vzctl - utility to control a Virtual Environment.
vzctl [flags] create veid --ostemplate name]
[--config name] [--private path] [--root
path] [--ipadd addr] [--hostname name]
vzctl [flags] set veid [parameters]
[--save]
vzctl [flags] destroy | mount | umount
| start | stop | restart | status | enter
veid
vzctl [flags] exec | exec2 veid
command [arg ...]
vzctl runscript veid script
vzctl --help | --version
Utility vzctl runs on Hardware Node (HN) and performs direct
manipulations with Virtual Environments (VEs).
Virtual Environments can be referred to by either numeric
veid or by name (see --name option). Note that VE ID <= 100
are reserved for OpenVZ internal purposes.
These flags can be used with almost any option.
- --quiet
- Disables logging to log file and screen.
- --verbose
- Sets logging level to maximum value.
- set veid [parameters] [--save]
- This command sets various VE parameters. If flag --save is given,
parameters are saved in VE configuration file vps.conf(5). If VE is
currently running, vzctl applies these parameters to VE.
The following options can be used with set command.
- Miscellaneous parameters
- --onboot yes|no
- Sets whether this VE will be started during system boot up. VE will not be
auto-started during system boot up unless this parameter is set to
yes.
- --root path
- Sets the path to root directory for this VE. This is essentially a mount
point for VE root. Value must contain string $VEID, which will be
substituted with numeric VE ID. Changing this parameter is not
recommended, better edit vz(5) global configuration file.
- --userpasswd user:password
- Sets password for the given user in VE, creating the user if it does not
exists. Note that this option is not saved in configuration file at all
(so --save flag is useless), it is applied to VE (by modifying its
/etc/passwd and
/etc/shadow files).
In case VE root is not mounted, it is automatically mounted,
then all appropriate file changes are applied, then it is unmounted.
Note that VE area should be created before using this
option.
- --disabled yes|no
- Disable VE start. To force the start of a disabled VE, use vzctl
start with --force option.
- --name name
- Add a name for a VE. The name can later be used in subsequent calls
to vzctl in place of veid.
- --setmode restart|ignore
- Whether to restart a VE after applying any parameters requiring that the
VE be restarted for those to take effect.
- Network related parameters
- --ipadd addr
- Adds IP address to a given VE. Note that this option is incremental, so
addr are added to already existing ones.
- --ipdel addr | all
- Removes IP address addr from a VE. If you want to remove all
addresses, use --ipdel all.
- --hostname name
- Sets VE hostname. vzctl writes it to the appropriate file inside a
VE (distribution-dependent).
- --nameserver addr
- Sets DNS server IP address for a VE. If you want to set several
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 gets overwritten.
- --searchdomain name
- Sets DNS search domains for a VE. 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 gets overwritten.
- --netif_add
ifname[,mac,host_ifname,host_mac]
- Adds a virtual ethernet device (veth) to a given VE. Here ifname is
the ethernet device name in the VE, 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. All parameters except ifname are optional
and are automatically generated if not specified.
- 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
VE.
--host_ifname name - interface name for virtual interface
in VE0.
--host_mac XX:XX:XX:XX:XX:XX - MAC address of interface in
VE0.
- --netif_del dev_name|all
- Removes virtual ethernet device from VE. If you want to remove all
devices, use all.
- 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.
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 veid --privvmpages
5M:6M should set privvmpages' 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).
- --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 different values does not
make practical sense.
- --vmguarpages pages[:pages]
- Memory allocation guarantee. This parameter controls how much memory is
available to a VE. The barrier is the amount of memory that VE's
applications are guaranteed to be able to allocate. The meaning of the
limit is currently unspecified; it should be set to 2,147,483,647.
- --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 leas, 30-50 KB typically. Very large processes 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 kernel will need to kill VE applications to keep the
kmemsize 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 VE processes needs
to send very large datagrams, the barrier 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 VE processes
needs to send 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 VE processes. The
barrier of this parameter is the out-of-memory guarantee. If the
oomguarpages usage is below the barrier, processes of this VE are
guaranteed not to be killed in out-of-memory situations. The meaning of
limit is currently unspecified; it should be set to 2,147,483,647.
