cloudstack-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Saksham Srivastava <>
Subject RE: Reserved Guest VM CIDR Question
Date Tue, 07 Oct 2014 05:25:22 GMT

The reason why reservation is not enabled in create stage is the case of External network
When using external devices like NetScaler, CloudStack will not have a 'real' cidr unless
the network has been implemented.
So a cidr like /24 used at time of create may turn to /20 when the network has been implemented
and then it make no sense for reservation in initial stage.
What I will suggest is to create a network offering with 'Persistent' as true.
So your network will be implemented when you create it and VR will be up. Once the network
has been implemented you can apply reservation.


-----Original Message-----
From: Logan Barfield [] 
Sent: Tuesday, October 7, 2014 12:27 AM
Subject: Reserved Guest VM CIDR Question

We have decided internally to set up a CIDR reservation with all new accounts to give us the
ability to easily attach dedicated hosts to existing VM networks.

We were thinking it would be easier to set up the reservation before deploying VMs.  Setting
up reservation after the fact can get complicated if a VM happens to be outside the intended
reservation range.

The issue we're having is that reservation is not allowed until the network is in the "Implemented"
state (i.e. after the first VM is deployed).

Why is reservation not allowed upon initial network creation?  If we try to apply reservation
after the first VM is online the command will fail occasionally because the first VM is deployed
outside the CIDR range.


Guest Net:
Reserved CIDR:

- Attempt reservation before deploying a VM: Fails due to network not being "Implemented"
- Attempt reservation after many VMs are deployed: Fails due to VMs being outside Reserved
CIDR (e.g.,, and requires a lot of work to change the VM's IP
- Attempt reservation after first VM is deployed: Either succeeds, or fails if the first VMs
IP is outside of the reserved CIDR.

How can we fix this without hacking work arounds into the deployment logic?
 (ex: Check network for, if it doesn't exist deploy the VM on that IP, if it already
exists deploy it wherever.)

Thank You,

Logan Barfield
Tranquil Hosting
View raw message