Re: [pve-devel] [PATCH ha-manager 2/3] watchdog: warn when about to expire

[Aaron Lauterer <a.lauterer@proxmox.com>]

On  2025-05-19  15:09, Maximiliano Sandoval wrote:
> Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
> ---
>   src/watchdog-mux.c | 26 ++++++++++++++++++++++++++
>   1 file changed, 26 insertions(+)
> 
> diff --git a/src/watchdog-mux.c b/src/watchdog-mux.c
> index a9017b3..e14c768 100644
> --- a/src/watchdog-mux.c
> +++ b/src/watchdog-mux.c
> @@ -29,15 +29,24 @@
>   
>   #define JOURNALCTL_BIN "/bin/journalctl"
>   
> +#define CLIENT_WATCHDOG_TIMEOUT_WARNING 50

some comment why 50 is used would be useful. Or alternatively it maybe 
could be defined differently a bit further below, using the 
client_watchdog_timeout as reference:

client_watchdog_timeout_warning = client_watchdog_timeout - 10;

This way would be clearer then that we want to react to the last 10 
seconds before we have the timeout. But that is just some idea.

> +
>   int watchdog_fd = -1;
>   int watchdog_timeout = 10;
>   int client_watchdog_timeout = 60;
>   int update_watchdog = 1;
>   
> +enum warning_state_t {
> +   NONE,
> +   WARNING_ISSUED,
> +   CRISIS_AVERTED,

I don't like the "CRISIS" vocabulary here. Why not call it 
"FENCE_AVERTED" or "HOST_FENCE_AVERTED" ?
It sounds less sensational and refers to what is averted

> +};
> +
>   typedef struct {
>       int fd;
>       time_t time;
>       int magic_close;
> +    enum warning_state_t warning_state;
>   } wd_client_t;
>   
>   #define MAX_CLIENTS 100
> @@ -54,6 +63,7 @@ alloc_client(int fd, time_t time)
>               client_list[i].fd = fd;
>               client_list[i].time = time;
>               client_list[i].magic_close = 0;
> +            client_list[i].warning_state = NONE;
>               return &client_list[i];
>           }
>       }
> @@ -244,6 +254,22 @@ main(void)
>                   time_t ctime = time(NULL);
>                   for (i = 0; i < MAX_CLIENTS; i++) {
>                       if (client_list[i].fd != 0 && client_list[i].time != 0) {
> +                        if (
> +                            client_list[i].warning_state == WARNING_ISSUED
> +                            && (ctime - client_list[i].time) <= CLIENT_WATCHDOG_TIMEOUT_WARNING
> +                        ) {
> +                            client_list[i].warning_state = CRISIS_AVERTED;
> +                            fprintf(stderr, "phew, client watchdog was updated before expiring\n");
> +                        }
> +
> +                        if (
> +                            client_list[i].warning_state != WARNING_ISSUED
> +                            && (ctime - client_list[i].time) > CLIENT_WATCHDOG_TIMEOUT_WARNING
> +                        ) {
> +                            client_list[i].warning_state = WARNING_ISSUED;
> +                            fprintf(stderr, "client watchdog is about to expire\n");
> +                        }
> +
>                           if ((ctime - client_list[i].time) > client_watchdog_timeout) {
>                               update_watchdog = 0;
>                               fprintf(stderr, "client watchdog expired - disable watchdog updates\n");



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