Daniel Hilst
c62434d22d
Both places that fork the install monitor repeat the same careful sequence: record the
attempt, block SIGCHLD, fork, unblock, and on failure record the exit so the next attempt
backs off. Two of those steps are ordering requirements rather than steps -- the attempt
must be recorded before the fork, because the child can die and be reaped before fork()
returns, and SIGCHLD must be blocked across the fork and the assignment, or the reaper
compares the dead child against a stale pid and misses it. Neither is apparent from
reading the code, and both were got wrong at least once while writing it. Leaving them
open-coded means the next caller -- $pid_UDP has the same never-respawned shape -- gets to
rediscover them.
Move the sequence into xCAT::RespawnUtils::supervise(), which takes the child body as a
block and the rest as named arguments:
($mon_respawn, $pid_MON) = supervise {
...the child...
} state => $mon_respawn, pid => $pid_MON, now => time();
The (&@) prototype is what allows the leading block, and it applies to a fully qualified
call, so no Exporter machinery is needed. It does require the module to be loaded with
`use` rather than `require`: under `require` the sub is unknown when the call is compiled,
the block is then read as a bare block and its value arrives as the first argument, which
fails at runtime rather than at compile time. Both call sites and the test use `use`, and
the constraint is written down next to the sub. Passing a live pid is a no-op, so a caller
that forgets to check does not end up with two children.
The module gains its first impure function, which is why it sits under its own heading with
the pure ones stated to be pure above it: those return new state and touch nothing, which is
what keeps them testable on a made-up clock and safe inside a signal handler. supervise()
forks, so it is tested by the fork-and-port case instead, which now drives it rather than
its own copy of the same sequence. POSIX and xCAT::Utils are required inside supervise()
rather than at the top, so loading the module for the pure functions still pulls in nothing.
xcatd loses $mon_chldmask and its :signal_h import along with the duplication.
Verified on a live MN: the startup fork goes through supervise() and produces a monitor
holding xcatiport, and two consecutive kills are recovered in 5s then 10s -- the backoff --
with the port reclaimed and the SSL listener holding its pid throughout.
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
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xCAT is made available under the EPL license: https://opensource.org/licenses/eclipse-1.0.php
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