ovs-vswitchd(8) Open vSwitch Manual ovs-vswitchd(8)
NAME
ovs-vswitchd - Open vSwitch daemon
SYNOPSIS
ovs-vswitchd [database]
DESCRIPTION
A daemon that manages and controls any number of Open vSwitch switches
on the local machine.
The database argument specifies how ovs-vswitchd connects to
ovsdb-server. The default is unix:/var/run/openvswitch/db.sock. The
following forms are accepted:
ssl:ip:port
The specified SSL port on the host at the given ip, which must
be expressed as an IP address (not a DNS name) in IPv4 or IPv6
address format. If ip is an IPv6 address, then wrap ip with
square brackets, e.g.: ssl:[::1]:6640. The --private-key,
--certificate, and --ca-cert options are mandatory when this
form is used.
tcp:ip:port
Connect to the given TCP port on ip, where ip can be IPv4 or
IPv6 address. If ip is an IPv6 address, then wrap ip with square
brackets, e.g.: tcp:[::1]:6640.
unix:file
On POSIX, connect to the Unix domain server socket named file.
On Windows, connect to a localhost TCP port whose value is writ‐
ten in file.
pssl:port[:ip]
Listen on the given SSL port for a connection. By default, con‐
nections are not bound to a particular local IP address and it
listens only on IPv4 (but not IPv6) addresses, but specifying ip
limits connections to those from the given ip, either IPv4 or
IPv6 address. If ip is an IPv6 address, then wrap ip with
square brackets, e.g.: pssl:6640:[::1]. The --private-key,
--certificate, and --ca-cert options are mandatory when this
form is used.
ptcp:port[:ip]
Listen on the given TCP port for a connection. By default, con‐
nections are not bound to a particular local IP address and it
listens only on IPv4 (but not IPv6) addresses, but ip may be
specified to listen only for connections to the given ip, either
IPv4 or IPv6 address. If ip is an IPv6 address, then wrap ip
with square brackets, e.g.: ptcp:6640:[::1].
punix:file
On POSIX, listen on the Unix domain server socket named file for
a connection.
On Windows, listen on a kernel chosen TCP port on the localhost.
The kernel chosen TCP port value is written in file.
ovs-vswitchd retrieves its configuration from database at startup. It
sets up Open vSwitch datapaths and then operates switching across each
bridge described in its configuration files. As the database changes,
ovs-vswitchd automatically updates its configuration to match.
ovs-vswitchd switches may be configured with any of the following fea‐
tures:
· L2 switching with MAC learning.
· NIC bonding with automatic fail-over and source MAC-based TX
load balancing ("SLB").
· 802.1Q VLAN support.
· Port mirroring, with optional VLAN tagging.
· NetFlow v5 flow logging.
· sFlow(R) monitoring.
· Connectivity to an external OpenFlow controller, such as NOX.
Only a single instance of ovs-vswitchd is intended to run at a time. A
single ovs-vswitchd can manage any number of switch instances, up to
the maximum number of supported Open vSwitch datapaths.
ovs-vswitchd does all the necessary management of Open vSwitch data‐
paths itself. Thus, external tools, such ovs-dpctl(8), are not needed
for managing datapaths in conjunction with ovs-vswitchd, and their use
to modify datapaths when ovs-vswitchd is running can interfere with its
operation. (ovs-dpctl may still be useful for diagnostics.)
An Open vSwitch datapath kernel module must be loaded for ovs-vswitchd
to be useful. Please refer to the INSTALL.Linux file included in the
Open vSwitch distribution for instructions on how to build and load the
Open vSwitch kernel module.
OPTIONS
--mlockall
Causes ovs-vswitchd to call the mlockall() function, to attempt
to lock all of its process memory into physical RAM, preventing
the kernel from paging any of its memory to disk. This helps to
avoid networking interruptions due to system memory pressure.
Some systems do not support mlockall() at all, and other systems
only allow privileged users, such as the superuser, to use it.
ovs-vswitchd emits a log message if mlockall() is unavailable or
unsuccessful.
DPDK Options
--dpdk Initialize ovs-vswitchd DPDK datapath. Refer to INSTALL.DPDK
for details.
Daemon Options
The following options are valid on POSIX based platforms.
--pidfile[=pidfile]
Causes a file (by default, ovs-vswitchd.pid) to be created indi‐
cating the PID of the running process. If the pidfile argument
is not specified, or if it does not begin with /, then it is
created in /var/run/openvswitch.
If --pidfile is not specified, no pidfile is created.
