuild it, that is much
better. Plus then it doesn't just limit us to rebuild, but the new key
could also be used after unshelving or cold migrating the instance.

This the point we are going to expand functionalities of
reboot/migrate/unshelving? Quoting the point you mentioned above "someone
may say we should also do it for the other APIs, like restart, evacuate,
start ? " What about password/name/image/flavor/user-data, one day these
can also be reset in reboot/migrate/unshelving/restart/evacuate/start API ?

  • Another perspective to think about this is that SPEC 2 is expanding
    > the functionality of reboot. What about one day user want to change
    > password/name/personality at a reboot?
    >

Kevin's spec does not propose any change to the reboot (or rebuild) APIs.

Yes, but if you change the key first, reboot may become the key step for
applying the key to VM. Reboot does not just reboot a VM, it takes a
new responsibility. For rebuild, SPEC 1 makes sense.

  • Cloud user may still have questions: why key pair can not be updated
    > during rebuilding ? Why name/image/personality can?
    > * If new API does not supporting running injection, the DB keypair and
    > guest keypair are inconsistent if cloud user forget a rebuiding,
    > reboot, unshelving API call.
    >

This is the same as the point made above, which I replied to, but anyone
calling the native APIs should be reading the docs and understanding what
they do. If they don't want that level of detail, use a GUI or
orchestration tool.

Discontinuous API results such concern. APIs are fixed, users are variable.

In conclusion, IMHO SPEC 1 is the reasonable way to set key pair for
rebuild API. It’s simple and easy.

SPEC 2 can be used for future running key injection. And it is still a
way for reboot API to deploy the new key. But the its disadvantages are as
stated above.

There already has some discuss [1] about this with Matt and Kevin.

Sincerely hope to receive your opinion. Feel free to ping me at IRC
openstack-nova, my nick is liuyulong. Thank you very much.

[1] http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23
openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07 <
http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%2
3openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07>



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e
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Thanks for at starting this discussion in the mailing list and summarizing
the concerns with both approaches.

--

Thanks,

Matt


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responded Sep 27, 2017 by liuyulong.xa_at_gmai (280 points)   1
0 votes

One thing I'd like to explore is what the functional difference between a
rebuild and a delete / create cycle is. With a rebuild you get to keep your
IP I suppose, but that could also be true of floating IPs for a delete /
create as well.

Operationally, why would I want to inject a new keypair? The scenario I can
think of is that there's data in that instance that I want, and I've lost
the keypair somehow. Unless that data is on an ephemeral, its gone if we do
a rebuild.

Michael

On Wed, Sep 27, 2017 at 4:05 PM, LIU Yulong liuyulong.xa@gmail.com wrote:

On Wed, Sep 27, 2017 at 10:29 AM, Matt Riedemann mriedemos@gmail.com
wrote:

On 9/23/2017 8:58 AM, LIU Yulong wrote:

Hi nova developers,

This mail is proposed to reconsider the key pair resetting of instance.
The nova queens PTG discuss is here: https://etherpad.openstack.org
/p/nova-ptg-queens https://etherpad.openstack.org/p/nova-ptg-queens L498.
And there are now two proposals.

  1. SPEC 1: https://review.openstack.org/#/c/375221/ <
    https://review.openstack.org/#/c/375221/ started by me (liuyulong)
    since sep 2016.

    This spec will allow setting the new key_name for the instance
    during rebuild API. That’s a very simple and well-understood approach:

  • Make consistent with rebuild API properties, such as name, imageRef,
    metadata, adminPass etc.
  • Rebuild API is something like recreating, this is the right way to
    do key pair updating. For keypair-login-only VM, this is the key
    point.
  • This does not involve to other APIs like reboot/unshelve etc.

This was one of the issues I brought up in IRC, is that if we just
implemented this for the rebuild API, then someone could also ask that we
do it for things like reboot, cold migrate/resize, unshelve, etc. Anything
that involves re-creating the guest.

IMHO, rebuild has its own meaning is that we are going to recreate a VM.
So those inputs such as name, key, password should have a chance to be
reset in this rebuild interface. Unlike reboot, cold migrate/resize,
unshelve, those actions does not have such potential implication. If
anything else involved, you are expanding those actions (reboot, cold
migrate/resize, unshelve).

  • Easy to use, only one API.
    >

Until someone says we should also do it for the other APIs, as noted
above.

