Re: File Locking to prevent "race condition" question

Hi

On Wed, 20 Mar 2024 12:56:33 -0700 Samuel Sieb wrote:
> On 3/20/24 12:36, Sbob wrote:
> > Question: will flock() properly lock a file in a way that incoming 
> > commands over ssh from multiple other servers will respect the lock?
> Yes, the command is still running on the same system.  It doesn't matter 
> where the connection comes from.

Right, but you can also define the failover as a systemd service. systemd will
do the locking itself since "systemctl start X" is a noop if X is started.

In addition, you get the control with systemctl and the log in the journal.

For example:

---------- X.service ----------

[Unit]
Description=%n

[Service]
Type=oneshot
SyslogIdentifier=%N
RemainAfterExit=yes

ExecStart=command doing the failover

---------- X.service ----------