Re: [PATCH cluster 1/5] add functions to determine warning level for high token timeouts

[Friedrich Weber <f.weber@proxmox.com>]

On 30/03/2026 16:46, Michael Köppl wrote:
> High token timeouts can lead to stability problems in clusters. To
> inform users about the timeout in their current setup (or expected
> timeouts when adding nodes) and give recommendations regarding the token
> coefficient setting, introduce function to calculate the timeout as well
> as determine the warning / recommendation levels.
> 
> Signed-off-by: Michael Köppl <m.koeppl@proxmox.com>
> ---
> The timeouts are chosen according to Friedrich's description in [0].
> 
> [0] https://bugzilla.proxmox.com/show_bug.cgi?id=7398
> 
>  src/PVE/Corosync.pm | 50 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/src/PVE/Corosync.pm b/src/PVE/Corosync.pm
> index aef0d31..41d4c6f 100644
> --- a/src/PVE/Corosync.pm
> +++ b/src/PVE/Corosync.pm
> @@ -534,4 +534,54 @@ sub resolve_hostname_like_corosync {
>      return $match_ip_and_version->($resolved_ip);
>  }
>  
> +sub calculate_total_timeout {
> +    my ($totemcfg, $node_count) = @_;
> +
> +    my $token_timeout = $totemcfg->{token} // 3000;
> +    my $token_coefficient = $totemcfg->{token_coefficient} // 650;
> +
> +    my $expected_token_timeout = $token_timeout;
> +    if ($node_count > 2) {
> +        $expected_token_timeout += ($node_count - 2) * $token_coefficient;
> +    }
> +
> +    my $expected_consensus_timeout = $totemcfg->{consensus} // $expected_token_timeout * 1.2;
> +    return ($expected_token_timeout + $expected_consensus_timeout) / 1000.0;
> +}
> +
> +sub get_timeout_warning_level {
> +    my ($total_timeout_secs) = @_;
> +
> +    if ($total_timeout_secs > 50) {
> +        return 'change-strongly-recommended';
> +    } elsif ($total_timeout_secs > 40) {
> +        return 'change-recommended';
> +    } elsif ($total_timeout_secs > 30) {
> +        return 'optimize';
> +    }
> +
> +    return undef;
> +}
> +
> +sub get_timeout_warning {
> +    my ($total_timeout_secs) = @_;
> +
> +    my $level = get_timeout_warning_level($total_timeout_secs);
> +    return undef if !defined($level);
> +
> +    my $level_msg;
> +    if ($level eq 'change-strongly-recommended') {
> +        $level_msg = "Changing the token coefficient is strongly recommended";
> +    } elsif ($level eq 'change-recommended') {
> +        $level_msg = "Changing the token coefficient is recommended";
> +    } elsif ($level eq 'optimize') {
> +        $level_msg = "Token coefficient can be optimized";
> +    }
> +
> +    return
> +        "Sum of Corosync token and consensus timeout is ${total_timeout_secs}s. "
> +        . "$level_msg. "
> +        . "See https://pve.proxmox.com/pve-docs/chapter-pvecm.html#_changing_the_token_coefficient for details.";
> +}

nit: I think a linebreak before the "See" would be nice.

I'm not sure what our policy is regarding docs links in the CLI. If we
don't want them, we could have something like "See the admin guide for
details" -- the "token coefficient" phrase should make the relevant
section easy to find.