how does carbonate interact with multiple caches ?

[rgevaert]

Hi,

I'm trying to figure out how carbonate works with multiple carbon caches running on the same host. It clearly has an impact when using e.g. carbon-lookup.

Am I correct one actually has to use the same DESTINATION in carbonate.conf as in carbon.conf?

E.g. with this in the config:

DESTINATIONS = graphite1.mynode.com:2104:1, graphite1.mynode.com:2204:2, graphite1.mynode.com:2304:3, graphite2.mynode.com:2104:1, graphite2.mynode.com:2204:2, graphite2.mynode.com:2304:3, graphite3.mynode.com:2104:1, graphite3.mynode.com:2204:2, graphite3.mynode.com:2304:3, graphite4.mynode.com:2104:1, graphite4.mynode.com:2204:2, graphite4.mynode.com:2304:3

On the other hand this doesn't seem to be right:

root@graphite1:~/scripts# carbon-hosts -c /etc/carbon/carbonate.conf 
graphite1.mynode.com
graphite1.mynode.com
graphite1.mynode.com
graphite2.mynode.com
graphite2.mynode.com
graphite2.mynode.com
graphite3.mynode.com
graphite3.mynode.com
graphite3.mynode.com
graphite4.mynode.com
graphite4.mynode.com
graphite4.mynode.com

[filippog]

from the README, ports are not taken into consideration so that seems expected

[jssjr]

The carbon-hosts tool will just list the hosts. However, the DESTINATIONS directive for your cluster should match what carbon itself uses. The hashing algorithm takes into account the host and instance name and ignores the port and carbonate does the same thing.

For example, given carbonate.conf:

[test]
DESTINATIONS = 192.168.251.40:2004:aggregator1, 192.168.254.40:2104:aggregator2, 192.168.254.40:2204:aggregator3, 192.168.254.40:2304:aggregator4, 192.168.254.40:2404:aggregator5
REPLICATION_FACTOR = 2

Then,

% bin/carbon-hosts -c conf/carbonate.conf -C test
192.168.251.40
192.168.254.40
192.168.254.40
192.168.254.40
192.168.254.40

and,

% bin/carbon-lookup -c conf/carbonate.conf -C test foo.bar
192.168.254.40:2404:aggregator5
192.168.254.40:2104:aggregator2

Make sense?