- --lockedpages pages[:pages]
- Maximum number of pages acquired by mlock(2).
- --privvmpages pages[:pages]
- Allows controlling the amount of memory allocated by the applications. For
shared (mapped as MAP_SHARED) pages, each VE 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), VE is charged either for a fraction of the size or
for the full size if the allocated address space. It 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 VE will be able to allocate that much
memory. The primary mechanism to control memory 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. Setting the barrier and the limit to
different values does not make practical sense.
- --numflock items[:items]
- Maximum number of file locks. Safety gap should be between barrier and
limit.
- --numpty items[:items]
- Number of pseudo-terminals (PTY). Note that in OpenVZ each VE 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 shortages 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 VE. Barrier should be set to 0, and limit should be set to
2,147,483,647.
- CPU fair scheduler parameters
-
These parameters control CPU usage by VE.
- --cpuunits num
- CPU weight for a VE. Argument is positive non-zero number, which passed to
and used in kernel fair scheduler. The larger the number is, the more CPU
time this VE get. Maximum value is 500000, minimal is 8. Number is
relative to weights of all the other running VEs. If cpuunits not
specified default value 1000 ia used.
You can set CPU weight for VE0 (hardware node 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 VE, 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
VE.
- Memory output parameters
-
This parameter control output of /proc/meminfo inside a VE
- --meminfo none
- No /proc/meminfo virtualization (the same as on host system).
- --meminfo mode:value
- Configure total memory output in a VE. Free memory is evaluated
accordingly to the mode being set.
You can use the following modes for mode:
pages:value - sets total memory in pages
privvmpages:value - sets total memory as privvmpages *
value
Default is privvmpages:1.
- Iptables control parameters
- --iptables name
- Restrict access to iptables modules inside a VE (by default all iptables
modules that are loaded in the host system are accessible inside a VE).
You can use the following values for name:
iptable_filter, iptable_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.
- Network devices control parameters
- --netdev_add name
- move network device from VE0 to a specified VE
- --netdev_del name
- delete network device from a specified VE
- Disk quota parameters
- --diskspace num[:num]
- sets soft and hard disk quotas, in blocks. First parameter is soft quota,
second is hard quota. One block is currently equal to 1Kb. Also suffixes
G, M, K can be specified (see Resource limits
section for more info).
- --diskinodes num[:num]
- sets soft and hard disk quotas, in i-nodes. First parameter is soft quota,
second is hard quota.
- --quotatime seconds
- sets soft overusage time limit for disk quota (also known as grace
period).
- --quotaugidlimit num
- sets maximum number of user/group IDs in a VE for which disk quota inside
the VE will be accounted. If this value is set to 0, user and group
quotas will not be accounted inside the VE.
Note that if you have previously set value of this parameter
to 0, changing it while the VE is running will not take
effect.
- Mount option
- --noatime yes|no
- Sets noatime flag (do not update inode access times) on file system.
- Capability option
- --capability capname:on|off
- Sets capability inside a VE. Note that setting capability when the VE is
running does not take immediate effect; restart VE in order for changes to
take effect. Note a VE has default set of capabilities, thus any operation
on capabilities is "logical and" with the default capability
mask.
You can use the following values for capname:
chown, dac_override, 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.
WARNING: setting some of those capabilities may have
far reaching security implications, so do not do it unless you know what
you are doing. Also note that setting setpcap:on for a VE will
most probably lead to inability to start it.
- Device access management
- --devnodes device:r|w|rw|none
- Give the VE an access (r - read, w - write, rw - read
write, none - no access) to a device designated by the special file
/dev/device. Device file is created in VE by vzctl.
- --devices
b|c:major:minor|all:[r|w|rw|none]
- Give the VE an access to a block or character device
designated by its major and minor numbers. Device file have
to be created manually.
- Features management
- --features name:on|off
- Enable or disable a specific VE feature. Known features are: sysfs,
nfs.
