Whether or not /e/n/i supports something correctly or just happens to work by sheer luck has no bearing on what is technically correct and sensical -- let's abstract this, what we need to concern ourselves with here is netplan, cloud-init and maas.
In the network world, it is absolutely true that DNS nameservers only make sense on a per-interface basis: nothing guarantees that a "globally-set" nameserver of 8.8.8.8 is reachable through all interfaces. It just happens to be that way on 99% of systems because they only connect to one network, through one interface. So, in light of the nameserver setting in MaaS under Settings being unspecified, there's /no other way/ but to either set the nameserver globally or try to guess the right interface (either by which is connected to MaaS, or which gets the default gateway, or which matches subnets). None of the detection options I could come up with strike me as particularly solid and foolproof. Next steps for netplan strike me as being to add support for global nameservers even if it's silly; we shouldn't expect users to have to have the level of knowledge of networking to know to set it up on a particular interface when it will work correctly as "global" for 99% of cases. In MaaS, my opinion is that every effort should be taken to allow network administrators to set things up correctly -- nothing guarantees that the systems deployed will remain accessible to MaaS, or that it will be their main interface to the network. Only allowing global DNS is brittle at best, and breaks at least what *I* have been taught were best practices, to have a separate "public" network from the authenticated "private" side where monitoring and/or deployment happens. Maybe I'm just the one who's particular in doing this. I'm not sure what next steps are for cloud-init -- given a valid configuration, I assumed it should just pass it through to netplan if it's v2. I'll take care of the "global DNS" implementation in netplan. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1750884 Title: [2.4, bionic] /etc/resolv.conf not configured correctly in Bionic, leads to no DNS resolution Status in cloud-init: New Status in MAAS: Triaged Status in nplan package in Ubuntu: New Status in systemd package in Ubuntu: New Bug description: When deploying Bionic, /etc/resolv.conf is not configured correctly, which leads to no DNS resolution. In the output below, you will see that netplan config is correctly to the 10.90.90.1 nameserver, but in resolv.conf that's a local address. Resolv.conf should really be configured to use the provided DNS server(s). That said, despite that fact, DNS resolution doesn't work with the local address. Bionic ------ ubuntu@node01:~$ cat /etc/netplan/50-cloud-init.yaml # This file is generated from information provided by # the datasource. Changes to it will not persist across an instance. # To disable cloud-init's network configuration capabilities, write a file # /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following: # network: {config: disabled} network: version: 2 ethernets: enp0s25: match: macaddress: b8:ae:ed:7d:17:d2 mtu: 1500 nameservers: addresses: - 10.90.90.1 search: - maaslab - maas set-name: enp0s25 bridges: br0: addresses: - 10.90.90.3/24 gateway4: 10.90.90.1 interfaces: - enp0s25 parameters: forward-delay: 15 stp: false ubuntu@node01:~$ cat /etc/resolv.conf # This file is managed by man:systemd-resolved(8). Do not edit. # # 127.0.0.53 is the systemd-resolved stub resolver. # run "systemd-resolve --status" to see details about the actual nameservers. nameserver 127.0.0.53 search maaslab maas ubuntu@node01:~$ ping google.com ping: google.com: Temporary failure in name resolution [...] ubuntu@node01:~$ sudo vim /etc/resolv.conf ubuntu@node01:~$ cat /etc/resolv.conf # This file is managed by man:systemd-resolved(8). Do not edit. # # 127.0.0.53 is the systemd-resolved stub resolver. # run "systemd-resolve --status" to see details about the actual nameservers. nameserver 10.90.90.1 search maaslab maas ubuntu@node01:~$ ping google.com PING google.com (172.217.0.174) 56(84) bytes of data. 64 bytes from mia09s16-in-f14.1e100.net (172.217.0.174): icmp_seq=1 ttl=52 time=4.46 ms 64 bytes from mia09s16-in-f14.1e100.net (172.217.0.174): icmp_seq=2 ttl=52 time=4.38 ms ============================= Xenial ============================== ubuntu@node05:~$ cat /etc/network/interfaces.d/50-cloud-init.cfg # This file is generated from information provided by # the datasource. Changes to it will not persist across an instance. # To disable cloud-init's network configuration capabilities, write a file # /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following: # network: {config: disabled} auto lo iface lo inet loopback dns-nameservers 10.90.90.1 dns-search maaslab maas auto enp0s25 iface enp0s25 inet static address 10.90.90.162/24 gateway 10.90.90.1 mtu 1500 ubuntu@node05:~$ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 10.90.90.1 search maaslab maas To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-init/+bug/1750884/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
