[pbs-devel] applied: [PATCH proxmox-backup v2] daemon: add hack for sd_notify

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

On 11.11.20 09:27, Dominik Csapak wrote:
> sd_notify is not synchronous, iow. it only waits until the message
> reaches the queue not until it is processed by systemd
> 
> when the process that sent such a message exits before systemd could
> process it, it cannot be associated to the correct pid
> 
> so in case of reloading, we send a message with 'MAINPID=<newpid>'
> to signal that it will change. if now the old process exits before
> systemd knows this, it will not accept the 'READY=1' message from the
> child, since it rejects the MAINPID change
> 
> since there is no (AFAICS) library interface to check the unit status,
> we use 'systemctl is-active <SERVICE_NAME>' to check the state until
> it is not 'reloading' anymore.
> 
> on newer systemd versions, there is 'sd_notify_barrier' which would
> allow us to wait for systemd to have all messages from the current
> pid to be processed before acknowledging to the child, but on buster
> the systemd version is to old...
> 
> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
> changes from v1:
> * only check the state in the parent pid, do not send ready
>   in the child in a loop
> * changed the comment to include "FIXME"
>  src/bin/proxmox-backup-api.rs   |  1 +
>  src/bin/proxmox-backup-proxy.rs |  1 +
>  src/tools/daemon.rs             | 26 ++++++++++++++++++++++++++
>  3 files changed, 28 insertions(+)
> 
>

applied, thanks! With the followups we spoke off-list.