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May 12, 2021
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Update sFlow HLD #755

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109 changes: 59 additions & 50 deletions doc/sflow/sflow_hld.md
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Original file line number Diff line number Diff line change
Expand Up @@ -2,16 +2,17 @@
### Rev 1.1
## Table of Contents

## 1. Revision
## 1. Revision
Rev | Rev Date | Author | Change Description
---------|--------------|-----------|-------------------
|v0.1 |05/01/2019 |Padmanabhan Narayanan | Initial version
|v0.2 |05/20/2019 |Padmanabhan Narayanan | Updated based on internal review comments
|v0.3 |06/11/2019 |Padmanabhan Narayanan | Update CLIs, remove sflowcfgd
|v0.3 |06/11/2019 |Padmanabhan Narayanan | Update CLIs, remove sflowcfgd
|v0.4 |06/17/2019 |Padmanabhan Narayanan | Add per-interface configurations, counter mode support and <br /> unit test cases. Remove genetlink CLI
|v0.5 |07/15/2019 |Padmanabhan Narayanan | Update CLI and DB schema based on comments from InMON : <br> Remove max-datagram-size from collector config <br/>Add CLI for counter polling interval <br/>Remvoe default header-size <br/>Add "all" interfaces option <br/> Separate CLI to set agent-id<br/>
|v1.0 |09/13/2019 |Sudharsan | Updating sequence diagram for various CLIs
|v1.0 |09/13/2019 |Sudharsan | Updating sequence diagram for various CLIs
|v1.1 |10/23/2019 |Padmanabhan Narayanan | Update SAI section to use SAI_HOSTIF_ATTR_GENETLINK_MCGRP_NAME instead of ID. Note on genetlink creation. Change admin_state values to up/down instead of enable/disable to be consistent with management framework's sonic-common.yang.
|v1.2 |03/07/2021 | Garrick He | Add VRF support and fix interface admin-status output.

## 2. Scope
This document describes the high level design of sFlow in SONiC
Expand Down Expand Up @@ -85,7 +86,7 @@ The newly introduced sflow container consists of:
* sflowmgrd : updates APP DB sFlow tables based on config updates

The swss container is enhanced to add the following component:
* sfloworch : which subscribes to the APP DB and acts as southbound interface to SAI for programming the SAI_SAMPLEPACKET sessions.
* sfloworch : which subscribes to the APP DB and acts as southbound interface to SAI for programming the SAI_SAMPLEPACKET sessions.
* copporch : Copporch gets the genetlink family name and multicast group from copp.json file, programs the SAI genetlink attributes and associates it with trap group present for sflow in copp.json

The syncd container is enhanced to support the SAI SAMPLEPACKET APIs.
Expand Down Expand Up @@ -139,7 +140,7 @@ The sFlow counter polling interval is set to 20 seconds. The pollBus/HSPEVENT_UP

#### sFlow utility interface
* sflow [options] {config | show} ...

An sflow utility command is provided to operate with sflow configuration
Also, the **config** and **show** commands would be extended to include the sflow option.

Expand All @@ -152,25 +153,26 @@ The sFlow counter polling interval is set to 20 seconds. The pollBus/HSPEVENT_UP
* ipv4-address : IP address of the collector in dotted decimal format for IPv4
* ipv6-address : x: x: x: x::x format for IPv6 address of the collector (where :: notation specifies successive hexadecimal fields of zeros)
* port (OPTIONAL): specifies the UDP port of the collector (the range is from 0 to 65535. The default is 6343.)
* vrf (OPTIONAL): specifies the VRF the collector is on. Only 'default' and 'mgmt' are supported (The default is 'default')

Note:
* A maximum of 2 collectors is allowed.

* **sflow collector del** *{collector-name}*

Delete the sflow collector with the given name

* **sflow agent-id <add | del>** *{interface-name}*

Where:
* agent-id: specify the interface name whose ipv4 or ipv6 address will be used as the agent-id in sFlow datagrams.
* agent-id: specify the interface name whose ipv4 or ipv6 address will be used as the agent-id in sFlow datagrams.

Note:
* This setting is global (applicable to both collectors) and optional. Only a single agent-id is allowed. If agent-id is not specified (with this CLI), an appropriate IP that belongs to the switch is used as the agent-id based on some simple heuristics.

* **sflow <enable|disable>**

Globally, sFlow is disabled by default. When sFlow is enabled globally, the sflow deamon is started and sampling will start on all interfaces which have sFlow enabled at the interface level (see “config sflow interface…”).
Globally, sFlow is disabled by default. When sFlow is enabled globally, the sflow deamon is started and sampling will start on all interfaces which have sFlow enabled at the interface level (see “config sflow interface…”).
When sflow is disabled globally, sampling is stopped on all relevant interfaces and sflow daemon is stopped.

