I'm using dogpile.cache.memcached in a OpenStack/Keystone scope and noticed when we do configure a backend URL including multiple hosts, for example:
I do see quite a lot of failed DNS lookups for the invalid DNS name:
which I have captured with the pcap dump: 10:06:27.923726 IP keystone_container-db00cc3b.43267 > 10.0.3.1.domain: 61056+ A? 172.29.237.236,172.29.238.219,172.29.239.40. (61) 10:06:27.923803 IP 10.0.3.1.domain > keystone_container-db00cc3b.43267: 61056 NXDomain 0/0/0 (61)
Once I do configure real host names, resolvable by DNS, I do not see even attempts to resolve those names and the dogpile memcache backend is not functioning at all. At this point I can not tell if the problem is with dogpile or python-memcache. Personally I think the issue seems to be inside the memcache library since that one is actually making the sockets.
What do you think?