Kube-faq

# Local DNS on MacOS X for developers

Sometimes you have the need of local DNS names. Typical this is in local development of VM's or kubernetes services.

The common method we are all using is to make entries in `/etc/hosts`.

I don't like this for a couple of reasons:

- it's easy to blow up the file and get problems after your next reboot

- this file is `root` only, though you have to edit it with sudo :-(

There should be a better way!

## Solution 

- Mac OS X resolver is capable to use multiple DNS servers very easily.

- There's a very lightweight and easy to configure DNS server: [dnsmasq](https://thekelleys.org.uk/dnsmasq/doc.html)

## Implementation

1. Install dnsmasq with [homebrew](https://brew.sh): `brew install dnsmasq`

1. configure it:

     ```shell

     cp /opt/homebrew/etc/dnsmasq.conf  /opt/homebrew/etc/dnsmasq.conf.orig

     echo "conf-dir=/opt/homebrew/etc/dnsmasq.d/,*.conf" | tee /opt/homebrew/etc/dnsmasq.conf

     ```

1. generate at least one DNS file in `/opt/homebrew/etc/dnsmasq.d/`:

     local.conf:

     ```conf

     # 192.168.50 is my local WLAN

     # for Parlament VM's (macbook air)

     address=/testvm1.local/192.168.50.47

     address=/testvm2.local/192.168.50.152

     address=/testvm3.local/192.168.50.32

     # testvm has 3 addresses

     address=/testvm.local/192.168.50.47

     address=/testvm.local/192.168.50.152

     address=/testvm.local/192.168.50.32

     # 192.168.205 is UTM.app local

     # local machines here

     address=/alma-arm-vm.local/192.168.205.7

     address=/alma-intel-vm.local/192.168.205.8

     # 192.168.254 is VMWare Fusion local

     address=/almavm.local/192.168.254.129

     ```

     pflaeging.net.conf:

     ```conf

     # 192.168.254 is VMWare Fusion local

     address=/gubernat1.pflaeging.net/192.168.254.130

     address=/ms1.pflaeging.net/192.168.254.131

     # this is a wildcard

     address=/.gubernat1.pflaeging.net/192.168.254.130

     # 192.168.50 is my local WLAN

     # gubernat VM's on MacBook Air

     address=/rhel9-gubernat.pflaeging.net/192.168.50.173

     # this is a wildcard

     address=/.rg.pflaeging.net/192.168.50.173

     ```

1. start your dnsmasq service: `sudo brew services start dnsmasq``

1. make Mac OS ready for a custom resolver: `sudo mkdir -p /etc/resolver`

1. set a pointer to your new resolvers and make them in high priority:

     contents of `/etc/resolver/local` (filename equals domain!):

     ```conf

     nameserver 127.0.0.1

     search_order 1

     ````

     Then create a file for each domain you configured above with the same content.

     (in this use case it would be `/etc/resolver/pflaeging.net`)

1. to be sure everythings working kick the original resolver and clean the caches:

     ```shell

     sudo dscacheutil -flushcache

     sudo killall -HUP mDNSResponder

     ```

1. when I change or add things in my dnsmasq config I'm restarting the dnsmasq job. This is not required but the easiest way: `sudo pkill dnsmasq`

## Debugging

- Show resolver config: `scutil --dns`

- Query the DNS resolver from the commandline: ` dscacheutil -q host -a name myfunnyname.domain.net` 

- Query the local dnsmasq instance: `dig myfunnyname.domain.net @localhost`