Understand QoS at OpenSwitch

danny

http://dannykim.me/danny/57771

2014.02.11 14:34:58 (*.193.128.184)

592

>>> Purpose
This document helps us understand how QoS works in OpenVSwitch.
This document can be used as a warming up before a good tutorial(URL is shown below at References)
to create a floodlight module to handle QoS.
>>> Reference
- How to create QoS Service Module
- man ovs-vsctl (Quality of Service (QoS) section)
>>> Outline
QoS is the service to differentiate delivery service.
In some packets, it is delivered at high speed, but others can be delivered at lower speed.
Based on my understanding, key essence of QoS at OpenVSwitch is to create queues with different speed, and put packets into different queues depending on QoS policy.
This document does not handle all of them, but just taste how to configure OpenVSwitch for QoS.
In detail. we just create a queue with low speed, and QoS use the queue.
We expect transfer rate is reduced (2Mbps) as a result.
Though this does not show all deployment of QoS, it can be a starting point of QoS.
For more detail, please refer to a Reference URL (above).
>>> Steps
- IPerf test (check speed)
- Create a qos with a low-speed queue
- IPerf test (check speed)
*** Appendix
- Some useful commands for qos.
>>> Environment
- SDN network (I do not use mininet)
  host1 - OVS - ... - OVS - host2
- OS: Ubuntu 12.04
>>> IPerf test
- receiver
[root@host2 ~]# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.2.15 port 5001 connected with 192.168.2.11 port 49038
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.3 sec   116 MBytes  94.1 Mbits/sec
*** To open 5001 port, use following commands in Receiver
(if you see "no connection..." message)
[root@host2 ~]# iptables -I INPUT -p tcp -j ACCEPT --dport=5001
[root@host2 ~]# iptables -L INPUT
Chain INPUT (policy ACCEPT)
target     prot opt source               destination        
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:commplex-link // <-- 5001 port
:
- sender
[root@host1 ~]# iperf -c host2 -p 5001
------------------------------------------------------------
Client connecting to host2, TCP port 5001
TCP window size: 22.9 KByte (default)
------------------------------------------------------------
[  3] local 192.168.2.11 port 49038 connected with 192.168.2.15 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec   116 MBytes  96.5 Mbits/sec       // <-- current maxium speed

>>> Choose a port in any switch on path

root@ovs-edge-app1:~# ovs-vsctl show
b03d92f0-bd5d-4a32-bc37-3542873b2e79
    Bridge "br0"
        Controller "tcp:192.168.1.1:6633"
            is_connected: true
        fail_mode: secure
Port "eth1"
            Interface "eth1"
        Port "vnet1"
            Interface "vnet1"
        Port "br0"
            Interface "br0"
                type: internal

*** Here, I choose eth1 that are on data path from host1 to host2. You can use any port that is on data path.

>>> Create a qos with a low-speed queue (at any switch on path)
Following command does ..
1) create a queue(q0)
q0 (2 Mbps): --id=@q0 create queue other-config:min-rate=2000000 other-config:max-rate=2000000
2) create a qos (newqos) and connect a queue into the qos
--id=@newqos create qos type=linux-htb queues=0=@q0
3) connect a created qos (newqos) to a existing port (eth1)
set port eth1 qos=@newqos
Thus, port(eth1) -- qos(newqos) -- queue(q1)
root@switch:~# ovs-vsctl set port eth1 qos=@newqos -- --id=@newqos create qos type=linux-htb queues=0=@q0 -- --id=@q0 create queue other-config:min-rate=2000000 other-config:max-rate=2000000
ea9aa386-8558-4df6-84dc-55b50eb795a1
340c74b1-7dc4-4959-b8c5-4d25c463556c
root@switch:~# ovs-vsctl list port eth1
_uuid               : 0fb256d5-df68-4d1a-8b56-74bdd0b4482a
bond_downdelay      : 0
bond_fake_iface     : false
bond_mode           : []
bond_updelay        : 0
external_ids        : {}
fake_bridge         : false
interfaces          : [737c5011-97cc-4c11-9370-07b845e94294]
lacp                : []
mac                 : []
name                : "eth1"
other_config        : {}
qos                 : ea9aa386-8558-4df6-84dc-55b50eb795a1    // added qos
statistics          : {}
status              : {}
tag                 : []
trunks              : []
vlan_mode           : []
root@switch:~# ovs-vsctl list qos
_uuid               : ea9aa386-8558-4df6-84dc-55b50eb795a1
external_ids        : {}
other_config        : {}
queues              : {0=340c74b1-7dc4-4959-b8c5-4d25c463556c}  // added queue
type                : linux-htb
root@switch:~# ovs-vsctl list queue
_uuid               : 340c74b1-7dc4-4959-b8c5-4d25c463556c
dscp                : []
external_ids        : {}
other_config        : {max-rate="2000000", min-rate="2000000"} // 2 Mbps
root@switch:~#
>>> IPerf test (check speed) again
- receiver
[root@host2 ~]# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.2.15 port 5001 connected with 192.168.2.11 port 49039
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-14.2 sec  3.25 MBytes  1.91 Mbits/sec    // <-- now, reduced to about 2 Mbps
- sender
[root@host1 ~]# iperf -c host2 -p 5001
------------------------------------------------------------
Client connecting to host2, TCP port 5001
TCP window size: 22.9 KByte (default)
------------------------------------------------------------
[  3] local 192.168.2.11 port 49039 connected with 192.168.2.15 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.3 sec  3.25 MBytes  2.65 Mbits/sec    // <-- now, reduced to about 2 Mbps
>>> Discussion
Here, we used just a queue. With multiple queues in a qos, we can handle packets for different services. 
That is, high-serviced packets are forwared to high-speed queue.
For more information, again you may want to refer a Reference URL (above at reference section)

