ROS boot hang on kernels (maybe>=4.14.36)

[niusmallnan]

RancherOS Version: (ros os version)
v1.4.1-rc2
kernel 4.14.67

Where are you running RancherOS? (docker-machine, AWS, GCE, baremetal, etc.)
docker-machine + VirtualBox

It only appears on the first boot, this should be related to ros-bootstrap.

dmesg output:

[   28.271974] random: fast init done
[   28.504239] input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input4
[   28.642856] e1000 0000:00:03.0 eth0: (PCI:33MHz:32-bit) 08:00:27:c0:a2:3e
[   28.643546] e1000 0000:00:03.0 eth0: Intel(R) PRO/1000 Network Connection
[   29.043658] e1000 0000:00:08.0 eth1: (PCI:33MHz:32-bit) 08:00:27:99:89:e0
[   29.044367] e1000 0000:00:08.0 eth1: Intel(R) PRO/1000 Network Connection
[  134.643987] random: crng init done
[  134.644523] random: 4 urandom warning(s) missed due to ratelimiting
[  134.889131] EXT4-fs (sda): mounted filesystem with ordered data mode. Opts: (null)
[  134.968344] udevd[51]: starting version 3.2.5
[  134.971086] udevd[52]: starting eudev-3.2.5
[  136.375081] EXT4-fs (sda): mounted filesystem with ordered data mode. Opts: (null)

It seems that linuxkit also hit this problem.
linuxkit/linuxkit#3032

[rootwuj]

RancherOS Version 1.4.1-rc3 9/17
Verified fixed

[niusmallnan]

When I create a ros instance using docker-machine+vbox, ros-bootstrap will run mkfs to format the disk on the first boot. The mkfs relies on the generation of random numbers. A commit in kernel 4.14.36 will result in the inability to use random numbers in early boot, and mkfs will get stuck for a long time. It is caused by the empty entropy source.
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v4.14.36&id=6e513bc20ca63f594632eca4e1968791240b8f18

By adding a entropy daemon to fill the entropy pool can solve this issue, so I run rngd in ros-boostrap.

About why I didn’t run rngd always, there are two reasons:

1. In addition to affecting mkfs, no other effects were found. When the system is fully booted, mkfs has no problems even without rngd.
2. In the the later build of CoreOS and Ubuntu, I didn’t see the built-in rngd or havegd.

So my plan is to run only once in ros-bootstrap to ensure that there is no problem with mkfs in bootstrap.
And rngd is already built into os-base, but it won’t run as daemon, I will follow feedback from the community and other distributions.

[niusmallnan]

Backported to v1.4.1.

[espigle]

I am still experiencing this issue using the latest 1.4.1 version as available from here:

https://releases.rancher.com/os/latest/rancheros-vmware.iso