Vzctl manual
From Proxmox VE
Introduction
Vzctl is the command line tool for managing OpenVZ containers.
Manual page (man vzctl)
vzctl: 3.0.23-1pve8
vzctl(8) Containers vzctl(8)
NAME
vzctl - utility to control an OpenVZ container.
SYNOPSIS
vzctl [flags] create CTID [--ostemplate name] [--config name] [--pri-
vate path] [--root path] [--ipadd addr] [--hostname name]
vzctl [flags] set CTID parameters [--save]
vzctl [flags] destroy | mount | umount | start | stop | restart | sta-
tus | enter CTID
vzctl [flags] exec | exec2 CTID command [arg ...]
vzctl runscript CTID script
vzctl --help | --version
DESCRIPTION
Utility vzctl runs on the host system (otherwise known as Hardware
Node, or HN) and performs direct manipulations with containers (CTs).
Containers can be referred to by either numeric CTID or by name (see
--name option). Note that CT ID <= 100 are reserved for OpenVZ internal
purposes.
OPTIONS
Flags
These flags can be used with almost any option.
--quiet
Disables logging to log file and screen.
--verbose
Sets logging level to maximum value.
Setting container parameters
set CTID parameters [--save] [--force]
This command sets various container parameters. If a --save flag is
given, parameters are saved in container configuration file
vps.conf(5). Use --force to save the parameters even if the cur-
rent kernel doesn't support OpenVZ. If the container is currently
running, vzctl applies these parameters to the container.
The following parameters can be used with set command.
Miscellaneous
--onboot yes|no
Sets whether the container will be started during system boot. The
container will not be auto-started unless this parameter is set to
yes.
--bootorder number
Sets the boot order priority for this CT. The higher the number is,
the earlier in the boot process this container starts. By default
this parameter is unset, which is considered to be the lowest pri-
ority, so containers with unset bootorder will start last.
--root path
Sets the path to root directory for this container. This is essen-
tially a mount point for container's root directory. Argument can
contain literal string $VEID, which will be substituted with the
numeric CT ID. Changing this parameter is not recommended, better
edit vz.conf(5) global configuration file.
--userpasswd user:password
Sets password for the given user in a container, creating the user
if it does not exists. Note that this option is not saved in con-
figuration file at all (so --save flag is useless), it is applied
to the container (by modifying its /etc/passwd and /etc/shadow
files).
In case container root filesystem is not mounted, it is automati-
cally mounted, then all the appropriate file changes are applied,
then it is unmounted.
Note that container should be created before using this option.
--disabled yes|no
Disable container start. To force the start of a disabled con-
tainer, use vzctl start --force.
--name name
Add a name for a container. The name can later be used in subse-
quent calls to vzctl in place of CTID.
--description string
Add a textual description for a container.
--setmode restart|ignore
Whether to restart a container after applying parameters that
require the container to be restarted in order to take effect.
Networking
--ipadd addr
Adds IP address to a given container. Note that this option is
incremental, so addr are added to already existing ones.
--ipdel addr | all
Removes IP address addr from a container. If you want to remove all
the addresses, use --ipdel all.
--hostname name
Sets container hostname. vzctl writes it to the appropriate file
inside a container (distribution-dependent).
--nameserver addr
Sets DNS server IP address for a container. If you want to set sev-
eral nameservers, you should do it at once, so use --nameserver
option multiple times in one call to vzctl, as all the name server
values set in previous calls to vzctl are overwritten.
--searchdomain name
Sets DNS search domains for a container. If you want to set several
search domains, you should do it at once, so use --searchdomain
option multiple times in one call to vzctl, as all the search
domain values set in previous calls to vzctl are overwritten.
