[MESOS-3806] 'mount --make-rslave /' does not work as expected on ubuntu 14.04

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.26.0
• Labels: mesosphere
• Assignee: Timothy Chen
• Reporter: Jie Yu
• Shepherd: Jie Yu
• Created: 26/Oct/15 21:11
• Updated: 26/Nov/18 12:21
• Resolved: 26/Nov/18 12:21

Description

The linux filesystem isolator rely on 'mount --make-rslve /' to make sure the mounts in the container (in a new mount namespace) does not propagate back to the host mount namespace.

However, this command does not work as expected on ubuntu 14.04. Here is a simple experiment:

$ cat /proc/self/mountinfo
42 22 8:1 /home/vagrant/tmp /home/vagrant/tmp rw,relatime shared:1 - ext4 /dev/disk/by-uuid/3af531bb-7c15-4e60-b23f-4853c47ccc91 rw,data=ordered
43 42 8:1 /home/vagrant/busybox /home/vagrant/tmp/mnt rw,relatime shared:2 - ext4 /dev/disk/by-uuid/3af531bb-7c15-4e60-b23f-4853c47ccc91 rw,data=ordered

$ sudo unshare -m /bin/bash
# cat /proc/self/mountinfo 
70 45 8:1 /home/vagrant/tmp /home/vagrant/tmp rw,relatime shared:1 - ext4 /dev/disk/by-uuid/3af531bb-7c15-4e60-b23f-4853c47ccc91 rw,data=ordered
71 70 8:1 /home/vagrant/busybox /home/vagrant/tmp/mnt rw,relatime shared:2 - ext4 /dev/disk/by-uuid/3af531bb-7c15-4e60-b23f-4853c47ccc91 rw,data=ordered

# mount --make-rslave /home/vagrant/tmp
# cat /proc/self/mountinfo
70 45 8:1 /home/vagrant/tmp /home/vagrant/tmp rw,relatime master:1 - ext4 /dev/disk/by-uuid/3af531bb-7c15-4e60-b23f-4853c47ccc91 rw,data=ordered
71 70 8:1 /home/vagrant/busybox /home/vagrant/tmp/mnt rw,relatime shared:2 - ext4 /dev/disk/by-uuid/3af531bb-7c15-4e60-b23f-4853c47ccc91 rw,data=ordered

If you repeat the above commands on CentOS, the command works as expected.