From 6301373c68990e8a92730de23a4da86b3442b4ef Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Petazzoni?= Date: Fri, 17 May 2013 10:20:30 -0700 Subject: [PATCH] Add some details about pre-3.8 kernels --- docs/sources/installation/kernel.rst | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/docs/sources/installation/kernel.rst b/docs/sources/installation/kernel.rst index 30ea192b1..2ec5940a7 100644 --- a/docs/sources/installation/kernel.rst +++ b/docs/sources/installation/kernel.rst @@ -54,6 +54,29 @@ want to check those articles on dotCloud's blog: and `about cgroups `_. +Important Note About Pre-3.8 Kernels +------------------------------------ + +As mentioned above, kernels before 3.8 are not stable when used with docker. +In some circumstances, you will experience kernel "oopses", or even crashes. +The symptoms include: + +- a container being killed in the middle of an operation (e.g. an ``apt-get`` + command doesn't complete); +- kernel messages including mentioning calls to ``mntput`` or + ``d_hash_and_lookup``; +- kernel crash causing the machine to freeze for a few minutes, or even + completely. + +While it is still possible to use older kernels for development, it is +really not advised to do so. + +Docker checks the kernel version when it starts, and emits a warning if it +detects something older than 3.8. + +See issue `#407 `_ for details. + + Extra Cgroup Controllers ------------------------