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Posted to dev@cloudstack.apache.org by Daniel Salvador <gu...@apache.org> on 2022/02/18 15:53:44 UTC
[Discussion] CentOS 7 KVM binaries
Hi all, hope you are doing fine.
The following discussion emerged from PR #5297[¹].
It is a known fact that, regarding KVM functionalities, CentOS7 default's
QEMU binary is quite limited. This is due to the removal of some features
of KVM default binary in CentOS (like VM's volume live migration,
memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
information can be found in CentOS forum's thread[²].
In my point of view, such limitations in the default QEMU binary in CentOS
make it unfeasible to build a cloud with CentOS and the default QEMU
binary, as operators lose a lot of useful/important operations or have to
go through workarounds, which cause VM's disruption (e.g. having to stop a
VM to migrate the volume between different storage pools, which triggers a
secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
which supports more features than the default one. Probably, most people
using KVM with CentOS are using the "ev" binary (I might be wrong though,
however, that seems to be the case when looking at the users' list).
PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
(live disk snapshot). The easiest solution (and, IHMO, is the best option)
is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
Further, it is important to mention that in our experience, it is not
possible to run a highly available cloud environment with CentOS7 and the
default binaries. In a cloud environment with thousands of VMs, sooner or
later the need to hotplug (increase) CPU/RAM, migrate volumes across
different storage pool tyles (such as iSCSI <> NFS), or some other type of
operation appear, and operators/final customers do not want service
disruption. Our customers, for instance, never shut down VMs for these
kinds of operations, and that is only possible because they are all using
KVM with Ubuntu now.
Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
that CloudStack should limit its features due to a dying operating system
that presents very limited features by default.
With that said, it would be interesting if dev/users that use CentOS7 could
share their experiences with the "qemu-kvm-ev" in this thread, so we can
decide which way to go. Or, users that only use the default binary, if they
are satisfied with it.
If almost no one is relying on default CentOS7 binaries, we could define as
a step in the documentation, that when using CentOS7 people must use the
"ev" binary. This would free us to evolve ACS more freely and avoid
headaches with workarounds to a limited operating system when there are
alternatives out there.
[¹] https://github.com/apache/cloudstack/pull/5297
[²] https://forums.centos.org/viewtopic.php?t=65618
Re: [Discussion] CentOS 7 KVM binaries
Posted by Andrija Panic <an...@gmail.com>.
BTW, if we make this a requirement (decide so, internally) we should have
this heavily emphasised in the next release Release Notes (and this also,
perhaps, warrants sending some special ANNOUNCE or similar email to user
and dev mailing lists - to avoid having seriously pissed off users.
On Thu, 24 Feb 2022, 23:06 Andrija Panic, <an...@gmail.com> wrote:
> Hi all,
>
> +1 in general,
>
> but keep in mind that the "regular" qemu-kmv-ev from the CentOS SIG repo
> does NOT support live storage migration (up to version 2.12 at least), and
> qemu-kmv-ev from the oVirt repo (essentially a RHEV) need(ed) to be used
> for live storage migration (virsh - - migrate-all...) to work. I'm not sure
> if this has changed. but perhaps Simon or someone using qemu-kmv-ev may
> advice.
>
> Cheers,
>
> On Thu, 24 Feb 2022, 15:58 Rohit Yadav, <ro...@shapeblue.com> wrote:
>
>> +1 I've seen a lot of users and some of our customers use qemu-kvm-ev in
>> production. However, we need to check if qemu-kvm-ev has 100% feature
>> parity (I remember my colleague Andrija suggesting something which was
>> missing in either stock qemu-kvm or qemu-kvm-ev).
>>
>>
>> Regards.
>>
>> ________________________________
>> From: Slavka Peleva <sl...@storpool.com.INVALID>
>> Sent: Wednesday, February 23, 2022 23:58
>> To: dev <de...@cloudstack.apache.org>
>> Subject: Re: [Discussion] CentOS 7 KVM binaries
>>
>> Hi Daniel,
>>
>> +1 for qemu-kvm-ev. We also advise our customers to use it.
>>
>> Best regards,
>> Slavka
>>
>> On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
>> wrote:
>>
>> > Daniel,
>> >
>> > We've used qemu-kvm-ev in production for years. A number of the
>> > enhancements we've pushed into Cloudstack have required it. I think
>> you'll
>> > find that most cloud providers based on Centos (or Alma/Rocky) are also
>> > using it.
>> >
>> > -Si
>> > ________________________________
>> > From: Daniel Salvador <gu...@apache.org>
>> > Sent: Friday, February 18, 2022 9:53 AM
>> > To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
>> > Subject: [Discussion] CentOS 7 KVM binaries
>> >
>> > Hi all, hope you are doing fine.
>> >
>> > The following discussion emerged from PR #5297[¹].
>> >
>> > It is a known fact that, regarding KVM functionalities, CentOS7
>> default's
>> > QEMU binary is quite limited. This is due to the removal of some
>> features
>> > of KVM default binary in CentOS (like VM's volume live migration,
>> > memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
>> > information can be found in CentOS forum's thread[²].
>> >
>> > In my point of view, such limitations in the default QEMU binary in
>> CentOS
>> > make it unfeasible to build a cloud with CentOS and the default QEMU
>> > binary, as operators lose a lot of useful/important operations or have
>> to
>> > go through workarounds, which cause VM's disruption (e.g. having to
>> stop a
>> > VM to migrate the volume between different storage pools, which
>> triggers a
>> > secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
>> > which supports more features than the default one. Probably, most people
>> > using KVM with CentOS are using the "ev" binary (I might be wrong
>> though,
>> > however, that seems to be the case when looking at the users' list).