--netif_add ifname[,mac,host_ifname,host_mac,bridge]
Adds a virtual Ethernet device (veth) to a given container. Here
ifname is the Ethernet device name in the container, mac is its MAC
address, host_ifname is the Ethernet device name on the host, and
host_mac is its MAC address. MAC addresses should be in the format
like XX:XX:XX:XX:XX:XX. bridge is an optional parameter which can
be used in custom network start scripts to automatically add the
interface to a bridge. All parameters except ifname are optional
and are automatically generated if not specified.
--netif_del dev_name | all
Removes virtual Ethernet device from a container. If you want to
remove all devices, use all.
Veth interface configuration
The following options can be used to reconfigure the already-created
virtual Ethernet interface. To select the interface to configure, use
--ifname name option.
--mac XX:XX:XX:XX:XX:XX
MAC address of interface inside a container.
--host_ifname name
interface name for virtual interface in the host system.
--host_mac XX:XX:XX:XX:XX:XX
MAC address of interface in the host system.
--bridge name
Bridge name. Custom network start scripts can use this value to
automatically add the interface to a bridge.
--mac_filter on|off
Enables/disables MAC address filtering for the Container veth
device and the possibility of configuring the MAC address of
this device from inside the Container. If the filtering is
turned on:
o the veth device accepts only those packets that have a MAC
address in their headers corresponding to that of this device
(excluding all broadcast and multicast packets);
o it is impossible to modify the veth MAC address from inside
the Container.
By default, this functionality is enabled for all veth devices
existing inside the Container.
Resource limits
The following options sets barrier and limit for various user
beancounters. Each option requires one or two arguments. In
case of one argument, vzctl sets barrier and limit to the same
value. In case of two colon-separated arguments, the first is a
barrier, and the second is a limit. Each argument is either a
number, a number with a suffix, or a special value unlimited.
Arguments are in items, pages or bytes. Note that page size is
architecture-specific, it is 4096 bytes on IA32 platform.
You can also specify different suffixes for set parameters
(except for the parameters which names start with num). For
example, vzctl set CTID --privvmpages 5M:6M should set privvm-
pages' barrier to 5 megabytes and its limit to 6 megabytes.
Available suffixes are:
g, G -- gigabytes.
m, M -- megabytes.
k, K -- kilobytes.
p, P -- pages (page is 4096 bytes on x86 architecture, other
architectures may differ).
You can also specify the literal word unlimited in place of a
number. In that case the corresponding value will be set to
LONG_MAX, i. e. the maximum possible value.
--numproc items[:items]
Maximum number of processes and kernel-level threads. Setting
the barrier and the limit to different values does not make
practical sense.
--numtcpsock items[:items]
Maximum number of TCP sockets. This parameter limits the number
of TCP connections and, thus, the number of clients the server
application can handle in parallel. Setting the barrier and the
limit to different values does not make practical sense.
--numothersock items[:items]
Maximum number of non-TCP sockets (local sockets, UDP and other
types of sockets). Setting the barrier and the limit to differ-
ent values does not make practical sense.
--vmguarpages pages[:pages]
Memory allocation guarantee. This parameter controls how much
memory is available to a container. The barrier is the amount of
memory that container's applications are guaranteed to be able
to allocate. The meaning of the limit is currently unspecified;
it should be set to unlimited.
--kmemsize bytes[:bytes]
Maximum amount of kernel memory used. This parameter is related
to --numproc. Each process consumes certain amount of kernel
memory - 16 KB at least, 30-50 KB typically. Very large pro-
cesses may consume a bit more. It is important to have a certain
safety gap between the barrier and the limit of this parameter:
equal barrier and limit may lead to the situation where the ker-
nel will need to kill container's applications to keep the kmem-
size usage under the limit.
--tcpsndbuf bytes[:bytes]
Maximum size of TCP send buffers. Barrier should be not less
than 64 KB, and difference between barrier and limit should be
equal to or more than value of numtcpsock multiplied by 2.5 KB.
--tcprcvbuf bytes[:bytes]
Maximum size of TCP receive buffers. Barrier should be not less
than 64 KB, and difference between barrier and limit should be
equal to or more than value of numtcpsock multiplied by 2.5 KB.
