Editing Vzctl for upstream kernel

{{DISPLAYTITLE: vzctl for upstream kernel}}

'''This article describes using OpenVZ tool vzctl as an alternative to LXC tools.'''

Recent vzctl releases (starting from version 4.0) can be used with upstream (non-OpenVZ) Linux kernels (that essentially means any recent 3.x kernel). At the moment, it provides just basic functionality.
It is currently possible to create, start and stop a container with the same steps as one would use for a normal OpenVZ container. Other features may be present with limited functionality, while some are not present at all. We appreciate all bug reports, please file to [http://bugzilla.openvz.org/enter_bug.cgi?component=vzctl bugzilla].

Running vzctl on upstream kernels is considered an experimental feature. See [[#Limitations]] below.

== Installation ==

{{Note|This section describes installation for RPM-based distros. See [[#Building]] below if you want to compile vzctl from source.}}

First, set up OpenVZ yum repository. Download [[download:openvz.repo|openvz.repo]] file and put it to your <code>/etc/yum.repos.d/</code> repository,
and import OpenVZ GPG key used for signing RPM packages. This can be achieved by the following commands, as root:
<pre><nowiki>
wget -P /etc/yum.repos.d/ http://download.openvz.org/openvz.repo
rpm --import http://download.openvz.org/RPM-GPG-Key-OpenVZ
</nowiki></pre>
In case you can not cd to /etc/yum.repos.d, it means either yum is not installed on your system, or yum version is too old.

Then, install vzctl-core package:

 yum install vzctl-core

== Usage ==

For supported features, usage is expected to be the same as standard vzctl tool. See {{man|vzctl|8}} for more information.

=== Networking ===
{{Note|IP mode networking (--ipadd / --ipdel) is currently not supported}}

Networking is available through the switches <code>--netdev_add</code>, <code>--netif_add</code>, and their respective deletion counterparts.
Unfortunately now it requires some manual configuration.

== Bridged networking ==

The following example assumes
* you already have a bridge configured on the host system
* bridge interface name is virbr0
* CT is running Red Hat like distro (CentOS)

 vzctl set $CTID --netif_add eth0,,,,virbr0 --save

 echo "NETWORKING=yes" > /vz/private/$CTID/etc/sysconfig/network

 cat << EOF > /vz/private/$CTID/etc/sysconfig/network-scripts/ifcfg-eth0
 DEVICE=eth0
 BOOTPROTO=dhcp
 ONBOOT=yes
 EOF

 vzctl start $CTID

After this, you can find CT IP using this:
 # ip netns exec $CTID ip address list

== Limitations ==

{{Note|We recommend using [[Download/kernel/rhel6|OpenVZ kernel]] for features, stability and security}}

The following vzctl commands are not working at all with the non-OpenVZ kernel:

* <code>quotaon</code>/<code>quotaoff</code>/<code>quotainit</code> (vzquota-specific)
* <code>convert</code>, <code>compact</code>, <code>snapshot*</code> (ploop-specific)
* <code>console</code> (needs a virtual /dev/console, /dev/ttyN device)
* <code>chkpnt</code>, <code>restore</code> (currently need OpenVZ-kernel-specific checkpointing, [http://criu.org/ CRIU] will be supported later)

The following binaries are not ported to work on top of upstream kernel:
* vzlist
* vzcalc
* vzcfgvalidate
* vzcpucheck
* vzmemcheck
* vzmigrate
* vzeventd
* vzpid
* vzsplit
* vzubc

=== /proc and /sys ===
Software that depend on information supplied by the proc filesystem may not work correctly, since there is not a full solution for full /proc virtualization. For instance, /proc/stat is not yet virtualized, and top will show distorted values.

=== Resource management ===

With non-OpenVZ kernel, setting resources like <code>--ram</code> and <code>--cpuunits</code> works, but there their effect is dependent on what the current kernel supports, through the cgroups subsystem. When a particular cgroup file is present, it will be used. Currently, vzctl will search for the following files:
* cpu.cfs_quota_us
* cpu.shares
* cpuset.cpus
* memory.limit_in_bytes
* memory.memsw.limit_in_bytes
* memory.kmem.limit_in_bytes
* memory.kmem.tcp.limit_in_bytes

== Building ==

In case you don't want to use packages provided by OpenVZ (available from [[Download/vzctl]]), but rather would like to compile vzctl from sources, read on.

=== Dependencies ===

The following software needs to be installed on your system:

* iproute2 >= 3.0.0 (runtime only)
* libcgroup >= 0.38

=== Download ===

You can get the latest released version from [[Download/vzctl/{{Latest vzctl}}#sources]] or directly from [[download:utils/vzctl/current/src/]].

If you are living on the bleeding edge, get vzctl sources from git. Then run autogen.sh to recreate auto* files:

 git clone <nowiki>git://git.openvz.org/pub/vzctl</nowiki>
 cd vzctl
 ./autogen.sh

=== Compile ===

Usual <code>./configure && make</code> should do. But you probably want to specify more options. It makes sense to:

* enable cgroup support
* add <code>--without-ploop</code> (unless you want [[ploop]] compiled it) because otherwise you will need ploop lib headers (available from [[Download/ploop]]).
* enable bash completion support
* set prefix to /usr

See <code>./configure --help</code> output for more details and options available.

So, the command will look like:

 $ ./configure --with-cgroup --without-ploop --enable-bashcomp --prefix=/usr 
 $ make -j4

=== Install ===

 # make install

vzctl is also bundled in some Linux distributions, so you can install vzctl using native distro tools (i.e. your package manager):

* vzctl in [https://launchpad.net/ubuntu/+source/vzctl Ubuntu Linux] [https://help.ubuntu.com/community/OpenVZ Description]
* vzctl-core in [https://apps.fedoraproject.org/packages/vzctl-core Fedora Linux] [https://fedoraproject.org/wiki/QA:Testcase_vzctl_base Description]
* sys-cluster/vzctl in [http://packages.gentoo.org/package/sys-cluster/vzctl Gentoo Linux]
* vzctl in [https://packages.debian.org/search?keywords=vzctl Debian Linux]
* vzctl in [http://packages.altlinux.org/vzctl ALT Linux] ([http://altlinux.org/OpenVZ description])

=== FAQ ===

# A container doesn't boot and udevd is in a process list
#: udev doesn't work, because uevent-s are not virtualized yet. If you don't know how to disable it, you can remove the package.
# You can't enter in CT and vzctl returns en error about pty
 Unable to open pty: No such file or directory
#: If a CT is executed in a user namespace, devpts must be mounted with the newinstance option. You can add this option in /etc/fstab.