This could not be acceptable. Other APIs does not have such recreating
background. For rebuild, you are going to renew an instance, so those
params for instance creation should have chance to be reset.

By the way, here is the patch (https://review.openstack.org/#/c/379128/
https://review.openstack.org/#/c/379128/) which has implemented this
spec. And it stays there more than one year too.

It's been open because the spec was never approved. Just a procedural
issue.

  1. SPEC 2 : https://review.openstack.org/#/c/506552/ <
    https://review.openstack.org/#/c/506552/ propose by Kevin_zheng.

This spec supposed to add a new updating API for one instance’s key
pair. This one has one foreseeable advantage for this is to do instance
running key injection.

But it may cause some issues:

  • This approach needs to update the instance key pair first (one step,
    API call). And then do a reboot/rebuild or any actions causing the
    vm restart (second step, another API call). Firstly, this is waste,
    it use two API calls. Secondly, if updating key pair was done, and
    the reboot was not. That may result an inconsistent between instance
    DB key pair and guest VM inside key. Cloud user may confused to
    choose which key should be used to login.
  1. I don't think multiple API calls is a problem. Any GUI or
    orchestration tool can stitch these APIs together for what appears to be a
    single operation for the end user. Furthermore, with multiple options about
    what to do after the instance.key_name is updated, something like a GUI
    could present the user with the option to picking if they want to reboot or
    rebuild after the key is updated.

We provided a discontinuous API, so we should take responsibilities for
it. This inconsistent between instance DB key pair and guest VM inside can
stay there. So GUI or orchestration tool can not be a reasonable support.
More API calls may cause more problems. What if the GUI or orchestration
tool user/developer forget the second API? What if the first API failed,
should the retry all the APIs? Which key should be used to login if first
API succeed and the second not succeed/not response? What if the second API
failed? They confused again and again.

  1. An orchestrator or GUI would make sure that both APIs are called. For
    a user that is updating the key_name, they should realize they need to make
    another API call to enable it. This would all be in the API reference
    documentation, CLI help, etc, that anyone doing this should read and
    understand.
  • For the second step (reboot), there is a strong constraint is that
    > cloud-init config needs to be set to running-per-booting. But if a
    > cloud platform all images are set cloud-init to per-deployment. In
    > order to achieve this new API goal, the entire cloud platform images
    > need updating. This will cause a huge upgrading work for entire
    > cloud platform images. They need to change all the images cloud-init
    > config from running-per-deployment to running-every-boot. But that
    > still can not solve the inconsistent between DB keypair and
    > guest-key. For instance, if the running VM is based on a
    > running-once-cloud-init image: 1. create image from this VM; 2.
    > change the keypair of the new VM; 3. reboot still can not work
    > because of the old config of per-deployment-running.
    >

This is per-cloud configuration, and as such it should be documented with
the cloud documentation. I can't say what is more "normal" for OpenStack
clouds to be doing with cloud-init here, that would be a good question for
the operators community (I've cross posted to the ops ML).

This upgrading issue could make a result that rebuild become the only
way to apply new key to VM.

  • For another second step (rebuild), if they have to rebuild, or
    > rebuild is the only one way to deployment new key, we are going back
    > to rebuild SPEC 1. Two steps for keypair updating are not good. Why
    > don’t directly using SPEC 1?
    >

Because of the points made above, which are if I can simply reboot my
instance to use the new keypair rather than rebuild it, that is much
better. Plus then it doesn't just limit us to rebuild, but the new key
could also be used after unshelving or cold migrating the instance.

This the point we are going to expand functionalities of
reboot/migrate/unshelving? Quoting the point you mentioned above "someone
may say we should also do it for the other APIs, like restart, evacuate,
start ? " What about password/name/image/flavor/user-data, one day these
can also be reset in reboot/migrate/unshelving/restart/evacuate/start API
?

  • Another perspective to think about this is that SPEC 2 is expanding
    > the functionality of reboot. What about one day user want to change
    > password/name/personality at a reboot?
    >

Kevin's spec does not propose any change to the reboot (or rebuild) APIs.

Yes, but if you change the key first, reboot may become the key step for
applying the key to VM. Reboot does not just reboot a VM, it takes a
new responsibility. For rebuild, SPEC 1 makes sense.