>> >
>> > PR #5297[¹] ran into one of the CentOS7 default's QEMU binary
>> limitations
>> > (live disk snapshot). The easiest solution (and, IHMO, is the best
>> option)
>> > is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
>> >
>> > Further, it is important to mention that in our experience, it is not
>> > possible to run a highly available cloud environment with CentOS7 and
>> the
>> > default binaries. In a cloud environment with thousands of VMs, sooner
>> or
>> > later the need to hotplug (increase) CPU/RAM, migrate volumes across
>> > different storage pool tyles (such as iSCSI <> NFS), or some other type
>> of
>> > operation appear, and operators/final customers do not want service
>> > disruption. Our customers, for instance, never shut down VMs for these
>> > kinds of operations, and that is only possible because they are all
>> using
>> > KVM with Ubuntu now.
>> >
>> > Moreover, CentOS7 is getting close to its EOL. Therefore, We do not
>> think
>> > that CloudStack should limit its features due to a dying operating
>> system
>> > that presents very limited features by default.
>> >
>> > With that said, it would be interesting if dev/users that use CentOS7
>> could
>> > share their experiences with the "qemu-kvm-ev" in this thread, so we can
>> > decide which way to go. Or, users that only use the default binary, if
>> they
>> > are satisfied with it.
>> >
>> > If almost no one is relying on default CentOS7 binaries, we could
>> define as
>> > a step in the documentation, that when using CentOS7 people must use the
>> > "ev" binary. This would free us to evolve ACS more freely and avoid
>> > headaches with workarounds to a limited operating system when there are
>> > alternatives out there.
>> >
>> >
>> > [¹] https://github.com/apache/cloudstack/pull/5297
>> > [²] https://forums.centos.org/viewtopic.php?t=65618
>> >
>>
>>
>>
>>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Andrija Panic <an...@gmail.com>.
Hi all,
+1 in general,
but keep in mind that the "regular" qemu-kmv-ev from the CentOS SIG repo
does NOT support live storage migration (up to version 2.12 at least), and
qemu-kmv-ev from the oVirt repo (essentially a RHEV) need(ed) to be used
for live storage migration (virsh - - migrate-all...) to work. I'm not sure
if this has changed. but perhaps Simon or someone using qemu-kmv-ev may
advice.
Cheers,
On Thu, 24 Feb 2022, 15:58 Rohit Yadav, <ro...@shapeblue.com> wrote:
> +1 I've seen a lot of users and some of our customers use qemu-kvm-ev in
> production. However, we need to check if qemu-kvm-ev has 100% feature
> parity (I remember my colleague Andrija suggesting something which was
> missing in either stock qemu-kvm or qemu-kvm-ev).
>
>
> Regards.
>
> ________________________________
> From: Slavka Peleva <sl...@storpool.com.INVALID>
> Sent: Wednesday, February 23, 2022 23:58
> To: dev <de...@cloudstack.apache.org>
> Subject: Re: [Discussion] CentOS 7 KVM binaries
>
> Hi Daniel,
>
> +1 for qemu-kvm-ev. We also advise our customers to use it.
>
> Best regards,
> Slavka
>
> On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
> wrote:
>
> > Daniel,
> >
> > We've used qemu-kvm-ev in production for years. A number of the
> > enhancements we've pushed into Cloudstack have required it. I think
> you'll
> > find that most cloud providers based on Centos (or Alma/Rocky) are also
> > using it.
> >
> > -Si
> > ________________________________
> > From: Daniel Salvador <gu...@apache.org>
> > Sent: Friday, February 18, 2022 9:53 AM
> > To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> > Subject: [Discussion] CentOS 7 KVM binaries
> >
> > Hi all, hope you are doing fine.
> >
> > The following discussion emerged from PR #5297[¹].
> >
> > It is a known fact that, regarding KVM functionalities, CentOS7 default's
> > QEMU binary is quite limited. This is due to the removal of some features
> > of KVM default binary in CentOS (like VM's volume live migration,
> > memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
> > information can be found in CentOS forum's thread[²].
> >
> > In my point of view, such limitations in the default QEMU binary in
> CentOS
> > make it unfeasible to build a cloud with CentOS and the default QEMU
> > binary, as operators lose a lot of useful/important operations or have to
> > go through workarounds, which cause VM's disruption (e.g. having to stop
> a
> > VM to migrate the volume between different storage pools, which triggers
> a
> > secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
> > which supports more features than the default one. Probably, most people
> > using KVM with CentOS are using the "ev" binary (I might be wrong though,
> > however, that seems to be the case when looking at the users' list).
> >
> > PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
> > (live disk snapshot). The easiest solution (and, IHMO, is the best
> option)
> > is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
> >
> > Further, it is important to mention that in our experience, it is not
> > possible to run a highly available cloud environment with CentOS7 and the
> > default binaries. In a cloud environment with thousands of VMs, sooner or
> > later the need to hotplug (increase) CPU/RAM, migrate volumes across
> > different storage pool tyles (such as iSCSI <> NFS), or some other type
> of
> > operation appear, and operators/final customers do not want service
> > disruption. Our customers, for instance, never shut down VMs for these
> > kinds of operations, and that is only possible because they are all using
> > KVM with Ubuntu now.
> >
> > Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
> > that CloudStack should limit its features due to a dying operating system
> > that presents very limited features by default.
> >
> > With that said, it would be interesting if dev/users that use CentOS7
> could
> > share their experiences with the "qemu-kvm-ev" in this thread, so we can
> > decide which way to go. Or, users that only use the default binary, if
> they
> > are satisfied with it.
> >
> > If almost no one is relying on default CentOS7 binaries, we could define
> as
> > a step in the documentation, that when using CentOS7 people must use the
> > "ev" binary. This would free us to evolve ACS more freely and avoid
> > headaches with workarounds to a limited operating system when there are
> > alternatives out there.
> >
> >
> > [¹] https://github.com/apache/cloudstack/pull/5297
> > [²] https://forums.centos.org/viewtopic.php?t=65618
> >
>
>
>
>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Rohit Yadav <ro...@shapeblue.com>.
Sounds good to me to move to qemu-kvm-ev, may be worth mentioning the ovirt repo in our docs if it is more featureful and widely used/maintained.