Now, you may want to disconnect qos from a port and remove queue and qos, then want to test speed again. For commands to remove, please see following appendix.

>>> Appendix: Some useful commands for qos.
Here, I show just screen captures related to qos.
- create a qos
root@switch:~# ovs-vsctl create qos type=linux-htb
26477113-cad7-4ba6-8210-a2e71d808134
root@switch:~# ovs-vsctl list qos
_uuid               : 26477113-cad7-4ba6-8210-a2e71d808134
external_ids        : {}
other_config        : {}
queues              : {}
type                : linux-htb
*** To remove qos, use following commands.
root@switch:~# ovs-vsctl --all destroy qos
- create a qos (specifying max-rate)
root@switch:~# ovs-vsctl create qos type=linux-htb other-config:max-rate=1000000000
e9187f85-333f-49db-bd15-183f76745f4d
root@switch:~# ovs-vsctl list qos
_uuid               : e9187f85-333f-49db-bd15-183f76745f4d
external_ids        : {}
other_config        : {max-rate="1000000000"}
queues              : {}
type                : linux-htb
root@switch:~# ovs-vsctl --all destroy qos
root@switch:~# ovs-vsctl list qos
- create a qos and a queue (for the qos)
root@switch:~# ovs-vsctl create qos type=linux-htb other-config:max-rate=1000000000 queues=0=@q0 -- --id=@q0 create queue other-config:min-rate=5000000 other-config:max-rate=5000000
0d6a738e-0597-4290-8c98-4c5593b1ca1f
8453ca2d-4931-4d55-b0f5-51b30c825d63
root@switch:~# ovs-vsctl list qos
_uuid               : 0d6a738e-0597-4290-8c98-4c5593b1ca1f
external_ids        : {}
other_config        : {max-rate="1000000000"}
queues              : {0=8453ca2d-4931-4d55-b0f5-51b30c825d63}
type                : linux-htb
root@switch:~# ovs-vsctl list queue
_uuid               : 8453ca2d-4931-4d55-b0f5-51b30c825d63
dscp                : []
external_ids        : {}
other_config        : {max-rate="5000000", min-rate="5000000"}
root@switch:~# ovs-vsctl destroy qos 0d6a738e-0597-4290-8c98-4c5593b1ca1f    // <-- UUID
root@switch:~# ovs-vsctl list qos
root@switch:~# ovs-vsctl list queue
_uuid               : 8453ca2d-4931-4d55-b0f5-51b30c825d63
dscp                : []
external_ids        : {}
other_config        : {max-rate="5000000", min-rate="5000000"}
root@switch:~# ovs-vsctl destroy queue 8453ca2d-4931-4d55-b0f5-51b30c825d63    // <-- UUID
root@switch:~# ovs-vsctl list queue
*** or
> ovs-vsctl --all destroy qos
> ovs-vsctl --all destroy queue
- create a qos and two queues(for the qos)
root@switch:~# ovs-vsctl create qos type=linux-htb other-config:max-rate=1000000000 queues=0=@q0,1=@q1 -- --id=@q0 create queue other-config:min-rate=1000000000 other-config:max-rate=1000000000 -- --id=@q1 create queue other-config:min-rate=2000000 other-config:max-rate=2000000
5e4d4e8e-5ed8-41c6-845d-c177cc443daf
511a5c4e-ee79-4af7-a911-a43b18a79bbb
13350643-4441-4bd4-9a64-b6e9f62310cb
root@switch:~# ovs-vsctl list qos
_uuid               : 5e4d4e8e-5ed8-41c6-845d-c177cc443daf
external_ids        : {}
other_config        : {max-rate="1000000000"}
queues              : {0=511a5c4e-ee79-4af7-a911-a43b18a79bbb, 1=13350643-4441-4bd4-9a64-b6e9f62310cb}
type                : linux-htb
root@switch:~# ovs-vsctl list queue
_uuid               : 511a5c4e-ee79-4af7-a911-a43b18a79bbb
dscp                : []
external_ids        : {}
other_config        : {max-rate="1000000000", min-rate="1000000000"}
_uuid               : 13350643-4441-4bd4-9a64-b6e9f62310cb
dscp                : []
external_ids        : {}
other_config        : {max-rate="2000000", min-rate="2000000"}
- create a qos and connect to a port
root@switch:~# ovs-vsctl set port eth1 qos=@newqos -- --id=@newqos create qos type=linux-htb
9c776df4-6113-44d2-853d-c2791fb180ac
root@switch:~# ovs-vsctl list port eth1
_uuid               : 0fb256d5-df68-4d1a-8b56-74bdd0b4482a
bond_downdelay      : 0
bond_fake_iface     : false
