DNS resolution whilst building containers fails quite often

[kierenevans]

dock-cli/src/Installer/DNS/Mac/DnsDock.php

Line 101 in 736ed18

$daemonArguments = '-H unix:///var/run/docker.sock --bip=172.17.42.1/16 --dns=172.17.42.1';

The above --dns flag leads to a lot of failures in DNS resolution when building or upping containers, for example @rocketage had the following error recently:

  [Composer\Downloader\TransportException]
  The "https://packages.firegento.com/packages.json" file could not be downloaded: php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution
  failed to open stream: php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution

and I have had very similar issues.

We could potentially rely on the virtualbox DNS resolver which will defer to the host's configuration.

Since removing the --dns flag locally, my DNS issues have stopped occurring.

[sroze]

That means that Docker would use the VM's DNS name resolver, that means that we won't be able to resolve .docker DNS names inside the containers. We should probably run a quick investigation about their usage but I know that I personally use them heavily in micro-services projects...

[kierenevans]

The dockerd --help documentation implies multiple DNS flags (or an array) are allowed:

  --dns=[]                                 DNS server to use
  --dns-opt=[]                             DNS options to use
  --dns-search=[]                          DNS search domains to use

The issue we have seen is dnsdock crashing when failing to look up addresses, so then subsequently non *.docker addresses also fail to be looked up.

A way around this would be to set up multiple DNS IPs, which I'll look into soon.

[sroze]

@kierenevans I'll looking forward your updated PR to use multiple DNSs 😛

[kierenevans]

All in good time, my friend :)

[sroze]

@kierenevans anything about that? 💃