RADIAL Support

Operating System

• Must support CASA
• Will need a patching/updating mechanism
• How to boot diskless OS images
  • I am not finding any new sexy software packages to automate PXE+DHCP+TFTP+NFS https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_storage_devices/setting-up-a-remote-diskless-system_managing-storage-devices
  • One OS image for both our use and locals use or multiple OS images?
  • Use containers (docker, singularity, kubernetes, mesos, etc)?
  • Ask Greg at CHTC what they use
• What Linux distrobution to use?
  • Can we use Red Hat with our current license?
  • Should we buy Red Hat licenses like we did for USNO?
    • USNO is between $10K and $15K per year for 81 licensed nodes.  This may not be an EDU license.
  • Do we even want to use Red Hat?
  • Rocky Linux or AlmaLinux since CentOS is essentially dead?

Third party software for VLASS

• CASA
• HTCondor
• Will need a way to maintain the software

Third party software for Local

• Will need a way to maintain software for the local site

Services

• DNS
• DHCP
• SMTP
• NTP
• NFS?
• LDAP?  How do we handle accounts?
• ssh
• rsync (nraorsync_plugin.py)
• NAT so the nodes can download/upload data
• TFTP
• condor (port 9618) https://htcondor-wiki.cs.wisc.edu/index.cgi/wiki?p=HowToMixFirewallsAndHtCondor

Management Access

• PDU
• UPS
• BMC/IPMI
• switch

Maintenance

• replace disk (local admin)
• replace/reseat DIMM (local admin)
• replace power supply (local admin)
• NRAO may handle replacement hardware. Drop ship. Spare ourselves?
• Patching OS images (NRAO)
• Patching third party software like CASA and HTCondor (NRAO)
• Altering OS images (NRAO)

Hardware

• Cabinet Rack:  Doors front and rear locking with mesh.  Width: 19".  Height: 42U is most common.  Depth: 42" is most common.  Rack must support at least 2,000 lbs static load
  
  • https://greatcabinets.com/product/es-ms/ This is what we usually get
  • https://www.apc.com/shop/us/en/products/APC-NetShelter-SX-Server-Rack-Enclosure-42U-Black-1991H-x-600W-x-1070D-mm/P-AR3100 APC NetShelter SX
  • https://www.apc.com/shop/us/en/products/APC-NetShelter-SX-Server-Rack-Enclosure-42U-Shock-Packaging-2000-lbs-Black-1991H-x-600W-x-1070D-mm/P-AR3100SP APC NetShelter SX designed for re-shipping after equipped.
• PDU: one PDU or two PDUs? What plug? What voltage? This may very across sites.  What if the site has two power sources?
  • https://www.apc.com/shop/us/en/products/APC-Rack-PDU-2G-switched-0U-30A-100V-to-120V-24-NEMA-5-20R-sockets/P-AP8932 24 NEMA 5-20R, 120V, 2.8kW, NEMA L5-30P 1Phase
  • https://www.apc.com/shop/us/en/products/APC-Rack-PDU-9000-switched-0U-8-6kW-208V-21-C13-and-C15-3-C19-and-C21-sockets/P-APDU9965 21 C13/C15 and 3 C19/C21, 208V, 8.6kW, NEMA L21-30P 3Phase
  • https://www.apc.com/shop/us/en/products/APC-Rack-PDU-9000-switched-0U-17-3kW-208V-42-C13-and-C15-6-C19-and-C21-sockets/P-APDU9967 42 C13/C15 and 6 C19/C21, 208V, 17kW, IEC60309 60A 3P+PE 3Phase
  • Stagger startups on PDU
• UPS: for just the head node and switch?  This may depend on the voltage of the PDUs.
• Switch: 10Gb/s.
• Environmental Monitoring:  Could the PDU do this?
• KVM: rackmount, not remote, and patch cables
• Ethernet cables:
• Power cables: single or Y calbes depending on number of PDUs and two power sources.
• Head Node: lots of disk.  Do the locals have access to this disk space?  Maybe not.
  • iDRAC: Ask CIS what they recommend
  • Memory: at least 32GB of RAM to help cache the OS image.  64GB would be even better.
  • Storage
    • OS RAID1+S (3 disks)
      