--overwrite-pidfile
By default, when --pidfile is specified and the specified pid‐
file already exists and is locked by a running process,
ovs-vswitchd refuses to start. Specify --overwrite-pidfile to
cause it to instead overwrite the pidfile.
When --pidfile is not specified, this option has no effect.
--detach
Causes ovs-vswitchd to detach itself from the foreground session
and run as a background process. ovs-vswitchd detaches only
after it has connected to the database, retrieved the initial
configuration, and set up that configuration.
--monitor
Creates an additional process to monitor the ovs-vswitchd dae‐
mon. If the daemon dies due to a signal that indicates a pro‐
gramming error (SIGABRT, SIGALRM, SIGBUS, SIGFPE, SIGILL, SIG‐
PIPE, SIGSEGV, SIGXCPU, or SIGXFSZ) then the monitor process
starts a new copy of it. If the daemon dies or exits for
another reason, the monitor process exits.
This option is normally used with --detach, but it also func‐
tions without it.
--no-chdir
By default, when --detach is specified, ovs-vswitchd changes its
current working directory to the root directory after it
detaches. Otherwise, invoking ovs-vswitchd from a carelessly
chosen directory would prevent the administrator from unmounting
the file system that holds that directory.
Specifying --no-chdir suppresses this behavior, preventing
ovs-vswitchd from changing its current working directory. This
may be useful for collecting core files, since it is common
behavior to write core dumps into the current working directory
and the root directory is not a good directory to use.
This option has no effect when --detach is not specified.
--user Causes ovs-vswitchd to run as a non root user specified in
"user:group", thus dropping all root privileges. Short forms
"user" and ":group" are also allowed, with current user or group
are assumed respectively. Only daemons started by the root user
accepts this argument.
On Linux, daemons will be granted CAP_IPC_LOCK and
CAP_NET_BIND_SERVICES before dropping root privileges. Daemons
interact with datapath, such as ovs-vswitchd, will be granted
two additional capabilities, namely CAP_NET_ADMIN and
CAP_NET_RAW.
On Windows, this option is not currently supported. For security
reasons, specifying this option will cause the daemon process
not to start.
Service Options
The following options are valid only on Windows platform.
--service
Causes ovs-vswitchd to run as a service in the background. The
service should already have been created through external tools
like SC.exe.
--service-monitor
Causes the ovs-vswitchd service to be automatically restarted by
the Windows services manager if the service dies or exits for
unexpected reasons.
When --service is not specified, this option has no effect.
Public Key Infrastructure Options
-p privkey.pem
--private-key=privkey.pem
Specifies a PEM file containing the private key used as
ovs-vswitchd's identity for outgoing SSL connections.
-c cert.pem
--certificate=cert.pem
Specifies a PEM file containing a certificate that certifies the
private key specified on -p or --private-key to be trustworthy.
The certificate must be signed by the certificate authority (CA)
that the peer in SSL connections will use to verify it.
-C cacert.pem
--ca-cert=cacert.pem
Specifies a PEM file containing the CA certificate that
ovs-vswitchd should use to verify certificates presented to it
by SSL peers. (This may be the same certificate that SSL peers
use to verify the certificate specified on -c or --certificate,
or it may be a different one, depending on the PKI design in
use.)
-C none
--ca-cert=none
Disables verification of certificates presented by SSL peers.
This introduces a security risk, because it means that certifi‐
cates cannot be verified to be those of known trusted hosts.
--bootstrap-ca-cert=cacert.pem
When cacert.pem exists, this option has the same effect as -C or
--ca-cert. If it does not exist, then ovs-vswitchd will attempt
to obtain the CA certificate from the SSL peer on its first SSL
connection and save it to the named PEM file. If it is success‐
ful, it will immediately drop the connection and reconnect, and
from then on all SSL connections must be authenticated by a cer‐
tificate signed by the CA certificate thus obtained.
This option exposes the SSL connection to a man-in-the-middle
attack obtaining the initial CA certificate, but it may be use‐
ful for bootstrapping.
This option is only useful if the SSL peer sends its CA certifi‐
cate as part of the SSL certificate chain. The SSL protocol
does not require the server to send the CA certificate.
This option is mutually exclusive with -C and --ca-cert.
Logging Options
-v[spec]
--verbose=[spec]
Sets logging levels. Without any spec, sets the log level for
every module and destination to dbg. Otherwise, spec is a list
of words separated by spaces or commas or colons, up to one from
each category below:
· A valid module name, as displayed by the vlog/list com‐
mand on ovs-appctl(8), limits the log level change to the
specified module.
