Proposal: Dynamic external srv Records need to be add in dns

[dudi123456]

Related to #132

Reasoning: 1. we are using mesos cluster for internal cloud. There are many services outside of mesos cluster, for example: mysql database, oracle database, legacy system, legacy hadoop cluster. The app deployed in mesos want to use these external services. 2. K8s define services wonderfully and the mesos-dns may borrows some design.

[sargun]

I'm currently in the process of writing documentation for this. I'd love to get your feedback when I get to a presentable level. Currently, we're recommending that if people have external services, they publish them into a third party service discovery system. Then, they point Mesos-DNS at a bind resolver which delegates these external services to a third party SDS.

Longer-term we're looking at ways to make this happen via software, and potentially introduce new backends to Mesos-DNS.

[dudi123456]

Thanks for reply. In our env, users want to admin their services in one place. BTW, if we use your recommendation, which software should we use? SkyDNS, Haproxy+Bamboo? One more, in our env, we use flannel to make docker containers across hosts communicate. but in the mesos-dns, the srv show like this: [root@mesos-slave1 ~]# dig _tomcat12._tcp.marathon.mesosasiainfo SRV

; <<>> DiG 9.9.4-RedHat-9.9.4-18.el7_1.5 <<>> _tomcat12._tcp.marathon.mesosasiainfo SRV ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 8313 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 3

;; QUESTION SECTION: ;_tomcat12._tcp.marathon.mesosasiainfo. IN SRV

;; ANSWER SECTION: _tomcat12._tcp.marathon.mesosasiainfo. 60 IN SRV 0 0 31481 tomcat12-4mepj-s5.marathon.slave.mesosasiainfo. _tomcat12._tcp.marathon.mesosasiainfo. 60 IN SRV 0 0 31348 tomcat12-ep8qk-s2.marathon.slave.mesosasiainfo. _tomcat12._tcp.marathon.mesosasiainfo. 60 IN SRV 0 0 31663 tomcat12-x56fr-s4.marathon.slave.mesosasiainfo.

;; ADDITIONAL SECTION: tomcat12-4mepj-s5.marathon.slave.mesosasiainfo. 60 IN A 10.1.241.130 tomcat12-x56fr-s4.marathon.slave.mesosasiainfo. 60 IN A 10.1.241.129 tomcat12-ep8qk-s2.marathon.slave.mesosasiainfo. 60 IN A 10.1.241.127

;; Query time: 3 msec ;; SERVER: 10.1.241.124#53(10.1.241.124) ;; WHEN: Tue Nov 24 15:34:24 CST 2015 ;; MSG SIZE rcvd: 370

[root@mesos-slave1 ~]# dig tomcat12.marathon.mesosasiainfo

; <<>> DiG 9.9.4-RedHat-9.9.4-18.el7_1.5 <<>> tomcat12.marathon.mesosasiainfo ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52252 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION: ;tomcat12.marathon.mesosasiainfo. IN A

;; ANSWER SECTION: tomcat12.marathon.mesosasiainfo. 60 IN A 172.18.63.2 tomcat12.marathon.mesosasiainfo. 60 IN A 172.18.90.2 tomcat12.marathon.mesosasiainfo. 60 IN A 172.18.10.2

;; Query time: 1 msec ;; SERVER: 10.1.241.124#53(10.1.241.124) ;; WHEN: Tue Nov 24 15:35:04 CST 2015 ;; MSG SIZE rcvd: 97

how we should use mesos-dns? like : curl http://omcat12.marathon.mesosasiainfo or curl http://omcat12.marathon.mesosasiainfo:8080