ASAP 1.1 Hybrid Manual

HP NonStop ASAP Hybrid Manual – 529729-004
Page 3-21
If any of these conditions are not met, domains cannot be removed and/or
cleaned up, resulting in the presence of unused domains on the NonStop host,
on the Linux system, or both.
To address this issue, ASAP provides several mechanisms for removing and
cleaning up domains interactively: the host-based ASAP command interpreter,
use of Linux signals, and the Linux-based asapremove utility.
Removing Down Domains Using the ASAP CI
If an application stops or fails prior to removing a domain, and that application
will not be restarted or will not reregister that domain, the domain must be
removed interactively. The preferred mechanism for doing so is to use the ASAP
CI’s STATUS PROXY <$name> REMOVE command. This command allows ASAP
on the host to remove the domains in question and notifies ASAP Hybrid for
Linux to remove the domains as well, thereby keeping the host and Linux sides
synchronized. For more information on this command, see ASAP Hybrid
Commands.
Removing Down Domains Using Linux Signals
If the ASAP CI cannot be used to remove one or more down domains, a second
approach is to use Linux signals. Sending a Linux SIGUSR1 signal to the ASAP
Hybrid for Linux server causes it to remove all down domains on that Linux
system. For example:
kill –s SIGUSR1 <server PID>
where <server PID> is the process ID of the ASAP Hybrid for Linux server process.
The down domains are marked as removed, and notifications of the removals are
sent to the host. Once the host acknowledges the removals, the Linux server
cleans up the removed domains.
Like the CI, this mechanism ensures that the Linux and NonStop sides remain in
sync. However, if the communication link to the NonStop system is down, or
ASAP is not running on that system, the removals remain pending on the Linux
system until communication is restored or ASAP is restarted.