· syslog, console, or file, to limit the log level change
to only to the system log, to the console, or to a file,
respectively.
On Windows platform, syslog is accepted as a word and is
only useful along with the --syslog-target option (the
word has no effect otherwise).
· off, emer, err, warn, info, or dbg, to control the log
level. Messages of the given severity or higher will be
logged, and messages of lower severity will be filtered
out. off filters out all messages. See ovs-appctl(8)
for a definition of each log level.
Case is not significant within spec.
Regardless of the log levels set for file, logging to a file
will not take place unless --log-file is also specified (see
below).
For compatibility with older versions of OVS, any is accepted as
a word but has no effect.
-v
--verbose
Sets the maximum logging verbosity level, equivalent to --ver‐
bose=dbg.
-vPATTERN:destination:pattern
--verbose=PATTERN:destination:pattern
Sets the log pattern for destination to pattern. Refer to
ovs-appctl(8) for a description of the valid syntax for pattern.
-vFACILITY:facility
--verbose=FACILITY:facility
Sets the RFC5424 facility of the log message. facility can be
one of kern, user, mail, daemon, auth, syslog, lpr, news, uucp,
clock, ftp, ntp, audit, alert, clock2, local0, local1, local2,
local3, local4, local5, local6 or local7. If this option is not
specified, daemon is used as the default for the local system
syslog and local0 is used while sending a message to the target
provided via the --syslog-target option.
--log-file[=file]
Enables logging to a file. If file is specified, then it is
used as the exact name for the log file. The default log file
name used if file is omitted is /var/log/open‐
vswitch/ovs-vswitchd.log.
--syslog-target=host:port
Send syslog messages to UDP port on host, in addition to the
system syslog. The host must be a numerical IP address, not a
hostname.
--syslog-method=method
Specify method how syslog messages should be sent to syslog dae‐
mon. Following forms are supported:
· libc, use libc syslog() function. This is the default
behavior. Downside of using this options is that libc
adds fixed prefix to every message before it is actually
sent to the syslog daemon over /dev/log UNIX domain
socket.
· unix:file, use UNIX domain socket directly. It is possi‐
ble to specify arbitrary message format with this option.
However, rsyslogd 8.9 and older versions use hard coded
parser function anyway that limits UNIX domain socket
use. If you want to use arbitrary message format with
older rsyslogd versions, then use UDP socket to localhost
IP address instead.
· udp:ip:port, use UDP socket. With this method it is pos‐
sible to use arbitrary message format also with older
rsyslogd. When sending syslog messages over UDP socket
extra precaution needs to be taken into account, for
example, syslog daemon needs to be configured to listen
on the specified UDP port, accidental iptables rules
could be interfering with local syslog traffic and there
are some security considerations that apply to UDP sock‐
ets, but do not apply to UNIX domain sockets.
Other Options
--unixctl=socket
Sets the name of the control socket on which ovs-vswitchd lis‐
tens for runtime management commands (see RUNTIME MANAGEMENT
COMMANDS, below). If socket does not begin with /, it is inter‐
preted as relative to /var/run/openvswitch. If --unixctl is not
used at all, the default socket is /var/run/open‐
vswitch/ovs-vswitchd.pid.ctl, where pid is ovs-vswitchd's
process ID.
On Windows, uses a kernel chosen TCP port on the localhost to
listen for runtime management commands. The kernel chosen TCP
port value is written in a file whose absolute path is pointed
by socket. If --unixctl is not used at all, the file is created
as ovs-vswitchd.ctl in the configured OVS_RUNDIR directory.
Specifying none for socket disables the control socket feature.
-h
--help Prints a brief help message to the console.
-V
--version
Prints version information to the console.
RUNTIME MANAGEMENT COMMANDS
ovs-appctl(8) can send commands to a running ovs-vswitchd process. The
currently supported commands are described below. The command descrip‐
tions assume an understanding of how to configure Open vSwitch.
GENERAL COMMANDS
exit Causes ovs-vswitchd to gracefully terminate.
qos/show interface
Queries the kernel for Quality of Service configuration and sta‐
tistics associated with the given interface.
bfd/show [interface]
Displays detailed information about Bidirectional Forwarding
Detection configured on interface. If interface is not speci‐
fied, then displays detailed information about all interfaces
with BFD enabled.
bfd/set-forwarding [interface] status
Force the fault status of the BFD module on interface (or all
interfaces if none is given) to be status. status can be
"true", "false", or "normal" which reverts to the standard
behavior.
cfm/show [interface]
Displays detailed information about Connectivity Fault Manage‐
ment configured on interface. If interface is not specified,
then displays detailed information about all interfaces with CFM
enabled.
cfm/set-fault [interface] status
Force the fault status of the CFM module on interface (or all
interfaces if none is given) to be status. status can be
"true", "false", or "normal" which reverts to the standard
behavior.
stp/tcn [bridge]
Forces a topology change event on bridge if it's running STP.