Daniel, it wasn't my comment but Andrija's and it's the other way around, the official qemu-kvm-ev releases have limitations/regressions. Quoting Andrija's comment:
" but keep in mind that the "regular" qemu-kmv-ev from the CentOS SIG repo does NOT support live storage migration (up to version 2.12 at least), and qemu-kmv-ev from the oVirt repo (essentially a RHEV) need(ed) to be used for live storage migration (virsh - - migrate-all...) to work. I'm not sure if this has changed. but perhaps Simon or someone using qemu-kmv-ev may"
Regards.
________________________________
From: Daniel Salvador <dv...@gmail.com>
Sent: Monday, February 28, 2022 21:39
To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
Subject: Re: [Discussion] CentOS 7 KVM binaries
Hi all,
Thank you all for the responses. Based on them (and as expected), to run
CloudStack + CentOS + KVM with all features, users install qemu-kvm-ev,
without any official guide provided by the community (at least no one said
the opposite).
Regarding Rohit's comment, stock qemu-kvm has limitations, qemu-kvm-ev was
created to supply the features limited by the default one.
With that said, I created a vote thread[¹] with the solution proposal for
this situation.
Best regards,
Daniel Salvador
[¹] https://lists.apache.org/thread/0qn12w71vclyklglf6zhp0grg99o4xbx
On Fri, Feb 25, 2022 at 5:07 PM Nicolas Vazquez <
Nicolas.Vazquez@shapeblue.com> wrote:
> Thanks Daniel and all,
>
> +1 as well from me. If no objections then we can move forward PR 5297 to
> including it on 4.17 with the remarks Andrija raised.
>
> Regards,
> Nicolas Vazquez
>
>
> From: Sven Vogel <S....@ewerk.com>
> Date: Thursday, 24 February 2022 at 19:24
> To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> Subject: Re: [Discussion] CentOS 7 KVM binaries
> We use only the qemu-kvm-ev.
>
> __
>
> Sven Vogel
> Senior Manager Research and Development - Cloud and Infrastructure
>
> EWERK DIGITAL GmbH
> Brühl 24, D-04109 Leipzig
> P +49 341 42649 - 99
> F +49 341 42649 - 98
> S.Vogel@ewerk.com
> www.ewerk.com<http://www.ewerk.com>
>
> Geschäftsführer:
> Dr. Erik Wende, Hendrik Schubert, Markus Böttcher
> Registergericht: Leipzig HRB 9065
>
> Support:
> +49 341 42649 555
>
> Zertifiziert nach:
> ISO/IEC 27001:2013
> DIN EN ISO 9001:2015
> DIN ISO/IEC 20000-1:2018
>
> ISAE 3402 Typ II Assessed
>
> EWERK-Blog<https://blog.ewerk.com/> | LinkedIn<
> https://www.linkedin.com/company/ewerk-group> | Xing<
> https://www.xing.com/company/ewerk> | Twitter<
> https://twitter.com/EWERK_Group> | Facebook<
> https://de-de.facebook.com/EWERK.Group/>
>
>
> Auskünfte und Angebote per Mail sind freibleibend und unverbindlich.
>
> Disclaimer Privacy:
> Der Inhalt dieser E-Mail (einschließlich etwaiger beigefügter Dateien) ist
> vertraulich und nur für den Empfänger bestimmt. Sollten Sie nicht der
> bestimmungsgemäße Empfänger sein, ist Ihnen jegliche Offenlegung,
> Vervielfältigung, Weitergabe oder Nutzung des Inhalts untersagt. Bitte
> informieren Sie in diesem Fall unverzüglich den Absender und löschen Sie
> die E-Mail (einschließlich etwaiger beigefügter Dateien) von Ihrem System.
> Vielen Dank.
>
> The contents of this e-mail (including any attachments) are confidential
> and may be legally privileged. If you are not the intended recipient of
> this e-mail, any disclosure, copying, distribution or use of its contents
> is strictly prohibited, and you should please notify the sender immediately
> and then delete it (including any attachments) from your system. Thank you.
>
> ________________________________
> Von: Rohit Yadav <ro...@shapeblue.com>
> Gesendet: Thursday, February 24, 2022 3:56:56 PM
> An: dev <de...@cloudstack.apache.org>
> Cc: Andrija Panic <an...@shapeblue.com>
> Betreff: Re: [Discussion] CentOS 7 KVM binaries
>
> +1 I've seen a lot of users and some of our customers use qemu-kvm-ev in
> production. However, we need to check if qemu-kvm-ev has 100% feature
> parity (I remember my colleague Andrija suggesting something which was
> missing in either stock qemu-kvm or qemu-kvm-ev).
>
>
> Regards.
>
> ________________________________
> From: Slavka Peleva <sl...@storpool.com.INVALID>
> Sent: Wednesday, February 23, 2022 23:58
> To: dev <de...@cloudstack.apache.org>
> Subject: Re: [Discussion] CentOS 7 KVM binaries
>
> Hi Daniel,
>
> +1 for qemu-kvm-ev. We also advise our customers to use it.
>
> Best regards,
> Slavka
>
> On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
> wrote:
>
> > Daniel,
> >
> > We've used qemu-kvm-ev in production for years. A number of the
> > enhancements we've pushed into Cloudstack have required it. I think
> you'll
> > find that most cloud providers based on Centos (or Alma/Rocky) are also
> > using it.
> >
> > -Si
> > ________________________________
> > From: Daniel Salvador <gu...@apache.org>
> > Sent: Friday, February 18, 2022 9:53 AM
> > To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> > Subject: [Discussion] CentOS 7 KVM binaries
> >
> > Hi all, hope you are doing fine.
> >
> > The following discussion emerged from PR #5297[¹].
> >
> > It is a known fact that, regarding KVM functionalities, CentOS7 default's
> > QEMU binary is quite limited. This is due to the removal of some features
> > of KVM default binary in CentOS (like VM's volume live migration,
> > memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
> > information can be found in CentOS forum's thread[²].