- Apply config
- --applyconfig name
- Read VE parameters from the VE sample configuration file
/etc/vz/conf/ve-name.conf-sample,
and apply them, if --save option specified save to the VE config file. The
following parameters are not changed: HOSTNAME, IP_ADDRESS,
OSTEMPLATE, VE_ROOT, and VE_PRIVATE.
- --applyconfig_map name
- Apply VE config parameters selected by name group, now only
name argument supported. Restore VE name based on NAME variable in
VE configuration file.
- I/O priority management
- --ioprio priority
- Assigns I/O priority to VE. Priority range is 0-7. The
greater priority is, the more time for I/O activity VE has. By
default each VE has priority of 4.
Checkpointing is a feature of OpenVZ kernel which allows to save a complete
state of a running VE, and to restore it later.
- chkpnt veid [--dumpfile name]
- This command saves a complete state of a running VE to a dump file, and
stops the VE. If an option --dumpfile is not set, default dump file
name /vz/dump/Dump.veid is used.
- restore veid [--dumpfile name]
- This command restores a VE from dump file created by the chkpnt
command.
- create veid [--ostemplate name]
[--config name] [--private path] [--root
path] [--ipadd addr] [--hostname
name]
- Creates a new VE area. This operation should be done once, before the
first start of the VE.
If the --config option is specified, values from
example configuration file
/etc/vz/conf/ve-
name.conf-sample are put into the
VE configuration file. If this VE configuration file already exists, it
will be removed.
You can use --root path option to sets the path
to the mount point for the VE root directory (default is VE_ROOT
specified in vz(5) file). Argument can contain string
$VEID, which will be substituted with numeric VE ID.
You can use --private path option to set the
path to directory in which all the files and directories specific to
this very VE are stored (default is VE_PRIVATE specified in
vz(5) file). Argument can contain string $VEID, which will
be substituted with numeric VE ID.
You can use --ipadd addr option to assign an IP
address to a VE. Note that this option can be used multiple times.
You can use --hostname name option to set a host
name for a VE.
- destroy
- Removes a VE private area by deleting all files, directories and
configuration file of this VE.
- start [--wait] [--force]
- Mounts (if necessary) and starts a VE. 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 VE which is
disabled (see --disabled).
- stop
- Stops and unmounts a VE.
- restart
- Restarts a VE, i.e. stops it if it is running, and starts again.
- status
- Shows a VE status. Basically this is a line with five words separated by
spaces. First word is literally VEID. Second word is the numeric
VE ID. Third word is showing whether this VE exists or not, it can
be either exist or deleted. Fourth word is showing the
status of the VE filesystem, it can be either mounted or
unmounted. Fifth word shows if the VE is running, it can be either
running or down.
This command can also be usable from scripts.
- mount
- Mounts VE private area.
- umount
- Unmounts VE private area. Note that stop does umount
automatically.
- exec veid command
- Executes command in a VE. Environment variables are not set inside
the VE. Signal handlers may differ from default settings. If
command is -, commands are read from stdin.
- exec2 veid command
- The same as exec, but return code is that of command.
- runscript
- Run specified shell script in a VE, if the VE is not runnning it will be
started.
- enter
- Enters into a VE. This option is a back-door for host root only.
- --help
- Prints help message with a brief list of possible options.
- --version
- Prints vzctl version.
To create and start "basic" VE 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
vps.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 barrier/limit to
16/20 PTYs:
vzctl set 1000 --numproc 80:100 -t 16:20 --save
To execute command ls -la in this VE:
vzctl exec 1000 /bin/ls -la
To execute command pipe ls -l / | sort in this VE:
vzctl exec 1000 'ls -l / | sort'
To stop this VE:
vzctl stop 1000
To permanently remove this VE:
vzctl destroy 1000
/etc/vz/vz.conf
/etc/vz/conf/veid.conf
/proc/vz/veinfo
/proc/vz/vzquota
/proc/user_beancounters
/proc/fairsched
vz.conf(5), vps.conf(5), vzquota(8),
Copyright (C) 2000-2007, SWsoft. Licensed under GNU GPL v2.