This may cause it to send Topology Change Notifications to its
peers and flush its MAC table.. If no bridge is given, forces a
topology change event on all bridges.
BRIDGE COMMANDS
These commands manage bridges.
fdb/flush [bridge]
Flushes bridge MAC address learning table, or all learning
tables if no bridge is given.
fdb/show bridge
Lists each MAC address/VLAN pair learned by the specified
bridge, along with the port on which it was learned and the age
of the entry, in seconds.
mdb/flush [bridge]
Flushes bridge multicast snooping table, or all snooping tables
if no bridge is given.
mdb/show bridge
Lists each multicast group/VLAN pair learned by the specified
bridge, along with the port on which it was learned and the age
of the entry, in seconds.
bridge/reconnect [bridge]
Makes bridge drop all of its OpenFlow controller connections and
reconnect. If bridge is not specified, then all bridges drop
their controller connections and reconnect.
This command might be useful for debugging OpenFlow controller
issues.
bridge/dump-flows bridge
Lists all flows in bridge, including those normally hidden to
commands such as ovs-ofctl dump-flows. Flows set up by mecha‐
nisms such as in-band control and fail-open are hidden from the
controller since it is not allowed to modify or override them.
BOND COMMANDS
These commands manage bonded ports on an Open vSwitch's bridges. To
understand some of these commands, it is important to understand a
detail of the bonding implementation called ``source load balancing''
(SLB). Instead of directly assigning Ethernet source addresses to
slaves, the bonding implementation computes a function that maps an
48-bit Ethernet source addresses into an 8-bit value (a ``MAC hash''
value). All of the Ethernet addresses that map to a single 8-bit value
are then assigned to a single slave.
bond/list
Lists all of the bonds, and their slaves, on each bridge.
bond/show [port]
Lists all of the bond-specific information (updelay, downdelay,
time until the next rebalance) about the given bonded port, or
all bonded ports if no port is given. Also lists information
about each slave: whether it is enabled or disabled, the time to
completion of an updelay or downdelay if one is in progress,
whether it is the active slave, the hashes assigned to the
slave. Any LACP information related to this bond may be found
using the lacp/show command.
bond/migrate port hash slave
Only valid for SLB bonds. Assigns a given MAC hash to a new
slave. port specifies the bond port, hash the MAC hash to be
migrated (as a decimal number between 0 and 255), and slave the
new slave to be assigned.
The reassignment is not permanent: rebalancing or fail-over will
cause the MAC hash to be shifted to a new slave in the usual
manner.
A MAC hash cannot be migrated to a disabled slave.
bond/set-active-slave port slave
Sets slave as the active slave on port. slave must currently be
enabled.
The setting is not permanent: a new active slave will be
selected if slave becomes disabled.
bond/enable-slave port slave
bond/disable-slave port slave
Enables (or disables) slave on the given bond port, skipping any
updelay (or downdelay).
This setting is not permanent: it persists only until the car‐
rier status of slave changes.
bond/hash mac [vlan] [basis]
Returns the hash value which would be used for mac with vlan and
basis if specified.
lacp/show [port]
Lists all of the LACP related information about the given port:
active or passive, aggregation key, system id, and system prior‐
ity. Also lists information about each slave: whether it is
enabled or disabled, whether it is attached or detached, port id
and priority, actor information, and partner information. If
port is not specified, then displays detailed information about
all interfaces with CFM enabled.
DPCTL DATAPATH DEBUGGING COMMANDS
The primary way to configure ovs-vswitchd is through the Open vSwitch
database, e.g. using ovs-vsctl(8). These commands provide a debugging
interface for managing datapaths. They implement the same features
(and syntax) as ovs-dpctl(8). Unlike ovs-dpctl(8), these commands work
with datapaths that are integrated into ovs-vswitchd (e.g. the netdev
datapath type).
dpctl/add-dp dp [netdev[,option]...]
Creates datapath dp, with a local port also named dp. This will
fail if a network device dp already exists.
If netdevs are specified, ovs-vswitchd adds them to the new
datapath, just as if add-if was specified.
dpctl/del-dp dp
Deletes datapath dp. If dp is associated with any network
devices, they are automatically removed.
dpctl/add-if dp netdev[,option]...