  • Cloud user may still have questions: why key pair can not be updated
    > during rebuilding ? Why name/image/personality can?
    > * If new API does not supporting running injection, the DB keypair and
    > guest keypair are inconsistent if cloud user forget a rebuiding,
    > reboot, unshelving API call.
    >

This is the same as the point made above, which I replied to, but anyone
calling the native APIs should be reading the docs and understanding what
they do. If they don't want that level of detail, use a GUI or
orchestration tool.

Discontinuous API results such concern. APIs are fixed, users
are variable.

In conclusion, IMHO SPEC 1 is the reasonable way to set key pair for
rebuild API. It’s simple and easy.

SPEC 2 can be used for future running key injection. And it is still a
way for reboot API to deploy the new key. But the its disadvantages are as
stated above.

There already has some discuss [1] about this with Matt and Kevin.

Sincerely hope to receive your opinion. Feel free to ping me at IRC
openstack-nova, my nick is liuyulong. Thank you very much.

[1] http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23
openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07 <
http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%2
3openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07>



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Thanks for at starting this discussion in the mailing list and
summarizing the concerns with both approaches.

--

Thanks,

Matt



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responded Sep 27, 2017 by Michael_Still (16,180 points)   3 6 13
0 votes

On 27 September 2017 at 09:23, Michael Still mikal@stillhq.com wrote:

Operationally, why would I want to inject a new keypair? The scenario I can
think of is that there's data in that instance that I want, and I've lost
the keypair somehow. Unless that data is on an ephemeral, its gone if we do
a rebuild.

This is quite a common scenario - staff member who started the
instance leaves, and you want to access data on the instance, or
maintain/debug the service running on the instance.

Hitherto, I have used direct db calls to update the key, so it would
be nice if there was an API call to do so.

Cheers,
Marcus.
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responded Sep 27, 2017 by Marcus_Furlong (840 points)   1 2
0 votes

On 09/27/2017 05:15 AM, Marcus Furlong wrote:
On 27 September 2017 at 09:23, Michael Still mikal@stillhq.com wrote:

Operationally, why would I want to inject a new keypair? The scenario I can
think of is that there's data in that instance that I want, and I've lost
the keypair somehow. Unless that data is on an ephemeral, its gone if we do
a rebuild.

This is quite a common scenario - staff member who started the
instance leaves, and you want to access data on the instance, or
maintain/debug the service running on the instance.

Hitherto, I have used direct db calls to update the key, so it would
be nice if there was an API call to do so.

But you also triggered a rebuild in the process? Or you tweaked the keys
and did a reboot? This use case came up in the room, but then we started
trying to figure out if the folks that mostly had it would also need it
on reboot.

-Sean

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responded Sep 27, 2017 by Sean_Dague (66,200 points)   4 8 14
0 votes

On 27 September 2017 at 10:55, Sean Dague sean@dague.net wrote:
On 09/27/2017 05:15 AM, Marcus Furlong wrote:

On 27 September 2017 at 09:23, Michael Still mikal@stillhq.com wrote:

Operationally, why would I want to inject a new keypair? The scenario I can
think of is that there's data in that instance that I want, and I've lost
the keypair somehow. Unless that data is on an ephemeral, its gone if we do
a rebuild.

This is quite a common scenario - staff member who started the
instance leaves, and you want to access data on the instance, or
maintain/debug the service running on the instance.

Hitherto, I have used direct db calls to update the key, so it would
be nice if there was an API call to do so.

But you also triggered a rebuild in the process? Or you tweaked the keys
and did a reboot? This use case came up in the room, but then we started
trying to figure out if the folks that mostly had it would also need it
on reboot.

No rebuild, no.

Update the key name and reboot, or, if someone has access, re-run cloud-init.

rm -fr /var/lib/cloud/instance/sem/

cloud-init --single -n ssh

Have also thought about just adding the above to a cronjob in the
images to facilitate this scenario (thus avoiding a reboot if noone
has access).

Cheers,
Marcus.

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responded Sep 27, 2017 by Marcus_Furlong (840 points)   1 2
0 votes

On Wed, Sep 27, 2017 at 5:15 PM, Marcus Furlong furlongm@gmail.com wrote:

On 27 September 2017 at 09:23, Michael Still mikal@stillhq.com wrote:

Operationally, why would I want to inject a new keypair? The scenario I
can
think of is that there's data in that instance that I want, and I've lost
the keypair somehow. Unless that data is on an ephemeral, its gone if we
do
a rebuild.

This is quite a common scenario - staff member who started the
instance leaves, and you want to access data on the instance, or
maintain/debug the service running on the instance.

