In answer to #3, Kapacitor round robins through the list of URLs for each of its queries to InfluxDB. In which case it will not work well using a primary/secondary approach to subscriptions, as Kapacitor will end up subscribing to both InfluxDB hosts and then Kapacitor will be getting duplicate data. How are you getting data to both your primary and secondary InfluxDB hosts? If you are using the influxdb-relay then you should add Kapacitor as a backend to the relay as well and disable subscriptions entirely. In that case passing both the primary and secondary will work well as the query load will be split across the servers.
On Tuesday, November 22, 2016 at 10:01:39 AM UTC-7, Sean Beckett wrote: > > > > On Tue, Nov 22, 2016 at 9:20 AM, <[email protected] <javascript:>> wrote: > >> Influxdb Gurus! >> >> I have following questions regarding Kapacitor which will help me >> appropriately decide its implementation in my env: >> >> 1) In TICK stack setup where kapacitor subscribes to influxdb for getting >> data stream, how many kapacitors can subscribe to one influxdb server? >> > > Lots. It depends on the load on the InfluxDB instance, but subscriptions > are just simple passthroughs of the data, so there's very little load on > the InfluxDB server. Some customers have dozens of Kapacitor instances > subscribed, and I suspect hundreds would be feasible, provided the InfluxDB > server can handle that many open connections. > > >> >> 2) when kapacitor subscribes to influxdb, is it one time job for influxdb >> to register the requesting kapacitor and start streaming data to it or does >> it have to actively manage kapacitor end point affecting its performance in >> some way? >> > > one time job, essentially. The load is just in maintaining the network > connection. If you use UDP it will be a negligible load. > > >> >> 3) If i give names of primary and secondary influxdb servers in >> kapacitor.conf file: >> [[influxdb]] >> # Connect to an InfluxDB cluster >> # Kapacitor can subscribe, query and write to this cluster. >> # Using InfluxDB is not required and can be disabled. >> enabled = true >> default = true >> name = "localhost" >> urls = ["http://primaryinfluxdb:8086","http://secondaryinfluxdb:8086";] >> >> then will kapacitor get data stream from both primary and secondary at >> the same time or will it try the second only if first one fails? >> > > Not sure, I'll ask. > > >> >> 4) Where is this streamed data stored in kapacitor (RAM ?). What happens >> to data in memory when kapacitor is restarted? Is it flushed to disk? If i >> have a tick script that alerts on mean value of last 24hr cpu usage, if >> data is in memory then how will kapacitor calculate mean if it gets >> restarted? >> > > Stream data is stored in RAM, and does not persist through a restart. > Using a 24 hour stream alert is probably not a good idea, since it will > take 24 hours for it to begin functioning after a restart. > > >> >> -- >> Remember to include the version number! >> --- >> You received this message because you are subscribed to the Google Groups >> "InfluxData" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to [email protected] >> <javascript:>. >> Visit this group at https://groups.google.com/group/influxdb. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/influxdb/30789f3d-354e-4e6f-8635-1e69c49e5c6f%40googlegroups.com >> . >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Sean Beckett > Director of Support and Professional Services > InfluxDB > -- Remember to include the version number! --- You received this message because you are subscribed to the Google Groups "InfluxData" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/influxdb. To view this discussion on the web visit https://groups.google.com/d/msgid/influxdb/da93dcc0-0e22-4632-988d-72d8acc6b5b8%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
