Dns

The DNS configuration is a critical aspect of our setup. To enable name resolution in our virtualized environment, follow these steps:

1. Create the primary DNS configuration file for the dnsmasq server:

2. /opt/dnsmasq/dnsmasq.conf

   strict-order
   bind-dynamic
   #log-queries
   bogus-priv
   dhcp-authoritative
   
   # BM Network IPv6
   dhcp-range=ipv6,2620:52:0:1305::11,2620:52:0:1305::20,64
   dhcp-option=ipv6,option6:dns-server,2620:52:0:1305::1
   
   resolv-file=/opt/dnsmasq/upstream-resolv.conf
   except-interface=lo
   dhcp-lease-max=81
   log-dhcp
   no-hosts
   
   # DHCP Reservations
   dhcp-leasefile=/opt/dnsmasq/hosts.leases
   
   # Include all files in a directory depending on the suffix
   conf-dir=/opt/dnsmasq/include.d/*.ipv6
   

Create the upstream resolver to delegate the non-local environments queries

• /opt/dnsmasq/upstream-resolv.conf

  nameserver 8.8.8.8
  nameserver 8.8.4.4
  

Create the different component DNS configurations

• /opt/dnsmasq/include.d/hosted-nodeport.ipv6

  host-record=api-int.hosted-ipv6.hypershiftbm.lab,2620:52:0:1305::5
  host-record=api-int.hosted-ipv6.hypershiftbm.lab,2620:52:0:1305::6
  host-record=api-int.hosted-ipv6.hypershiftbm.lab,2620:52:0:1305::7
  host-record=api.hosted-ipv6.hypershiftbm.lab,2620:52:0:1305::5
  host-record=api.hosted-ipv6.hypershiftbm.lab,2620:52:0:1305::6
  host-record=api.hosted-ipv6.hypershiftbm.lab,2620:52:0:1305::7
  address=/apps.hosted-ipv6.hypershiftbm.lab/2620:52:0:1305::60
  dhcp-host=aa:aa:aa:aa:04:11,hosted-worker0,[2620:52:0:1305::11]
  dhcp-host=aa:aa:aa:aa:04:12,hosted-worker1,[2620:52:0:1305::12]
  dhcp-host=aa:aa:aa:aa:04:13,hosted-worker2,[2620:52:0:1305::13]
  

• /opt/dnsmasq/include.d/hub.ipv6

  host-record=api-int.hub-ipv6.hypershiftbm.lab,2620:52:0:1305::2
  host-record=api.hub-ipv6.hypershiftbm.lab,2620:52:0:1305::2
  address=/apps.hub-ipv6.hypershiftbm.lab/2620:52:0:1305::3
  dhcp-host=aa:aa:aa:aa:03:01,ocp-master-0,[2620:52:0:1305::5]
  dhcp-host=aa:aa:aa:aa:03:02,ocp-master-1,[2620:52:0:1305::6]
  dhcp-host=aa:aa:aa:aa:03:03,ocp-master-2,[2620:52:0:1305::7]
  dhcp-host=aa:aa:aa:aa:03:06,ocp-installer,[2620:52:0:1305::8]
  dhcp-host=aa:aa:aa:aa:03:07,ocp-bootstrap,[2620:52:0:1305::9]
  

• /opt/dnsmasq/include.d/infra.ipv6

  host-record=registry.hypershiftbm.lab,2620:52:0:1305::1
  

To proceed, we must create a systemd service for the management of the dnsmasq service and disable the system's default dnsmasq service:

• /etc/systemd/system/dnsmasq-virt.service

  [Unit]
  Description=DNS server for Openshift 4 Clusters.
  After=network.target
  
  [Service]
  User=root
  Group=root
  ExecStart=/usr/sbin/dnsmasq -k --conf-file=/opt/dnsmasq/dnsmasq.conf
  
  [Install]
  WantedBy=multi-user.target
  

The commands to do so:

systemctl daemon-reload
systemctl disable --now dnsmasq
systemctl enable --now dnsmasq-virt