> >
> > In my point of view, such limitations in the default QEMU binary in
> CentOS
> > make it unfeasible to build a cloud with CentOS and the default QEMU
> > binary, as operators lose a lot of useful/important operations or have to
> > go through workarounds, which cause VM's disruption (e.g. having to stop
> a
> > VM to migrate the volume between different storage pools, which triggers
> a
> > secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
> > which supports more features than the default one. Probably, most people
> > using KVM with CentOS are using the "ev" binary (I might be wrong though,
> > however, that seems to be the case when looking at the users' list).
> >
> > PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
> > (live disk snapshot). The easiest solution (and, IHMO, is the best
> option)
> > is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
> >
> > Further, it is important to mention that in our experience, it is not
> > possible to run a highly available cloud environment with CentOS7 and the
> > default binaries. In a cloud environment with thousands of VMs, sooner or
> > later the need to hotplug (increase) CPU/RAM, migrate volumes across
> > different storage pool tyles (such as iSCSI <> NFS), or some other type
> of
> > operation appear, and operators/final customers do not want service
> > disruption. Our customers, for instance, never shut down VMs for these
> > kinds of operations, and that is only possible because they are all using
> > KVM with Ubuntu now.
> >
> > Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
> > that CloudStack should limit its features due to a dying operating system
> > that presents very limited features by default.
> >
> > With that said, it would be interesting if dev/users that use CentOS7
> could
> > share their experiences with the "qemu-kvm-ev" in this thread, so we can
> > decide which way to go. Or, users that only use the default binary, if
> they
> > are satisfied with it.
> >
> > If almost no one is relying on default CentOS7 binaries, we could define
> as
> > a step in the documentation, that when using CentOS7 people must use the
> > "ev" binary. This would free us to evolve ACS more freely and avoid
> > headaches with workarounds to a limited operating system when there are
> > alternatives out there.
> >
> >
> > [¹] https://github.com/apache/cloudstack/pull/5297
> > [²] https://forums.centos.org/viewtopic.php?t=65618
> >
>
>
>
>
>
>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Daniel Salvador <dv...@gmail.com>.
Hi all,
Thank you all for the responses. Based on them (and as expected), to run
CloudStack + CentOS + KVM with all features, users install qemu-kvm-ev,
without any official guide provided by the community (at least no one said
the opposite).
Regarding Rohit's comment, stock qemu-kvm has limitations, qemu-kvm-ev was
created to supply the features limited by the default one.
With that said, I created a vote thread[¹] with the solution proposal for
this situation.
Best regards,
Daniel Salvador
[¹] https://lists.apache.org/thread/0qn12w71vclyklglf6zhp0grg99o4xbx
On Fri, Feb 25, 2022 at 5:07 PM Nicolas Vazquez <
Nicolas.Vazquez@shapeblue.com> wrote:
> Thanks Daniel and all,
>
> +1 as well from me. If no objections then we can move forward PR 5297 to
> including it on 4.17 with the remarks Andrija raised.
>
> Regards,
> Nicolas Vazquez
>
>
> From: Sven Vogel <S....@ewerk.com>
> Date: Thursday, 24 February 2022 at 19:24
> To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> Subject: Re: [Discussion] CentOS 7 KVM binaries
> We use only the qemu-kvm-ev.
>
> __
>
> Sven Vogel
> Senior Manager Research and Development - Cloud and Infrastructure
>
> EWERK DIGITAL GmbH
> Brühl 24, D-04109 Leipzig
> P +49 341 42649 - 99
> F +49 341 42649 - 98
> S.Vogel@ewerk.com
> www.ewerk.com<http://www.ewerk.com>
>
> Geschäftsführer:
> Dr. Erik Wende, Hendrik Schubert, Markus Böttcher
> Registergericht: Leipzig HRB 9065
>
> Support:
> +49 341 42649 555
>
> Zertifiziert nach:
> ISO/IEC 27001:2013
> DIN EN ISO 9001:2015
> DIN ISO/IEC 20000-1:2018
>
> ISAE 3402 Typ II Assessed
>
> EWERK-Blog<https://blog.ewerk.com/> | LinkedIn<
> https://www.linkedin.com/company/ewerk-group> | Xing<
> https://www.xing.com/company/ewerk> | Twitter<
> https://twitter.com/EWERK_Group> | Facebook<
> https://de-de.facebook.com/EWERK.Group/>
>
>
> Auskünfte und Angebote per Mail sind freibleibend und unverbindlich.
>
> Disclaimer Privacy:
> Der Inhalt dieser E-Mail (einschließlich etwaiger beigefügter Dateien) ist
> vertraulich und nur für den Empfänger bestimmt. Sollten Sie nicht der
> bestimmungsgemäße Empfänger sein, ist Ihnen jegliche Offenlegung,
> Vervielfältigung, Weitergabe oder Nutzung des Inhalts untersagt. Bitte
> informieren Sie in diesem Fall unverzüglich den Absender und löschen Sie
> die E-Mail (einschließlich etwaiger beigefügter Dateien) von Ihrem System.
> Vielen Dank.
>
> The contents of this e-mail (including any attachments) are confidential
> and may be legally privileged. If you are not the intended recipient of
> this e-mail, any disclosure, copying, distribution or use of its contents
> is strictly prohibited, and you should please notify the sender immediately
> and then delete it (including any attachments) from your system. Thank you.
>
> ________________________________
> Von: Rohit Yadav <ro...@shapeblue.com>
> Gesendet: Thursday, February 24, 2022 3:56:56 PM
> An: dev <de...@cloudstack.apache.org>
> Cc: Andrija Panic <an...@shapeblue.com>
> Betreff: Re: [Discussion] CentOS 7 KVM binaries
>
> +1 I've seen a lot of users and some of our customers use qemu-kvm-ev in
> production. However, we need to check if qemu-kvm-ev has 100% feature
> parity (I remember my colleague Andrija suggesting something which was
> missing in either stock qemu-kvm or qemu-kvm-ev).
>
>
> Regards.
>
> ________________________________
> From: Slavka Peleva <sl...@storpool.com.INVALID>
> Sent: Wednesday, February 23, 2022 23:58
> To: dev <de...@cloudstack.apache.org>
> Subject: Re: [Discussion] CentOS 7 KVM binaries
>
> Hi Daniel,
>
> +1 for qemu-kvm-ev. We also advise our customers to use it.