I can think of several ways to solve this problem:
1) reset the password by using the admin_pass API (if available)
2) libguestfs the instance dist directly

Hitherto, I have used direct db calls to update the key, so it would
be nice if there was an API call to do so.

These are some tricks for unusual scenarios. Nova API needs to stay robust
and general.

Cheers,
Marcus.
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responded Sep 28, 2017 by liuyulong.xa_at_gmai (280 points)   1
0 votes

On Wed, Sep 27, 2017 at 4:23 PM, Michael Still mikal@stillhq.com wrote:

One thing I'd like to explore is what the functional difference between a
rebuild and a delete / create cycle is. With a rebuild you get to keep your
IP I suppose, but that could also be true of floating IPs for a delete /
create as well.

The neutron port which was used by the VM does not changed, so the floating
IP will not need to be recreate.

Operationally, why would I want to inject a new keypair? The scenario I
can think of is that there's data in that instance that I want, and I've
lost the keypair somehow. Unless that data is on an ephemeral, its gone if
we do a rebuild.

"The old VM was using a wrong image, I want to change it. Bad things
happened in the VM, I want reinstall the OS. Oh, I lost my old private key.
I can reset the image, but I can't login it." -- A cloud user's whisper.
Rebuild is try to recreate, a new param added to the existing rebuild API
meets the renew purpose.

Michael

On Wed, Sep 27, 2017 at 4:05 PM, LIU Yulong liuyulong.xa@gmail.com
wrote:

On Wed, Sep 27, 2017 at 10:29 AM, Matt Riedemann mriedemos@gmail.com
wrote:

On 9/23/2017 8:58 AM, LIU Yulong wrote:

Hi nova developers,

This mail is proposed to reconsider the key pair resetting of instance.
The nova queens PTG discuss is here: https://etherpad.openstack.org
/p/nova-ptg-queens https://etherpad.openstack.org/p/nova-ptg-queens L498.
And there are now two proposals.

  1. SPEC 1: https://review.openstack.org/#/c/375221/ <
    https://review.openstack.org/#/c/375221/ started by me (liuyulong)
    since sep 2016.

    This spec will allow setting the new key_name for the instance
    during rebuild API. That’s a very simple and well-understood approach:

  • Make consistent with rebuild API properties, such as name, imageRef,
    metadata, adminPass etc.
  • Rebuild API is something like recreating, this is the right way to
    do key pair updating. For keypair-login-only VM, this is the key
    point.
  • This does not involve to other APIs like reboot/unshelve etc.

This was one of the issues I brought up in IRC, is that if we just
implemented this for the rebuild API, then someone could also ask that we
do it for things like reboot, cold migrate/resize, unshelve, etc. Anything
that involves re-creating the guest.

IMHO, rebuild has its own meaning is that we are going to recreate a VM.
So those inputs such as name, key, password should have a chance to be
reset in this rebuild interface. Unlike reboot, cold migrate/resize,
unshelve, those actions does not have such potential implication. If
anything else involved, you are expanding those actions (reboot, cold
migrate/resize, unshelve).

  • Easy to use, only one API.
    >

Until someone says we should also do it for the other APIs, as noted
above.

This could not be acceptable. Other APIs does not have such recreating
background. For rebuild, you are going to renew an instance, so those
params for instance creation should have chance to be reset.

By the way, here is the patch (https://review.openstack.org/#/c/379128/
https://review.openstack.org/#/c/379128/) which has implemented this
spec. And it stays there more than one year too.

It's been open because the spec was never approved. Just a procedural
issue.

  1. SPEC 2 : https://review.openstack.org/#/c/506552/ <
    https://review.openstack.org/#/c/506552/ propose by Kevin_zheng.

This spec supposed to add a new updating API for one instance’s key
pair. This one has one foreseeable advantage for this is to do instance
running key injection.

But it may cause some issues:

  • This approach needs to update the instance key pair first (one step,
    API call). And then do a reboot/rebuild or any actions causing the
    vm restart (second step, another API call). Firstly, this is waste,
    it use two API calls. Secondly, if updating key pair was done, and
    the reboot was not. That may result an inconsistent between instance
    DB key pair and guest VM inside key. Cloud user may confused to
    choose which key should be used to login.
  1. I don't think multiple API calls is a problem. Any GUI or
    orchestration tool can stitch these APIs together for what appears to be a
    single operation for the end user. Furthermore, with multiple options about
    what to do after the instance.key_name is updated, something like a GUI
    could present the user with the option to picking if they want to reboot or
    rebuild after the key is updated.

