[MESOS-6052] Unable to launch containers on CNI networks on CoreOS

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.0
• Fix Version/s: 1.0.3, 1.1.0
• Component/s: containerization
• Labels: mesosphere

Environment

Linux

• Target Version/s: 1.0.3
• Epic Link: CNI Support
• Sprint: Mesosphere Sprint 41, Mesosphere Sprint 42
• Story Points: 1
• Assignee: Avinash Sridharan
• Reporter: Avinash Sridharan
• Shepherd: Jie Yu
• Created: 17/Aug/16 17:03
• Updated: 30/Jan/17 18:36
• Resolved: 07/Sep/16 23:09

Description

CoreOS does not have an `/etc/hosts`. Currently, in the `network/cni` isolator, if we don't see a `/etc/hosts` on the host filesystem we don't bind mount the containers `hosts` file to this target for the `command executor`. On distros such as CoreOS this fails the container launch since the `libprocess` initialization of the `command executor` fails cause it can't resolve its `hostname`.

We should be creating the `/etc/hosts` and `/etc/hostname` files when they are absent on the host filesystem since creating these files should not affect name resolution on the host network namespace, and it will allow the `/etc/hosts` file to be bind mounted correctly and allow name resolution in the containers network namespace as well.