      • OS: We have been making 40GB partitions for / for over a decade and that looks to still work with RHEL8.
      • Swap: 0 or 8GB at most
      • /export/home/<hostnmae>: free hog
    • Images RAID1+S (nmpost-serv-1 is RAID1, cvpost isn't even RAID)
      • nmpost-serv-1 has 2TB for OS images and is using1.2TB of it.
    • Working data (local and nrao)? RAID6+S or RAID10+2S?
      • An SE imaging input data size is about 10GB per job
      • We need maybe 20TB+ of total space or more so maybe 60TB/2
      • Software share (nrao and local)
  • Software RAID, ZFS, RAID card?
• 30 1U nodes or 15 2U nodes or mix?  NVMe drives for nodes.  Swap drive?
  • NVMe for scratch and swap
• GPUs:  Do we get GPUs?  Do we get 1U nodes with room for 1 or 2 Tesla T4 GPUs or 2U nodes with room for 1 or 2 regular GPU?

Using

• Get NRAO jobs on the remote racks.  This may depend on how we want to use these remote racks. If we want them to do specific types of jobs then ClassAd options may be the solution. If we want them as overflow for jobs run at NRAO then flocking may be the solution. Perhaps we want both flocking and ClassAd options.  Actually flocking may be the best method because I think it doesn't require the execute nodes to have external network access.
  • Flocking?
  • Classad options?
  • Other?
• Remote HTCondor concerns
  • Do we want our jobs to run a an NRAO user like vlapipe or nobody?
  • Do we want local jobs to run as the local user, some dedicated user, or nobody?Remote HTCondor concerns
• Need to support 50% workload for NRAP and 50% workload for local.  How?
  • Could have 15 nodes for us and 15 nodes for them
  • What if we do nothing?  HTCondor's fair-share algorithm may do the work for us if all our jobs are run as user vlapipe or something like that.
  • Use RANK, and therefore preemption.  https://htcondor-wiki.cs.wisc.edu/index.cgi/wiki?p=HowToConfigPrioritiesForUsers
  • Group Accounting
  • User Priority https://htcondor-wiki.cs.wisc.edu/index.cgi/wiki?p=HowToSetUserPriority
• Share disk space on head node 50% NRAO and 50% local
  • Two partitions: one for NRAO and one for local?

Documentation

• A projectbook like we did for USNO could be appropriate
• Process diagrams (how systems boot, how jobs get started from NRAO and run, how locals start jobs, etc)

Other

• Keep each rack as similar to the other racks as possible.
• Test system at NRAO should be one of everything.

Since we are making our own little OSG, should we try to leverage OSG for this or not?  Or do we want to make each POD a pool and flock?

Should we try to buy as much as we can from one vendor like Dell to simplify things?

APC sells a packaged rack on a pallet ready for shipping.  We could fill this with gear and ship it.  Not sure if that is a good idea or not.

Site Questions

• Door width and height and path to server room.
  • Can a rack-on-pallet fit?  Height: 85.79inches (2179mm) Width: 43.5inches (1105mm)
  • Can it fit upright on casters?  Height: 78.39inches (1991mm) Width: 23.62inches (600mm)
  • NRAO-NM wide server door Height: 84inches (2133mm) Width: 48inches (1219mm)
• Voltage in server room (120V or 208V or 240V)
• Receptacles in server room (L5-30R or L21-30R or ...)
• Single or dual power feeds
• Firewalls

Resources

• USNO correlator (Mark Wainright)
• VLBA Control Computers (William Colburn)
• Red Hat maintenance (William Colburn)
• Virtual kickstart (William Colburn)
• HTCondor best practices (Greg Thain)
• OSG (Lauren Michael)