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Posted to users@cloudstack.apache.org by "raniers1 (via GitHub)" <gi...@apache.org> on 2026/05/04 19:59:38 UTC

[D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

GitHub user raniers1 created a discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

Hi everyone,

I would like to get some feedback regarding the following Global Configuration parameters related to KVM High Availability in our staging environment running Apache CloudStack.

We know that these settings can be changed via the Web UI, API, or directly in the database. We would like to know if there are any concerns or restrictions regarding changing these parameters directly in the database.

The parameters in question:

| Parameter | Value |
|---|---|
| kvm.ha.recover.failure.threshold | 1 |
| kvm.ha.degraded.max.period | 300s |
| kvm.ha.activity.check.failure.ratio | ? |
| kvm.ha.activity.check.max.attempts | 5 |

Some questions:

- Is modifying these settings directly in the database safe, or could it cause cache inconsistencies in the Management Server (ACS 4.21.0.0 )?

Additionally, we have a second concern: we have templates that were uploaded **without HA enabled**. Once a template is uploaded, the HA option is no longer available through the Web UI. In this case, is it safe to enable HA directly in the database for both the templates and the VMs that were deployed from them?

- Is there any risk in enabling HA directly in the database for existing templates and VMs?

Thanks in advance!

GitHub link: https://github.com/apache/cloudstack/discussions/13100

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Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by za...@gmail.com.

@raniers1

1. Direct DB modification of Global Configs

No cache issue here. CloudStack reads global configs through the
standard DAO layer, which queries the DB at read time — no stale cache
involved. For those KVM HA parameters
(kvm.ha.recover.failure.threshold etc.), just update the configuration
table directly. No MS restart needed.

In production, API/UI is still the safer route to avoid human error,
but functionally direct DB mod is fine.

2. Enabling HA on already-uploaded templates

HA flags on templates (vm_template) and VMs (vm_instance) are
independent. Modifying the template's HA flag in DB only affects VMs
deployed after the change; existing VMs are not impacted. Low risk.

If you also need HA on already-deployed VMs, you'll need to update
vm_instance — template change alone won't cover that.

Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by "jgotteswinter (via GitHub)" <gi...@apache.org>.

GitHub user jgotteswinter added a comment to the discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

imho this should be fine, restart the management server afterwards.

GitHub link: https://github.com/apache/cloudstack/discussions/13100#discussioncomment-16812335

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Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by "raniers1 (via GitHub)" <gi...@apache.org>.

GitHub user raniers1 closed a discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

Hi everyone,

I would like to get some feedback regarding the following Global Configuration parameters related to KVM High Availability in our staging environment running Apache CloudStack.

We know that these settings can be changed via the Web UI, API, or directly in the database. We would like to know if there are any concerns or restrictions regarding changing these parameters directly in the database.

The parameters in question:

| Parameter | Value |
|---|---|
| kvm.ha.recover.failure.threshold | 1 |
| kvm.ha.degraded.max.period | 300s |
| kvm.ha.activity.check.failure.ratio | ? |
| kvm.ha.activity.check.max.attempts | 5 |

Some questions:

- Is modifying these settings directly in the database safe, or could it cause cache inconsistencies in the Management Server (ACS 4.21.0.0 )?

Additionally, we have a second concern: we have templates that were uploaded **without HA enabled**. Once a template is uploaded, the HA option is no longer available through the Web UI. In this case, is it safe to enable HA directly in the database for both the templates and the VMs that were deployed from them?

- Is there any risk in enabling HA directly in the database for existing templates and VMs?

Thanks in advance!

GitHub link: https://github.com/apache/cloudstack/discussions/13100

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Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by "raniers1 (via GitHub)" <gi...@apache.org>.

GitHub user raniers1 added a comment to the discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

Hy @DaanHoogland,

This is a staging environment, and my question is whether CloudStack configuration changes should always be done via WebUI/API, or if changing them directly in the database is acceptable in this specific case. We know the best practice is to use the Web UI or API, but we would like to understand whether there is any technical restriction beyond that, especially for these KVM HA global configuration parameters:

**kvm.ha.recover.failure.threshold
kvm.ha.degraded.max.period
kvm.ha.activity.check.failure.ratio
kvm.ha.activity.check.max.attempts**

We also have templates that were uploaded without HA enabled. Since the HA option is no longer available in the Web UI after upload, is it safe to enable HA directly in the database for those templates and for VMs deployed from them?

Is there any risk in doing this directly in the database?

At the moment, we are running ACS 4.21.0 and plan to upgrade to 4.22 in the future.

Our motivation is only to clarify this doubt, and we do not intend to make direct database changes in production.

thanks!

GitHub link: https://github.com/apache/cloudstack/discussions/13100#discussioncomment-16832176

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Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by "DaanHoogland (via GitHub)" <gi...@apache.org>.

GitHub user DaanHoogland added a comment to the discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

@raniers1 , you would have to investigate the code to see how it is retrieved. Settings are quite old and basically two different ways of retrieving are still in use in the code-base. When restarting all management servers this would usually work (provided you use the right table, because there are configurations and (resource) details. Both of which appear as configuration at different levels.

Hope this explains,

GitHub link: https://github.com/apache/cloudstack/discussions/13100#discussioncomment-16837692

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Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by "DaanHoogland (via GitHub)" <gi...@apache.org>.

GitHub user DaanHoogland added a comment to the discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

Why would you want to do that?
Where would you change them?

I would say no, but do not know your motivation.

GitHub link: https://github.com/apache/cloudstack/discussions/13100#discussioncomment-16826232

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Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by "raniers1 (via GitHub)" <gi...@apache.org>.

GitHub user raniers1 added a comment to the discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

So, is it okay to change the global configs directly on the DB? 

GitHub link: https://github.com/apache/cloudstack/discussions/13100#discussioncomment-16819880

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Re: [D] KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates [cloudstack]

Posted by "raniers1 (via GitHub)" <gi...@apache.org>.

GitHub user raniers1 added a comment to the discussion: KVM HA configuration via database: Global Config parameters and enabling HA on uploaded templates

ok, thanks!  @DaanHoogland 

GitHub link: https://github.com/apache/cloudstack/discussions/13100#discussioncomment-16841242

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