>
> Best regards,
> Slavka
>
> On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
> wrote:
>
> > Daniel,
> >
> > We've used qemu-kvm-ev in production for years. A number of the
> > enhancements we've pushed into Cloudstack have required it. I think
> you'll
> > find that most cloud providers based on Centos (or Alma/Rocky) are also
> > using it.
> >
> > -Si
> > ________________________________
> > From: Daniel Salvador <gu...@apache.org>
> > Sent: Friday, February 18, 2022 9:53 AM
> > To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> > Subject: [Discussion] CentOS 7 KVM binaries
> >
> > Hi all, hope you are doing fine.
> >
> > The following discussion emerged from PR #5297[¹].
> >
> > It is a known fact that, regarding KVM functionalities, CentOS7 default's
> > QEMU binary is quite limited. This is due to the removal of some features
> > of KVM default binary in CentOS (like VM's volume live migration,
> > memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
> > information can be found in CentOS forum's thread[²].
> >
> > In my point of view, such limitations in the default QEMU binary in
> CentOS
> > make it unfeasible to build a cloud with CentOS and the default QEMU
> > binary, as operators lose a lot of useful/important operations or have to
> > go through workarounds, which cause VM's disruption (e.g. having to stop
> a
> > VM to migrate the volume between different storage pools, which triggers
> a
> > secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
> > which supports more features than the default one. Probably, most people
> > using KVM with CentOS are using the "ev" binary (I might be wrong though,
> > however, that seems to be the case when looking at the users' list).
> >
> > PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
> > (live disk snapshot). The easiest solution (and, IHMO, is the best
> option)
> > is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
> >
> > Further, it is important to mention that in our experience, it is not
> > possible to run a highly available cloud environment with CentOS7 and the
> > default binaries. In a cloud environment with thousands of VMs, sooner or
> > later the need to hotplug (increase) CPU/RAM, migrate volumes across
> > different storage pool tyles (such as iSCSI <> NFS), or some other type
> of
> > operation appear, and operators/final customers do not want service
> > disruption. Our customers, for instance, never shut down VMs for these
> > kinds of operations, and that is only possible because they are all using
> > KVM with Ubuntu now.
> >
> > Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
> > that CloudStack should limit its features due to a dying operating system
> > that presents very limited features by default.
> >
> > With that said, it would be interesting if dev/users that use CentOS7
> could
> > share their experiences with the "qemu-kvm-ev" in this thread, so we can
> > decide which way to go. Or, users that only use the default binary, if
> they
> > are satisfied with it.
> >
> > If almost no one is relying on default CentOS7 binaries, we could define
> as
> > a step in the documentation, that when using CentOS7 people must use the
> > "ev" binary. This would free us to evolve ACS more freely and avoid
> > headaches with workarounds to a limited operating system when there are
> > alternatives out there.
> >
> >
> > [¹] https://github.com/apache/cloudstack/pull/5297
> > [²] https://forums.centos.org/viewtopic.php?t=65618
> >
>
>
>
>
>
>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Nicolas Vazquez <Ni...@shapeblue.com>.
Thanks Daniel and all,
+1 as well from me. If no objections then we can move forward PR 5297 to including it on 4.17 with the remarks Andrija raised.
Regards,
Nicolas Vazquez
From: Sven Vogel <S....@ewerk.com>
Date: Thursday, 24 February 2022 at 19:24
To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
Subject: Re: [Discussion] CentOS 7 KVM binaries
We use only the qemu-kvm-ev.
__
Sven Vogel
Senior Manager Research and Development - Cloud and Infrastructure
EWERK DIGITAL GmbH
Brühl 24, D-04109 Leipzig
P +49 341 42649 - 99
F +49 341 42649 - 98
S.Vogel@ewerk.com
www.ewerk.com<http://www.ewerk.com>
Geschäftsführer:
Dr. Erik Wende, Hendrik Schubert, Markus Böttcher
Registergericht: Leipzig HRB 9065
Support:
+49 341 42649 555
Zertifiziert nach:
ISO/IEC 27001:2013
DIN EN ISO 9001:2015
DIN ISO/IEC 20000-1:2018
ISAE 3402 Typ II Assessed
EWERK-Blog<https://blog.ewerk.com/> | LinkedIn<https://www.linkedin.com/company/ewerk-group> | Xing<https://www.xing.com/company/ewerk> | Twitter<https://twitter.com/EWERK_Group> | Facebook<https://de-de.facebook.com/EWERK.Group/>
Auskünfte und Angebote per Mail sind freibleibend und unverbindlich.
Disclaimer Privacy:
Der Inhalt dieser E-Mail (einschließlich etwaiger beigefügter Dateien) ist vertraulich und nur für den Empfänger bestimmt. Sollten Sie nicht der bestimmungsgemäße Empfänger sein, ist Ihnen jegliche Offenlegung, Vervielfältigung, Weitergabe oder Nutzung des Inhalts untersagt. Bitte informieren Sie in diesem Fall unverzüglich den Absender und löschen Sie die E-Mail (einschließlich etwaiger beigefügter Dateien) von Ihrem System. Vielen Dank.
The contents of this e-mail (including any attachments) are confidential and may be legally privileged. If you are not the intended recipient of this e-mail, any disclosure, copying, distribution or use of its contents is strictly prohibited, and you should please notify the sender immediately and then delete it (including any attachments) from your system. Thank you.
________________________________
Von: Rohit Yadav <ro...@shapeblue.com>
Gesendet: Thursday, February 24, 2022 3:56:56 PM
An: dev <de...@cloudstack.apache.org>
Cc: Andrija Panic <an...@shapeblue.com>
Betreff: Re: [Discussion] CentOS 7 KVM binaries
+1 I've seen a lot of users and some of our customers use qemu-kvm-ev in production. However, we need to check if qemu-kvm-ev has 100% feature parity (I remember my colleague Andrija suggesting something which was missing in either stock qemu-kvm or qemu-kvm-ev).
