Daniel Hilst
008f83d2e4
xCAT's DHCP behaviour is tested from two directions today, neither of which
touches the wire: xCAT-test/unit/dhcp_*.t assert on generated config text, and
xCAT-test/integration/dhcp_{isc,kea}_config_validation.t feed that config to a
real daemon and check it parses. Both stop at "the server accepted our
config". Nothing verifies that a client sending option 93 = 0x000b actually
gets an aarch64 loader back.
The one existing wire tool, xCAT-probe/subcmds/detect_dhcpd, hand-packs a
fixed DISCOVER carrying no option 60, 77 or 93 (so it never reaches any arch
branch), parses replies by regexing tcpdump output, and binds an
IO::Socket::INET to a local address, so it cannot run on a provisioning NIC
that has no address yet.
dhcptest fills that gap. It is a Python 3 tool using only the standard library
plus Scapy, speaking raw Layer 2, driving DHCP transactions declared in INI
files and asserting on what came back:
dhcptest run -i eth1 --set net=10.0.0.0/24 conf/full-lease.conf
dhcptest validate conf/*.conf # no root, no network, no scapy
dhcptest list conf/*.conf
dhcptest discover -i eth1 # ad-hoc, no conf file
Scenarios cover DISCOVER/OFFER, the full lease, renew and rebind, reserved
versus pooled addresses, deliberate silence, the PXE architecture matrix and
the iPXE user-class split. Assertions are a small DSL -- target, operator,
value -- over message type, BOOTP header fields, options by number or name,
subnet membership, and the boot file a client would actually use (option 67
or the header, since servers differ on which they fill).
Two boundaries are enforced by unit test rather than by convention:
- The tool is implementation-agnostic. It exchanges packets and checks
fields; it never reads the xCAT database, never runs an xCAT command, and
names no DHCP implementation. Anything that differs between servers is
expressed by whoever writes the .conf.
- Only runner.py imports scapy, so validate and list stay usable in CI on a
host with neither scapy nor root.
Host networking is never modified. The client MAC defaults to a synthetic
locally-administered address, everything goes over a raw L2 socket, no leased
address is ever configured, and the ARP responder answers only for addresses
the session was actually granted.
Variables in .conf files are configparser's own BasicInterpolation, %(name)s,
fed from [vars] and --set. $offer.address and friends are resolved separately
at step-execution time, because they name a reply that has not arrived when
the file is read; BasicInterpolation gives $ no meaning, so the two coexist
without escaping.
Packaging and CI:
- xCAT-test.spec installs dhcptest alongside unit/ and integration/, and
only recommends python3-scapy: it lives in EPEL on EL, and a hard Requires
would make xCAT-test uninstallable on a management node without EPEL.
The deb depends on it outright.
- github_action_xcat_test.pl runs the unit tests and `dhcptest validate`
last, after the fast regression.
- autotest/testcase/dhcptest/cases0 carries the two offline cases plus a
wire case that stands down with an explanation when no provisioning NIC
is available.
Verified against a real DHCP server in a network namespace: 34 lease, renew,
rebind, reservation and silence assertions and 22 PXE/iPXE assertions all
pass, and host networking is untouched before and after.
Signed-off-by: Daniel Hilst <392820+dhilst@users.noreply.github.com>
xCAT
xCAT is a toolkit for deployment and administration of clusters of all sizes.
The xCAT sunset was only a quick eclipse
Dear xCAT Community,
The xCAT sunset has changed course. VersatusHPC has been invited to join the xCAT Consortium, and future development will move toward direct upstream contributions coordinated with the Consortium and its existing member companies.
That matters most for Enterprise Linux 10 (EL10). EL10 support is coming to xCAT, restoring a future operating-system path for sites that still rely on xCAT. This is an important change from the previous sunset guidance, where the lack of an EL10 path was one of the strongest reasons to move away from xCAT.
The xCAT Consortium continues to recommend Confluent as the long-term successor to xCAT, and that remains the Consortium position. Users planning new cluster-management deployments should evaluate Confluent and its xCAT comparison documentation.
At the same time, xCAT is no longer sunsetted. The Consortium and participating companies will continue updating xCAT while there is community and user demand for it.
In summary:
- xCAT development is continuing upstream through the Consortium and participating companies.
- Enterprise Linux 10 support is coming.
- Confluent remains the Consortium-recommended successor and migration path.
- xCAT updates will continue while there is community and user demand.
We want to thank the xCAT Consortium and community for keeping this project moving. The sun went behind the moon for a moment, but xCAT is still here.
For more information on Confluent and how to get started, please visit the Confluent: Project Page, Documentation or Confluent vs xCAT comparison.
With thanks,
The xCAT Consortium
Documentation
xCAT Documentation is hosted on Read The Docs: https://xcat-docs.readthedocs.io
Status
| xCAT Version | Build Status |
|---|---|
| Latest (master branch) | |
| Stable (latest release) |
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Open Source License
xCAT is made available under the EPL license: https://opensource.org/licenses/eclipse-1.0.php
Developers
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