--othersockbuf bytes[:bytes]
Maximum size of other (non-TCP) socket send buffers. If con-
tainer's processes needs to send very large datagrams, the bar-
rier should be set accordingly. Increased limit is necessary
for high performance of communications through local (UNIX-
domain) sockets.
--dgramrcvbuf bytes[:bytes]
Maximum size of other (non-TCP) socket receive buffers. If con-
tainer's processes needs to receive very large datagrams, the
barrier should be set accordingly. The difference between the
barrier and the limit is not needed.
--oomguarpages pages[:pages]
Guarantees against OOM kill. Under this beancounter the kernel
accounts the total amount of memory and swap space used by the
container's processes. The barrier of this parameter is the
out-of-memory guarantee. If the oomguarpages usage is below the
barrier, processes of this container are guaranteed not to be
killed in out-of-memory situations. The meaning of limit is
currently unspecified; it should be set to unlimited.
--lockedpages pages[:pages]
Maximum number of pages acquired by mlock(2).
--privvmpages pages[:pages]
Allows controlling the amount of memory allocated by the appli-
cations. For shared (mapped as MAP_SHARED) pages, each con-
tainer really using a memory page is charged for the fraction of
the page (depending on the number of others using it). For
"potentially private" pages (mapped as MAP_PRIVATE), container
is charged either for a fraction of the size or for the full
size if the allocated address space. In the latter case, the
physical pages associated with the allocated address space may
be in memory, in swap or not physically allocated yet.
The barrier and the limit of this parameter control the upper
boundary of the total size of allocated memory. Note that this
upper boundary does not guarantee that container will be able to
allocate that much memory. The primary mechanism to control mem-
ory allocation is the --vmguarpages guarantee.
--shmpages pages[:pages]
Maximum IPC SHM segment size. Setting the barrier and the limit
to different values does not make practical sense.
--numfile items[:items]
Maximum number of open files. In most cases the barrier and the
limit should be set to the same value. Setting the barrier to 0
effectively disables pre-charging optimization for this bean-
counter in the kernel, which leads to the held value being pre-
cise but could slightly degrade file open performance.
--numflock items[:items]
Maximum number of file locks. Safety gap should be between bar-
rier and limit.
--numpty items[:items]
Number of pseudo-terminals (PTY). Note that in OpenVZ each con-
tainer can have not more than 255 PTYs. Setting the barrier and
the limit to different values does not make practical sense.
--numsiginfo items[:items]
Number of siginfo structures. Setting the barrier and the limit
to different values does not make practical sense.
--dcachesize bytes[:bytes]
Maximum size of filesystem-related caches, such as directory
entry and inode caches. Exists as a separate parameter to impose
a limit causing file operations to sense memory shortage and
return an errno to applications, protecting from memory short-
ages during critical operations that should not fail. Safety
gap should be between barrier and limit.
--numiptent num[:num]
Number of iptables (netfilter) entries. Setting the barrier and
the limit to different values does not make practical sense.
--physpages pages[:pages]
This is currently an accounting-only parameter. It shows the
usage of RAM by this container. Barrier should be set to 0, and
limit should be set to unlimited.
--swappages pages[:pages]
The limit, if set, is used to show a total amount of swap space
available inside the container. The barrier of this parameter is
currently ignored. The default value is unlimited, meaning
total swap will be reported as 0.
Note that in order for the value to be shown as total swap
space, --meminfo parameter should be set to value other than
none.
CPU fair scheduler parameters
These parameters control CPU usage by container.
--cpuunits num
CPU weight for a container. Argument is positive non-zero num-
ber, passed to and used in the kernel fair scheduler. The larger
the number is, the more CPU time this container gets. Maximum
value is 500000, minimal is 8. Number is relative to weights of
all the other running containers. If cpuunits are not speci-
fied, default value of 1000 is used.