Regards.
________________________________
From: Slavka Peleva <sl...@storpool.com.INVALID>
Sent: Wednesday, February 23, 2022 23:58
To: dev <de...@cloudstack.apache.org>
Subject: Re: [Discussion] CentOS 7 KVM binaries
Hi Daniel,
+1 for qemu-kvm-ev. We also advise our customers to use it.
Best regards,
Slavka
On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
wrote:
> Daniel,
>
> We've used qemu-kvm-ev in production for years. A number of the
> enhancements we've pushed into Cloudstack have required it. I think you'll
> find that most cloud providers based on Centos (or Alma/Rocky) are also
> using it.
>
> -Si
> ________________________________
> From: Daniel Salvador <gu...@apache.org>
> Sent: Friday, February 18, 2022 9:53 AM
> To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> Subject: [Discussion] CentOS 7 KVM binaries
>
> Hi all, hope you are doing fine.
>
> The following discussion emerged from PR #5297[¹].
>
> It is a known fact that, regarding KVM functionalities, CentOS7 default's
> QEMU binary is quite limited. This is due to the removal of some features
> of KVM default binary in CentOS (like VM's volume live migration,
> memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
> information can be found in CentOS forum's thread[²].
>
> In my point of view, such limitations in the default QEMU binary in CentOS
> make it unfeasible to build a cloud with CentOS and the default QEMU
> binary, as operators lose a lot of useful/important operations or have to
> go through workarounds, which cause VM's disruption (e.g. having to stop a
> VM to migrate the volume between different storage pools, which triggers a
> secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
> which supports more features than the default one. Probably, most people
> using KVM with CentOS are using the "ev" binary (I might be wrong though,
> however, that seems to be the case when looking at the users' list).
>
> PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
> (live disk snapshot). The easiest solution (and, IHMO, is the best option)
> is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
>
> Further, it is important to mention that in our experience, it is not
> possible to run a highly available cloud environment with CentOS7 and the
> default binaries. In a cloud environment with thousands of VMs, sooner or
> later the need to hotplug (increase) CPU/RAM, migrate volumes across
> different storage pool tyles (such as iSCSI <> NFS), or some other type of
> operation appear, and operators/final customers do not want service
> disruption. Our customers, for instance, never shut down VMs for these
> kinds of operations, and that is only possible because they are all using
> KVM with Ubuntu now.
>
> Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
> that CloudStack should limit its features due to a dying operating system
> that presents very limited features by default.
>
> With that said, it would be interesting if dev/users that use CentOS7 could
> share their experiences with the "qemu-kvm-ev" in this thread, so we can
> decide which way to go. Or, users that only use the default binary, if they
> are satisfied with it.
>
> If almost no one is relying on default CentOS7 binaries, we could define as
> a step in the documentation, that when using CentOS7 people must use the
> "ev" binary. This would free us to evolve ACS more freely and avoid
> headaches with workarounds to a limited operating system when there are
> alternatives out there.
>
>
> [¹] https://github.com/apache/cloudstack/pull/5297
> [²] https://forums.centos.org/viewtopic.php?t=65618
>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Sven Vogel <S....@ewerk.com>.
We use only the qemu-kvm-ev.
__
Sven Vogel
Senior Manager Research and Development - Cloud and Infrastructure
EWERK DIGITAL GmbH
Brühl 24, D-04109 Leipzig
P +49 341 42649 - 99
F +49 341 42649 - 98
S.Vogel@ewerk.com
www.ewerk.com
Geschäftsführer:
Dr. Erik Wende, Hendrik Schubert, Markus Böttcher
Registergericht: Leipzig HRB 9065
Support:
+49 341 42649 555
Zertifiziert nach:
ISO/IEC 27001:2013
DIN EN ISO 9001:2015
DIN ISO/IEC 20000-1:2018
ISAE 3402 Typ II Assessed
EWERK-Blog<https://blog.ewerk.com/> | LinkedIn<https://www.linkedin.com/company/ewerk-group> | Xing<https://www.xing.com/company/ewerk> | Twitter<https://twitter.com/EWERK_Group> | Facebook<https://de-de.facebook.com/EWERK.Group/>
Auskünfte und Angebote per Mail sind freibleibend und unverbindlich.
Disclaimer Privacy:
Der Inhalt dieser E-Mail (einschließlich etwaiger beigefügter Dateien) ist vertraulich und nur für den Empfänger bestimmt. Sollten Sie nicht der bestimmungsgemäße Empfänger sein, ist Ihnen jegliche Offenlegung, Vervielfältigung, Weitergabe oder Nutzung des Inhalts untersagt. Bitte informieren Sie in diesem Fall unverzüglich den Absender und löschen Sie die E-Mail (einschließlich etwaiger beigefügter Dateien) von Ihrem System. Vielen Dank.
The contents of this e-mail (including any attachments) are confidential and may be legally privileged. If you are not the intended recipient of this e-mail, any disclosure, copying, distribution or use of its contents is strictly prohibited, and you should please notify the sender immediately and then delete it (including any attachments) from your system. Thank you.
________________________________
Von: Rohit Yadav <ro...@shapeblue.com>
Gesendet: Thursday, February 24, 2022 3:56:56 PM
An: dev <de...@cloudstack.apache.org>
Cc: Andrija Panic <an...@shapeblue.com>
Betreff: Re: [Discussion] CentOS 7 KVM binaries
+1 I've seen a lot of users and some of our customers use qemu-kvm-ev in production. However, we need to check if qemu-kvm-ev has 100% feature parity (I remember my colleague Andrija suggesting something which was missing in either stock qemu-kvm or qemu-kvm-ev).
Regards.
________________________________
From: Slavka Peleva <sl...@storpool.com.INVALID>
Sent: Wednesday, February 23, 2022 23:58
To: dev <de...@cloudstack.apache.org>
Subject: Re: [Discussion] CentOS 7 KVM binaries
Hi Daniel,
+1 for qemu-kvm-ev. We also advise our customers to use it.