* **sflow interface <enable|disable>** *<{interface-name}|**all**>*
Expand All @@ -181,7 +183,7 @@ When sflow is disabled globally, sampling is stopped on all relevant interfaces

* **sflow interface sample-rate** *{interface-name} {value}*

Configure the sample-rate for a specific interface.
Configure the sample-rate for a specific interface.

The default sample rate for any interface is (ifSpeed / 1e6) where ifSpeed is in bits/sec. So, the default sample rate based on interface speed is:

Expand Down Expand Up @@ -228,7 +230,7 @@ When sflow is disabled globally, sampling is stopped on all relevant interfaces

&#35; sflow collector add collector1 10.100.12.13

&#35; sflow collector add collector2 10.144.1.2 port 6344
&#35; sflow collector add collector2 10.144.1.2 --port 6344 --vrf mgmt

&#35; sflow agent-id add loopback0

Expand All @@ -246,10 +248,12 @@ The configDB objects for the above CLI is given below:
"collector1": {
"collector_ip": "10.100.12.13",
"collector_port": "6343"
"collector_vrf": "default"
},
"collector2": {
"collector_ip": "10.144.1.2",
"collector_port": "6344"
"collector_vrf": "mgmt"
}
},

Expand Down Expand Up @@ -284,7 +288,7 @@ If user issues a "config sflow interface disable all", the SFLOW_SESSION will ha
}
```

&#35; show sflow
&#35; show sflow

Displays the current configuration, global defaults as well as user configured values including collectors.

Expand All @@ -303,58 +307,60 @@ Agent ID: loopback0 (10.0.0.10)
Displays the current running configuration of sflow interfaces.

```
Interface Admin Status Sampling rate
Interface Admin Status Sampling rate
--------- ------------ -------------
Ethernet0 Disabled 40000
Ethernet1 Enabled 40000
Ethernet2 Enabled 40000
Ethernet3 Enabled 40000
Ethernet4 Enabled 40000
Ethernet5 Enabled 40000
Ethernet6 Enabled 40000
Ethernet7 Enabled 40000
Ethernet8 Enabled 40000
Ethernet9 Enabled 40000
Ethernet10 Enabled 40000
Ethernet11 Enabled 40000
Ethernet12 Enabled 40000
Ethernet13 Enabled 40000
Ethernet14 Enabled 40000
Ethernet15 Enabled 40000
Ethernet16 Enabled 32768
Ethernet17 Enabled 40000
Ethernet18 Enabled 40000
Ethernet19 Enabled 40000
Ethernet20 Enabled 40000
Ethernet21 Enabled 40000
Ethernet22 Enabled 40000
Ethernet23 Enabled 40000
Ethernet24 Enabled 40000
Ethernet25 Enabled 40000
Ethernet26 Enabled 40000
Ethernet27 Enabled 40000
Ethernet28 Enabled 40000
Ethernet29 Enabled 40000
Ethernet30 Enabled 40000
Ethernet31 Enabled 40000
Ethernet0 down 40000
Ethernet1 up 40000
Ethernet2 up 40000
Ethernet3 up 40000
Ethernet4 up 40000
Ethernet5 up 40000
Ethernet6 up 40000
Ethernet7 up 40000
Ethernet8 up 40000
Ethernet9 up 40000
Ethernet10 up 40000
Ethernet11 up 40000
Ethernet12 up 40000
Ethernet13 up 40000
Ethernet14 up 40000
Ethernet15 up 40000
Ethernet16 up 32768
Ethernet17 up 40000
Ethernet18 up 40000
Ethernet19 up 40000
Ethernet20 up 40000
Ethernet21 up 40000
Ethernet22 up 40000
Ethernet23 up 40000
Ethernet24 up 40000
Ethernet25 up 40000
Ethernet26 up 40000
Ethernet27 up 40000
Ethernet28 up 40000
Ethernet29 up 40000
Ethernet30 up 40000
Ethernet31 up 40000

```

### 6.6 **DB and Schema changes**

#### ConfigDB Table & Schema

A new SFLOW_COLLECTOR ConfigDB table entry would be added.
A new SFLOW_COLLECTOR ConfigDB table entry would be added.
```
SFLOW_COLLECTOR|{{collector_name}}
"collector_ip": {{ip_address}}
"collector_port": {{ uint32 }} (OPTIONAL)
"collector_vrf": {{string}}

; Defines schema for sFlow collector configuration attributes
key = SFLOW_COLLECTOR:collector_name ; sFlow collector configuration
; field = value
COLLECTOR_IP = IPv4address / IPv6address ; Ipv4 or IpV6 collector address
COLLECTOR_PORT = 1*5DIGIT ; destination L4 port : a number between 0 and 65535
COLLECTOR_VRF = "default" | "mgmt" ; the VRF for the collector, currently only 'default' and 'mgmt' is supported

