Daniel Hilst
4bf66d7c0b
makedhcp wrote the interface list into /etc/default/isc-dhcp-server as
INTERFACES="..."
which is no longer always the variable the daemon is started with. The
systemd unit sources that file and expands exactly one variable onto dhcpd's
command line, and which one changed with the package:
14.04 4.2.4-7ubuntu12 sysvinit only $INTERFACES
16.04 4.3.3-5ubuntu12 unit $INTERFACES
18.04 4.3.5-3ubuntu7 unit $INTERFACES
20.04 4.4.1-2.1ubuntu5 unit $INTERFACES
22.04 4.4.1-2.3ubuntu2 unit $INTERFACESv4
24.04 4.4.3-P1-4ubuntu2 unit $INTERFACESv4
26.04 4.4.3-P1-4ubuntu2 unit $INTERFACESv4
with the matching v6 unit reading $INTERFACES before the change and
$INTERFACESv6 after it. Note the boundary is not an upstream ISC release:
20.04 and 22.04 both ship upstream 4.4.1 and are told apart only by the
Debian revision, so it has to be decided on the whole package version.
The sysvinit script does copy INTERFACES into INTERFACESv4 when the latter is
empty, but the unit is what starts the daemon on any of these releases and it
has no such bridge. So from 22.04 on, the unit ran
exec dhcpd -user dhcpd -group dhcpd -f -4 ... -cf $CONFIG_FILE $INTERFACESv4
against a variable xCAT never set. An unset variable expands to nothing, so
dhcpd was launched with no interface argument at all. It does not fail for
that: it binds every interface it can find and only warns about the ones with
no subnet declaration. site.dhcpinterfaces and servicenode.dhcpinterfaces
were therefore silently inert -- the provisioning NIC was served because
makedhcp had also emitted a subnet stanza for it, not because anything
honoured the setting, and any other interface on that subnet was served
alongside it.
The line match compounded it. m/^$dhcpd_key/ is not anchored on the
assignment, and INTERFACES is a prefix of both variables the package ships.
Since 18.04 the postinst seeds only INTERFACESv4="" and INTERFACESv6="" --
no INTERFACES line exists to match -- so the rewrite claimed those two lines
instead and overwrote both, discarding whatever debconf or the administrator
had put there and leaving a file with two INTERFACES assignments and nothing
either unit reads.
Pick the variables through a dispatcher keyed on the installed
isc-dhcp-server version, so both behaviours are served rather than one being
traded for the other, and anchor the match on the '=' so a key cannot claim a
line it is merely a prefix of. When the version cannot be established the
dispatcher writes every spelling, since an unset variable is the outcome that
leaves dhcpd bound to everything. Duplicate assignments left behind by the
old writer are collapsed to one, which repairs a file already damaged on an
upgraded management node.
The EL and SLES paths keep their single DHCPDARGS / DHCPD_INTERFACE /
DHCPD6_INTERFACE key and are unchanged.
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
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|---|---|
| Latest (master branch) | |
| Stable (latest release) |
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xCAT is made available under the EPL license: https://opensource.org/licenses/eclipse-1.0.php
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