Hi Simon, On Tue, Jun 24, 2014 at 09:15:13AM +0900, Simon Horman wrote: > Hi Willy, > > Malcolm has asked me to open a discussion with you regarding adding > email alerts to haproxy and that is the purpose of this email. > > In essence the motivation is to provide a lightweight email alert > feature that may be used in situations where a full-blown monitoring > system is not in use. > > There is some discussion of this topic and several solutions, > including patches to haproxy, on the loadbalancer.org log. > > http://blog.loadbalancer.org/3-ways-to-send-haproxy-health-check-email-alerts/ > > Would you be open to including such a feature in haproxy? > > If so I had it in mind to have haproxy send emails using the sendmail command, > a variation of the mailx implementation at the link above, avoiding the > need to implement an SMTP client. > > I was thinking it could be configured using directives like the following, > borrowing ideas from my recent external-agent patch. > > global > email-alert > > listen ... > > option email-alert > email-alert command sendmail > email-alert path /usr/sbin:/usr/lib > email-alert from [email protected] > email-alert to [email protected] > email-alert cc [email protected], [email protected] > email-alert bcc [email protected] > email-alert subject Loadbalancer alert > email-alert custom-header X-Custom: foo > > It might be nice to allow the use of printf style directives in > the subject to allow it to include the name of the proxy and other > useful information. I expect that different users have different needs > there.
We had such an idea in the past, however the principle was to use the address of a smart relay host. We cannot use a command because the process is supposed to be chrooted. Also, in my opinion the SMTP relay should be per section (ie: supported in the defaults section) because in shared environments, customers want to use a different gateway and e-mail settings. In fact in the ALOHA we have implemented a daemon which watches the unix socket to send e-mails because by then it was too much work to implement it natively. Now it should be much simpler. I was just wondering whether we should not go slightly further and support "mailer" sections just like we have peers. I'd like to do the same for DNS resolving later and I think it makes the configs more understandable, and more flexible (eg: later we can think about having multiple mail relays). We also want to have the ability to define what events can result in an e-mail alert. For example, I know some hosting providers who absolutely want to know when a service is operational again (so that they can drive back home), while others absolutely refuse to be spammed with such info. Sections also make it possible to add extra settings for the mail relays, for example SSL + a certificate. Or maybe some default from/to/... Maybe we should bring this discussion to the mailing list so that other users can suggest some features we don't have in mind ? Thanks, Willy
