The document discusses resource pool balancing for virtual machines (VMs) at Penn State Applied Research Lab. It describes implementing resource pools to prioritize critical VMs and ensure fair balancing during contention. An automated PowerShell script is used to read tags assigned to resource pools and virtual applications to calculate CPU and memory shares based on the number of VMs and tag values. This allows the shares to be automatically rebalanced over time as VM configurations change.

1. VM Resource Pool
Rebalancing
DAN BARR, PENN STATE ARL
CENTRAL PA VMUG, JULY 16, 2015

2. Penn State Applied Research Lab
University Center of Excellence in Defense science, systems, and technologies
U.S. Navy UARC (University-Affiliated Research Center)
Approximately 1100 researchers and support staff
ARL IT Services division manages VMs for lab-wide infrastructure, business
applications, and hosting for numerous research departments
Production clusters (x2): 10 hosts, 250 VMs
Project-specific clusters (x3): 16 hosts, 60 VMs, several “monster” VMs

3. Resource Pool Balancing
Use Resource Pools to prioritize critical VMs and ensure fair balancing during contention
Rule 1: Resource Pools are NOT folders!
◦ They have a real impact on resource distribution during contention
Rule 2: Share values are arbitrary but relative
◦ Pick base per-VM values and be consistent with share weighting
◦ No default (Low/Normal/High) values on pools
Rule 3: Don’t mix Resource Pools and VMs at the same inventory level
Rule 4: vApps are Resource Pools, too
How do we balance the shares, and more importantly keep them balanced over time?

4. Default Settings = Unexpected Results
Gold
Shares = High (8000)
…
40 VMs =
200 shares per VM
Silver
Shares = Normal (4000)
…
20 VMs =
200 shares per VM
Bronze
Shares = Low (2000)
5 VMs =
400 shares per VM

5. Automated Balancing
Tags assigned to all Resource Pools & vApps
◦ Tag Category: Shares Per VM
◦ Tags: 50, 100, 150, 200, “Parent”
◦ Parent = Resource Pool with child Pools
PowerShell Script
◦ Reads the tags from each RP/vApp & calculates share value
◦ CPU & Memory Shares = (# of VMs) * (tag value)
◦ Parent pools = sum of child pools
◦ Email notification of changes made, warning on pools with no tag

6. Example End Result
Department A: 100 shares/VM, 5 VMs = 500 shares
Department B: 100 shares/VM, 8 VMs = 800 shares
Infrastructure: 6200 shares
Gold: 200 shares/VM, 10 VMs = 2000 shares
Business Apps: 4300 shares
Silver: 100 shares/VM, 35 VMs = 3500 shares
Bronze: 50 shares/VM, 14 VMs = 700 shares
Prod: 150 shares/VM, 18 VMs = 2700 shares
Dev: 50 shares/VM, 22 VMs = 1100 shares
Test vApp: 100 shares/VM, 5 VMs = 500 shares

7. THANK YOU!
QUESTIONS?
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