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@@ -1,151 +0,0 @@
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-:title: Kernel Requirements
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-:description: Kernel supports
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-:keywords: kernel requirements, kernel support, docker, installation, cgroups, namespaces
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-
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-.. _kernel:
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-
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-Kernel Requirements
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-===================
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-
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-In short, Docker has the following kernel requirements:
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-
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-- Linux version 3.8 or above.
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-
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-- Cgroups and namespaces must be enabled.
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-
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-*Note: as of 0.7 docker no longer requires aufs. AUFS support is still available as an optional driver.*
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-
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-The officially supported kernel is the one recommended by the
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-:ref:`ubuntu_linux` installation path. It is the one that most developers
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-will use, and the one that receives the most attention from the core
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-contributors. If you decide to go with a different kernel and hit a bug,
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-please try to reproduce it with the official kernels first.
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-
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-If you cannot or do not want to use the "official" kernels,
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-here is some technical background about the features (both optional and
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-mandatory) that docker needs to run successfully.
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-
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-
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-Linux version 3.8 or above
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---------------------------
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-
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-Kernel versions 3.2 to 3.5 are not stable when used with docker.
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-In some circumstances, you will experience kernel "oopses", or even crashes.
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-The symptoms include:
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-
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-- a container being killed in the middle of an operation (e.g. an ``apt-get``
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- command doesn't complete);
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-- kernel messages including mentioning calls to ``mntput`` or
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- ``d_hash_and_lookup``;
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-- kernel crash causing the machine to freeze for a few minutes, or even
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- completely.
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-
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-Additionally, kernels prior 3.4 did not implement ``reboot_pid_ns``,
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-which means that the ``reboot()`` syscall could reboot the host machine,
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-instead of terminating the container. To work around that problem,
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-LXC userland tools (since version 0.8) automatically drop the ``SYS_BOOT``
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-capability when necessary. Still, if you run a pre-3.4 kernel with pre-0.8
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-LXC tools, be aware that containers can reboot the whole host! This is
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-not something that Docker wants to address in the short term, since you
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-shouldn't use kernels prior 3.8 with Docker anyway.
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-
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-While it is still possible to use older kernels for development, it is
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-really not advised to do so.
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-
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-Docker checks the kernel version when it starts, and emits a warning if it
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-detects something older than 3.8.
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-
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-See issue `#407 <https://github.com/dotcloud/docker/issues/407>`_ for details.
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-
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-
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-Cgroups and namespaces
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-----------------------
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-
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-You need to enable namespaces and cgroups, to the extent of what is needed
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-to run LXC containers. Technically, while namespaces have been introduced
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-in the early 2.6 kernels, we do not advise to try any kernel before 2.6.32
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-to run LXC containers. Note that 2.6.32 has some documented issues regarding
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-network namespace setup and teardown; those issues are not a risk if you
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-run containers in a private environment, but can lead to denial-of-service
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-attacks if you want to run untrusted code in your containers. For more details,
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-see `LP#720095 <https://bugs.launchpad.net/ubuntu/+source/linux/+bug/720095>`_.
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-
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-Kernels 2.6.38, and every version since 3.2, have been deployed successfully
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-to run containerized production workloads. Feature-wise, there is no huge
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-improvement between 2.6.38 and up to 3.6 (as far as docker is concerned!).
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-
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-
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-
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-
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-Extra Cgroup Controllers
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-------------------------
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-
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-Most control groups can be enabled or disabled individually. For instance,
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-you can decide that you do not want to compile support for the CPU or memory
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-controller. In some cases, the feature can be enabled or disabled at boot
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-time. It is worth mentioning that some distributions (like Debian) disable
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-"expensive" features, like the memory controller, because they can have
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-a significant performance impact.
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-
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-In the specific case of the memory cgroup, docker will detect if the cgroup
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-is available or not. If it's not, it will print a warning, and it won't
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-use the feature. If you want to enable that feature -- read on!
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-
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-
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-Memory and Swap Accounting on Debian/Ubuntu
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--------------------------------------------
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-
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-If you use Debian or Ubuntu kernels, and want to enable memory and swap
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-accounting, you must add the following command-line parameters to your kernel::
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-
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- cgroup_enable=memory swapaccount=1
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-
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-On Debian or Ubuntu systems, if you use the default GRUB bootloader, you can
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-add those parameters by editing ``/etc/default/grub`` and extending
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-``GRUB_CMDLINE_LINUX``. Look for the following line::
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-
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- GRUB_CMDLINE_LINUX=""
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-
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-And replace it by the following one::
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-
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- GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1"
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-
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-Then run ``update-grub``, and reboot.
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-
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-Details
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--------
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-
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-To automatically check some of the requirements below, you can run `lxc-checkconfig`.
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-
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-Networking:
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-
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-- CONFIG_BRIDGE
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-- CONFIG_NETFILTER_XT_MATCH_ADDRTYPE
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-- CONFIG_NF_NAT
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-- CONFIG_NF_NAT_IPV4
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-- CONFIG_NF_NAT_NEEDED
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-
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-LVM:
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-
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-- CONFIG_BLK_DEV_DM
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-- CONFIG_DM_THIN_PROVISIONING
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-- CONFIG_EXT4_FS
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-
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-Namespaces:
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-
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-- CONFIG_NAMESPACES
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-- CONFIG_UTS_NS
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-- CONFIG_IPC_NS
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-- CONFIG_PID_NS
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-- CONFIG_NET_NS
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-
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-Cgroups:
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-
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-- CONFIG_CGROUPS
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-
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-Cgroup controllers (optional but highly recommended):
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-
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-- CONFIG_CGROUP_CPUACCT
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-- CONFIG_BLK_CGROUP
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-- CONFIG_MEMCG
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-- CONFIG_MEMCG_SWAP
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Andy Rothfusz