bond_mode           : []
bond_updelay        : 0
external_ids        : {}
fake_bridge         : false
interfaces          : [737c5011-97cc-4c11-9370-07b845e94294]
lacp                : []
mac                 : []
name                : "eth1"
other_config        : {}
qos                 : 9c776df4-6113-44d2-853d-c2791fb180ac   // <-- qos
statistics          : {}
status              : {}
tag                 : []
trunks              : []
vlan_mode           : []
root@switch:~# ovs-vsctl list qos
_uuid               : 9c776df4-6113-44d2-853d-c2791fb180ac
external_ids        : {}
other_config        : {}
queues              : {}
type                : linux-htb
root@switch:~# ovs-vsctl clear port eth1 qos
root@switch:~# ovs-vsctl list port eth1
_uuid               : 0fb256d5-df68-4d1a-8b56-74bdd0b4482a
bond_downdelay      : 0
bond_fake_iface     : false
bond_mode           : []
bond_updelay        : 0
external_ids        : {}
fake_bridge         : false
interfaces          : [737c5011-97cc-4c11-9370-07b845e94294]
lacp                : []
mac                 : []
name                : "eth1"
other_config        : {}
qos                 : []              // <-- clear qos
statistics          : {}
status              : {}
tag                 : []
trunks              : []
vlan_mode           : []
root@switch:~# ovs-vsctl list qos
_uuid               : 9c776df4-6113-44d2-853d-c2791fb180ac
external_ids        : {}
other_config        : {}
queues              : {}
type                : linux-htb
root@switch:~# ovs-vsctl --all destroy qos
root@switch:~# ovs-vsctl list qos
- create a qos and two queues(for the qos) and connect the qos into a port
Following command does ..
1) create two queues (q1, q2)
q1 (1000 Mbps): --id=@q0 create queue other-config:min-rate=1000000000 other-config:max-rate=100000000
q2 (2 Mbps): --id=@q1 create queue other-config:min-rate=2000000 other-config:max-rate=2000000
2) create a qos (newqos) and connect two queues into the qos
--id=@newqos create qos type=linux-htb queues=0=@q0,1=@q1
3) connect a created qos (newqos) to a existing port (eth1)
set port eth1 qos=@newqos
Thus, port(eth1) -- qos(newqos) -- queues(q1,q2)
root@switch:~# ovs-vsctl set port eth1 qos=@newqos -- --id=@newqos create qos type=linux-htb queues=0=@q0,1=@q1 -- --id=@q0 create queue other-config:min-rate=1000000000 other-config:max-rate=100000000 -- --id=@q1 create queue other-config:min-rate=2000000 other-config:max-rate=2000000
cad117b3-7ef8-4884-b946-1360b510ebbc
ec0ccbcd-c772-49e8-a970-3b1f67e564d4
4b9ad7d3-a171-4abb-96e1-92bc7634d444
root@switch:~# ovs-vsctl list port eth1
_uuid               : 0fb256d5-df68-4d1a-8b56-74bdd0b4482a
bond_downdelay      : 0
bond_fake_iface     : false
bond_mode           : []
bond_updelay        : 0
external_ids        : {}
fake_bridge         : false
interfaces          : [737c5011-97cc-4c11-9370-07b845e94294]
lacp                : []
mac                 : []
name                : "eth1"
other_config        : {}
qos                 : cad117b3-7ef8-4884-b946-1360b510ebbc
statistics          : {}
status              : {}
tag                 : []
trunks              : []
vlan_mode           : []
root@switch:~# ovs-vsctl list qos
_uuid               : cad117b3-7ef8-4884-b946-1360b510ebbc
external_ids        : {}
other_config        : {}
queues              : {0=ec0ccbcd-c772-49e8-a970-3b1f67e564d4, 1=4b9ad7d3-a171-4abb-96e1-92bc7634d444}
type                : linux-htb
root@switch:~# ovs-vsctl list queue
_uuid               : ec0ccbcd-c772-49e8-a970-3b1f67e564d4
dscp                : []
external_ids        : {}
other_config        : {max-rate="100000000", min-rate="1000000000"}
_uuid               : 4b9ad7d3-a171-4abb-96e1-92bc7634d444
dscp                : []
external_ids        : {}
other_config        : {max-rate="2000000", min-rate="2000000"}