As our PowerVC customers continue to grow in scale, one of the requests we have had is to reduce the amount of input required when they deploy a new virtual machine. 

To create a new virtual machine with PowerVC, the administrator must specify the following information:

  • Virtual Machine name
  • Compute size
  • Storage template
  • Networks

    • Virtual Machine IP address or specify the use of DHCP

Although our clients do occasionally need to provide a specific IP address for a virtual machine, they have also indicated that they would like to have the flexibility to automate IP address assignment but have more control than comes with DHCP.

The OpenStack community has implemented a concept for pooling IP addresses that the PowerVC team is considering adding to a future release of PowerVC. This would give PowerVC customers the ease of automatic IP address assignment, while still controlling the addresses that are used. The screens below reflect a potential implementation of IP address pools in PowerVC.

 

IP Address pools would be an added element on top of the Static network section of the Power VC management interface. For customers using an external DHCP server for a given network, there would not be an IP address pool.  This is because an external entity is managing the IP addresses.

Creating an IP Address Pool would require the network to be Static as in the example below:

Administrators could optionally fill in the IP address range.  Once defined, users would be able to view the IP pool in the Network view.

Note that the IP pool would be composed of a subnet (either the full subnet, or the partial range specified when created). This is consistent with the design preferred by the OpenStack community.

The IP Address pool would provide the following features:

  • Automatically attach an available  IP address from the pool to a new virtual machine
  • Provide a description  about how the IP address is being used
  • Lock an IP address to prevent PowerVC from assigning it.  See the below picture for the Lock option.  This would force PowerVC to avoid specific IP Addresses from being used on deploy (perhaps in use by another system not managed by PowerVC)
  • Unlock an IP address.  Selecting a Locked IP Address would then provide an Unlock button which could be used to remove the Locked IP address, thus making it available for use.

In this example, we can see that the first three addresses are in use by the virtual machines. 

One key feature that we are looking to add is the description on the IP address.  The lock description would be an optional field that provides the administrator with a way to document why the IP address is locked. 

This view could be useful to customers that still choose to specify IP addresses on each deploy.  Any deploys done with a targeted IP address would be automatically added to this view. 

The introduction of IP address pools would also cause some minor changes in the deploy path for virtual machines.  Below is an example of some of the new options.

The two major changes to notice here:

  • When using IP address pools, users could now deploy multiple instances simultaneously from the deploy screen without requiring the use of an external DHCP server.  Each instance would be given a unique IP address based on the networks specified.  Locked or In Use IP addresses would not be candidates for use, but any other addresses in the IP address pool would be available for use during deployment.
  • Users would still have the ability to specify an IP address (the default option) but, as you see in the picture above, the user could unclick ‘Specify IP address’ option to use the IP address pool.

 

As you can see, IP address pools could simplify the PowerVC deployment process and provide enablement for future simplification.

2 comments on"Overview – IP Address Pools"

  1. How to lock IP adresses in pool (via command line) from being used by PowerVC ?

  2. SriRamPisupati January 25, 2020

    You can create a port using the fixed ip address you want to reserve, so that the IP can be reserved to a port. PowerVC will not allocate such ip to any virtual machine.

    Example: openstack port create –network net1 –fixed-ip subnet=subnet1,ip-address=192.0.2.40 port1

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