You can set CPU weight for CT0 (host system itself) as well (use
vzctl set 0 --cpuunits num). Usually, OpenVZ initscript
(/etc/init.d/vz) takes care of setting this.
--cpulimit num[%]
Limit of CPU usage for the container, in per cent. Note if the
computer has 2 CPUs, it has total of 200% CPU time. Default CPU
limit is 0 (no CPU limit).
--cpus num
sets number of CPUs available in the container.
Memory output parameters
This parameter control output of /proc/meminfo inside a con-
tainer.
--meminfo none
No /proc/meminfo virtualization (the same as on host system).
--meminfo mode:value
Configure total memory output in a container. Reported free mem-
ory is evaluated accordingly to the mode being set. Reported
swap is evaluated according to the settings of --swappages
parameter.
You can use the following modes for mode:
o pages:value - sets total memory in pages;
o privvmpages:value - sets total memory as privvmpages * value.
Default is privvmpages:1.
Iptables control parameters
--iptables name
Allow to use the functionality of name iptables module inside
the container. To specify multiple names, repeat --iptables for
each, or use space-separated list as an argument (enclosed in
single or double quotes to protect spaces).
The default list of enabled iptables modules is specified by the
IPTABLES variable in vz.conf(5).
You can use the following values for name: iptable_filter, ipt-
able_mangle, ipt_limit, ipt_multiport, ipt_tos, ipt_TOS,
ipt_REJECT, ipt_TCPMSS, ipt_tcpmss, ipt_ttl, ipt_LOG,
ipt_length, ip_conntrack, ip_conntrack_ftp, ip_conntrack_irc,
ipt_conntrack, ipt_state, ipt_helper, iptable_nat, ip_nat_ftp,
ip_nat_irc, ipt_REDIRECT, xt_mac, ipt_owner.
Network devices control parameters
--netdev_add name
move network device from the host system to a specified con-
tainer
--netdev_del name
delete network device from a specified container
Disk quota parameters
--diskspace num[:num]
sets soft and hard disk quota limits, in blocks. First parameter
is soft limit, second is hard limit. One block is currently
equal to 1Kb. Suffixes G, M, K can also be specified (see
Resource limits section for more info on suffixes).
--diskinodes num[:num]
sets soft and hard disk quota limits, in i-nodes. First parame-
ter is soft limit, second is hard limit.
--quotatime seconds
sets quota grace period. Container is permitted to exceed its
soft limits for the grace period, but once it has expired, the
soft limit is enforced as a hard limit.
--quotaugidlimit num
sets maximum number of user/group IDs in a container for which
disk quota inside the container will be accounted. If this value
is set to 0, user and group quotas inside the container will not
be accounted.
Note that if you have previously set value of this parameter to
0, changing it while the container is running will not take
effect.
Mount option
--noatime yes | no
Sets noatime flag (do not update inode access times) on filesys-
tem.
Capability option
--capability capname:on|off
Sets a capability for a container. Note that setting capability
when the container is running does not take immediate effect;
restart the container in order for the changes to take effect.
Note a container has default set of capabilities, thus any oper-
ation on capabilities is "logical and" with the default capabil-
ity mask.
You can use the following values for capname: chown, dac_over-
ride, dac_read_search, fowner, fsetid, kill, setgid, setuid,
setpcap, linux_immutable, net_bind_service, net_broadcast,
net_admin, net_raw, ipc_lock, ipc_owner, sys_module, sys_rawio,
sys_chroot, sys_ptrace, sys_pacct, sys_admin, sys_boot,
sys_nice, sys_resource, sys_time, sys_tty_config, mknod, lease,
setveid, ve_admin. For detailed description, see capabili-
ties(7).
WARNING: setting some of those capabilities may have far reach-
ing security implications, so do not do it unless you know what
you are doing. Also note that setting setpcap:on for a container
will most probably lead to inability to start it.