;value annotations
collector_name = 1*16VCHAR
Expand Down Expand Up @@ -412,6 +418,7 @@ SONIC CLI parameter| hsflowd.conf equivalent
-------------------|------------------------
collector ip-address | collector.ip
collector port| collector.UDPPort
collecttor vrf| collector.vrf
agent ip-address | agentIP
max-datagram-size | datagramBytes
sample-rate | sampling
Expand All @@ -431,7 +438,7 @@ hsflowd bus/events|SONiC callback actions
pollBus/HSPEVENT_UPDATE_NIO | poll interface state from STATE_DB:PORT_TABLE and update counter stats in SFLHost_nio_counters from COUNTER DB
pollBus/HSPEVENT_CONFIG_CHANGED)| Change sampling rate (/ port speed changed)
packetBus/HSPEVENT_CONFIG_CHANGED | open netlink socket and register HsflowdRx()

Refer to host-sflow/src/Linux/hsflowd.h for a list of events.

### 6.8 **SWSS and syncd changes**
Expand All @@ -448,7 +455,7 @@ Considering that sFlow backoff mechanism is not being implemented, users should

### 6.9 **SAI changes**

Creating sFlow sessions and setting attributes (e.g. sampling rate) is described in SAI proposal : https://github.com/opencomputeproject/SAI/tree/master/doc/Samplepacket
Creating sFlow sessions and setting attributes (e.g. sampling rate) is described in SAI proposal : https://github.com/opencomputeproject/SAI/tree/master/doc/Samplepacket

As per the sFlow specification, each packet sample should have certain minimal meta data for processing by the sFlow analyser. The psample infrastructure (http://man7.org/linux/man-pages/man8/tc-sample.8.html) already describes the desired metadata fields (which the SAI driver needs to add to each sample):

Expand Down Expand Up @@ -571,7 +578,7 @@ sai_host_table_attr[1].id= SAI_HOSTIF_TABLE_ENTRY_ATTR_TRAP_ID;
sai_host_table_attr[1].value=sflow_trap_id; // Object referencing SAMPLEPACKET trap

sai_host_table_attr[2].id= SAI_HOSTIF_TABLE_ENTRY_ATTR_CHANNEL;
sai_host_table_attr[2].value= SAI_HOSTIF_TABLE_ENTRY_CHANNEL_TYPE_GENETLINK;
sai_host_table_attr[2].value= SAI_HOSTIF_TABLE_ENTRY_CHANNEL_TYPE_GENETLINK;

sai_host_table_attr[3].id= SAI_HOSTIF_TABLE_ENTRY_ATTR_HOST_IF;
sai_host_table_attr[3].value=host_if_id; // host interface of type file descriptor for GENETLINK
Expand All @@ -595,7 +602,6 @@ On the SONiC VS, SAI calls would map to the tc_sample commands on the switchport

## 10 **Restrictions**
* /etc/hsflowd.conf should not be modified manually. While it should be possible to change /etc/hsflowd.conf manually and restart the sflow container, it is not recommended.
* Management VRF support: TBD
* configuration updates will necessitate hsflowd service restart

## 11 **Unit Test cases**
Expand All @@ -610,7 +616,7 @@ Unit test case one-liners are given below:
| 5 | Verify that it is possible to enable and disable sflow using the SFLOW table's admin_state field in CONFIG_DB |
| 6 | Verify that interfaces can be enabled/disabled using additions/deletions in SFLOW_SESSION table in CONFIG_DB |
| 7 | Verify that it is possible to change the counter polling interval using the SFLOW table in CONFIG_DB |
| 8 | Verify that it is possible to change the agent-id using the SFLOW table in CONFIG_DB
| 8 | Verify that it is possible to change the agent-id using the SFLOW table in CONFIG_DB
| 9 | Verify that it is possible to change the sampling rate per interface using SFLOW_SESSION interface sample_rate field in CONFIG_DB |
| 10 | Verify that changes to SFLOW_SESSION CONFIG_DB entry is pushed to the corresponding table in APP_DB and to ASIC_DB by sFlowOrch |
| 11 | Verify that collector and per-interface changes get reflected using the "show sflow" and "show sflow interface" commands |
Expand All @@ -628,6 +634,9 @@ Unit test case one-liners are given below:
| 23 | Verify sFlow functionality with valid startup configuration and after a normal reboot, fast-boot and warm-boot. |
| 24 | Verify that the sFlow hsflowd logs are emitted to the syslog file for various severities. |
| 25 | Verify that the swss restart works without issues when sflow is enabled and continues to sample as configured. |
| 26 | Verify that collector functions properly on 'default' VRF and can send counter and flow samples |
| 27 | Verify that collector functions properly on 'mgmt' VRF and can send counter and flow samples |

## 12 **Action items**
* Determine if it is possible to change configuration without restarting hsflowd
* Check host-sflow licensing options