We provided a discontinuous API, so we should take responsibilities for
it. This inconsistent between instance DB key pair and guest VM inside can
stay there. So GUI or orchestration tool can not be a reasonable support.
More API calls may cause more problems. What if the GUI or orchestration
tool user/developer forget the second API? What if the first API failed,
should the retry all the APIs? Which key should be used to login if first
API succeed and the second not succeed/not response? What if the second API
failed? They confused again and again.

  1. An orchestrator or GUI would make sure that both APIs are called. For
    a user that is updating the key_name, they should realize they need to make
    another API call to enable it. This would all be in the API reference
    documentation, CLI help, etc, that anyone doing this should read and
    understand.
  • For the second step (reboot), there is a strong constraint is that
    > cloud-init config needs to be set to running-per-booting. But if a
    > cloud platform all images are set cloud-init to per-deployment. In
    > order to achieve this new API goal, the entire cloud platform images
    > need updating. This will cause a huge upgrading work for entire
    > cloud platform images. They need to change all the images cloud-init
    > config from running-per-deployment to running-every-boot. But that
    > still can not solve the inconsistent between DB keypair and
    > guest-key. For instance, if the running VM is based on a
    > running-once-cloud-init image: 1. create image from this VM; 2.
    > change the keypair of the new VM; 3. reboot still can not work
    > because of the old config of per-deployment-running.
    >

This is per-cloud configuration, and as such it should be documented
with the cloud documentation. I can't say what is more "normal" for
OpenStack clouds to be doing with cloud-init here, that would be a good
question for the operators community (I've cross posted to the ops ML).

This upgrading issue could make a result that rebuild become the only
way to apply new key to VM.

  • For another second step (rebuild), if they have to rebuild, or
    > rebuild is the only one way to deployment new key, we are going back
    > to rebuild SPEC 1. Two steps for keypair updating are not good. Why
    > don’t directly using SPEC 1?
    >

Because of the points made above, which are if I can simply reboot my
instance to use the new keypair rather than rebuild it, that is much
better. Plus then it doesn't just limit us to rebuild, but the new key
could also be used after unshelving or cold migrating the instance.

This the point we are going to expand functionalities of
reboot/migrate/unshelving? Quoting the point you mentioned above "someone
may say we should also do it for the other APIs, like restart, evacuate,
start ? " What about password/name/image/flavor/user-data, one day these
can also be reset in reboot/migrate/unshelving/restart/evacuate/start
API ?

  • Another perspective to think about this is that SPEC 2 is expanding
    > the functionality of reboot. What about one day user want to change
    > password/name/personality at a reboot?
    >

Kevin's spec does not propose any change to the reboot (or rebuild) APIs.

Yes, but if you change the key first, reboot may become the key step for
applying the key to VM. Reboot does not just reboot a VM, it takes a
new responsibility. For rebuild, SPEC 1 makes sense.

  • Cloud user may still have questions: why key pair can not be updated
    > during rebuilding ? Why name/image/personality can?
    > * If new API does not supporting running injection, the DB keypair and
    > guest keypair are inconsistent if cloud user forget a rebuiding,
    > reboot, unshelving API call.
    >

This is the same as the point made above, which I replied to, but anyone
calling the native APIs should be reading the docs and understanding what
they do. If they don't want that level of detail, use a GUI or
orchestration tool.

Discontinuous API results such concern. APIs are fixed, users
are variable.

In conclusion, IMHO SPEC 1 is the reasonable way to set key pair for
rebuild API. It’s simple and easy.

SPEC 2 can be used for future running key injection. And it is still a
way for reboot API to deploy the new key. But the its disadvantages are as
stated above.

There already has some discuss [1] about this with Matt and Kevin.

Sincerely hope to receive your opinion. Feel free to ping me at IRC
openstack-nova, my nick is liuyulong. Thank you very much.

[1] http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23
openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07 <
http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%2
3openstack-nova.2017-09-22.log.html#t2017-09-22T14:05:07>



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Thanks for at starting this discussion in the mailing list and
summarizing the concerns with both approaches.

--

Thanks,

Matt



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responded Sep 28, 2017 by liuyulong.xa_at_gmai (280 points)   1
...