Device access management
--devnodes device:[r][w][q]|none
Give the container an access (r - read, w - write, q - disk
quota management, none - no access) to a device designated by
the special file /dev/device. Device file is created in a
container by vzctl. Example: vzctl set 777 --devnodes sdb:rwq.
--devices b|c:major:minor|all:[r][w][q]|none
Give the container an access to a block or character device des-
ignated by its major and minor numbers. Device file have to be
created manually.
Features management
--features name:on|off
Enable or disable a specific container feature. Known features
are: sysfs, nfs, sit, ipip, ppp.
Apply config
--applyconfig name
Read container parameters from the container sample configura-
tion file /etc/vz/conf/ve-name.conf-sample, and apply them, if
--save option specified save to the container config file. The
following parameters are not changed: HOSTNAME, IP_ADDRESS,
OSTEMPLATE, VE_ROOT, and VE_PRIVATE.
--applyconfig_map group
Apply container config parameters selected by group. Now only
name argument is supported, to restore container name based on
NAME variable in container configuration file.
I/O priority management
--ioprio priority
Assigns I/O priority to container. Priority range is 0-7. The
greater priority is, the more time for I/O activity container
has. By default each container has priority of 4.
Checkpointing and restore
Checkpointing is a feature of OpenVZ kernel which allows to save a com-
plete state of a running container, and to restore it later.
chkpnt CTID [--dumpfile name]
This command saves a complete state of a running container to a
dump file, and stops the container. If an option --dumpfile is not
set, default dump file name /vz/dump/Dump.CTID is used.
restore CTID [--dumpfile name]
This command restores a container from the dump file created by the
chkpnt command.
Performing container actions
create CTID [--ostemplate name] [--config name] [--private path]
[--root path] [--ipadd addr] [--hostname name]
Creates a new container area. This operation should be done once,
before the first start of the container.
If the --config option is specified, values from example configura-
tion file /etc/vz/conf/ve-name.conf-sample are put into the con-
tainer configuration file. If this container configuration file
already exists, it will be removed.
You can use --root path option to sets the path to the mount point
for the container root directory (default is VE_ROOT specified in
vz.conf(5) file). Argument can contain literal string $VEID, which
will be substituted with the numeric CT ID.
You can use --private path option to set the path to directory in
which all the files and directories specific to this very container
are stored (default is VE_PRIVATE specified in vz.conf(5) file).
Argument can contain literal string $VEID, which will be substi-
tuted with the numeric CT ID.
You can use --ipadd addr option to assign an IP address to a con-
tainer. Note that this option can be used multiple times.
You can use --hostname name option to set a host name for a con-
tainer.
destroy | delete
Removes a container private area by deleting all files, directories
and the configuration file of this container.
start [--wait] [--force]
Mounts (if necessary) and starts a container. Unless --wait option
is specified, vzctl will return immediately; otherwise an attempt
to wait till the default runlevel is reached will be made by vzctl.
Specify --force if you want to start a container which is disabled
(see --disabled).
stop [--fast]
Stops and unmounts a container. Normally, halt(8) is executed
inside a container; option --fast makes vzctl use reboot(2) syscall
instead which is faster but can lead to unclean container shutdown.
restart
Restarts a container, i.e. stops it if it is running, and starts
again. Accepts all the start and stop options.
status
Shows a container status. This is a line with five words separated
by spaces. First word is literally CTID. Second word is the
numeric CT ID. Third word is showing whether this container exists
or not, it can be either exist or deleted. Fourth word is showing
the status of the container filesystem, it can be either mounted or
unmounted. Fifth word shows if the container is running, it can be
either running or down.