Adds each netdev to the set of network devices datapath dp moni‐
tors, where dp is the name of an existing datapath, and netdev
is the name of one of the host's network devices, e.g. eth0.
Once a network device has been added to a datapath, the datapath
has complete ownership of the network device's traffic and the
network device appears silent to the rest of the system.
A netdev may be followed by a comma-separated list of options.
The following options are currently supported:
type=type
Specifies the type of port to add. The default type is
system.
port_no=port
Requests a specific port number within the datapath. If
this option is not specified then one will be automati‐
cally assigned.
key=value
Adds an arbitrary key-value option to the port's configu‐
ration.
ovs-vswitchd.conf.db(5) documents the available port types and
options.
dpctl/set-if dp port[,option]...
Reconfigures each port in dp as specified. An option of the
form key=value adds the specified key-value option to the port
or overrides an existing key's value. An option of the form
key=, that is, without a value, deletes the key-value named key.
The type and port number of a port cannot be changed, so type
and port_no are only allowed if they match the existing configu‐
ration.
dpctl/del-if dp netdev...
Removes each netdev from the list of network devices datapath dp
monitors.
dpctl/dump-dps
Prints the name of each configured datapath on a separate line.
dpctl/show [-s | --statistics] [dp...]
Prints a summary of configured datapaths, including their data‐
path numbers and a list of ports connected to each datapath.
(The local port is identified as port 0.) If -s or --statistics
is specified, then packet and byte counters are also printed for
each port.
The datapath numbers consists of flow stats and mega flow mask
stats.
The "lookups" row displays three stats related to flow lookup
triggered by processing incoming packets in the datapath. "hit"
displays number of packets matches existing flows. "missed" dis‐
plays the number of packets not matching any existing flow and
require user space processing. "lost" displays number of pack‐
ets destined for user space process but subsequently dropped
before reaching userspace. The sum of "hit" and "miss" equals to
the total number of packets datapath processed.
The "flows" row displays the number of flows in datapath.
The "masks" row displays the mega flow mask stats. This row is
omitted for datapath not implementing mega flow. "hit" displays
the total number of masks visited for matching incoming packets.
"total" displays number of masks in the datapath. "hit/pkt" dis‐
plays the average number of masks visited per packet; the ratio
between "hit" and total number of packets processed by the data‐
path".
If one or more datapaths are specified, information on only
those datapaths are displayed. Otherwise, ovs-vswitchd displays
information about all configured datapaths.
DATAPATH FLOW TABLE DEBUGGING COMMANDS
The following commands are primarily useful for debugging Open vSwitch.
The flow table entries (both matches and actions) that they work with
are not OpenFlow flow entries. Instead, they are different and consid‐
erably simpler flows maintained by the Open vSwitch kernel module. Use
ovs-ofctl(8), instead, to work with OpenFlow flow entries.
The dp argument to each of these commands is optional when exactly one
datapath exists, in which case that datapath is the default. When mul‐
tiple datapaths exist, then a datapath name is required.
dpctl/dump-flows [-m | --more] [dp] [filter=filter]
Prints to the console all flow entries in datapath dp's flow ta‐
ble. Without -m or --more, output omits match fields that a
flow wildcards entirely; with -m or --more, output includes all
wildcarded fields.
If filter=filter is specified, only displays the flows that
match the filter. filter is a flow in the form similiar to that
accepted by ovs-ofctl(8)'s add-flow command. (This is not an
OpenFlow flow: besides other differences, it never contains
wildcards.) The filter is also useful to match wildcarded
fields in the datapath flow. As an example, fil‐
ter='tcp,tp_src=100' will match the datapath flow containing
'tcp(src=80/0xff00,dst=8080/0xff)'.
dpctl/add-flow [dp] flow actions
dpctl/mod-flow [--clear] [--may-create] [-s | --statistics] [dp] flow
actions
Adds or modifies a flow in dp's flow table that, when a packet
matching flow arrives, causes actions to be executed.
The add-flow command succeeds only if flow does not already
exist in dp. Contrariwise, mod-flow without --may-create only
modifies the actions for an existing flow. With --may-create,
mod-flow will add a new flow or modify an existing one.
If -s or --statistics is specified, then mod-flow prints the
modified flow's statistics. A flow's statistics are the number
of packets and bytes that have passed through the flow, the
elapsed time since the flow last processed a packet (if ever),
and (for TCP flows) the union of the TCP flags processed through
the flow.