Best regards,
Slavka
On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
wrote:
> Daniel,
>
> We've used qemu-kvm-ev in production for years. A number of the
> enhancements we've pushed into Cloudstack have required it. I think you'll
> find that most cloud providers based on Centos (or Alma/Rocky) are also
> using it.
>
> -Si
> ________________________________
> From: Daniel Salvador <gu...@apache.org>
> Sent: Friday, February 18, 2022 9:53 AM
> To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> Subject: [Discussion] CentOS 7 KVM binaries
>
> Hi all, hope you are doing fine.
>
> The following discussion emerged from PR #5297[¹].
>
> It is a known fact that, regarding KVM functionalities, CentOS7 default's
> QEMU binary is quite limited. This is due to the removal of some features
> of KVM default binary in CentOS (like VM's volume live migration,
> memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
> information can be found in CentOS forum's thread[²].
>
> In my point of view, such limitations in the default QEMU binary in CentOS
> make it unfeasible to build a cloud with CentOS and the default QEMU
> binary, as operators lose a lot of useful/important operations or have to
> go through workarounds, which cause VM's disruption (e.g. having to stop a
> VM to migrate the volume between different storage pools, which triggers a
> secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
> which supports more features than the default one. Probably, most people
> using KVM with CentOS are using the "ev" binary (I might be wrong though,
> however, that seems to be the case when looking at the users' list).
>
> PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
> (live disk snapshot). The easiest solution (and, IHMO, is the best option)
> is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
>
> Further, it is important to mention that in our experience, it is not
> possible to run a highly available cloud environment with CentOS7 and the
> default binaries. In a cloud environment with thousands of VMs, sooner or
> later the need to hotplug (increase) CPU/RAM, migrate volumes across
> different storage pool tyles (such as iSCSI <> NFS), or some other type of
> operation appear, and operators/final customers do not want service
> disruption. Our customers, for instance, never shut down VMs for these
> kinds of operations, and that is only possible because they are all using
> KVM with Ubuntu now.
>
> Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
> that CloudStack should limit its features due to a dying operating system
> that presents very limited features by default.
>
> With that said, it would be interesting if dev/users that use CentOS7 could
> share their experiences with the "qemu-kvm-ev" in this thread, so we can
> decide which way to go. Or, users that only use the default binary, if they
> are satisfied with it.
>
> If almost no one is relying on default CentOS7 binaries, we could define as
> a step in the documentation, that when using CentOS7 people must use the
> "ev" binary. This would free us to evolve ACS more freely and avoid
> headaches with workarounds to a limited operating system when there are
> alternatives out there.
>
>
> [¹] https://github.com/apache/cloudstack/pull/5297
> [²] https://forums.centos.org/viewtopic.php?t=65618
>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Rohit Yadav <ro...@shapeblue.com>.
+1 I've seen a lot of users and some of our customers use qemu-kvm-ev in production. However, we need to check if qemu-kvm-ev has 100% feature parity (I remember my colleague Andrija suggesting something which was missing in either stock qemu-kvm or qemu-kvm-ev).
Regards.
________________________________
From: Slavka Peleva <sl...@storpool.com.INVALID>
Sent: Wednesday, February 23, 2022 23:58
To: dev <de...@cloudstack.apache.org>
Subject: Re: [Discussion] CentOS 7 KVM binaries
Hi Daniel,
+1 for qemu-kvm-ev. We also advise our customers to use it.
Best regards,
Slavka
On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
wrote:
> Daniel,
>
> We've used qemu-kvm-ev in production for years. A number of the
> enhancements we've pushed into Cloudstack have required it. I think you'll
> find that most cloud providers based on Centos (or Alma/Rocky) are also
> using it.
>
> -Si
> ________________________________
> From: Daniel Salvador <gu...@apache.org>
> Sent: Friday, February 18, 2022 9:53 AM
> To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> Subject: [Discussion] CentOS 7 KVM binaries
>
> Hi all, hope you are doing fine.
>
> The following discussion emerged from PR #5297[¹].
>
> It is a known fact that, regarding KVM functionalities, CentOS7 default's
> QEMU binary is quite limited. This is due to the removal of some features
> of KVM default binary in CentOS (like VM's volume live migration,
> memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
> information can be found in CentOS forum's thread[²].
>
> In my point of view, such limitations in the default QEMU binary in CentOS
> make it unfeasible to build a cloud with CentOS and the default QEMU
> binary, as operators lose a lot of useful/important operations or have to
> go through workarounds, which cause VM's disruption (e.g. having to stop a
> VM to migrate the volume between different storage pools, which triggers a
> secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
> which supports more features than the default one. Probably, most people
> using KVM with CentOS are using the "ev" binary (I might be wrong though,
> however, that seems to be the case when looking at the users' list).
>
> PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
> (live disk snapshot). The easiest solution (and, IHMO, is the best option)
> is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
>
> Further, it is important to mention that in our experience, it is not
> possible to run a highly available cloud environment with CentOS7 and the
> default binaries. In a cloud environment with thousands of VMs, sooner or
> later the need to hotplug (increase) CPU/RAM, migrate volumes across
> different storage pool tyles (such as iSCSI <> NFS), or some other type of
> operation appear, and operators/final customers do not want service
> disruption. Our customers, for instance, never shut down VMs for these
> kinds of operations, and that is only possible because they are all using
> KVM with Ubuntu now.
>
> Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
> that CloudStack should limit its features due to a dying operating system
> that presents very limited features by default.
>
> With that said, it would be interesting if dev/users that use CentOS7 could
> share their experiences with the "qemu-kvm-ev" in this thread, so we can
> decide which way to go. Or, users that only use the default binary, if they
> are satisfied with it.
>
> If almost no one is relying on default CentOS7 binaries, we could define as
> a step in the documentation, that when using CentOS7 people must use the
> "ev" binary. This would free us to evolve ACS more freely and avoid
> headaches with workarounds to a limited operating system when there are
> alternatives out there.