This command can also be usable from scripts.
mount
Mounts container private area.
umount
Unmounts container private area. Note that stop does umount auto-
matically.
exec CTID command
Executes command in a container. Environment variables are not set
inside the container. Signal handlers may differ from default set-
tings. If command is -, commands are read from stdin.
exec2 CTID command
The same as exec, but return code is that of command.
runscript
Run specified shell script in a container, if the container is not
running it will be started.
enter
Enters into a container. This option is a back-door for host root
only.
Other options
--help
Prints help message with a brief list of possible options.
--version
Prints vzctl version.
EXIT STATUS
Returns 0 upon success, or an appropriate error code in case of an
error:
1 Failed to set a UBC parameter
2 Failed to set a fair scheduler parameter
3 Generic system error
5 The running kernel is not an OpenVZ kernel (or some OpenVZ mod-
ules are not loaded)
6 Not enough system resources
7 ENV_CREATE ioctl failed
8 Command executed by vzctl exec returned non-zero exit code
9 Container is locked by another vzctl invocation
10 Global OpenVZ configuration file vz.conf(5) not found
11 A vzctl helper script file not found
12 Permission denied
13 Capability setting failed
14 Container configuration file vps.conf(5) not found
15 Timeout on vzctl exec
16 Error during vzctl chkpnt
17 Error during vzctl restore
18 Error from setluid() syscall
20 Invalid command line parameter
21 Invalid value for command line parameter
22 Container root directory (VE_ROOT) not set
23 Container private directory (VE_PRIVATE) not set
24 Container template directory (TEMPLATE) not set
28 Not all required UBC parameters are set, unable to start con-
tainer
29 OS template is not specified, unable to create container
31 Container not running
32 Container already running
33 Unable to stop container
34 Unable to add IP address to container
40 Container not mounted
41 Container already mounted
43 Container private area not found
44 Container private area already exists
46 Not enough disk space
47 Bad/broken container (/sbin/init or /bin/sh not found)
48 Unable to create a new container private area
49 Unable to create a new container root area
50 Unable to mount container
51 Unable to unmount container
52 Unable to delete a container
53 Container private area not exist
61 vzquota init failed
62 vzquota on or vzquota setlimit failed
63 Parameter DISKSPACE not set
64 Parameter DISKINODES not set
66 vzquota off failed
67 ugid quota not initialized
71 Incorrect IP address format
74 Error changing password
78 IP address already in use
79 Container action script returned an error
82 Config file copying error
89 IP address not available
91 OS template not found
100 Unable to find container IP address
104 VE_NETDEV ioctl error
105 Container start disabled
106 Unable to set iptables on a running container
107 Distribution-specific configuration file not found
109 Unable to apply a config
129 Unable to set meminfo parameter
130 Error setting veth interface
131 Error setting container name
133 Waiting for container start failed
139 Error saving container configuration file
EXAMPLES
To create and start "basic" container with ID of 1000 using fedora-
core-5 OS template and IP address of 192.168.10.200:
vzctl create 1000 --ostemplate fedora-core-5 --config basic
vzctl set 1000 --ipadd 192.168.10.200 --save
vzctl start 1000
To set number of processes barrier/limit to 80/100, and PTY bar-
rier/limit to 16/20 PTYs:
vzctl set 1000 --numproc 80:100 -t 16:20 --save
To execute command ls -la in this container:
vzctl exec 1000 /bin/ls -la
To execute command pipe ls -l / | sort in this container:
vzctl exec 1000 'ls -l / | sort'
To stop this container:
vzctl stop 1000
To permanently remove this container:
vzctl destroy 1000
FILES
/etc/vz/vz.conf
/etc/vz/conf/CTID.conf
/proc/vz/veinfo
/proc/vz/vzquota
/proc/user_beancounters
/proc/bc/*
/proc/fairsched
SEE ALSO
vz.conf(5), vps.conf(5), vzquota(8), http://wiki.openvz.org/UBC.
LICENSE
Copyright (C) 2000-2009, Parallels, Inc. Licensed under GNU GPL.
OpenVZ 17 Nov 2009 vzctl(8)