With --clear, mod-flow zeros out the flow's statistics. The
statistics printed if -s or --statistics is also specified are
those from just before clearing the statistics.
dpctl/del-flow [-s | --statistics] [dp] flow
Deletes the flow from dp's flow table that matches flow. If -s
or --statistics is specified, then del-flow prints the deleted
flow's statistics.
dpctl/get-flow [dp] ufid:ufid
Fetches the flow from dp's flow table with unique identifier
ufid. ufid must be specified as a string of 32 hexadecimal
characters.
dpctl/del-flows [dp]
Deletes all flow entries from datapath dp's flow table.
DPIF-NETDEV COMMANDS
These commands are used to expose internal information (mostly statis‐
tics) about the ``dpif-netdev'' userspace datapath. If there is only
one datapath (as is often the case, unless dpctl/ commands are used),
the dp argument can be omitted.
dpif-netdev/pmd-stats-show [dp]
Shows performance statistics for each pmd thread of the datapath
dp. The special thread ``main'' sums up the statistics of every
non pmd thread. The sum of ``emc hits'', ``masked hits'' and
``miss'' is the number of packets received by the datapath.
Cycles are counted using the TSC or similar facilities (when
available on the platform). To reset these counters use dpif-
netdev/pmd-stats-clear. The duration of one cycle depends on the
measuring infrastructure.
dpif-netdev/pmd-stats-clear [dp]
Resets to zero the per pmd thread performance numbers shown by
the dpif-netdev/pmd-stats-show command. It will NOT reset data‐
path or bridge statistics, only the values shown by the above
command.
DATAPATH DEBUGGING COMMANDS
These commands query and modify datapaths. They are are similar to
ovs-dpctl(8) commands. dpif/show has the additional functionality,
beyond dpctl/show of printing OpenFlow port numbers. The other com‐
mands are redundant and will be removed in a future release.
dpif/dump-dps
Prints the name of each configured datapath on a separate line.
dpif/show
Prints a summary of configured datapaths, including statistics
and a list of connected ports. The port information includes
the OpenFlow port number, datapath port number, and the type.
(The local port is identified as OpenFlow port 65534.)
dpif/dump-flows [-m] dp
Prints to the console all flow entries in datapath dp's flow ta‐
ble. Without -m, output omits match fields that a flow wildcards
entirely; with -m output includes all wildcarded fields.
This command is primarily useful for debugging Open vSwitch.
The flow table entries that it displays are not OpenFlow flow
entries. Instead, they are different and considerably simpler
flows maintained by the datapath module. If you wish to see the
OpenFlow flow entries, use ovs-ofctl dump-flows.
dpif/del-flows dp
Deletes all flow entries from datapath dp's flow table and
underlying datapath implementation (e.g., kernel datapath mod‐
ule).
This command is primarily useful for debugging Open vSwitch. As
discussed in dpif/dump-flows, these entries are not OpenFlow
flow entries.
OFPROTO COMMANDS
These commands manage the core OpenFlow switch implementation (called
ofproto).
ofproto/list
Lists the names of the running ofproto instances. These are the
names that may be used on ofproto/trace.
ofproto/trace [dpname] odp_flow [-generate | packet]
ofproto/trace bridge br_flow [-generate | packet]
ofproto/trace-packet-out [-consistent] [dpname] odp_flow [-generate |
packet] actions
ofproto/trace-packet-out [-consistent] bridge br_flow [-generate |
packet] actions
Traces the path of an imaginary packet through switch and
reports the path that it took. The initial treatment of the
packet varies based on the command:
· ofproto/trace looks the packet up in the OpenFlow flow
table, as if the packet had arrived on an OpenFlow port.
· ofproto/trace-packet-out applies the specified OpenFlow
actions, as if the packet, flow, and actions had been
specified in an OpenFlow ``packet-out'' request.
The packet's headers (e.g. source and destination) and metadata
(e.g. input port), together called its ``flow,'' are usually all
that matter for the purpose of tracing a packet. You can spec‐
ify the flow in the following ways:
dpname odp_flow
odp_flow is a flow in the form printed by ovs-dpctl(8)'s
dump-flows command. If all of your bridges have the same
type, which is the common case, then you can omit dpname,
but if you have bridges of different types (say, both
ovs-netdev and ovs-system), then you need to specify a
dpname to disambiguate.
bridge br_flow
br_flow is a flow in the form similar to that accepted by
ovs-ofctl(8)'s add-flow command. (This is not an Open‐
Flow flow: besides other differences, it never contains
wildcards.) bridge names of the bridge through which
br_flow should be traced.
Most commonly, one specifies only a flow, using one of the forms
above, but sometimes one might need to specify an actual packet
instead of just a flow:
Side effects.
