Dynamic HA-Proxy and DNS update based on rancher metadata

This image starts confd that periodically polls the rancher metadata service so it autoconfigures a default load balancer and also updates records in a dns directory based on labels on other stacks.

The idea is forked from https://github.com/Mikroways/rancher-haproxy

How it works

• Create your custom stack as usual
• Configure your containers as mentioned in https://github.com/Mikroways/rancher-haproxy
• Add an environment variable called DNS_SERVER to the container instantiated from this image pointing to you DNS server (either an IP adress or the domain name may be specified here).

Some reading that helps troubleshooting of might be interesting for further development

• https://en.wikipedia.org/wiki/Nsupdate
• http://dns.measurement-factory.com/tools/dnstop/dnstop.8.html
• https://debian-administration.org/article/591/Using_the_dynamic_DNS_editor_nsupdate
• http://wiki.alpinelinux.org/wiki/Alpine_Linux_package_management