DNS Resolution

DNS Names for your containers

Within the labels section of the docker-compose file you can specify labels that will control the DNS name of your containers. DNS names are in the format of [name].[image].vm (e.g web.outrigger.vm)

  • com.dnsdock.name - This is the type of container. Usually something like web, db, cache, etc.

  • com.dnsdock.image - This is generally your project name (e.g outrigger, drupal, etc.)

Note

All DNS names of Outrigger containers will end in .vm

If you need multiple domains mapped to a container you can use the com.dnsdock.alias setting. It takes a full domain name and can take a comma separated list (e.g. otherhost.outrigger.vm or alexandria.phase2.vm). Additionally, dnsdock supports longer domain queries meaning if you have a service named web.outrigger.vm, you can also use something.web.outrigger.vm and it will resolve to the same IP address.

For all other DNS configuration options, please see the dnsdock label documentation

DNS Forwarders

Outrigger can be configured to use additional name servers to forward DNS requests if the record cannot be resolved by dnsdock.

An example is if you connect to a VPN and need to resolve addresses to private servers within a VPN. To enable this you need to configure the RIG_NAMESERVERS environment variable to a comma separated list of ip:port (example: 10.10.7.2:53,8.8.8.8:53) before running either rig start or rig dns. We suggest putting this env var configuration in your ~/.bashrc or ~/.zshrc so that it is always present when needed. If you just need this temporarily, you can pass the configuration in with the --nameservers command line option to rig start or rig dns.

This configuration will try each forwarder name server, in order, to resolve names until success or all name servers have been exhausted.

DNS Command

There is also a rig dns command that will launch and configure our DNS services on any Docker Host. If you want to configure DNS on a Docker Host other than dev be sure to specify the --name parameter on rig.

DNS Debugging

If you want to see what containers have registered names, use the rig dns-records command. This command will list all registered container names and aliases along with the container's IP address.