Some actions have side effects. For example, the normal
action can update the MAC learning table, and the learn
action can change OpenFlow tables. The trace commands
only perform side effects when a packet is specified. If
you want side effects to take place, then you must supply
a packet.
(Output actions are obviously side effects too, but the
trace commands never execute them, even when one speci‐
fies a packet.)
Incomplete information.
Most of the time, Open vSwitch can figure out everything
about the path of a packet using just the flow, but in
some special circumstances it needs to look at parts of
the packet that are not included in the flow. When this
is the case, and you do not supply a packet, then a trace
command will tell you it needs a packet.
If you wish to include a packet as part of a trace operation,
there are two ways to do it:
-generate
This option, added to one of the ways to specify a flow
already described, causes Open vSwitch to internally gen‐
erate a packet with the flow described and then to use
that packet. If your goal is to execute side effects,
then -generate is the easiest way to do it, but -generate
is not a good way to fill in incomplete information,
because it generates packets based on only the flow
information, which means that the packets really do not
have any more information than the flow.
packet This form supplies an explicit packet as a sequence of
hex digits. An Ethernet frame is at least 14 bytes long,
so there must be at least 28 hex digits. Obviously, it
is inconvenient to type in the hex digits by hand, so the
ovs-pcap(1) and ovs-tcpundump(1) utilities provide easier
ways.
With this form, packet headers are extracted directly
from packet, so the odp_flow or br_flow should specify
only metadata. The metadata can be:
skb_priority
Packet QoS priority.
pkt_mark
Mark of the packet.
tun_id The tunnel ID on which the packet arrived.
in_port
The port on which the packet arrived.
The in_port value is kernel datapath port number for the first
format and OpenFlow port number for the second format. The num‐
bering of these two types of port usually differs and there is
no relationship.
ofproto-trace-packet-out accepts an additional -consistent
option. With this option specified, the command rejects actions
that are inconsistent with the specified packet. (An example of
an inconsistency is attempting to strip the VLAN tag from a
packet that does not have a VLAN tag.) Open vSwitch ignores
most forms of inconsistency in OpenFlow 1.0 and rejects incon‐
sistencies in later versions of OpenFlow. The option is neces‐
sary because the command does not ordinarily imply a particular
OpenFlow version. One exception is that, when actions includes
an action that only OpenFlow 1.1 and later supports (such as
push_vlan), -consistent is automatically enabled.
ofproto/self-check [switch]
Runs an internal consistency check on switch, if specified, oth‐
erwise on all ofproto instances, and responds with a brief sum‐
mary of the results. If the summary reports any errors, then
the Open vSwitch logs should contain more detailed information.
Please pass along errors reported by this command to the Open
vSwitch developers as bugs.
VLOG COMMANDS
These commands manage ovs-vswitchd's logging settings.
vlog/set [spec]
Sets logging levels. Without any spec, sets the log level for
every module and destination to dbg. Otherwise, spec is a list
of words separated by spaces or commas or colons, up to one from
each category below:
· A valid module name, as displayed by the vlog/list com‐
mand on ovs-appctl(8), limits the log level change to the
specified module.
· syslog, console, or file, to limit the log level change
to only to the system log, to the console, or to a file,
respectively.
On Windows platform, syslog is accepted as a word and is
only useful along with the --syslog-target option (the
word has no effect otherwise).
· off, emer, err, warn, info, or dbg, to control the log
level. Messages of the given severity or higher will be
logged, and messages of lower severity will be filtered
out. off filters out all messages. See ovs-appctl(8)
for a definition of each log level.
Case is not significant within spec.
Regardless of the log levels set for file, logging to a file
will not take place unless ovs-vswitchd was invoked with the
--log-file option.
For compatibility with older versions of OVS, any is accepted as
a word but has no effect.
vlog/set PATTERN:destination:pattern
Sets the log pattern for destination to pattern. Refer to
ovs-appctl(8) for a description of the valid syntax for pattern.
vlog/list
Lists the supported logging modules and their current levels.
vlog/list-pattern
Lists logging patterns used for each destination.
vlog/reopen
Causes ovs-vswitchd to close and reopen its log file. (This is
useful after rotating log files, to cause a new log file to be
used.)
This has no effect unless ovs-vswitchd was invoked with the
--log-file option.
vlog/disable-rate-limit [module]...
vlog/enable-rate-limit [module]...
