feat(linux): set/unset urunit environment variable for default route#284
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In the case of Linux guests, urunit by default used to set as the default route the eth0 interface. However, this was creating issues with docker and nerdctl, where the container could not reach the outside network. Nevertheless, this was required in k8s set ups, since the IP of the container could be in a different subnet than the gateway and the Linux kernel can not handle such network configuration. To fix the above, use a specific environment variable for urunit, called `URUNIT_DEFROUTE`, which urunc sets it only when the IP of the container is in a different subnet than the gateway. Otherwise urunc will not set it. From urunit's side, if the environment variable is set, then it will use the eth0 interface as the default route. PR: #284 Signed-off-by: Charalampos Mainas <cmainas@nubificus.co.uk> Reviewed-by: Anastassios Nanos <ananos@nubificus.co.uk> Approved-by: Anastassios Nanos <ananos@nubificus.co.uk>
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In the case of Linux guests, urunit by default used to set as the default route the eth0 interface. However, this was creating issues with docker and nerdctl, where the container could not reach the outside network. Nevertheless, this was required in k8s set ups, since the IP of the container could be in a different subnet than the gateway and the Linux kernel can not handle such network configuration. To fix the above, use a specific environment variable for urunit, called `URUNIT_DEFROUTE`, which urunc sets it only when the IP of the container is in a different subnet than the gateway. Otherwise urunc will not set it. From urunit's side, if the environment variable is set, then it will use the eth0 interface as the default route. PR: urunc-dev#284 Signed-off-by: Charalampos Mainas <cmainas@nubificus.co.uk> Reviewed-by: Anastassios Nanos <ananos@nubificus.co.uk> Approved-by: Anastassios Nanos <ananos@nubificus.co.uk>
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In the case of Linux guests, urunit by default used to set as the default route the eth0 interface. However, this was creating issues with docker and nerdctl, where the container could not reach the outside network. Nevertheless, this was required in k8s set ups, since the IP of the container could be in a different subnet than the gateway and the Linux kernel can not handle such network configuration. To fix the above, use a specific environment variable for urunit, called `URUNIT_DEFROUTE`, which urunc sets it only when the IP of the container is in a different subnet than the gateway. Otherwise urunc will not set it. From urunit's side, if the environment variable is set, then it will use the eth0 interface as the default route. PR: urunc-dev#284 Signed-off-by: Charalampos Mainas <cmainas@nubificus.co.uk> Reviewed-by: Anastassios Nanos <ananos@nubificus.co.uk> Approved-by: Anastassios Nanos <ananos@nubificus.co.uk>
This was referenced Jun 8, 2026
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In the case of Linux guests, urunit by default used to set as the default route the eth0 interface. However, this was creating issues with docker and nerdctl, where the container could not reach the outside network. Nevertheless, this was required in k8s set ups, since the IP of the container could be in a different subnet than the gateway and the Linux kernel can not handle such network configuration.
To fix the above, use a specific environment variable for urunit, called
URUNIT_DEFROUTE, which urunc sets it only when the IP of the container is in a different subnet than the gateway. Otherwise urunc will not set it. From urunit's side, if the environment variable is set, then it will use the eth0 interface as the default route.