>
>
> [¹] https://github.com/apache/cloudstack/pull/5297
> [²] https://forums.centos.org/viewtopic.php?t=65618
>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Slavka Peleva <sl...@storpool.com.INVALID>.
Hi Daniel,
+1 for qemu-kvm-ev. We also advise our customers to use it.
Best regards,
Slavka
On Fri, Feb 18, 2022 at 8:51 PM Simon Weller <sw...@ena.com.invalid>
wrote:
> Daniel,
>
> We've used qemu-kvm-ev in production for years. A number of the
> enhancements we've pushed into Cloudstack have required it. I think you'll
> find that most cloud providers based on Centos (or Alma/Rocky) are also
> using it.
>
> -Si
> ________________________________
> From: Daniel Salvador <gu...@apache.org>
> Sent: Friday, February 18, 2022 9:53 AM
> To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
> Subject: [Discussion] CentOS 7 KVM binaries
>
> Hi all, hope you are doing fine.
>
> The following discussion emerged from PR #5297[¹].
>
> It is a known fact that, regarding KVM functionalities, CentOS7 default's
> QEMU binary is quite limited. This is due to the removal of some features
> of KVM default binary in CentOS (like VM's volume live migration,
> memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
> information can be found in CentOS forum's thread[²].
>
> In my point of view, such limitations in the default QEMU binary in CentOS
> make it unfeasible to build a cloud with CentOS and the default QEMU
> binary, as operators lose a lot of useful/important operations or have to
> go through workarounds, which cause VM's disruption (e.g. having to stop a
> VM to migrate the volume between different storage pools, which triggers a
> secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
> which supports more features than the default one. Probably, most people
> using KVM with CentOS are using the "ev" binary (I might be wrong though,
> however, that seems to be the case when looking at the users' list).
>
> PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
> (live disk snapshot). The easiest solution (and, IHMO, is the best option)
> is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
>
> Further, it is important to mention that in our experience, it is not
> possible to run a highly available cloud environment with CentOS7 and the
> default binaries. In a cloud environment with thousands of VMs, sooner or
> later the need to hotplug (increase) CPU/RAM, migrate volumes across
> different storage pool tyles (such as iSCSI <> NFS), or some other type of
> operation appear, and operators/final customers do not want service
> disruption. Our customers, for instance, never shut down VMs for these
> kinds of operations, and that is only possible because they are all using
> KVM with Ubuntu now.
>
> Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
> that CloudStack should limit its features due to a dying operating system
> that presents very limited features by default.
>
> With that said, it would be interesting if dev/users that use CentOS7 could
> share their experiences with the "qemu-kvm-ev" in this thread, so we can
> decide which way to go. Or, users that only use the default binary, if they
> are satisfied with it.
>
> If almost no one is relying on default CentOS7 binaries, we could define as
> a step in the documentation, that when using CentOS7 people must use the
> "ev" binary. This would free us to evolve ACS more freely and avoid
> headaches with workarounds to a limited operating system when there are
> alternatives out there.
>
>
> [¹] https://github.com/apache/cloudstack/pull/5297
> [²] https://forums.centos.org/viewtopic.php?t=65618
>
Re: [Discussion] CentOS 7 KVM binaries
Posted by Simon Weller <sw...@ena.com.INVALID>.
Daniel,
We've used qemu-kvm-ev in production for years. A number of the enhancements we've pushed into Cloudstack have required it. I think you'll find that most cloud providers based on Centos (or Alma/Rocky) are also using it.
-Si
________________________________
From: Daniel Salvador <gu...@apache.org>
Sent: Friday, February 18, 2022 9:53 AM
To: dev@cloudstack.apache.org <de...@cloudstack.apache.org>
Subject: [Discussion] CentOS 7 KVM binaries
Hi all, hope you are doing fine.
The following discussion emerged from PR #5297[¹].
It is a known fact that, regarding KVM functionalities, CentOS7 default's
QEMU binary is quite limited. This is due to the removal of some features
of KVM default binary in CentOS (like VM's volume live migration,
memory/CPU hotplug/hot-unplug, live disk snapshot, and so on); more
information can be found in CentOS forum's thread[²].
In my point of view, such limitations in the default QEMU binary in CentOS
make it unfeasible to build a cloud with CentOS and the default QEMU
binary, as operators lose a lot of useful/important operations or have to
go through workarounds, which cause VM's disruption (e.g. having to stop a
VM to migrate the volume between different storage pools, which triggers a
secondary storage usage). There is an alternative binary, "qemu-kvm-ev",
which supports more features than the default one. Probably, most people
using KVM with CentOS are using the "ev" binary (I might be wrong though,
however, that seems to be the case when looking at the users' list).
PR #5297[¹] ran into one of the CentOS7 default's QEMU binary limitations
(live disk snapshot). The easiest solution (and, IHMO, is the best option)
is to guide users to upgrade CentOS7 QEMU binary to "qemu-kvm-ev".
Further, it is important to mention that in our experience, it is not
possible to run a highly available cloud environment with CentOS7 and the
default binaries. In a cloud environment with thousands of VMs, sooner or
later the need to hotplug (increase) CPU/RAM, migrate volumes across
different storage pool tyles (such as iSCSI <> NFS), or some other type of
operation appear, and operators/final customers do not want service
disruption. Our customers, for instance, never shut down VMs for these
kinds of operations, and that is only possible because they are all using
KVM with Ubuntu now.
Moreover, CentOS7 is getting close to its EOL. Therefore, We do not think
that CloudStack should limit its features due to a dying operating system
that presents very limited features by default.
With that said, it would be interesting if dev/users that use CentOS7 could
share their experiences with the "qemu-kvm-ev" in this thread, so we can
decide which way to go. Or, users that only use the default binary, if they
are satisfied with it.
If almost no one is relying on default CentOS7 binaries, we could define as
a step in the documentation, that when using CentOS7 people must use the
"ev" binary. This would free us to evolve ACS more freely and avoid
headaches with workarounds to a limited operating system when there are
alternatives out there.
[¹] https://github.com/apache/cloudstack/pull/5297
[²] https://forums.centos.org/viewtopic.php?t=65618