When address-allocation is off, 1.25.1 uses dhcp for containers. The code in apiserver/provisioner/provisioner.go has changed a great deal in 1.25.2 (specifically prepareOrGetContainerInterfaces) and now renders a manual interface.
Example of /e/n/i for a container with 1.25.1:
# loopback interface
auto lo
iface lo inet loopback
# interface "eth0"
auto eth0
iface eth0 inet dhcp
With 1.25.2:
# loopback interface
auto lo
iface lo inet loopback
# interface "eth0"
auto eth0
iface eth0 inet manual
pre-up ip address add 172.16.0.5/32 dev eth0 &> /dev/null || true
up ip route replace 172.16.0.1 dev eth0
up ip route replace default via 172.16.0.1
down ip route del default via 172.16.0.1 &> /dev/null || true
down ip route del 172.16.0.1 dev eth0 &> /dev/null || true
post-down ip address del 172.16.0.5/32 dev eth0 &> /dev/null || true
Our code for getting nameservers and DNS search from resolv.conf is only triggered when address allocation is on. This change probably needs reverting (why was it made?) or we need to use resolv.conf unconditionally for containers, not just when address allocation is on.
When address-allocation is off, 1.25.1 uses dhcp for containers. The code in apiserver/ provisioner/ provisioner. go has changed a great deal in 1.25.2 (specifically prepareOrGetCon tainerInterface s) and now renders a manual interface.
Example of /e/n/i for a container with 1.25.1:
# loopback interface
auto lo
iface lo inet loopback
# interface "eth0"
auto eth0
iface eth0 inet dhcp
With 1.25.2:
# loopback interface
auto lo
iface lo inet loopback
# interface "eth0"
auto eth0
iface eth0 inet manual
pre-up ip address add 172.16.0.5/32 dev eth0 &> /dev/null || true
up ip route replace 172.16.0.1 dev eth0
up ip route replace default via 172.16.0.1
down ip route del default via 172.16.0.1 &> /dev/null || true
down ip route del 172.16.0.1 dev eth0 &> /dev/null || true
post-down ip address del 172.16.0.5/32 dev eth0 &> /dev/null || true
Our code for getting nameservers and DNS search from resolv.conf is only triggered when address allocation is on. This change probably needs reverting (why was it made?) or we need to use resolv.conf unconditionally for containers, not just when address allocation is on.