By default, ovs-vswitchd limits the rate at which certain mes‐
sages can be logged. When a message would appear more fre‐
quently than the limit, it is suppressed. This saves disk
space, makes logs easier to read, and speeds up execution, but
occasionally troubleshooting requires more detail. Therefore,
vlog/disable-rate-limit allows rate limits to be disabled at the
level of an individual log module. Specify one or more module
names, as displayed by the vlog/list command. Specifying either
no module names at all or the keyword any disables rate limits
for every log module.
The vlog/enable-rate-limit command, whose syntax is the same as
vlog/disable-rate-limit, can be used to re-enable a rate limit
that was previously disabled.
MEMORY COMMANDS
These commands report memory usage.
memory/show
Displays some basic statistics about ovs-vswitchd's memory
usage. ovs-vswitchd also logs this information soon after
startup and periodically as its memory consumption grows.
COVERAGE COMMANDS
These commands manage ovs-vswitchd's ``coverage counters,'' which count
the number of times particular events occur during a daemon's runtime.
In addition to these commands, ovs-vswitchd automatically logs coverage
counter values, at INFO level, when it detects that the daemon's main
loop takes unusually long to run.
Coverage counters are useful mainly for performance analysis and debug‐
ging.
coverage/show
Displays the averaged per-second rates for the last few seconds,
the last minute and the last hour, and the total counts of all
of the coverage counters.
OPENVSWITCH TUNNELING COMMANDS
These commands query and modify OVS tunnel components. Ref to README-
native-tunneling.md for more info.
ovs/route/add ipv4_address/plen output_bridge [GW]
Adds ipv4_address/plen route to vswitchd routing table. out‐
put_bridge needs to be OVS bridge name. This command is useful
if OVS cached routes does not look right.
ovs/route/show
Print all routes in OVS routing table, This includes routes
cached from system routing table and user configured routes.
ovs/route/del ipv4_address/plen
Delete ipv4_address/plen route from OVS routing table.
tnl/arp/show
OVS builds ARP cache by snooping are messages. This command
shows ARP cache table.
tnl/arp/set bridge ip mac
Adds or modifies an ARP cache entry in bridge, mapping ip to
mac.
tnl/arp/flush
Flush ARP table.
tnl/egress_port_range [num1] [num2]
Set range for UDP source port used for UDP based Tunnels. For
example VxLAN. If case of zero arguments this command prints
current range in use.
OPENFLOW IMPLEMENTATION
This section documents aspects of OpenFlow for which the OpenFlow spec‐
ification requires documentation.
Packet buffering.
The OpenFlow specification, version 1.2, says:
Switches that implement buffering are expected to expose,
through documentation, both the amount of available buffering,
and the length of time before buffers may be reused.
Open vSwitch maintains a separate set of 256 packet buffers for each
OpenFlow connection. Any given packet buffer is preserved until it is
referenced by an OFPT_FLOW_MOD or OFPT_PACKET_OUT request or for 5 sec‐
onds, whichever comes first.
LIMITS
We believe these limits to be accurate as of this writing. These lim‐
its assume the use of the Linux kernel datapath.
· ovs-vswitchd started through ovs-ctl(8) provides a limit of
65535 file descriptors. The limits on the number of bridges and
ports is decided by the availability of file descriptors. With
the Linux kernel datapath, creation of a single bridge consumes
three file descriptors and adding a port consumes "n-handler-
threads" file descriptors per bridge port. Performance will
degrade beyond 1,024 ports per bridge due to fixed hash table
sizing. Other platforms may have different limitations.
· 2,048 MAC learning entries per bridge, by default. (This is
configurable via other-config:mac-table-size in the Bridge ta‐
ble. See ovs-vswitchd.conf.db(5) for details.)
· Kernel flows are limited only by memory available to the kernel.
Performance will degrade beyond 1,048,576 kernel flows per
bridge with a 32-bit kernel, beyond 262,144 with a 64-bit ker‐
nel. (ovs-vswitchd should never install anywhere near that many
flows.)
· OpenFlow flows are limited only by available memory. Perfor‐
mance is linear in the number of unique wildcard patterns. That
is, an OpenFlow table that contains many flows that all match on
the same fields in the same way has a constant-time lookup, but
a table that contains many flows that match on different fields
requires lookup time linear in the number of flows.
· 255 ports per bridge participating in 802.1D Spanning Tree Pro‐
tocol.
· 32 mirrors per bridge.
· 15 bytes for the name of a port. (This is a Linux kernel limi‐
tation.)
SEE ALSO
ovs-appctl(8), ovsdb-server(1), INSTALL.Linux in the Open vSwitch dis‐
tribution.
Open vSwitch 2.4.90 ovs-vswitchd(8)