[Beowulf] [EXTERNAL] Re: Have machine, will compute: ESXi or bare metal?

Lux, Jim (US 337K) james.p.lux at jpl.nasa.gov
Wed Feb 12 13:13:30 PST 2020

I've used zeroconf quite effectively on a couple clusters of beagleboards.  If you do it, then you can let the nodes use DHCP to get their IP addresses, which is handy if you're sharing a WiFi network, for instance. 

On the other hand, for a "training experience", having to go through the process of manually assigning IP addresses, and node identifiers (hostname) and keeping them all straight is a useful thing.  Having done that, you really appreciate zeroconf/bonjour and DHCP.

My two configurations are:
Head node is a Macbook running OS X
Configuration 1: Macbook using Wireless to connect to the "internet" and wired to connect to the cluster, which is 4 BeagleBoard Green with wired ethernet.
Configuration 2: Macbook using wireless to connect to the "internet" and wired to an 802.11b/g access point, then the cluster is 4 BeagleBoard Green Wireless.

In both cases, I wind up setting up a bridge from the cluster to the outside world via the macbook, so that I can run things like "apt get" on the nodes to install software.
I use a combination of screen, ssh, and pdsh to work with the nodes, and scp (with pdsh) to move files around.

Note that with beagles (and Rpis) you usually use a "network over USB" to get it up originally (the gadget interface)

´╗┐On 2/11/20, 7:57 PM, "Beowulf on behalf of Skylar Thompson" <beowulf-bounces at beowulf.org on behalf of skylar.thompson at gmail.com> wrote:

    On Tue, Feb 11, 2020 at 06:25:24AM +0800, Benson Muite wrote:
    > On Tue, Feb 11, 2020, at 9:31 AM, Skylar Thompson wrote:
    > > On Sun, Feb 09, 2020 at 10:46:05PM -0800, Chris Samuel wrote:
    > > > On 9/2/20 10:36 pm, Benson Muite wrote:
    > > > 
    > > > > Take a look at the bootable cluster CD here:
    > > > > http://www.littlefe.net/
    > > > 
    > > > From what I can see BCCD hasn't been updated for just over 5 years, and the
    > > > last email on their developer list was Feb 2018, so it's likely a little out
    > > > of date now.
    > > > 
    > > > http://bccd.net/downloads
    > > > 
    > > > http://bccd.net/pipermail/bccd-developers/
    > > > 
    > > > On the other hand their TRAC does list some ticket updates a few months ago,
    > > > so perhaps there are things going on but Skylar needs more hands?
    > > > 
    > > > https://cluster.earlham.edu/trac/bccd-ng/report/1?sort=created&asc=0&page=1
    > > 
    > > Wow, I had no idea people on the Beowulf list were still thinking of BCCD.
    > > :)
    > > 
    > > I've been working on a major BCCD update for a while now (modern Debian,
    > > better node auto-detection) but a combination of life interference and a
    > > shift in focus for the project to curriculum development has slowed me
    > > down.
    > > 
    > > At the end of the day, BCCD has three has three main goals:
    > > 
    > > 1. Non-destructive in its default mode
    > > 2. Simple ("just press enter")
    > > 3. Ready with pedagogically-useful ("validated, verified, and accredited")
    > > curriculum modules
    > > 
    > > One thing I'm hoping can come out of this major update is to decouple the BCCD
    > > from the underlying distribution, since that's been a barrier for some
    > > people in using BCCD. That's just an aspiration right now, but we'll see
    > > where it goes.
    > Can you give more details on how you expect to decouple it?
    There's a couple things that are tightly integrated with the init process
    * Network setup - prompts the user for information (which NIC to run on,
      whether to use DHCP to assign addresses, etc.), detects other BCCD
      systems on the network, etc.
    * SSH public key broadcast (pkbcast) - needs to run after a user logs in to
      ensure that authorized_keys is setup on other participating systems.
    The network setup in particular is a challenge in the systemd world, since
    getting STDIN from systemd-invoked processes is not trivial. We've also had
    some users wanting better integration between networking and desktop
    applications, which pushed me to try to make use of the existing
    systemd/networkd toolchain rather than rolling our own tooling.
    Right now the challenge is the node auto-detection, though I'm hoping that
    we might be able to use mDNS and zeroconf-assigned addressing rather than
    depending on custom DHCP tags which have been problematic in the past.
    zeroconf might also mitigate the biggest problem we have in workshops:
    someone jumping the gun and starting up a head node before we're ready to
    While I'm not the biggest fan of systemd, it does have the potential to
    allow us to get away from custom scripts and use functionality common
    across more than one distribution.
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